- 69
A friend and I seem top diagree on the certain topic of exhast and larger amounts of horsepower. The questions is : Adding a larger and more air-flow efficant exaust system increase the horsepower on your car or decrease it?
Exhast and HP Please Vote!
- Thread starter ChopShadez
- 16 comments
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- 10,081
- WFG9
i've never heard of it decreasing it. i assume if all other components are set up well, it should increase hp, at least to a point.
- 8,128
- 2 smacks past uranus
- Somebodyshootme
Well it is a matter of the engine you have. If you throw a 3.5 inch cat-back to muffler exhaust system into a 4 banger, there is a possiblity of horsepower loss due to no back pressure. There are exhausts out there that actually will lower a stock engine's hp because they were designed to be used in conjunction with other mods on the car. Take the 350Z for example. The first exhaust system that they put onto it as an aftermarket part was taken from a porsche design. It lowered the horsepower on the car about 5hp on a dyno. It all depends on the engine you have. a 4 banger does not need anything big, nor will it use a dual cat-back exhaust effectively. You want to have at least three cyclinders per exhaust, I prefer 4 cyclinders per exhaust on a car. Now a V6 or inline 6 or boxer six would do better with a dual exhaust then a 4 banger would. Plus you probably would want a medium to bigger size pipes, headers and muffler with it.
On my Iroc, it is suggested to put a 3.5inch pipes and muffler from the headers back. but that is a 8 cyclinder there.
On my Iroc, it is suggested to put a 3.5inch pipes and muffler from the headers back. but that is a 8 cyclinder there.
- 5,677
yeah why would people buy stuff to make their car slower?
- 8,128
- 2 smacks past uranus
- Somebodyshootme
Well, it is not a fact of making the car slower. The perfect example of this is buying an exhaust that was specially made to use a turbo and throw it on a NA car before the turbo was put in. In the short term until that turbo is in the car will be slower but the gains after the turbo is put is more then another exhaust that you put on the car to work with the NA.
- 1,494
ah, my dear man... its all about rice, rule number TWO in the book of rice states, "more pipes = better"
it is then followed by a clear example of the perfect exhaust system:
though seriously, i asked this question a while back and everyone seemed confused but i'll go with miata13b's answer, that is dependant on the engine size, configuration and aspiration type. just go to a shop and lookup all the exhausts for ur car and pick the nicest one and install it. since it wont lower/raise ur HP all that much u may as well just get the best looking one
i think its safe to assume that removing the muffler/catalyst on the end of ur exhaust will generally increase hp, so converting that into just a pipe on a stock car will generally increase hp. but i may be wrong since its car specific
- 5,677
what the hell is that car?
- 5,677
hell you could use those exhaust pipes to launch mortars during a war...
- 1,494
bwahahaha
- 1,695
If you open up the exhaust too much on a low hp car. Or something with a small engine, it loses torque at low rpms. Basically the size of the exhaust determines how high you produce peak torque. If you open it too much there will be no torque to even start off, and this may lead to a drop in hp. You need to have an exhaust that acheives perfect back pressure at your ideal rpm's. For hardcore extremist's, a huge exhaust will increase hp at very high rpms, which is good for race cars. With a somewhat restricted exhaust, you'll get torque lower because you acheive perfect back pressure with less exhaust flow (lower rpms). In higher rpms you will be restricted and the engine will lose power.
- 1,494
hey thanks for that, pretty good info there! anyone know exactly what backpressure does to an engine that optimises the torque?
