Whats up everyone, i just installed an HKS hi-power 30th (with the tapered end sawed off and fitted to a full 3", roadrace/ultimate racing dp, and road race hi-flo cat, and the butt dyno doesn't really feel the power. Well, it feels a little bit more, but the 0-60 time from my TT is the exact same.

Now, some people say that the power from a tb is gained at the top end, but im having a little trouble understanding this.

Does top end mean like freeway speeds, or high on the rpms?

B/c if it IS freeway speed topend that shows the gain, then i understand why my 0-60 time wouldn't change. But im not sure i understand how you could make gains ONLY at high speeds since all the engine is seeing is the rpm's.

 

Have you leaned it out and raised the boost? You might have gained a bit of power but at 15 psi theres not a whole lot more flow needed. Get another 5 psi and some decent tuning, then the exhaust will make the car sing.

 

reset the ecu

disconnect the battery and reconnect it

 

You'll feel a lot more gains when you get a downpipe. The largest gain I felt was when I got a test pipe too. Too bad it's a HUGE fine in CA, that's why I took it out and now the evo feels really tame.

 

he says he has a downpipe coolguy

 

Oh yeah, i didnt see that.

 

When I put my cat back in, the first thing I noticed was how hard it is for the car to fly from 40 to 60 like it did before. I then noticed how hard its' trying to go from 80 - 100 too. Definately slower with the stock cat. I miss my test pipe, but it's not worth getting pulled over. You can smell it from a mile away.

 

i didnt see that either

 

It means both.

Your engine is also seeing different loads, gearing, and the time that it spends moving up the rpms.

In 1st gear the amount of time the engine spends going through the rpms is very quick as compared with being in 4th gear.

Oh yeah, you will see alot more gain if you get your set-up tuned.

 

i didnt use stock cat. i use ultimate racing's 3" hi flow cat. Pretty good. Gave me decent gains.

 

I have Buschur's 3 inch turbo-back with high flow cat and it made a world of difference. You can definately feel more power in all ranges of the powerband. I never re-set the ECU and it felt powerful from the start. The ECU on the EVO is very quick to learn compared to a WRX. WRX's would need about 75 miles of driving if you didn't re-set the ECU. So alex alex I don't know why your car doesn't feel very different. Did you check for exhaust leaks? High flow cats are directional. Make sure your have the in side toward you downpipe and the out side toward your cat-back. Other than that, I can't explain the lack of performance. Nice side effects also are 1.5 to 2.0 mph increase, no more black crap out the tailpipe. Oh and my car gets a stinger! The system expands in length almost a half inch.

Gumpy

 

so the evo smokes/stinks real bad with straight threw 3" no cat?

 

It will just smell from the hydocarbons (unburnt fuel) not getting
diminished in the cat,that all.As for smoke,if it didn't smoke before with the cat on,then it wont smoke with cat off.

 

Have you ever thought of welding on the heat shielding from another cat to your test pipe? Won't help with the smell issue, but at a glance it'll look like a normal cat.

 

Hahah....already working on that.