Highest HP Exhaust

[KING1307]

Hey all, so if my knowledge about engines are correct, the faster you get the exhaust out of the car, the most hp you would gain right? So the quickest way for that would have to be simply straight from the engine and out somewhere under the car. Now i know this would also sound ridiculously loud, and bad for the environment and,,,, anything else? But in theory, that would gain the most hp since there is basically no restriction right? Now im not one for loud exhausts, my stock ms3 is loud enough for me. but ive seen electric valves that basically T the exhaust, one would go through the stock system, the other i was thinking straight out under the car. Does this sound plausible, any problems you can see from doing this?
Thanks!

[KING1307]

http://shop.quicktimeperformance.com...ct_detail&p=34

for example

[dentinger]

unless you're building a high horsepower, high performance engine, you wont notice much of a difference between any of the aftermarket exhausts, other than a different tone.

your best bet, would be a larger diameter downpipe, and say, a 3" catback.
i ran a 3" downpipe on my GTI, with the stock downpipe, and the difference was definetly noticeable. however, just a catback alone wont do too much,

[klspeed3]

unless you're building a high horsepower, high performance engine, you wont notice much of a difference between any of the aftermarket exhausts, other than a different tone.

your best bet, would be a larger diameter downpipe, and say, a 3" catback.
i ran a 3" downpipe on my GTI, with the stock downpipe, and the difference was definetly noticeable. however, just a catback alone wont do too much,

don't really think this is what he's asking...my understanding is he wants to basically delete his muffler/cat and dump the exhaust as soon as possible under the car similar to the exhaust on this i'm assuming:



that would result in an HP gain for sure, but i'm 99.9% sure it's illegal lol...you'd be dumping carbon straight into the air, not to mention the noise would be crazy loud lol. if this is a track only car then i'd assume you are fine.

[KING1307]

don't really think this is what he's asking...my understanding is he wants to basically delete his muffler/cat and dump the exhaust as soon as possible under the car similar to the exhaust on this i'm assuming:



that would result in an HP gain for sure, but i'm 99.9% sure it's illegal lol...you'd be dumping carbon straight into the air, not to mention the noise would be crazy loud lol. if this is a track only car then i'd assume you are fine.

thanks, thats exactly what i wanted to know. and yes, i want my ms3 to be exactly like that! haha

[Snotrocket]

Most cars these days require some back pressure to operate efficiently... In fact increased back pressure can actually increase torque output.. Having a nice free flowing exhaust without cats usually give you the opportunity to make the most horsepower and turbo spool if that applies to you. Hope that helps. i also imagine if you are considering this on a mazdaspeed you would probably encounter some harmful boost spikes..

[dentinger]

the turbo usually makes enough backpressure, so that isnt as much as a problem as it would be on a N/A car.

[Snotrocket]

This is true but does the turbo not require some back pressure?

[theo575]

i suppose not - the exhaust gases coming from the header must do the work before the exhaust system does anything, in turn given the back-pressure require to clear the cylinders nicely? hope i'm close to being right lol


so then for a nice sounding, properly spec'd (back pressure for the 2.3 N/A) exhaust which companies would you look at?

[Rob23]

that is so illegal. who knows what the fine would be for removing the cat, and everyone will know cuz they will smell it right away.

[standsideways]

This is true but does the turbo not require some back pressure?

No, a turbocharger is most efficient with ZERO backpressure.

[standsideways]

that is so illegal. who knows what the fine would be for removing the cat, and everyone will know cuz they will smell it right away.

$500 fine, same fine as removing your pcv breather hose, "modifying emissions control system"

Things arent SO illegal, they are illegal or they arent.