Accord Euro Dyno Results

[Suntzu]

OK, I got the RBC as you know. I have now fixed/ tighted my header. That helped.

AND

I have replaced my flexpipe with a double braided on on the topspeed SS header. It was cracked.

Its a LOT quieter and it seems to have more torque and smoother power delivery. Its noticeable.

On thing I do notice now its all fixed is that its doesnt seem to be reving as hard at 6000rpm +. Then again that could be pyschological as its quieter.

Is it possible that with my mods the stock exhaust is now restricting my top end? I didnt notice it with the flex pipe as it was cracked an releasing pressure no doubt...

I have:

Jtune Mild
Comptech Icebox with KN mod
Topspeed SS Header ( flexpipe fixed)
300 cell Cat
RBC
TB Bypass
Hondata heatshield Gasket

Might be time to dyno again think...

[Crapdaz]

Do it!!!
What was your last dyno figure russ?

[Chris_F]

Replacing the stock exhaust with a dual outlet exhaust has minimal gains on a stock standard car with no ecu tuning. Maybe a few hp if you're lucky.

But your car is far from standard and, with the reflashed ECU, I have a feeling the stock exhaust might be holding you back a little (hard to know without dyno testing). If you want to maximise your gains, single outlet 2.5" to 3" exhausts are proven to work well with modified k series engines. A good exhaust shop will be able to make you a 2.5" single outlet exhaust, 1 resonator (good brand like magnaflow), 1 muffler (good brand like magnaflow) and mandrel bent stainless steel piping for about $1k.

But if you want to keep the dual outlet look of the exhaust you'll be looking at a few hundred more if you go custom. There's also plenty of aftermarket options from Japan and the US. But with the Aussie dollar the way it is at the moment though your going to be paying more than usual.

I'm keen to see a new dyno for your car!

[Crapdaz]

Replacing the stock exhaust with a dual outlet exhaust has minimal gains on a stock standard car with no ecu tuning. Maybe a few hp if you're lucky.

But your car is far from standard and, with the reflashed ECU, I have a feeling the stock exhaust might be holding you back a little (hard to know without dyno testing). If you want to maximise your gains, single outlet 2.5" to 3" exhausts are proven to work well with modified k series engines. A good exhaust shop will be able to make you a 2.5" single outlet exhaust, 1 resonator (good brand like magnaflow), 1 muffler (good brand like magnaflow) and mandrel bent stainless steel piping for about $1k.

But if you want to keep the dual outlet look of the exhaust you'll be looking at a few hundred more if you go custom. There's also plenty of aftermarket options from Japan and the US. But with the Aussie dollar the way it is at the moment though your going to be paying more than usual.

I'm keen to see a new dyno for your car!

just wondering on a side note if you have 2 resonators, 1 hotdog and other larger which one would be best to remove?

[Suntzu]

Replacing the stock exhaust with a dual outlet exhaust has minimal gains on a stock standard car with no ecu tuning. Maybe a few hp if you're lucky.

But your car is far from standard and, with the reflashed ECU, I have a feeling the stock exhaust might be holding you back a little (hard to know without dyno testing). If you want to maximise your gains, single outlet 2.5" to 3" exhausts are proven to work well with modified k series engines. A good exhaust shop will be able to make you a 2.5" single outlet exhaust, 1 resonator (good brand like magnaflow), 1 muffler (good brand like magnaflow) and mandrel bent stainless steel piping for about $1k.

But if you want to keep the dual outlet look of the exhaust you'll be looking at a few hundred more if you go custom. There's also plenty of aftermarket options from Japan and the US. But with the Aussie dollar the way it is at the moment though your going to be paying more than usual.

I'm keen to see a new dyno for your car!

I think our stock exhaust is 57mm. ( about 2.25 inch). Id love to try a 2.5 single custom system but theres a few people here ( Junyu I think) who tried this and got a lot of noise and resonance and I cant stand that. Im totally happy witht he amount of noise my car generates for the power at the moment. So I would do it but dunno if i can take any rice droning.

That being said, the 06-08TSX went to a 62.5mm exhaust and that was after a small power increase of about 7kw I think.
So it must be worth it as 62mm is about 2.5 inch.

My last dyno was 118kw and normal euros were about 102kw ( on that dyno) so im up about 15kw, plus my latest mods Im guessing around 125kwatw now easy.

So gieven honda upped the exhaust for 7kw, i may be hitting the limit for the 57mm exhaust.

Hard to say...

[aaronng]

If you stick with dual outlet, make sure that your exhaust guy does the split and bends perfectly, as those are the sections that restrict flow compared to a single outlet of the same diameter.

[Chris_F]

I think our stock exhaust is 57mm. ( about 2.25 inch). Id love to try a 2.5 single custom system but theres a few people here ( Junyu I think) who tried this and got a lot of noise and resonance and I cant stand that. Im totally happy witht he amount of noise my car generates for the power at the moment. So I would do it but dunno if i can take any rice droning.

That being said, the 06-08TSX went to a 62.5mm exhaust and that was after a small power increase of about 7kw I think.
So it must be worth it as 62mm is about 2.5 inch.

My last dyno was 118kw and normal euros were about 102kw ( on that dyno) so im up about 15kw, plus my latest mods Im guessing around 125kwatw now easy.

So gieven honda upped the exhaust for 7kw, i may be hitting the limit for the 57mm exhaust.

Hard to say...

Yea I have a 2.5" custom exhaust with a supercat 2.5" (internal) resonator and a supercat 2.25" (internal) muffler. It's loud, probably twice as loud as a J's racing exhaust so it's definitely not for everyone. It also has a really aggressive exhaust note which some will love and others will hate. The car literally screams at high rpm and feels a bit stronger on the butt dyno then when I had the J's racing.

A couple of larger, good quality resonators would take the volume down without impacting the flow too seriously, if at all. So it's definitely possible to have a custom exhaust that sounds good with no rice droning - you just have to find an exhaust shop that knows what they're talking about, sells good quality mufflers like supercat/magnaflow and knows how to design a system that will meet your sound level requirements.

From the dynos I've seen in the states most highly modified k-series are running 3" exhausts. But they're putting out in excess of 230whp which is the equivalent of about 200-210whp (147/150wkw) on an Australian dyno.

With the J's racing I was putting out about 124kw, a stock euro with only k&N panel filter put out about 111kw on the same day on the same dyno. So the ecu flash has definitely added a fair whack of power to your car if your putting out 15-16kw more than a standard car. Based on that, and what you've said, a 2.5" exhaust definitely wouldn't hurt with your setup. I'm just not sure how much more flow you'd get out a dual system if you decide to go that way.

Once I get my car tuned I'm hoping the true benift of my maxim works header and 2.5" single outlet exhaust is exposed. The difference between components (header, exhuast, intake etc.) is much harder to judge untill they've been tuned. Since your car has already been flashed, you should notice an improvement straight away from the less restrictive exhaust.

If you stick with dual outlet, make sure that your exhaust guy does the split and bends perfectly, as those are the sections that restrict flow compared to a single outlet of the same diameter.

That's good advice. It's also part of the reason I went with a single outlet setup. The high-end off the shelf jap exhausts like Fujitsubo have well designed splits but when you go custom it can be a different story... it adds complexity, more welding and more possibility for the exhaust shop to stuff up.

[Suntzu]

Awesome advice. The problem is that in my area I dont trust any of the exhaust joints I have spoken too...

Did you get a plug or your missing gap when the other dual exhaust is? What others mods have you got as im trying to get an idea of the improvements your exhaust might have had.

[Chris_F]

Awesome advice. The problem is that in my area I dont trust any of the exhaust joints I have spoken too...

Did you get a plug or your missing gap when the other dual exhaust is? What others mods have you got as im trying to get an idea of the improvements your exhaust might have had.

Yea, I'd say it's best to avoid custom exhausts untill you find a shop you can trust. It might be worth asking around at a few performance orientated workshops to see who they recommend.

I was trying for months to get the OEM exhaust plug to fill the gap. Cost was abot $80 but the guy who offered to send the part over backed out.

Mods at the time of dyno:

GruppeM intake
Maxim works exhaust manifold
JDM Accord Euro R metal substrate catalyic convertor (300 CEL i believe)
J's racing 60rs single outlet exhaust

Result = 124.5kw

The maxim works header made the most noticeable difference to power on the butt dyno. The gruppeM felt a bit better than the 60rs in terms of gains. The custom exhaust felt like a slight improvement when compared to the 60rs at high RPM.

If we conservatively say my car gained 12kw over a standard car, the break down in gains (in my opinion) from the parts would be:

Maxim works exhaust manfiold: 6kw atw
Gruppe M intake: 4kw atw
J's racing Exhaust: 2kw atw

With the larger 2.5" exhaust I might say 3-4kw, only a very slight improvement over the J's racing 2.35" (60mm) exhaust.

I definitely feel like the car needs a tune now to get the most out of the mods- the power band has really shifted to high rpm. If I can find my dyno sheet I'll post it up for you. You'll be able to see the big spike in power once vtec engages. A lower vtec point and some changes to ignition/fuel and VTC would make a world of difference. I would be hoping for at least another 10kw with my mods after tuning.

Summary: single outlet exhaust does no where near as much as a good header, but with tuning/reflashed ecu, your much more likely to take advantage of the increased flow it provides.

[Suntzu]

Might get a custom exhaust then. Maybe 2.5 inch single with twin resonators and a loop muffler to quieten it down. Mild steel to save costs and my car wont wear out an exhaust in the next 18 months ( when i get a new car).

You reckon a single 2.5 inch will do it ok over stock?

[enkay]

anyone see this?
http://hondata.com/kpro_dual_ecu_tsx.html

[Chris_F]

Might get a custom exhaust then. Maybe 2.5 inch single with twin resonators and a loop muffler to quieten it down. Mild steel to save costs and my car wont wear out an exhaust in the next 18 months ( when i get a new car).

You reckon a single 2.5 inch will do it ok over stock?

A 2.5" exhaust should make a noticable difference. Will be intersesting to see what sort of gains you get with the flash.