Modifying the stock Throttle body for more air flow

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

Aim: To 'open up' the OEM Throttle body (TB) to promote more air flow.

Since the tps will be removed for this mod,U should calibrate it when U put it back on,U should anyways lol

So here's how to do it:

Calibrate the tps

Enjoy!

Required: A small round file
Sand paper (for metal)

http://i99.photobucket.com/albums/l2...2/100_2864.jpg

Steps: Remove the TB from the car and take it apart,try to remember how it came apart so U can put it back together again.I have steps below on how to do this so don't worry to much.It's just that TB's vary,so your's may be different? Any TB can be adapted to this DIY and I believe all engines will benefit from this mod because U are not changing anything just removing the restrictions to promote more air flow into the engine.

All work was done on my d16y4.

If your tps is riveted on,U can hacksaw them off,dont need a grinder:

http://i774.photobucket.com/albums/y...4/100_2935.jpg

Replace with screws,the screws U need are in the tps thread:

http://i774.photobucket.com/albums/y...4/100_2953.jpg

Grab ya small round file and file that sucker out! Don't buy a cheap crap file,they dont work.

http://i774.photobucket.com/albums/y...4/100_2898.jpg

You will feel how much to file out.The main thing is to not file where the TB plate sits/seals and the rear,where it mounts up to the IM.It's very easy to file,I think the material is aliminium.

2 hours later,done! Make sure U polish that sucker up with say 3 stages of sand paper,finishing with a super fine paper to get it smooth/polished.Comparison pics:

http://i774.photobucket.com/albums/y...4/100_2905.jpg

No flash

http://i774.photobucket.com/albums/y...4/100_2904.jpg

Take ya stock TB plate and arm and do the same! U can use an electric sander if U have one to take off the majority,save time (I've done 6 now,so it's a good tool to have.)

http://i99.photobucket.com/albums/l2...2/100_2826.jpg

Done!

http://i99.photobucket.com/albums/l2...2/100_2824.jpg

http://i99.photobucket.com/albums/l2...2/100_2837.jpg

http://i99.photobucket.com/albums/l2...2/100_2834.jpg

http://i99.photobucket.com/albums/l2...2/100_2855.jpg

http://i99.photobucket.com/albums/l2...2/100_2856.jpg

http://i99.photobucket.com/albums/l2...2/100_2840.jpg

http://i99.photobucket.com/albums/l2...2/100_2841.jpg

Just looking at the inner 2 parts,not the TB

http://i99.photobucket.com/albums/l2...2/100_2844.jpg

http://i99.photobucket.com/albums/l2...2/100_2843.jpg

http://i99.photobucket.com/albums/l2...2/100_2849.jpg

http://i99.photobucket.com/albums/l2...2/100_2850.jpg

Next ya wanna get those 2 screws that hold the TB plate smaller,any way ya can!

The screw

http://i774.photobucket.com/albums/y...4/100_2914.jpg

The easiest way is with an electric sander,if not just file it!

http://i774.photobucket.com/albums/y...4/100_2915.jpg

http://i774.photobucket.com/albums/y...4/100_2916.jpg

Yes,it sanded the metal screws hehehe

http://i774.photobucket.com/albums/y...4/100_2917.jpg

Do the other side!

http://i774.photobucket.com/albums/y...4/100_2918.jpg

Put em' in and sand it to near flat (need a little sticking through to grab)

The finished product!

http://i774.photobucket.com/albums/y...4/100_2906.jpg

http://i774.photobucket.com/albums/y...4/100_2911.jpg

http://i774.photobucket.com/albums/y...4/100_2912.jpg

http://i774.photobucket.com/albums/y...4/100_2913.jpg

Next,check to see that your TB is opening 100%,most I've found are 96,97,98% If your's is like this,just file a bit off the throttle rotor until it is.Check regulary so you don't go too far

100%

http://i774.photobucket.com/albums/y...4/100_2906.jpg

If not file here

http://i774.photobucket.com/albums/y...4/100_2919.jpg

http://i774.photobucket.com/albums/y...4/100_2923.jpg

Putting it back together: Can be tricky at first..

Put the spring on the rotor to get it ready

http://i774.photobucket.com/albums/y...4/100_2947.jpg

http://i774.photobucket.com/albums/y...4/100_2946.jpg

Next put the other spring on the tps side like this

http://i774.photobucket.com/albums/y...4/100_2943.jpg

Then put the arm in,like this

http://i774.photobucket.com/albums/y...4/100_2944.jpg

Turn the arm clockwise 180 degrees and hold it there under tension.

Then fit the spring on like this.I didn't get a pic of it but there is a 2cm long metal tube thing that sits under the spring (oops..)

http://i774.photobucket.com/albums/y...4/100_2948.jpg

Hold it all there,dont let go! Now turn the rotor anti clockwise 180 degrees and push it on the arm,then put the washer and nut back on.

http://i774.photobucket.com/albums/y...4/100_2949.jpg

Will look like this on the other side now

http://i774.photobucket.com/albums/y...4/100_3041.jpg

Then put the tps on,like this

http://i774.photobucket.com/albums/y...4/100_2953.jpg

Then put the TB plate in there

http://i774.photobucket.com/albums/y...4/100_2950.jpg

Wiggle the plate around and get it to sit as closed as possible,then tighten the screws up.

http://i774.photobucket.com/albums/y...4/100_3047.jpg

Put it back in and Calibrate the tps and ya done!

Other comments:

Idle issues will only happen if U have filed too much off the TB plate and it is not sealing properly.

You can see mine isn't 100% sealed

http://i774.photobucket.com/albums/y...4/100_2911.jpg

Luckily I had a bit in my idle/air screw to play with,so I screwed that in and got it to idle perfectly.Now,no air goes through my idle/air screw and it idles from that small gap there,perfect.

On Tim's car the idle/air screw was turned right in,so we had to unscrew the throttle stop (TS) screw a bit so the plate would seal more.This put CT @ 0.43V and WOT remains @ 4.5V (The voltages U want are 0.48-.49V @ CT and 4.5V @ WOT) BUT that dosen't matter cause the car is running just awesome.

If the surging starts in the idle again we can still unscrew the TS screw to get it to seal more but if it throws the tps out too much ad/or it affects the running of the car,we will swap in another one I done.

Well! Time for a shower and a break!

Hello :wave:

http://i774.photobucket.com/albums/y...4/100_2925.jpg

Can U see the Great Cormorant?

http://i774.photobucket.com/albums/y...4/100_2926.jpg

http://i774.photobucket.com/albums/y...4/100e2927.jpg

He supported me,all day! :thumbsup:

http://i774.photobucket.com/albums/y...4/100e2930.jpg

Oh,I guess ya wanna know the RESULTS?!?!

Yup! We have a winner! Kinda feels like after a Suburu upper engine clean,revs more freely now,accelerates quicker,smoother running.

I'm Loving it!

A 60mm TB is too much on a slightly modified d-series.U need to have done ECU or internal work for it to work.

This is what got me thinking,well,what can I do to my TB then? :D

Hope U liked it,

Brett.

oh i loved it lol:p

beeza did this with my y4 tb i couldnt notice a difference because i changed it when i swap the intake manifold but im sure with how beez has described the difference i can aggree with that, very thoughtful of you to post it up here an very detailed diy good job bro:D

I'm a share-er :)

Nice work Beeza! Could I suggest using a 'half round file' instead of the small round file. Will be much easier to use/control and easier to keep uniformity around the area to be filed.

http://ecx.images-amazon.com/images/I/41uWPFAlTuL.jpg

awesome job, luv u work!

i believe you are the new king of DIY. Good stuff Brett, those D engines go forever and are great to learn with.

great write up! +1

Thanks guys!!

I did buy one of those files from the $2 shop Dean and it lasted 2 minutes lol but forsure that would make the job quicker forsure :)

Well,I got up at a birds fart this mornin',moon still shinin'

http://i774.photobucket.com/albums/y...4/100_3024.jpg

And got stuck into Chris's (gio's) TB :)

http://i774.photobucket.com/albums/y...4/100_3026.jpg

As the day came in

http://i774.photobucket.com/albums/y...4/100_3028.jpg

Finished filing

http://i774.photobucket.com/albums/y...4/100_3029.jpg

And polished up

http://i774.photobucket.com/albums/y...4/100_3032.jpg

3rd one down! Ready to be installed when U are Chris :)

Nice work, +1 for you how much mm you think its at now ?

Beez you are a glorious beacon of light in terms of your rep, how funny is that haha. Good work bro! Loving the morning.

Quote:

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Originally Posted by Premature Vtec

Nice work, +1 for you how much mm you think its at now ?

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Thanks mate,it's still 56mm,stock size,that's where the TB plate seals but I've opened it up at the front there.It does make a difference.

Thanks Chris,beautiful winters mornings now,so nice!

There's no reason why any of U guys can't do this,it's easy and there are great benefits/gains to be had.

Just trying to motivate U guys as I feel a large chunk of members on here lack it,while the other handful don't.

Either way,this is a good mod,a good thing to do,it's fun,hell U cant lose,so do it!

All my hard thinking/work is already done in this easy to follow DIY.

Get motivated and get workin already!!

:)

Motivation and time is all you need which most of us lack :(

Make time,it ain't hard!!!

Grab a spare TB from da wreckers.And instead of getting pissed and being hungover the next day,do this,let your creative juices floW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

bit off topic here,

but where are you from?

i need to let my creative juices flow

^^ Yes yes,let the Love and light in brotha!

Quote:

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Originally Posted by Chr1s

bit off topic here,

but where are you from?

---

haha,what do U mean Chris?

I'm living @ Murwillumbah which is from behind byron bay :)

nice job i just did this on my car. and also did the intake manifold .

actually increased flow by 1~2 psi LOL according to intake boost gauge.

previously i was reading 10 now iam reading 12.

thats really impressive

Awesome brotha!!!

Great news :)

Hey any reason you went file? I saw what you were doing and the first thought was DREMEL THAT BITCH! Why didnt you go down that route to at least do the major part of the removal, then perhaps level it all out. Too inaccurate?

Great write up BTW.

dremel barely removes anything man.,

use file and get the chunky shit out of way, then use dremel to smoothy it . use the course sanding thing first then the light one

Quote:

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Originally Posted by SnowWhiteLude

Hey any reason you went file? I saw what you were doing and the first thought was DREMEL THAT BITCH! Why didnt you go down that route to at least do the major part of the removal, then perhaps level it all out. Too inaccurate?

Great write up BTW.

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Thanks mate,appreciate that!

I haven't used a dremel before but I would imagine it would be hard to keep it all even.A file is easy to keep it even,U feel it,U can get it real nice with a file.

Quote:

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Originally Posted by hisoka

nice job i just did this on my car. and also did the intake manifold .

actually increased flow by 1~2 psi LOL according to intake boost gauge.

previously i was reading 10 now iam reading 12.

thats really impressive

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Fark good shit bro!! Nice one again beez

Thanks brotha!

Also, if you don't file as much metal off of the side of the throttle shaft where the head of the screws sit, you can counter-sink the holes and use flat screws to make it flow even better. Wish I had a picture.

A pitchure would be great..

Thanks for the input mate.

BUMP 4 FREE Power!

ummmm....how much kw @ the wheel does it actually make? hahahaha

breeza, have you worried about the piece holding the plate in being too thin?
Thought of this but i'm not sure as i'm worried on a boosted car the plate may get pushed back and stuff my intake?

But anyway, great mod idea!

Cheers mate!

Nah,the thickness is fine.

I would just leave more off the screw thread pokeing through,i.e. dont shave so much off.

That will ensure (more piece of mind) it wont be ripped out under boost pressure but I believe the way I have done wouldn't allow that to happen anyways.

The screw looks dodgy but locks in there real good.It's just the way the it's designed.It grabs/bites the thin metal real good,so less is best.

Did this on my b16 not that long ago, felt an instant change in throttle response, much smoother an there is definally a power gain, it even sounds nicer:thumbsup: Good upgrade which cost nothing:)

Hey Beeza, how would this go with a throttle body spacer for the fd1? And would this be any help on the FD1's? I want to give it a go when i have time. Thanks! Great write up by the way

Thanks mate,cheers!

A throttle body spacer wont affect anything/won't make a difference bacause all that's doing is lengthening distance between where the tb and IM meet.

This mod is dealing with the entry part of the air on the tb i.e. the front/top,not the other end.That end is not file out so tb will just match up as per usual with the spacer and then the IM.


Thanks Timmy,your car just feels brilliant,it would suck if U had to go back to stock now :)

I just finished 2 more for the y4 I had lying around the last 2 mornings.


This mod will benefit every car,because U are not changing the size of the tb and therefore the engines design,U are just opening it up and removing the restrictions,which allows for more air flow.

btw did U get a performance gain with the tb spacer?

Thing is, ive been reading alot about the tb spacer, and it made like a 4.5kw gain on the Si. Not sure about the fd1, but people saying that it feels better and sounds different too. Apparently, the Throttle body spacer, allows more air flow, much like your DIY, so i was assuming that if i combined that 2 then i would get a better result xD

4.5kw? Dont always believe what your told.

Quote:

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Originally Posted by Limbo

breeza, have you worried about the piece holding the plate in being too thin?
Thought of this but i'm not sure as i'm worried on a boosted car the plate may get pushed back and stuff my intake?

But anyway, great mod idea!

---

I worried about this too but seems to be working fine. If it came off the bolts would fly into the engine via the manifold and it's game over.

haha yeah,it's looks dodgy but I would be VERY suprised if it did,they bite/lock real good!

Quote:

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Originally Posted by ekay1

Thing is, ive been reading alot about the tb spacer, and it made like a 4.5kw gain on the Si. Not sure about the fd1, but people saying that it feels better and sounds different too. Apparently, the Throttle body spacer, allows more air flow, much like your DIY, so i was assuming that if i combined that 2 then i would get a better result xD

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I reckon so!

im not interested in the kw gain really, just hoping for a better "feel" of the car after these two.

It definately achieves that,that's exactly what it does.

Guys i would highly suggest the use of locktite on those screws because they can back themselves out and it will grenade your motor

Other than that good diy
Also for people wanting to use a dremal you can buy special bits for alloy they look like sandpaper they work real well I got some for my die grinder it bored out my intake manifold really easly

Hrm I was thining of doing a similar mod to this but I personally wouldnt touch the butterfly valve nor the screws etc. The gap shown in the DIY photos illustrates the potential leaks. PErsonally this would not beacceptable and I would not want to 'tune this out' with the IACV etc.

If you stomp on your throttle and your cable is a litle tight you might just snap the axle/rod that holds the butterfly plate so i definately wouldnt take it down that much.. you REALLY dont want to snap your butterfly plate (or the rod/axle) on the track or EVEN WORSE on the street.. imagine permanent WOT in daily traffic ???!!!

If you look at the science of this (and what spoon has done also) you see that it is increasing the potential air velocity (speed) but it wont actually increase the flow as there is no increase to the diameter of the actual 'valve' itself. I guess the faster moving air would increase the pressure and therefore squeeze more air through the TB.. Those changes to the Butterfly plate and rod/axle (and screws) could also create some turbulence (possibly) however I think the reduced restriction by doing this wouldnt be worth the sacrifice in reliability/durability etc.

The spoon TB's actually have the centre re-bored and a replacement butterfly plate with larger diameter to suit. doing this increases the velocity AND the flow and hence can give you a snappier response and power gain.

Quote:

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Originally Posted by cotties

Guys i would highly suggest the use of locktite on those screws because they can back themselves out and it will grenade your motor

Other than that good diy
Also for people wanting to use a dremal you can buy special bits for alloy they look like sandpaper they work real well I got some for my die grinder it bored out my intake manifold really easly

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Locktite wont do much,if anything cause there's no real thread that the screw grabs onto..it simply grabs it real good.

U can weld it if worried.

Got anypics of the work ya did on the IM?

Quote:

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Originally Posted by VT3C

Hrm I was thining of doing a similar mod to this but I personally wouldnt touch the butterfly valve nor the screws etc. The gap shown in the DIY photos illustrates the potential leaks. PErsonally this would not beacceptable and I would not want to 'tune this out' with the IACV etc.

If you stomp on your throttle and your cable is a litle tight you might just snap the axle/rod that holds the butterfly plate so i definately wouldnt take it down that much.. you REALLY dont want to snap your butterfly plate (or the rod/axle) on the track or EVEN WORSE on the street.. imagine permanent WOT in daily traffic ???!!!

If you look at the science of this (and what spoon has done also) you see that it is increasing the potential air velocity (speed) but it wont actually increase the flow as there is no increase to the diameter of the actual 'valve' itself. I guess the faster moving air would increase the pressure and therefore squeeze more air through the TB.. Those changes to the Butterfly plate and rod/axle (and screws) could also create some turbulence (possibly) however I think the reduced restriction by doing this wouldnt be worth the sacrifice in reliability/durability etc.

The spoon TB's actually have the centre re-bored and a replacement butterfly plate with larger diameter to suit. doing this increases the velocity AND the flow and hence can give you a snappier response and power gain.

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Are U saying this mod won't work?

Quote:

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Originally Posted by beeza

Are U saying this mod won't work?

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nope I am not saying this mod wont work, I am weighing up the reliability of this moving part that has a fair bit of pressure on it from the suction of the motor through to the air-velocity running through the TB and also the tension from the Throttle cable and your right foot stomping on it.

and also I think the potential vac leak issues wouldnt be worth the 'gain'.

would love to see flow-bench tests on this between stock IM and this modification !!

i agree that the air-horn style bored-out mouth of the TB would be beneficial, however modification of the throttle plate without increasing the actual bore the 'gain' might just be noise caused by increased turbulence.

awsome write up mate!

^^ Thanks Lyle,cheers brotha!

Quote:

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Originally Posted by VT3C

nope I am not saying this mod wont work, I am weighing up the reliability of this moving part that has a fair bit of pressure on it from the suction of the motor through to the air-velocity running through the TB and also the tension from the Throttle cable and your right foot stomping on it.

and also I think the potential vac leak issues wouldnt be worth the 'gain'.

would love to see flow-bench tests on this between stock IM and this modification !!

i agree that the air-horn style bored-out mouth of the TB would be beneficial, however modification of the throttle plate without increasing the actual bore the 'gain' might just be noise caused by increased turbulence.

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haha yeah,might be aye.

beautiful write! I've been looking for a way to modify my tb for that better flow. Was thinking off just going straight to a new J's racing 70mm TB at one stage haha.

haha yeah lol

Yeah this DIY works really well.

Cheers!

when i first read this article i put it in the 'too hard' basket - but now i think im going to buy a dremel and give it ago

ps Beeza - that muffler i bought from you is still going strong but i think its at the end of its days lol

Oh true,at least it was cheap then! :)

U don't need a dremel Saint,just a half round file!

Yeah if U can get a spare TB,that would be best.

Have to calibrate the TPS too..it's not hard though,if U just keep reading the DIY's,they sink in.

I gots a spare y4 one :)

http://i774.photobucket.com/albums/y...4/100_0824.jpg

do they have to be calibrated per car or are they much the same?

wanna sell me one thats calibrated and port/polished? lol

U can calibrate the tps on any car cause it's the TB opening and closing that it's measuring.

Then U would just bolt it on and adjust the accelerator cable,then check the idleing,adjust it via the idle/air screw,then reset the ecu!

hello, will this have any effect on a dc5 type s integra tb?

Definately.Will work on all tb's!

just finished doing this on a D16y1 TB and installed it onto D15b7

used a dremel for most of the work

im getting idle hunt now - only a little - not as bad as when u unplug a vac line

trying to trouble shoot it - i may have to put a spare butterfly in that is unmodified and see if it makes a difference

TESTING REPORT

ok so at first i was getting hunting idle - i went back over all bolts, screws, nuts, seals etc without taking the TB off the car and it dramatically reduced
but occasionally it will still hunt a couple of times at a stop sign or lights etc than flatten out
i have noticed that the idle isnt constant now either - its slowly waves up and down - but almost not noticable

the TPS voltage adjustment has made a huge difference - the acc pedal has alot more control and response in it now
its alot easier to control the speed of the car without having to go up and down gears rapidly

im not too sure how much difference the PnP has made...
things i have noticed are that i have heeps more bottom end - like alot more torque and response down low
but i feel like theres a slight loss just above midrange and than it gets going again towards the top end
it is a tad louder now as well
overall i think its an improvement

when i get time ill be finishing the PnP on the D15b7 intake manifold and the D15b7 throttlebody i just took off the car
i also have a D16y1 intake manifold to do and eventually i will do the D16z6 intake manifold that is on my car as well

currently rebuilding a D16y1 head to mini-me onto the D15b7 block with a y8 headgasket
i wont go too far into it - u can read up on it in my build thread

there are also pics of my TB + PnP work in my build thread =)

Awesome awesome Saint.

They are sensitive things bu U have already reduced it a lot,so I'm sure U will reduce it more in time and learn more in the process.

The main thing is getting the butterfly plate to seal properly OR mine has a slight gap at the top which lets air in and with the idle/air screw closed,that's how my car idles.

Just gotta make sure the spring on the tb has good torque in it i.e. the butterfly plate springs shut firm.(The tb should be hard to hold open with your hand after a short time..)

Always good to reset the ecu regualary/after playing It helps to smoothen everything out after making changes.

Keep us updated mate!

great work and great write up mate!!!
but dont think that worth the hard work since the internal diameter thru the TB disc is still the same
so the air flow rate stay same unless the internal diameter is enlarged all the way...
considering spending a whole afternoon filing it i rather wax my car lol

^^^ Lol the internal diamater is the same but the throttle plate takes up less space at WOT which will increase the maximum poitential of air flow and it smooths out the casting imprefections giving you a more laminar flow. matching the throttle body opening to the intake piping will also help reduce turbulance at the transition from the intake piping to the throttle body. Very small increases but every thing you do on the d series counts :)

Exactly brotha!

:)

got an old woodworking tip for u guys, once u remove the butterfly and rod, spray paint the inside with a light coat of contrasting colour paint. Red is best as the alloy filings will turn black.

Now when u file and sand, just ensure there is paint left where the butterfly seals.

U can do this on the butterfly disc also and personally i would only knife-edge one edge of the butterfly not both, keeping as much material there as possible.

If this was reliable, honda, and every tuner company would do it so i would be very cautious when shavind the axle and screws.

i doubt they would do it anyway - waaaaay too much work involved for such little gain lol

little gain...

I thought is was a nice lil' bump up!