clinicallyill

So Ive been reading up that H22's are responding well to 3" exhausts all motor... but I was just wondering if anybody with some first hand experience or knowledge on the subject can verify that there is any torque loss... or maybe a bigger torque gain in 2.5 over 3... if this is the case I may consider 2.75 piping... mandrel bent side exit no cat or muffler... I just don't want to sacrifice torque... (Im also a muscle car guy lol... so I like my torque to a degree)

Str8EJ

improving exhaust flow shouldn't reduce torque; rather, the opposite.

Katastrophic

you might see a tiny amount of torque loss down low from less backpressure but increasing your exhaust size should always net higher numbers because the engine can breathe better with less force in the exhaust system.

clinicallyill

Yeah but isn't it quite dependent on the ability to flow the exhaust pressure through the exhaust... you need back pressure for torque in some situations... you put a 3" exhaust on a D or B series motor... most likely going to loss ALOT of low/mid range HP and mayyybe gain a little way up top... and probably look TQ across your entire curve (keep in mind Im not speaking about turbo'd applications or extreme HP applications) I want the ability to flow big numbers up top (as I am probably gonna be revving to 9000) but I want some good mid range punch aswell to get me there, and the torque to keep it moving... some people are telling me 2.75" will yield me more torque and a bit better mid range punch but cost me a few ponies up top... which wouldn't be the worst thing if the hp sacrifice wasn't insane then I would think it would be worthy of a few torque... something harder to come by in Honda's

Krut

Good info in this thread about backpressure misconceptions
https://honda-tech.com/forums/all-motor-naturally-aspirated-44/full-3-exhaust-b20-lost-torque-2971507/
Do the 3".

clinicallyill

That was a good read :-) thanks, yea I'll probably just go with a 3" side exit, probably a Vibrant Performance 3" super quiet resonator coming off Bisimoto headers. we'll see how I fare with that

clinicallyill

Ugh... I just read a thread which is making me reconsider my Bisimoto header choice... it showed significant mid range loss... however this was on an engine running with like 200whp... I'm looking for nearly 300. faaaaack decisions decisions!!

00Red_SiR

So what makes you think that the Bisimoto header will perform any different on a 300hp motor? It was custom built for the 200whp motor and look how it did....

clinicallyill

Yeah I didn't go through the entire 14 pages of arguing... all I know is it wasn't built for the motor that it was dyno'd on from my understanding... but I'll probably go with a different header now after reading that, that mid range loss was way too much for my likings.

00Red_SiR

That's just it, it was built for a nearly identical engine and lost that amount of power. When people started to say "hey, that motor wasn't identical to what it was intended for which is why it lost power", people started measuring their "custom built to their individual specs" bisimoto headers and found little or NO difference between a 1.8L or 2+L header. That in itself negates the "not the identical motor" arguement.

clinicallyill

Yea that's true enough I think I'll go with one of those Tri Y headers and save me some money and some mid range haha

AznBlueBoy

wait...you're looking for nearly 300whp and you're asking if you should go with a 3" exhaust?
Sounds to me like you won't get near 300whp.

turbodcxbro

iTrader: (1)

I just went with full 3" on my stock B20 (non VTEC) and did notice a very slight loss in bottom end torque, it wasn't much but it was noticeable by the butt dyno. However the car pulls much better all the way through the powerband and pulls all the way to redline now where it used to fall off up top.

Oh, and don't use the word "backpressure" on here... these guys take offense to that word for some reason...

00Red_SiR

So how do you know for sure, that you lost any power down low, if you were using a butt dyno?

To me, that is making a subjective statement, not a factual one when it comes to suggesting exhaust sizing to go with. The other arguement would be that even if you did lose some bottom end torque, who's to say that it couldn't be corrected with additional tuning, now that the engine can breathe better?

Going to a 3" exhaust and properly tuning it afterwards, should always give you more power everywhere.

snaileg

I have a header that would probably out-perform just about any header available to the h2b market. Let me know if your interested I don't want to turn your thread into a FS.