<=400whp Goal - Exhaust Manifold Options?

[BlazedGlory]

In the very near future I plan on doing some major upgrading to my redtop. My goal is for 400whp at the most. I've been trying to search for some info on manifolds, but I'm having some problems finding all the information I need.

It seems that it is accepted fact that equal length manifolds are best. I've tried to search for some options, but am having some hard times. I'm sure I'd be happy with a full-race manifold, but I don't really want to fork out that kind of money. What other companies make reliable equal length manifolds that don't cost $1000? Is there such a company?

What kind of difference would there be if I didn't go with an equal length manifold? What are some good companies that make non-equal length manifolds?

Thanks in advance...

[Onizuka]

You can hit 400whp using the stock cast manifold. Nothing more reliable than that.

[BlazedGlory]

But would it not help if I got a different manifold? Just like the intake manifold, or cams, etc. I'm sure if I got an intake/exhaust manifold, perhaps cams then I could use a smaller turbo to get the same hp, but probably a better power curve...

[Onizuka]

Sure you would gain some power from a exaust manifold, but if your goals are 400hp and best reliability, the stocker is fine. If its a stainless steel exaust manifold, it will crack eventually, it doesnt matter who makes it.

[eyustfu]

i agree, go with the stock manifold, you won't have to worry about cracking mani's

[spanishricer]

I just can't comprehend why there seems to be such problems with aftermarket stainless manifolds cracking in the SR motor. Or is this a common problem shared by all turbocharged cars? Because I had an aftermarket stainless exhaust manifold on my Prelude for 4+ years, and I never had an issue with it. Is it the higher exhaust gas temperatures that cause the manifolds to have such a short life span?

[jgauspohl]

if you're looking 400 and going top mount the best I've seen is wasabigarge.com they're beautiful and really well made . I've got a gt2871r ...getting one of these manifolds soon...need to run an aftermarket wastegate though ...you'll want something big like bigger than a 38mm more like in the 40's.

[getnrowdy23]

those manis look good from wasabi, but how much are they? anyone ever had one?

[Onizuka]

I just can't comprehend why there seems to be such problems with aftermarket stainless manifolds cracking in the SR motor. Or is this a common problem shared by all turbocharged cars? Because I had an aftermarket stainless exhaust manifold on my Prelude for 4+ years, and I never had an issue with it. Is it the higher exhaust gas temperatures that cause the manifolds to have such a short life span?

There arnt such problems, I have had my $350 stainless steel mani on my car for 8000 miles no problem, but I accept the fact that they are not indestructable like cast iron ones. I saw a AWD galant VR4 lay down over 400 horsepower, and he was using an aftermarket cast iron manifold simply because he didnt want any hassles with SS. We dont need an aftermarket cast iron manifold for the SR20 because the stock one can do the job.

[808DRFTR]

Before you think about a manifold think about a turbo also, if your going top mount or bottom mount. Also if your going bottom mount maybe a cheap megan racing type manifold could be good but eventually will crack but hey for $150+ compared to $1000+ Just remember you get what you paid for.

[SRMatt]

my manifold just cracked so i put the stock one back on and it works just as good

[cheez80]

james at g-dimension runs the wasabi topmount on his car. iirc, he's running gt30r turbo, tial wastegate, etc., or something like that. he says he really likes it.

on my racecar, i'll also be running wasabi topmount, but with the hks gt-rs and hks gtii wastegate.

[jgauspohl]

I have a top mount wasabi garage too...james sold it to me ...wonderful now if you want to go f'in nuts and have your manifold cost alot more than your car go to full race ...hehe

[boost_creep]

correct me if im wrong,but im starting to believe the reason why the manis crack,and turbos come loose(see my post),is because we go with these aftermarket exhuast setups that dont have a flexpipe.im sure the sr has a stock flexpipe in the exhuast.i mean,think about it,pretty much all the weight of ur exhuast is pulling on the turbo/mani.and when ur revvin it the motor is shakin ,it puts alot of stress on those two points.thats why i decided that when i do my turbo upgrade,ill be putting a 3" flexpipe on my downpipe.

just my 2 cents.

[PhoenixTurboEric]

I would also like to add, Yeah you get your joe schmoe building crappy manifolds outta his garage or the ebay crap that more often then not crack, but if you do some research you can get an equal length manifold that will not crack.

Eric

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[codyace]

Best bet for reliability:Extrude Hone OEM Manifold and Turbine Housing!

[ILikeMy240sx]

My guess is turbocharged cars go through higher exhaust gas temperature fluctuations and puts the manifold under greater thermal stress also someone mentioned not having a flex pipe.

[teddy]

a step you can take to help prolong the ss mani's from cracking other than a flexpipe is to use solid Nismo exhaust hangers and brace the downpipe to part of the car. it helps reduce excessive vibration on the exhaust and mani.

[Hijacker]

the big thing is the the turbo. the motor is vibrating at all times, but the turbo is vibrating at a slightly different rate since it's not rigidly attached to the motor. After a while, this puts a stress at the collector and it will crack. The best way to counter this is to build a bracket that connects the collector to the block.

[jgauspohl]

that's why I like wasabi garage manifolds...they have braces built on them...even the wastegate flange has a brace. I will definitely be putting a flexpipe on mine too though.

[Jesse SR20]

I just can't comprehend why there seems to be such problems with aftermarket stainless manifolds cracking in the SR motor.

Like others have mentioned, there are certain steps you can take to prolong the life of a stainless manifold.

1. Brace the turbo. Build brackets to support the actuall turbo that attach to the block. I have yet to see someone do this with a SR, but I've seen it on other applications. Doing this will take 100% of the weight of the turbo and exhaust off of the manifold. (but the brackets must have a rubber mount to prevent excessive vibration.)

2. Put a flex joint in the downpipe. Very simple.

3. Allow for thermal expansion. Don't use a one piece flange; it should have seperate flanges for each exhaust port. And make sure the holes in the flange are larger than the stud in diameter (so you don't shear studs).

I bet if someone did all that, their manifold would last forever.

[VitaminT]

I just can't comprehend why there seems to be such problems with aftermarket stainless manifolds cracking in the SR motor. Or is this a common problem shared by all turbocharged cars? Because I had an aftermarket stainless exhaust manifold on my Prelude for 4+ years, and I never had an issue with it. Is it the higher exhaust gas temperatures that cause the manifolds to have such a short life span?

I don't know if your prelude was na, but most all Honda products use a donut gasket with a spring loaded flange to allow flex.

im sure the sr has a stock flexpipe in the exhuast

Not true. There are no flex points on the stock system. All solid flush bolt flanges.

[codyace]

You could always extrude hone your manifold as well...which IMO would gain you some ponies, as well as speed up spool time! Some good gains from that, but you still retain the stock cast strength!!!

[stevesrt4]

400whp can be achieved on the stock manifold, what turbo? I thought the 2871 was the biggest that would go on the stock manifold. and that 350whp was it for that set up.... Please educate me, I am a bit new to the sr world. thanks guys.

[namwons_240]

Yes, u can make 400 hp on the 2871r on stock manifold but at what pressure, 25+psi which will cause even more back pressure in the manifold and start choking the turbo and engine. On one of scott enthralpy's threads about this they were building a 500hp car and gained 60hp!!! JUST from the exaust manifold alone before tuning to 500hp. So u dont need one but your engine will be alot happier with one, just get a quality one. The straighter, free flowing an engine is, the more power and efficiency your will get, thats why turbojet engines make so much power.

[codyace]

Yes, u can make 400 hp on the 2871r on stock manifold but at what pressure, 25+psi which will cause even more back pressure in the manifold and start choking the turbo and engine. On one of scott enthralpy's threads about this they were building a 500hp car and gained 60hp!!! JUST from the exaust manifold alone before tuning to 500hp. So u dont need one but your engine will be alot happier with one, just get a quality one. The straighter, free flowing an engine is, the more power and efficiency your will get, thats why turbojet engines make so much power.

The .64 a/r GT2871 has been proven to make 370-380 whp on stock manifolds at 18-19 psi, so I'd feal that 20-21 psi would net you the magical 400 on the .64. This is very dependent on having the right mods though!

Now the .86 GT2871 being more of a top end turbo shoudl be able to achieve 400 whp at 18-19 psi with the rights mods.

[jgauspohl]

I talked to a guy that runs formula D runs a .64 (can't remember his name but has that olive metallic kouki running fno1rc's was at ATL this year) he said his was running right @ about 398 to the ground...said also the internal w/g would spike to 25 psi...I don't know what this turbo maxes out at as far as efficiency but I know it's well into the 20's...I plan on finding out here soon this early spring. Car's almost ready to start ...have to get fabrication done on the intercooler piping 3" and and 3"-3.5" DP....I also plan on getting a bigger turbo...if I feel I want more.