stock exhaust pipe vs straight exhaust pipe

[rick lakay]

hi guys,i am planning to replace my stock exhaust pipe to a straight exhaust pipe…will this affect the hp of my ef honda civic???and is it true that backpressure is needed for torque?….i am planning to use a 2.25 inch pipe,,is this a good pipe size?

thanks!!!

Topic

[Lord Ihcalam]

gotta ask, if the manufacturer makes these things so dialed in to the rest of the car why can you boost hp and mileage with things like cat back systems and CAI units? headers and mandrel bent exhausts? you see alot of shows on tv that do these swaps and they seem to increase power. Are you sure cost of material doesnt have something to do with it?

[EricTheCarGuy]

[quote=”ricklakay” post=45612][quote=”EricTheCarGuy” post=45586]I don’t recommend you do it. Engineers spend a great deal of time trying to make sure their engines perform as good as possible and ‘tuning’ the exhaust is a big part of that. I’ve even seen performance changes when aftermarket exhaust parts are used as compared to OE. Engineering is a balancing act. You can’t change one part without effecting another. It’s all a matter of balance and what you propose puts things out of balance.[/quote]

thanks eric…you mean i should stick with the stock set up?how about aftermarket exhaust parts,would that still cause imbalance?[/quote]

Aftermarket part companies often don’t engineer their parts for any other purpose than to sell parts. As a result they find the cheapest way possible to make and produce the part and sell it for as much as they can. SOME companies re-engineer a part for a particular need but I think you’ll find these parts come with a much higher price tag than a standard aftermarket part.

[Steffen Nyegaard]

@Ricklakay

I do agree with you that there is plenty of HP to gain from what you propose but for such a serious build you are putting in 25-50% of the cars value on top… that is not what most people do.
The common things are performance filters, CAI/SRI, axle or cat back exhaust. The more expensive jobs includes headers, porting, cat deletes etc. and should all be accompanied by a tune. Unfortunately even then I have seen quite a few vehicles lose HP or redistribute them around in a more useless manor (top end HP and no mid to low end torque… gives you bragging rights, but makes you car annoying to drive).
The car companies are not cheating you off free HP that they couldn’t have gotten themselves. It is correct that restrictions like noise and emission play a part, but not nearly as much as you should think (i.e. you are chasing margins while polluting and waking up the entire neighbourhood).

@ Eric
I totally agree. You can’t just put a large diameter exhaust on with less bends and expect it to perform better because it is larger with less restrictions. That is a very common mistake and since there are quite a few of these for the avg. Joe who wants to get a few more HP, a run-through of it all would be nice for the beginners on here.

[rick lakay]

thanks for the info guys!!!!! 🙂

[Author]

Replies