hey all, iam tryin to decide which exhaust to go with and i came across the aps 3.5" turboback exhaust. now i was wondering, since my car is pretty stock, will i be loosing too much backpressure with this exhaust to the point that iam actually loosing power? i wanted to get this exhaust because by summer i wanna throw on a dif turbo and maybe rebuild the motor. so iam wonderin if this exhast would do more harm than good right now? thanks for your advice/opinions.

 

Depending on what size turbo you plan on running, a 3.5inch is slight overkill for the application. Many people run 28psi with GT35Rs (LARGE turbos!) and 3" is fine.

Do not worry about backpressure. Turbo cars dont need any backpressure at all, in fact you want NONE possible. Remember that guy Corky Bell said ... "best exhaust for a turbo is NO exhaust!" ... something of that sort!

 

What he said. Basically the only thing you have to worry about is diminishing returns, i.e. Is it worth it to spend the extra money on a 3.5" system when a 3" would be almost as good.

Also check this out:

http://www.tantrumwerks.com/html/Spl...t%20theory.pdf

It basically explains all about ideal turbosystem exhaust design.

 

might wanna check out the rsr, thats what i have and if i remember correctly it is slightly bigger than 3 inch

 

Main concern is you want to go as large as possible, while not losing exhaust gas velocity... or stalling of the gases. You don't want to lose any exhuast scavenging effects.

 

thanks amdrew20195, thats great little article. thanks for the advice guys and one more question. and now with the 3.5 inch exhaust, would their be any fitamint issues. since it is a pretty big exhaust, any of yous that ahve installed an exhasut on an evolution that see a potential problem anywhere if you ran a bigger exhaust? once again thanks for your help fellas.

 

I always thought the scavenging effects were negligible in a turbo-back exhaust. Doesn't the turbo basically interrupt whatever scavenging is going on in the header?

I always thought the whole idea when designing a turbo exhaust system was to have as little backpressure as possible in order to increase the pressure differential between turbine inlet and outlet, thereby having the highest turbine velocity.

Just out of curiosity, did you read the article I linked? Since you seem to disagree with it, can you explain why? (I'm not trying to be a jerk here, I am genuinely curious)

 

wow that article is well written but a bit too well for my brain... what i got from it is that turbo engines should have the least restrictive turbo back exhaust, the headers should have the most back pressure, but i didnt understand the part about a downpipe and wastegate, so the bellmouth inlet is good or bad? what should be done about the wastegate outlet?

 

all your Japanese exhausts are going to be 80mm which is 3.17". unless you plan on installing a T88 or GT42R, i don't see a need for anything larger than what most people have. APS has nice stuff but it's overpriced.

 

I have installed this turbo-back kit on my friends EVO. The fitment of it was perfect. Came with every bolt and nut for the installment. Sounds amazing!! I would recomend this exhaust!

 

You know wats crazy, one of the evo owners here has a 5" tip and a 3.5" custom pipes running straight to his headers with no bolts or flanges. The damn thing is welded together!!!!

 

need.... to get..... to ..... 50 .....posts.....

 

your lower tie bars may not fit with a 3.5" exhaust. I can only fit one of two lower tie bars with a 3" dp/cat delete combo. I think my issue is with the dp. Fitment may be an issue if you want to keep the lower tie bars in tact.

 

The APS kit comes with washers to lower the lower tie bars so the downpipe will fit.

 

I have the exhaust on my car... Sounds awesome, performs well, and fit great!! Only thing I ask myself is was it worth that much extra money for such a small difference in size??? However, I would reccomend it to anyone...