cb169

ALL MOTOR GUYS
what size exhaust are u guys running with ur H22's 3" or 2 1/2, I know most bolt on exhaust systems are 2 1/2 but heard from a few people who had experience making more power on 3" exhaust system, anyone ever dyno tested this theory? I know turbo cars require at least 3" exhaust.

Prudz_lude

iTrader: (1)

2.13 is the best size

russlan44

im running 2.5 all the way

autoluder

2.5 for maximum top end, < 2.5 for low end, but 2.5 will not kill your performance. 3" on na could be bad.

MLBZ521

iTrader: (6)

It all depends on what type of power you're going to make. One NA build might be better with 2.25" Piping, another 2.5", and another 3.0", it depends.. Not every build is the same...

Most Aftermarket Exhaust Systems are 60mm I think actually..

People will need more information on your build to give proper advice..

BlackCatt

2.25 is the best for my setup (n/a) , but as MLBZ521 suggested it really does depend on what work you have done to your engine or are planning on doing in the future. If you are running or are going to run a turbo, you will need a 3 inch setup.

mgags7

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by autoluder &raquo;</TD></TR><TR><TD CLASS="quote">2.5 for maximum top end, &lt; 2.5 for low end, but 2.5 will not kill your performance. 3" on na could be bad.</TD></TR></TABLE>

Go away and don't come back.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlackCatt &raquo;</TD></TR><TR><TD CLASS="quote">2.25 is the best for my setup (n/a) , but as MLBZ521 suggested it really does depend on what work you have done to your engine or are planning on doing in the future. If you are running or are going to run a turbo, you will need a 3 inch setup.</TD></TR></TABLE>

See above.

OP: Don't make threads with all those symbols, it hurts my eyes in the morning.

There is no theory in this thread either. hit the search button

PirateMcFred

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by autoluder &raquo;</TD></TR><TR><TD CLASS="quote">2.5 for maximum top end, &lt; 2.5 for low end, but 2.5 will not kill your performance. 3" on na could be bad.</TD></TR></TABLE>

Hmm. I made 183wtq on 2.5" and I made 200whp even without VTEC on 2.5" exhaust. I made 185 on a different tune.

When I had the H22 VTEC I made 203whp on 2.25" crush-bent exhaust...

My vote is 2.5"+ exhaust.

98vtec

going with 3" eventually

NirVTEC

Going to contribute mine because its kind of weird.
I run a 2.5" "Y" Pipe into 2.5" piping into 2.5" Muffler.
When I made my original Dyno runs, we tested out the "Y" pipe and it only made 2whp more than my 2.5" exhaust did. Now mind you my exhaust is stupid loud.
I am making just over 200whp and it appears that the 2.5" complete system is 99% efficient as opposed to an Open header setup.
I don't have any experience with 3"+ N/A but I think at the 200whp+ mark its not going to hurt anything except your ears.
As I stated in a previous thread, I would love to see how a 3" System with a resonator would compare against a 2.5" w/o resonator. Why? To find the perfect balance between sound and power. The most quiet, making the most power would be ideal IMHO.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by autoluder &raquo;</TD></TR><TR><TD CLASS="quote">2.5 for maximum top end, &lt; 2.5 for low end, but 2.5 will not kill your performance. 3" on na could be bad.</TD></TR></TABLE>
Not off to a good start.....I suggest spectating a little longer.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">
OP: Don't make threads with all those symbols, it hurts my eyes in the morning.
</TD></TR></TABLE>
x2

117

My dyno from an exhaust that starts at 2.5" at the header, then goes into a Coast Fab muffler, roughly where the stock cat is located. The muffler has a 3" outlet, so the exhaust is 3" from the muffler back and turns down right in front of the rear LCA. Basically it's a 2.5" exhaust for about 18" then a 3" exhaust the rest of the way.

My low end torque looks okay to me.



The same exhaust on a dyno at NPM06, where the dyno was reading about 10WHP low according to everyone there.

NirVTEC

After looking at that again Billy I do have to say its amazing what cams do for setups. At similar peak power my old 196whp setup had spots with 10-15tq more. It seems like your setup is very peaky.....but it is stock cams.
I guess its becoming more and more apparent to me over time that my Vibrant header is choking up my setup BIG TIME! HyTech here I come!



Modified by ::NirVTEC:: at 10:59 AM 10/11/2007

117

Do you have a dyno plot?

I'd love to add cams, but that would push me to H1. I wonder how light I could get the car under H1 rules... I still have these roller cams and rockers here.

NirVTEC

Now thats what I am talking about!!!!!! H1 H22 FTW!
If Chris/Corey can get 220-230whp from an H1 H22 what can you get? I say an Easy 240! Are there NOT H1 5th gens out there?
This is the best I can do right now Billy w/o a scanner. The far right verticle dotted line is 7500rpms and the HP/TQ scale is the same. Its a pretty sloppy curve because I was tuning with just a VAFC and chipped ECU.
We're running similar compression and those dyno runs were with a 2.36" Full exhaust off a Vibrant 4-2-1 header. Below is JUN cams vs S2S1 cams! Love that powerband!

117

No H1 5Gens that I know of. You can't get them anywhere near the 2,400 lb min weight. Chris F is the only Prelude I know of in H1.

I'm hoping to buy scales this year to see exactly what my car weighs. Min weight is 2,600 in H2.

I don't think my power is peaky. Look at the torque. It's fairly flat.

With the engine I was building, I was hoping for 240WHP with some really high compression.

NirVTEC

Your curves are amazing but it just seems like with Stock cams in there it doesn't really start to outshine the typical bolt on H22 until higher RPMs whereas a Cammed setup outshines across the board.

I don't think you'd need really high compression to hit 240. Chris hit 232(on a high dyno) with a meager 11:1........Its all in the Cams!

I'll keep trying though Billy......I just want to see what your awesome work would do on a higher compression Cammed motor!!! If you can get 204whp out of basically a JDM Compression level motor with stock cams what can you do with no limits?!?!
I wish I could just drop an 89mm block/95mm crank/12:1 slugs and JUN cams on your doorstep! Then plop a Portflow head on it with ITBs and a sick RACE header! I could almost guarantee it would be an Epic H series build!

Hahaha.....we jacked his thread!
We're allowed to do it because he used all those Symbols to get our attention!

cb169

The same exhaust on a dyno at NPM06, where the dyno was reading about 10WHP low according to everyone there.
[/QUOTE]

what did u change or tune to get the extra power from 6200rpm's and up, nice gain, was that all just from tuning the fuel ratio?

TylerC161

Im going to post my dyno results, for the information of this thread:

Dynoded: 182.62whp and 163.76wtq





Skunk2 Intake manifold, Injen CAI, ACT Flywheel, 3" exhaust from the B pipe to a 20" resonator, to a vibrant flat black muffler. stock header, stock cams.

Only other mods are fuel related (walbro, dsm injectors, aem rail).

NirVTEC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cb169 &raquo;</TD></TR><TR><TD CLASS="quote">

The same exhaust on a dyno at NPM06, where the dyno was reading about 10WHP low according to everyone there. </TD></TR></TABLE>
Eh, who knows with that......Billy's was really the only respectable Prelude run there. I was having tuning issues so I can't compare unfortunately.

All I know is it was a shitty shop with a shitty owner thats lucky he didn't catch an *** whipping from me that day. I just couldn't justify beating the crap out of a guy who was 1/2 my size....not to mention ending up in a St Louis jail!
I mean who doesn't check the straps before a Dyno pull?!?! A strap broke and my car almost flew off the dyno into a crowd of people. No apology nothing. Yes, I am still a little bitter about that. The owner of LIGHTSPEED is just a bitch.
Sorry bout that......I'm done now.

Those numbers above seem pretty high for stock cams/header. We can't use those as a valid comparison.

Acidcrakker

Hey guys i hate to but in but the OP says hes runing 2.5 all the way. What type of downpipe are u using, IM looking for a dwnpipe with 2.5 outlet.<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlackCatt &raquo;</TD></TR><TR><TD CLASS="quote">2.25 is the best for my setup (n/a) , but as MLBZ521 suggested it really does depend on what work you have done to your engine or are planning on doing in the future. If you are running or are going to run a turbo, you will need a 3 inch setup.</TD></TR></TABLE>

NirVTEC

Make one for a DC header or just buy a Race header.

117

I run an SMSP header with a 2.5" collector.

Clint, I didn't realize that happened. I wouldn't be happy if I had a strap break either. That shop no longer exists, AFAIK. It shut down shortly after NPM, is what I was told. This spare block I have isn't H1 legal, and I put a ton of money into it. I wish I could sell it for a decent price and do another build. I was thinking of selling just the illegal parts (modified Type-S pistons, Crower Maxi-Lite rods, and lightened crank) and starting fresh, but the block was honed for those pistons.

Also, if you think the power I got out of my car is impressive, you should see David's. 195 to 197WHP on an all OEM build, less compression, and a DC header with GReddy exhaust! We're going to change over to my SMSP and a more open exhaust this off-season. I'm hoping for 210WHP out of his engine.

No power difference. It was just a second pull in a different gear (3rd vs 4th). There was something really flaky about that dyno, not to mention it was in a closed off area of the shop that was super hot. I'd say it was 110F+ in the shop, so the difference is probably due to dyno calibration as gear selection shouldn't make a difference in dyno output.

Acidcrakker

I got two megan megan racing headers.
one for the H23a1 and the collector on that is 2''.

I bought one for the H22a the other day(still megan) and it is yet to arrive but im guessing its gonna be 2'' as well.

So you are saying the DC header comes with a 2.5 collector on it?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ::NirVTEC:: &raquo;</TD></TR><TR><TD CLASS="quote">Make one for a DC header or just buy a Race header.</TD></TR></TABLE>

Finest

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Acidcrakker &raquo;</TD></TR><TR><TD CLASS="quote">So you are saying the DC header comes with a 2.5 collector on it?
</TD></TR></TABLE>

No, you modify it with a 2.5" collector. There's a write up here somewhere.

autoluder

For those of you who were flaming me. What I said earlier, was a simplied statement. From my experience with my lude which i have had for 7 years, I have a Thermal 2.5" exhaust on a h23, with CAI, and DC Header. More than half the time I had the car with that setup the mid range to top end was where the car shines. Just about 2 years ago i removed the cat and put on 2 resonators, and low end improved and top end suffered. SO THAT is why i said 2.5 is better for top end, and less than 2.5" would help the low end acceleration. And 3" on NA would probably only benifit on higher horsepower applications.