increasing throttle response? flywheel or throttle body?

[dsee2]

hi. what's the better option to get better throttle response? i just want more acceleration as it feels too sluggish when flooring it.

1. 3.7kg lightened flywheel (with stock clutch)
2. Bigger throttle body.

Generally, would it be recommended to just get a lightened flywheel and use back the OEM clutch? I'm not sure what clutch i've got as i bought my car from a dealer who cant provide me with any modification details.


Cheers guys.

[Toilet]

What intake are you running?
I found that the stock oem air-box was sluggish compared to an aftermarket pod filter. Although despite having felt better throttle response with a pod, I don't believe the power increased whatsoever. It actually probably hindered performance.

Definitely look into getting a cold air intake for starters if you haven't got one, you should get improved throttle response and more of a slightly happy feeling when 'flooring it' so to speak..
I know I definitely haven't looked back since upgrading to a CAI.
This thread is definitely helpful for intake noobies :thumbsup:

http://www.ozhonda.com/forum/showthread.php?t=42865&highlight=Throttle+Response

As for bigger throttle body and flywheel, etc etc. So far, I'll admit that's been well out of my depth and income. :o

[vinnY]

what size are you wheels?
not cheap just to do the flywheel and unless you get itb's or something changing the throttle body won't really do much

[GSi_PSi]

get a heavy duty clutch with a lighter flywheel, car will be heaps quicker in the throttle.
What engine btw

[dsee2]

what size are you wheels?
not cheap just to do the flywheel and unless you get itb's or something changing the throttle body won't really do much
does the wheel size really matter? 15".


get a heavy duty clutch with a lighter flywheel, car will be heaps quicker in the throttle.
What engine btw
b16a2. i/h/e done. stock im. what i wanna know is whether it is ok to get a brand new lightened flywheel and use back on my current clutch (I'm not sure what clutch i've got on now as i dont have any history on this). i don't wish to buy a HD clutch to find that i've already got one on!

[JohnL]

If the stock clutch doesn't slip with your current power output (and you don't plan to increase that), then you don't need a heavier duty unit. Whether you replace the current clutch (whether with stock or HD) depends on how worn you find it to be when you pull it out. You don't want to be seperating the engine / box again in a few months if you can help it, so I wouldn't reuse the clutch unless it was in pretty good nick, or money was very tight.

For improved throttle response you want a lighter flywheel (mostly noticably in the lowest gears and when 'rev-matching' for downshifts with the box in neutral). Having said that, you need to ask; is your current lack of throttle response (as you are percieving it) actually caused by an overly heavy flywheel, or is there some other issue with the engine?

[Webby_roller]

sorry to hijack.... Currently waiting on installation of lightened flywheel on vtir integra... Is it advised to change the clutch no matter what??? or just wait to see what sort of condition the clutch is in???

[vinnY]

people usually recommend changing it since the gearbox is off anyway
but if it's fairly new or in good condition theres no real reason to

[beeza]

Try this,it's free!

http://www.ozhonda.com/forum/showthread.php?t=120191

[Webby_roller]

people usually recommend changing it since the gearbox is off anyway
but if it's fairly new or in good condition theres no real reason to

:) Cheers

[beeza]

When ya come over next Webby,lets do the Tps sensor mod above!

:)

[Webby_roller]

yeh man.. defiantly... well im on holidays for uni for a week starting next week... maybe towards the end of the week... Pm me ur number, i lost my phone and need to collect my numbers again.....

I will hopefully have the flywheel on next week, so we will get to go for another 'exciting' cruise down the road... We will just have to make sure it isnt a sunday this time :)

[beeza]

haha yeah :)

Sounds good mate,just check to make sure the voltage's we are looking for are 0.48-0.49V closed throttle and 4.5V Wide Open Throttle and not different for the b18c.

It should be that but just make sure.

[hussLEr]

If you plan to do the flywheel, might as well save up the extra loot and bolt up a HD clutch and Type R 'box with 4.7 FD.

[string]

If the stock clutch doesn't slip with your current power output (and you don't plan to increase that), then you don't need a heavier duty unit.

It's a matter of preference IMO. I have stock clutch on one of my B18's and a "HD" on the other. The stock clutch doesn't slip under power but doesn't have anywhere near the power transmitting ability (of the"HD") when you're slipping it (off the line for example).

[dougie_504]

Is your intake SRI or CAI? CAI will respond better and I think a CAI that is setup as a SRI with a cold air feed & heat shield will respond better than simply relocating the pod into the bumper (but just more work).

Otherwise take off your IM and give it a good rinse/clean in Subaru engine cleaner. Also take it to your TB as well. Car will breathe like friggin' black hole :)

[JohnL]

It's a matter of preference IMO. I have stock clutch on one of my B18's and a "HD" on the other. The stock clutch doesn't slip under power but doesn't have anywhere near the power transmitting ability (of the"HD") when you're slipping it (off the line for example).

I know what you're saying, and I tend to agree (I personally prefer a clutch with a bit of 'bite', within reason). My point was only that if the standard duty clutch was coping OK then there is no imperative to change it to a heavier duty unit for the sake of it.

This is especially considering that a heavier duty clutch may well be somewhat more expensive, and may also possibly be somewhat less 'user friendly', which may not be to everyone's taste or pleasant in traffic bound city driving (be careful what you wish for sometimes...).

[JohnL]

Try this,it's free!

Since it's free, I'll check mine tomorrow. Thanks beeza....

[Webby_roller]

If you plan to do the flywheel, might as well save up the extra loot and bolt up a HD clutch and Type R 'box with 4.7 FD.

Man, i have wished about this for soo long... but the money involved is a bit more then i can accumulate in a sensible amount of time... I got the flywheel cheap.... and i dont have any issues with the standard clutch so i was looking at an exedy oem replacment.... would go heavy duty but then traffic does suck....

[Scholzey]

a bigger throttle body will make throttle response worse, but may increase peak power a tiny bit. i wouldnt upgrade it unless you are going for big power. and plan on upgrading alot of other things too

[dsee2]

a bigger throttle body will make throttle response worse, but may increase peak power a tiny bit. i wouldnt upgrade it unless you are going for big power. and plan on upgrading alot of other things too

does it? sheez. thanks mate.

[beeza]

Since it's free, I'll check mine tomorrow. Thanks beeza....

Cheers John,your welcome mate!

Mate,you need to learn how to service your car,therefore have it runnin' in top condition all the time.You will be suprised how well your car will go.Here's a list,an old post I made:

"If you want to get your engine up and running good cheap then you can do this yourself (Note: 3 years ago I knew nothing about cars):

This is just dealing with the running of your engine,not suspension.

- Upper engine clean your engine (foam stuff in a can).The Suburu UEC is the best
- Clean Throttle body,especially the Intake air control valve with carby cleaner
- Collaborate voltage on tps sensor on the throttle body
- Clean/replace spark plugs and set gap correctly
- Check resistance in your leads is fine
- Clean contact points in the dizzy and lightly sand the rotor on the outer edge where it sparks on the contact points
- Adjust tappets - VERY IMPORTANT!
- Clean air filter OR replace with pod filter and good cold air piping/Cold air intake.The point is COLD AIR/air from outside the engine bay (Make sure you re-connect the IAT sensor on the new intake arm)
- Get a wheel/camber/toe alignment and check your tyre pressure is correct once a week
- Change the oil and oil filter (every 5000km's)
- Change the fuel filter every 2nd oil change
- Transmission oil is every 20,000km's
- Charge your battery to full
- Expell air in coolant system through the radiator
- Adjust accelerator cable correctly
- Check for engine codes and get familiar with how to do it!
- And get used to doing regular checks of everything in the engine bay,I have found many problems like this! - Like bolts I forgot to do up!
- And check for air leaks everywhere,all the clamps on the intake,all the gaskets on the engine and all the gaskets on the exhaust system! Important! No use having the whole thing running 100% if it's just gonna lose it somewhere.
- Make your car as light as possible
- Use BP Ultimate 98 fuel only (1/2 a tank max at a time if your keen)
- Just a small amount of windshield water too!
_ Also for $40 an injector (well worth it) you can get the spray pattern and flow rate adjusted correctly
- Also look into advancing the timing 2-3 degrees.
- Insulate your fuel lines - prevent the fuel from getting warm/hot
- Check your timing is correct

Do all that and your car will feel much better,then see if your satified,if not,another engine/car is in order

I think everyone should 'work with what they got' and learn first.Then you will know where you want to go afterwards!"

[bennjamin]

want to increase response ? Reduce rotational mass of both engine/drivetrain components , and wheels. For example , lightweight flywheel - smaller /lighter rims etc.

Reduce overall vehicle mass....reduce static parts that are not required IE spare tyre , sound deadening etc.

[GSi_PSi]

imo i dunoo a car with a heavy duty clutch+light flywheel feels like it has more off the line torque compared to stock. Like it just makes the car jump lol.
Stock clutches feel laggy

[JohnL]

...make sure the voltage's we are looking for are 0.48-0.49V closed throttle and 4.5V Wide Open Throttle ...

Checked mine (CB7 Accord).

WOT was 4.52v, closed throttle was only 0.44v. Now, the WOT number suggested that the TPS was correctly adjusted (i.e. TPS rotation relative to throttle plate), but that the throttle stop was probably slightly worn allowing the throttle plate to close slightly more than it's supposed to do (throttle stop contact being a probable wear point over an extended period of time).

To raise the closed throttle voltage (since it seemed probable that the TPS was already correctly positioned), rather than attempt to rotate the TPS relative to the throttle plate (which would bring the closed throttle into spec but at the expense of throwing off the WOT voltage), I adjusted the throttle stop slightly until the closed throttle number rose to 0.5v.

This was maybe half a turn or less on the adjuster. I'm not sure exactly because turning the adjuster screw was rather awkward, but it wasn't much. I now have; closed throttle = 0.5v and WOT = 4.52v. This opened the throtle plate a touch which raised the base idle by about 100rpm, which I readjusted by closing the idle speed screw slightly.

Since then I've only had the chance to drive the car with a load full of passengers (which isn't normal operating conditions for this car), so (being conscious of possible placebo effects) I'm not 100% sure but impressions so far are that low rpm / light throttle torque seems to be significantly improved (I'll know better after some driver only time).

This seems most noticable when taking off from rest, appearing to require less clutch slippage with the engine feeling more 'muscular' at low rpm / light throttle opening. There also seems to be some improvement to throttle response when 'blipping' for 'rev matching' on downshift.

[JohnL]

imo i dunoo a car with a heavy duty clutch+light flywheel feels like it has more off the line torque compared to stock.....

A lightweight flywheel wil make the engine feel as if it had less low rpm torque, which in effect it will because there will be less kinetic energy 'stored' in the inertial mass of the rotating flywheel.

If you imagine an extreme hypothetical example of a flywheel with zero mass, then when taking off from rest all the power required to get the car's mass into motion must come from the power that the engine is producing at the moment the clutch engages, which won't be enough unless the rpm is substantially raised (increasing energy 'stored' in the engines rotational masses such as cranshaft), and / or the throttle opened significantly wider (to make more instantaneous power), and / or the clutch is slipped substantially.


.......Like it just makes the car jump lol.
Stock clutches feel laggy

Because you're revving the engine higher and / or opening the throttle wider, and dumping the clutch harder. The extra torque is coming from the engine being somewhat higher in the rpm range (where torque is higher), wider throttle opening, and from the kinetic energy embodied in the faster spinning rotational mass being higher due to the higher rpm. It's not because of a lighter flywheel...

[JohnL]

Cheers John,your welcome mate!

Mate,you need to learn how to service your car,therefore have it runnin' in top condition all the time.You will be suprised how well your car will go.Here's a list,an old post I made:


Beeza,
My engine is already well maintained and runs very nicely. Checking the TPS is just one of those things I've been meaning to do but haven't yet gotten around to doing since the engine was running well with good economy. Your posting of the voltage specs prompted me to check mine since not knowing the spec was no longer a valid excuse to leave this on the back burner...

PS a small number of things on your list are open to debate...

[beeza]

Sorry John!

That was for the OP,dsee2,Oops!,I didn't make myself clear in the post...

Your knowledge of cars is incredible John,I wouldn't say something like that to you mate!

Tell me the things you speak of! :)

P.S. I soooo stoked I've 'helped' to give back to ya!!

[JohnL]

Your knowledge of cars is incredible John,I wouldn't say something like that to you mate!

I'm no automotive encyclopaedia, and there are 'real' experts out there, but I have learnt at least a few things over the years. I have large blind spots in my knowledge, mostly to do with all the electrickery in modern engine management systems.


Tell me the things you speak of! :)

It's only a few things, I agree with most of it. I'll get back to you, domesticity calls...


P.S. I soooo stoked I've 'helped' to give back to ya!!

Yes it has definitely helped, the engine is significantly more 'drivable' now. It's producing more part throttle torque so is more effortless / relaxing to drive in a sedatish manner (but of course there is no discernable difference at large throttle openings).

Less clutch slippage is now needed on take off and some hills that used to need a downshift or largish throttle opening can now be driven up on a light throttle with no downshift. Downshift 'blips' are definitely more consistent / predictable with noticably faster rpm rise.

I've been meaning to check this for ages, but since the engine was running acceptably I kept forgetting about it. I'm a bit surprised how much difference there is between 0.44v and 0.5v...

[SHU-ES1]

can I check my d17 tps the same way you guys have tested your d16s I'm assuming? Our tb's are vertical, and I think the d16 are horizontal? I'd like to do this but my car is only reaching 8 years old. Do you think it would improve my throttle response? I could do with not downshifting and light throttle while going up hill!!! Sounds like an awesome maintenance tip!!

[JohnL]

can I check my d17 tps the same way you guys have tested your d16s I'm assuming? Our tb's are vertical, and I think the d16 are horizontal?

The orientation of the TPS won't make any difference.

My car is an Accord (with an f22a9 engine). I did some checking online, and from what I've found it seems that all Honda TPSs use a potentiometer with the same output values, and so the WOT / closed throttle outputs should be 4.5v and 0.5v for all models.


I'd like to do this but my car is only reaching 8 years old. Do you think it would improve my throttle response?

Only if your TPS is giving the ECU a significantly incorrectly calibrated signal, you won't know unless you check it. I don't really know what constitutes the lower end of 'significant' in this case, but I can tell you that 0.06v below 0.5v is significant.

Note that with my car I didn't disassemble the TPS, clean it etc, only checked the voltage output at closed throttle and WOT. I wouldn't be removing / opening up the TPS just to clean it, only if I were already going to the trouble of removing the attachment bolts from the TB (in order to be able rotate the TPS).

Note that the TPS attachment fasteners are bolts, but ones that have no means by which they can be turned (such as a hex head, screwdriver slot etc). To remove them you need to cut a slot in the head in order to get a screwdriver to engage the bolts, I can't see why it's necessary to cut the head completely off one as beeza has done (but he may know something I don't...).

Don't assume that if the closed voltage output is below spec that the TPS actually needs to be adjusted (rotated). Over time the throttle stop contact point is bound to wear to some degree (or someone may have ignorantly fiddled with the stop adjustment at some point...), so in high mileage cars it's probably inevitable (?) that the closed throttle TPS voltage eventually falls somewhat below spec. This is not a TPS problem, it's a throttle stop problem...

With my car I found that the WOT voltage was almost pefect, but only the closed voltage was out of spec. In this case any adjustment to the TPS itself (to bring the closed voltage into spec) was going to throw the WOT setting off, so I made an adjustment to the throttle stop that only affected the closed voltage output (noting that the throttle plate should never actually be fully closed in the 'closed' position).


I could do with not downshifting and light throttle while going up hill!!! Sounds like an awesome maintenance tip!!

It's worked beyond expectations with my engine. The TPS output is at least worth checking (but you can't fix it if it ain't broke...).

[JohnL]

Beeza,
As promised, here’s my critique on some of your earlier points. Please prefix IMO to the front of my comments.

You wrote:
“Clean contact points in the dizzy and lightly sand the rotor on the outer edge where it sparks on the contact points”

The build up on the rotor arm tip and cap electrodes is a good conductor from which a spark propagates easily. Sanding it off increases the gap and does more harm than leaving the build up alone. Excessive build up and / or erosion should be addressed by replacing the rotor arm and dizzy cap.

“Change the oil and oil filter (every 5000km's)”

This isn’t a bad idea of course, but not really needed unless you are doing a lot of slow city driving and / or short trips that don’t allow the oil to remain at full operating temperature for reasonably long periods. If you do a lot of highway / open road driving, then 10,000 km oil changes should be fine. City driving is bad for oil, higher speed / longer distance runs is much less demanding.

Driving in dusty conditions is also a good reason to go to 5000km changes, as is driving involving a lot of hard acceleration.

“Change the fuel filter every 2nd oil change”

Not a bad idea, but overkill, especially as EFI filters aren’t all that cheap. Fuel filters don’t block up all that quickly unless you have an unfortunate encounter with particularly dirty fuel. Other than that I’d stick to Hondas recommended service interval (every 40,000km). If in doubt, do a fuel flow test before replacing the filter.

“Transmission oil is every 20,000km's”

Yes for auto transmission fluid.

For manual gearboxes it can’t hurt, but oil lasts a very long time when not exposed to and contaminated by combustion by-products. I’d put 100,000kms on this, especially if using a purpose formulated manual transmission oil (rather than engine oil).

“Use BP Ultimate 98 fuel only (1/2 a tank max at a time if your keen)”

Too sweeping a statement. Brands aside, and all else being equal, using a higher octane fuel than the engine actually requires doesn’t result in greater power output or better economy than using a lower octane fuel, so long as the engine can use the lower octane without detonation. If the engine runs fine on lower octane fuel then using a higher octane fuel will most probably result in a very slightly lower power output and worsened economy.

This is because the ****tail of chemicals used to increase the octane rating are added to the brew in substantial quantities, displacing a very significant % of the base ‘petrol’ content with substances that have a significantly lesser calorific value, i.e. there is less energy embodied in each CC of higher octane fuel than in each CC of lower octane fuel (i.e. lower octane petrol fuels have a higher calorific value per unit of volume than higher octane).

Note that an engine gains power output and improved economy as the CR is increased. As the CR is increased the need to use higher octane fuel increases, but this is only to avoid ‘detonation’ of the compressing air / fuel mixture. The power and economy increases comes from the higher CR, not from the higher octane fuel.

“Also look into advancing the timing 2-3 degrees”

I won’t say that this won’t improve power output because it well might, but I’d only try this if I were measuring the outcome on a dynamometer. Note that detonation / pre-ignition is usually audible as a ping or rattle, but not always...

“Insulate your fuel lines - prevent the fuel from getting warm/hot”

Any research data to back this up? There may be some potential benefit, but my bet is that at best it’s microscopically small...

[beeza]

Thank John!

Do you mind if I use a quote or 2 of your's in my DIY on the tps,just to show people how effective this mod is?

I had to cut the top of the rivets off because the tps needs to be screwed down,much easier to replace it with a screw then stuff around with the rivet.I couldn't see it working with the rivet.

[beeza]

Beeza,
As promised, here’s my critique on some of your earlier points. Please prefix IMO to the front of my comments.

You wrote:
“Clean contact points in the dizzy and lightly sand the rotor on the outer edge where it sparks on the contact points”

The build up on the rotor arm tip and cap electrodes is a good conductor from which a spark propagates easily. Sanding it off increases the gap and does more harm than leaving the build up alone. Excessive build up and / or erosion should be addressed by replacing the rotor arm and dizzy cap....

Gotcha :thumbsup:


“Change the oil and oil filter (every 5000km's)”

This isn’t a bad idea of course, but not really needed unless you are doing a lot of slow city driving and / or short trips that don’t allow the oil to remain at full operating temperature for reasonably long periods. If you do a lot of highway / open road driving, then 10,000 km oil changes should be fine. City driving is bad for oil, higher speed / longer distance runs is much less demanding.

Driving in dusty conditions is also a good reason to go to 5000km changes, as is driving involving a lot of hard acceleration.

Yes I agree.5000 is a bit of overkill but your car will run better when the oil is changed.So $75 vs a lil better performance.Every car will be different here but certainly my car runs better.


“Change the fuel filter every 2nd oil change”

Not a bad idea, but overkill, especially as EFI filters aren’t all that cheap. Fuel filters don’t block up all that quickly unless you have an unfortunate encounter with particularly dirty fuel. Other than that I’d stick to Hondas recommended service interval (every 40,000km). If in doubt, do a fuel flow test before replacing the filter.

It certainly sounds like it! But I just changed mine,it would have been a bit more than 20k,maybe 30k... but it again made a significant difference! A noticeable difference.I was quite suprised.


“Transmission oil is every 20,000km's”

Yes for auto transmission fluid.

For manual gearboxes it can’t hurt, but oil lasts a very long time when not exposed to and contaminated by combustion by-products. I’d put 100,000kms on this, especially if using a purpose formulated manual transmission oil (rather than engine oil).

It's the same story as the engine oil.My car is an auto,so changing the fluid in mine makes a great difference.Not real sure about manual transmissions.


“Use BP Ultimate 98 fuel only (1/2 a tank max at a time if your keen)”

Too sweeping a statement. Brands aside, and all else being equal, using a higher octane fuel than the engine actually requires doesn’t result in greater power output or better economy than using a lower octane fuel, so long as the engine can use the lower octane without detonation. If the engine runs fine on lower octane fuel then using a higher octane fuel will most probably result in a very slightly lower power output and worsened economy.

This is because the ****tail of chemicals used to increase the octane rating are added to the brew in substantial quantities, displacing a very significant % of the base ‘petrol’ content with substances that have a significantly lesser calorific value, i.e. there is less energy embodied in each CC of higher octane fuel than in each CC of lower octane fuel (i.e. lower octane petrol fuels have a higher calorific value per unit of volume than higher octane).

Note that an engine gains power output and improved economy as the CR is increased. As the CR is increased the need to use higher octane fuel increases, but this is only to avoid ‘detonation’ of the compressing air / fuel mixture. The power and economy increases comes from the higher CR, not from the higher octane fuel.

Gotcha,Cheers! I will putting in 91 octane then! Or should I...I cant hear my car ping or anything but at 100km/h when cruising on the freeway is does little hesitates/surges/misfire (but not),it only does it on 91 octane fuel and only at 100-100km/h?


“Also look into advancing the timing 2-3 degrees”

I won’t say that this won’t improve power output because it well might, but I’d only try this if I were measuring the outcome on a dynamometer. Note that detonation / pre-ignition is usually audible as a ping or rattle, but not always...

Forsure forsure.Worth giving a shot though!


“Insulate your fuel lines - prevent the fuel from getting warm/hot”

Any research data to back this up? There may be some potential benefit, but my bet is that at best it’s microscopically small...

Probably but it all adds up! Logically it makes sense,a cooler fuel going into the mix will be more compressed and therefore produce more power.

It took me 10 minutes to insulate my fuel lines with air conditioning tape :thumbsup:

[JohnL]

Do you mind if I use a quote or 2 of your's in my DIY on the tps,

No worries.


just to show people how effective this mod is?

Sorry to be pedantic, but it's not really a modification as such, it's returning the TPS to it's correct stock condition, so it's more like 'tuning'.

I think it would be better to say 'can be' rather than 'is', because the effectiveness will vary according to how far the calibration has driffted over time.

Out of curiosity, how far out were your voltages before you 'tuned' them? Also, when you rotated the TPS, did you move the WOT voltage off spec in order to achieve the correct closed throttle spec? If 'yes' then you might want to consider returning the WOT voltage to spec and resetting the closed throttle to spec using the throttle stop screw.


I had to cut the top of the rivets off because the tps needs to be screwed down,much easier to replace it with a screw then stuff around with the rivet.I couldn't see it working with the rivet.

While checking around to verify whether your quoted voltages applied to my Accord, I saw a couple of references to the stock TPS "rivets" actually being blind headed bolts threaded into the TB casting (so can't be undone with 'normal' tools, Honda obviously doesn't want anyone messing with the TPS setting). So if this is correct there should have been no need to grind the head off, just cut a screwdriver slot...

[JohnL]

Yes I agree.5000 is a bit of overkill but your car will run better when the oil is changed.So $75 vs a lil better performance.Every car will be different here but certainly my car runs better.

75$? You're using fully synthetic aren't you? A good synthetic should last longer than a good mineral based oil, so IMO you're really throwing money away. If you're going to change the oil every 5000km you might as well use a good mineral oil.

What you seem to be doing might be reasonable insurance for a very high performance / stressed / high $ build engine, but not otherwise, really.


It certainly sounds like it! But I just changed mine,it would have been a bit more than 20k,maybe 30k... but it again made a significant difference! A noticeable difference.I was quite suprised.

Then I'll bet you got a dose (or doses) of dirty fuel somewhere / sometime before the changeover. I've changed a fuel filter that had at least 100,000km on it, and seen no performance change, not that I really expected there to be one since the filter had passed a flow test with flying colours (I just felt I should change it 'just in case' and that it was so old).

Be careful of placebo affects too. I'll swear that my car goes harder and even handles better after I've cleaned it...


Gotcha,Cheers! I will putting in 91 octane then! Or should I...I cant hear my car ping or anything but at 100km/h when cruising on the freeway is does little hesitates/surges/misfire (but not),it only does it on 91 octane fuel and only at 100-100km/h?

Use 91 if that's the fuel specified by Honda for your engine (and you haven't increased the CR or supercharged it). Without being able to make any categorical statement, I suspect your problem above to be either coincidental with some other problem, and / or maybe you have had some bad 91 octane fuel.

You should always try to buy fuel from a high turnover outlet as fuel that's been sitting in the servo's tanks too long can go stale and lose octane rating along with some of the properties that make it ignite readily in the combustion chamber...


Forsure forsure.Worth giving a shot though!

Advancing the ignition timing on speculation is potentially dangerous because you may get what is in effect pre-ignition, which can cause damage (the dyno will tell you what's what...). If you do this I suspect the ECU may well 'retard' the timing back to stock in any case, unless you advance the base timing so far it's beyond the ECUs parameters to correct...


Probably but it all adds up! Logically it makes sense,a cooler fuel going into the mix will be more compressed and therefore produce more power.

Many things (very many, and not just to do with cars...) seem to be 'common sense' or "logical", but in reality are incorrect assumptions. Cooler fuel may be very slightly denser, so the mixture may be very slightly richer with a cooler fuel, which may or may not be a good thing. Cooler fuel may very slightly lower the temperature of the inducted air, cooling it ever so slightly more as the fuel is injected resulting in a very slightly greater quantity of air being inducted, but at best it will be a miniscule difference...

I tried this when karting, i.e. chilling the fuel in an esky and using an insulated tank and lines on the kart. Never made a jot of difference as far as I could tell, and didn't show up on the stop watch either...

[beeza]

No worries.

Thanks mate :thumbsup:


Sorry to be pedantic, but it's not really a modification as such, it's returning the TPS to it's correct stock condition, so it's more like 'tuning'.

I think it would be better to say 'can be' rather than 'is', because the effectiveness will vary according to how far the calibration has driffted over time.

Out of curiosity, how far out were your voltages before you 'tuned' them? Also, when you rotated the TPS, did you move the WOT voltage off spec in order to achieve the correct closed throttle spec? If 'yes' then you might want to consider returning the WOT voltage to spec and resetting the closed throttle to spec using the throttle stop screw.

True true,I always get excited when I come accross a good find :p

Mine was 0.42,so a significant improvement.

I set mine at 0.51 for 1 week,put it back to 0.48 and damn,BIG difference! :thumbsup:

I pretty sure my throttle stop screw is welded on.I know what you are saying and I will add it to the thread.Thanks so much John!!


While checking around to verify whether your quoted voltages applied to my Accord, I saw a couple of references to the stock TPS "rivets" actually being blind headed bolts threaded into the TB casting (so can't be undone with 'normal' tools, Honda obviously doesn't want anyone messing with the TPS setting). So if this is correct there should have been no need to grind the head off, just cut a screwdriver slot...

It is a screw but I couldn't see you being able to cut a slot in the top without the top of the rivet falling apart.Prove me wrong :D

[beeza]

75$? You're using fully synthetic aren't you? A good synthetic should last longer than a good mineral based oil, so IMO you're really throwing money away. If you're going to change the oil every 5000km you might as well use a good mineral oil.

What you seem to be doing might be reasonable insurance for a very high performance / stressed / high $ build engine, but not otherwise, really.

I know what your saying.Maybe I just like to think my d16y4 is a high performance machine :p


Then I'll bet you got a dose (or doses) of dirty fuel somewhere / sometime before the changeover. I've changed a fuel filter that had at least 100,000km on it, and seen no performance change, not that I really expected there to be one since the filter had passed a flow test with flying colours (I just felt I should change it 'just in case' and that it was so old).

Be careful of placebo affects too. I'll swear that my car goes harder and even handles better after I've cleaned it..

It suprises me! I mean I've cleaned the injectors,fuel tank but still a noticeable difference...

Yes,I learnt about placebo effect :D


Use 91 if that's the fuel specified by Honda for your engine (and you haven't increased the CR or supercharged it). Without being able to make any categorical statement, I suspect your problem above to be either coincidental with some other problem, and / or maybe you have had some bad 91 octane fuel.

You should always try to buy fuel from a high turnover outlet as fuel that's been sitting in the servo's tanks too long can go stale and lose octane rating along with some of the properties that make it ignite readily in the combustion chamber..

Forsure forsure.All my problems are fixed now,OMG,can't believe I'm saying that :eek: My car is going 100%!! :thumbsup: :thumbsup: :thumbsup:


Advancing the ignition timing on speculation is potentially dangerous because you may get what is in effect pre-ignition, which can cause damage (the dyno will tell you what's what...). If you do this I suspect the ECU may well 'retard' the timing back to stock in any case, unless you advance the base timing so far it's beyond the ECUs parameters to correct..

Definately.Retarding dosen't seem a problem though as mine was retarded 10 degrees for 1 year and 9 months!!!!


Many things (very many, and not just to do with cars...) seem to be 'common sense' or "logical", but in reality are incorrect assumptions. Cooler fuel may be very slightly denser, so the mixture may be very slightly richer with a cooler fuel, which may or may not be a good thing. Cooler fuel may very slightly lower the temperature of the inducted air, cooling it ever so slightly more as the fuel is injected resulting in a very slightly greater quantity of air being inducted, but at best it will be a miniscule difference...

I tried this when karting, i.e. chilling the fuel in an esky and using an insulated tank and lines on the kart. Never made a jot of difference as far as I could tell, and didn't show up on the stop watch either...

Wow,you are full of Knowledge John :thumbsup:

[JohnL]

Mine was 0.42,so a significant improvement.

I set mine at 0.51 for 1 week,put it back to 0.48 and damn,BIG difference! :thumbsup:

I'm quite happy with mine at 0.5v, very significantly better than it was at 0.44v. From what I can gather on the net, 0.5v does seem to be the most commonly quoted CT voltage. Where did you get your 0.48v - 0.49v figure?


I pretty sure my throttle stop screw is welded on.I know what you are saying and I will add it to the thread.Thanks so much John!!

If it's the same as the Accord TS, then there will be a lock nut underneath the TB casting. I didn't manage to get a screwdriver to turn the TS screw (awkward with having to come at the TS screw vertically from underneath, with shit in the way, and I couldn't really see anything without removing the TB which I wanted to avoid), but after loosening the locknut (easy) I could turn the TS screw from the top using pliers.


It is a screw but I couldn't see you being able to cut a slot in the top without the top of the rivet falling apart.Prove me wrong :D

Cut a shallow slot in the fastener head with a hack saw, it'll be fine...

[JohnL]

Wow,you are full of Knowledge John :thumbsup:

I have been told that I'm "full of it..."

[beeza]

I'm quite happy with mine at 0.5v, very significantly better than it was at 0.44v. From what I can gather on the net, 0.5v does seem to be the most commonly quoted CT voltage. Where did you get your 0.48v - 0.49v figure?

I think from Honda-tech.Do what I did,try it at 0.48 after a week or so and see if there's a difference :thumbsup:



If it's the same as the Accord TS, then there will be a lock nut underneath the TB casting. I didn't manage to get a screwdriver to turn the TS screw (awkward with having to come at the TS screw vertically from underneath, with shit in the way, and I couldn't really see anything without removing the TB which I wanted to avoid), but after loosening the locknut (easy) I could turn the TS screw from the top using pliers.

I'll check mine.

Cut a shallow slot in the fastener head with a hack saw, it'll be fine...[/QUOTE]

:D

[beeza]

I have been told that I'm "full of it..."

Haha,me too :thumbsup:

[beeza]

The y4 dosen't have a screw just solid metal,so no adjustment needed:

(Don't worry about the bottom bit)

http://i99.photobucket.com/albums/l287/beeza2/100_1131-1.jpg

[bennjamin]

whats all this to do with increasing response ?

[beeza]

Because Calibrating the Voltage on the Tps Sensor (http://www.ozhonda.com/forum/showthread.php?p=2476685#post2476685) will achieve this,to a degree,but it will make a nice difference to throtle response,acceleration etc etc etc,heaps of things.

A must do.

[JohnL]

The y4 dosen't have a screw just solid metal,so no adjustment needed

It doesn't necessarily mean that no TS adjustment is ever needed, just that it may not be so easy when it is (?).

The Accord TS set up (with the adjustable threaded TS screw installed in the TB) is "solid metal" too, but over deep time the contacting points (steel to steel) obviously wear slightly (it doesn't seem to take much wear at all to cause a significant closed throttle voltage change, so it's good that wear will be very slow to occur).

If the y4 TS is steel contacting against the softer aluminium of the TB casting, then the aluminium contact point might wear faster than the Accord's steel on steel TS contacts (but I'm not sure, it would depend on the size of the contacting area). There may be a 'tab' on the cable pulley / wheel that can be 'tweaked' in order to adjust the TS...? It might also ber possible to adjust it by say gluing some metal shim onto the contact point???

Adjustment to the TS will only be needed if the TPS closed throttle (CT) voltage is off spec. If the WOT voltage is off spec then the the TPS rotational position needs adjusting (as per beeza's 'how-to').

So:

If only the CT voltage is off spec, then only the TS needs adjusting.

If only the WOT voltage is off spec, then the TPS itself needs to be rotated to bring the WOT voltage back into spec, and the CT voltage must then be re-adjusted using the TS.

If both the WOT and CT voltages are off spec, then the TPS needs to be rotated until either both the WOT and CT voltages are within spec, or, the WOT is within spec and the CT then adjusted using the TS.

In all cases the TS should only be used to adjust the CT TPS voltage and NOT the idle speed. Any adjustment to idle speed should be by means of the idle speed screw.

[JohnL]

whats all this to do with increasing response ?

Because if the TPS CT voltage is off spec then the light throttle / low rpm torque will be adversely affected and the engine will be lacking in immediate response to lighter throttle inputs (and you spend 99% of the time at light throttle openings). This adversely affects the drivabilty of the car, and probably fuel economy as well.

Lack of low rpm torque is especially noticable when taking off from rest, requiring more care / skill with balancing of the throttle input and clutch slippage because the engine is in greater danger of stalling.

You might think that if light throttle torque is poor then why not just open the throttle more, but this doesn't really work so well for 'normal' driving (you can get the same affect, but the engine feels like it's working a lot harder to achieve it). Having the TPS correctly calibrated can make the car much nicer to drive, particularly in traffic / around town.

[beeza]

It doesn't necessarily mean that no TS adjustment is ever needed, just that it may not be so easy when it is (?).

The Accord TS set up (with the adjustable threaded TS screw installed in the TB) is "solid metal" too, but over deep time the contacting points (steel to steel) obviously wear slightly (it doesn't seem to take much wear at all to cause a significant closed throttle voltage change, so it's good that wear will be very slow to occur).

If the y4 TS is steel contacting against the softer aluminium of the TB casting, then the aluminium contact point might wear faster than the Accord's steel on steel TS contacts (but I'm not sure, it would depend on the size of the contacting area). There may be a 'tab' on the cable pulley / wheel that can be 'tweaked' in order to adjust the TS...? It might also ber possible to adjust it by say gluing some metal shim onto the contact point???

Adjustment to the TS will only be needed if the TPS closed throttle (CT) voltage is off spec. If the WOT voltage is off spec then the the TPS rotational position needs adjusting (as per beeza's 'how-to').

So:

If only the CT voltage is off spec, then only the TS needs adjusting.

If only the WOT voltage is off spec, then the TPS itself needs to be rotated to bring the WOT voltage back into spec, and the CT voltage must then be re-adjusted using the TS.

If both the WOT and CT voltages are off spec, then the TPS needs to be rotated until either both the WOT and CT voltages are within spec, or, the WOT is within spec and the CT then adjusted using the TS.

In all cases the TS should only be used to adjust the CT TPS voltage and NOT the idle speed. Any adjustment to idle speed should be by means of the idle speed screw.

Gotcha John! :thumbsup:

I'll summerise the above into the Tps thread,thanks heaps mate,this fills a void that was forming in my mind.

There is slight wear on the metal contact point,it's slight but it's there,I'll get a pic up soon :thumbsup:

If the wear was bigger you could glue/weld a bit of metal on there.Maybe you could just give the aluminum part on the TB (that holds the accelerator cable) a little tweak with some pliers.Just 'bend' it ever so slightly?

I'll check my accelerator cable for some adjustment 'tab' :D

I realise now I need to include adjustment of the accelerator cable in the DIY cause if there's slack there it sucks :p

[JohnL]

this fills a void that was forming in my mind.

I've got thousands of those, and more as I get older...


If the wear was bigger you could glue/weld a bit of metal on there.


If you use shim stock the metal can be very very thin. I really don't know how practical or not such a 'repair' might be without seeing the metal bits.


Maybe you could just give the aluminum part on the TB (that holds the accelerator cable) a little tweak with some pliers.Just 'bend' it ever so slightly?

Risky, you don't know how ductile (or not) the casting is. It may break if you attempt to bend it. I would expect the alloy chosen for the TB is most likely selected for ease of machining (and minimal heat expansion?) more than strength, and such alloys tend to be less ductile, i.e. more brittle...


I'll check my accelerator cable for some adjustment 'tab' :D

I was meaning a 'tab' of some sort on the cable 'pulley thingy' that the cable wraps around at the TB. If it exists it will be right where the 'pulley thingy' contacts the TB casting, i.e. it will be the bit that contacts the TB casting.


I realise now I need to include adjustment of the accelerator cable in the DIY cause if there's slack there it sucks :p

Throttle cables should be adjusted to have just a little bit of free play at CT, but at WOT there should be no significant load on the cable nor on the TB WOT stop, i.e. some part of the pedal should hit a stop (under the pedal pad or at the top near where the cable is attached) just as the TB WOT stop is contacted.

[beeza]

Found the TS screw John!

Updated DIY: Tps thread!!

Thanks mate!!!!

[beeza]

Here's where it contacts at WOT:

http://i99.photobucket.com/albums/l287/beeza2/100_1143.jpg

http://i99.photobucket.com/albums/l287/beeza2/100_1144.jpg

But adjusting the screw will allow you to adjust the Tps correctly,so nothing needed here right?

[JohnL]

Deleted due to incorrect information.

[beeza]

At WOT? Does this mean that the CT position has no adjustable TS screw? The Accord's f22A TB has an adjustable screw TS for the CT, but not for the WOT TS (which is steel contacting the alloy of the TB casting with no adjustment).

Yes it does,I just didn't post the pics here,only in the Tps thread...

http://i99.photobucket.com/albums/l287/beeza2/100_1141.jpg

http://i99.photobucket.com/albums/l287/beeza2/100_1142.jpg

http://i99.photobucket.com/albums/l287/beeza2/100_1136.jpg





If the WOT voltage is off spec then this should be adjusted with the TS screw.

If the CT voltage is off spec then this should be adjusted by loosening and rotating the TPS until the CT is in spec, then if necessary the WOT adjusted using the TS screw.


OK,say you have 0.48V CT and 4.33V WOT you would need to wind the TS screw up to throttle cable plate,bringing the CT voltage up,to say 0.65 (being the 0.17 that WOT is lacking).That should make WOT 4.5V.Then move the Tps to get the correct Voltages on both CT and WOT?

This is exactly my thing atm.See,I can get 4.5V if I put my foot through the floor but it's not correct.It needs calibrating.I was doing this,this morning but ran out of time before work...

I have the day off tomorrow and will attack it then.

If I wind the TS screw out the throttle cable plate dosen't hit it,so it has no effect on it.So I WILL have to wind the TS screw up as stated above?

[JohnL]

beeza,
The CT TS pictured in your post #53 is the same as my Accord, so your TB does have an adjustable CT TS. The TS pictured in your post #51 is for WOT, and is NOT adjustable?

If your WOT TS is not adjustable then ignore what I said in my post #52, it is incorrect.

If your WOT TS is adjustable, then all TPS voltage adjustments (WOT and CT) can be made using the WOT TS and the CT TS, negating any need to rotate the TPS itself.

[beeza]

The WOT is not adjustable,it's just a metal plate it hits.

[JohnL]

Then what I said in my post #46 is relevent to your TPS and TB. Ignore my post #56.

[beeza]

If only the WOT voltage is off spec, then the TPS itself needs to be rotated to bring the WOT voltage back into spec, and the CT voltage must then be re-adjusted using the TS.

:thumbsup:

I will report back on Friday mate,Legend!

:honda:

P.S. It can get damn confusing aye :D

[beeza]

Oh btw,you are bloody right about that TS being a biatch to get too!!

[GSi_PSi]

dude i think yous need to like discover msn messenger lol jkss

[JohnL]

dude i think yous need to like discover msn messenger lol jkss

I think we've covered it all now....

[joyride]

not yet lol. i'm sort of hijacknig the thread but its still about increasing throttle response.

lets say you have a carb motor. to allow more airflow into the throat you remove the choke throttle. if you do so, would the engine suffer from a cold start? wouldnt the remedy for this would be to say, get some sheet metal and cover the throat so there is more pressure in the carb to force more fuel into the carb?
i think i wrote it correctly...
well once the engine is warm you can just take that sheet metal off and away you go...?

[JohnL]

lets say you have a carb motor. to allow more airflow into the throat you remove the choke throttle.

IMO with most carbs any airflow gain will be minimal at best, and most probably undetectable.

BTW, it's not a "choke throttle", it's a choke plate. 'Throttle' is a term that relates purely to the butterfly valve that controls airflow to control power output.


if you do so, would the engine suffer from a cold start?

Yes.


wouldnt the remedy for this would be to say, get some sheet metal and cover the throat so there is more pressure in the carb to force more fuel into the carb?
i think i wrote it correctly...

'Correct' would be; 'reduced pressure in the venturi', or maybe; 'a greater pressure differential between the pressure in the venturi and in the fuel reseviour'. Expressed either way, this results in more fuel flow as atmospheric pressure pushes the fuel through the jets.


well once the engine is warm you can just take that sheet metal off and away you go...?

Mate, so much hassle, a complete pain. In any case, that's what the choke plate does, either automatically or at the simple pull / push of a knob on the dash...

If you really have a need to get rid of the choke plate then fit a Weber or Dellorto which have a cold start fuel enrichment jet instead of a choke plate.

[beeza]

The reason I couldn't get WOT value or if I set WOT,CT was 0.80,was because gearbox cable was too tight.My car being an automatic has the gearbox cable was too tight,therefore restricting movement of the accelerator cable!

http://i99.photobucket.com/albums/l287/beeza2/100_1326.jpg

I loosened off the cable and got the values straight away!

Tps thread updated!

[joyride]

thanks johnL for your answers :)

[beeza]

Throttle cables should be adjusted to have just a little bit of free play at CT, but at WOT there should be no significant load on the cable nor on the TB WOT stop, i.e. some part of the pedal should hit a stop (under the pedal pad or at the top near where the cable is attached) just as the TB WOT stop is contacted.

So when you put your foot down it the voltage reading should go directly to and stop at 4.5V solidly?

Mine kinda is pushing from 4.43 or so till 4.5 and even goes over too 4.55...

So it should STOP at 4.5 when it contacts the WOT plate?

If so I would set WOT at 4.5 upon contact of the WOT plate then set CT via the TS yeah?

[JohnL]

So when you put your foot down it the voltage reading should go directly to and stop at 4.5V solidly?

Yes. If you're having to push the pedal hard to reach the max output voltage then I suspect the pedal might be hitting the carpet before the throttle wheel hits the TS on the TB?

If the TB TS is coming into play before the pedal hits it's stop, then when you push harder on the pedal the cable, throttle wheel, spindle shaft and shaft bearings may become excessively loaded (wear and tear).


Mine kinda is pushing from 4.43 or so till 4.5 and even goes over too 4.55...

Erratic voltages at the CT and WOT might suggest wear in the spindle and / or bearings...?


So it should STOP at 4.5 when it contacts the WOT plate?

That's the number I kept seeing when researching on the net...


If so I would set WOT at 4.5 upon contact of the WOT plate then set CT via the TS yeah?

That's what I'd do...