I have B16A head/B20B block. I want to move my peak torque to higher rpms and also hold the peak torque longer (right now probably around 4500 rpms peak). I'm wondering if by increasing the pipe size of my catback from 2" become 2.5" will help. But my primary collector now is only 2" (4-2-1 header). My engine is lightly modified and not yet ported and polished (but thinking to do it soon). Thanks.

 

A bigger diameter exhaust won't move where your car hits peak torque, rather you'll lose torque all over the board but gain top end horsepower.

 

You want to look for a single stage manifold if you are still running the stock manifold. Also a set of cams that moves vtec further back will shift everything farther back.

 

Well,I change my header already.Only the secondary header pipe and exhaust pipe is 2". I don't use any catalytic converter. So,I'm thinking to change my secondary header pipe and exhaust pipe to 2.25" or 2.5", which one is better? Thanks.

 

read

 

So what does this mean? ...that he just needs to get his rpms higher in order to accelerate? Personally, I'd like to feel more torque in lower RPMs. Thanks!

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95 civic DX, short ram intake, hiflo cat/catback exhaust.

 

If the pipe becomes too big, you begin to lose velocity and it loses the vacuum effect of pulling gases from the manifold. This would be beneficial in higher RPM however as now you have the diameter piping to flow more gases. Likewise, you want some backpressure to keep from the exhaust gases from being expelled too quickly out of the engine, which reduces overlap essentially and you end up losing bottom end torque.

 

What can I do to get more torque at lower RPMs? I notice a decent amount of acceleration when my engine sounds like it's getting ready to liftoff, but I'm also trying to make my car last for another few years (i don't think redlining every day will help). For under 500 bucks, what kinds of things can i do? I was considering DC sports 4-2-1 headers, but I don't know what else or if that's the next thing I should do.

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95 civic DX, short ram intake, hiflo cat/catback exhaust.

 

A header would reduce torque slightly versus your stock exhaust manifold. Unfortunately, torque is made with displacement or forced induction. Honda's just don't have enough capacity to make big torque numbers. For under $500, you really don't have any options.

 

Ok,Thanks for the info.Just wondering,anyone here with B16head and B20 block,how many inch you use for secondary header pipe and cat back exhaust?