hey i am confuzed.... hks downpipe is 2.65.... common sense says a 3'' will give us more power... but i hear that evos will lose power on stock turbo w/ 3'' downpipe... can anyone hep me out

 

I believe pretty much all 3" downpipes are increasing HP with the stock turbo.

Where do you hear it loses power?

 

Most of the tuner info I have seen makes mention that the 3" turbo backs/ 3" dp's were designed with upgraded turbos in mind. I'm sure a 3" would make more power up top than a 2.5 but what about torque in the mid/bottom end range?

I'm gonna hold off until I see some dyno numbers comparing the different downpipes.

 

You're right, you will lose power at low rpms.

For those who counter that the dyno plots suggest otherwise, you're right, too!

Fact is, a 3" pipe WILL lose low end torque at PART throttle applications. ie. the normal driving you do 98% of the time.

But at WOT applications, the 3" pipe will make more power at any rpm compared to the stock dp.

It's up to you to decide which is appropriate for your needs. If all you car about is racing the car, then the 3" is for you. If the car is your primary driver and you are not the type to get into it at every chance, then a smaller diameter dp is your best bet.

 

There are so many posts about this with all the tuners chiming in on it. I believe it was Shiv who said that the turbo is the real source of the backpressure down low, even with the larger 3" and you really don't lose anything.


Obvioulsy if you are putting on an exhaust your not going to stop there. Who knows how far you'll go, do you want to buy another exhaust later? The big difference for a lot of these people is the brace interference. Suck it up and change the brace, get the 3". I am sure you won't be disappointed. But that's just my opinion. I am waiting on my 3" RMR cat back and am installing the downpipe and brace tomorrow. The HKS is hardly bigger than the stock pipe, what is the point to pay the money and only limit yourself later.