[Guest]

I've just fitted an aftermarket exhaust on my E5-- Apex'i N1 cat-back (but no downpipe). No instrumented testing, but my seat-of-the-pants dyno says that the car is even SLOWER now than it was with the stock exhaust. Is this possible? What's going on here?

I did the filter first, and the car felt great. Throttle response seemed to sharpen up a bit. Now that the exhaust is in place, I've lost some low-end torque (more or less expected,) but the car now appears to pull LESS furiously even high-up in the rev-range!

As far as other mods, just have a K and amp;N filter (open type, not drop-in) and boost controller. Am running 1.1bar boost maximum. The cat is still in place, too.

Anyone heard of such a situation?

Thanks!

 

[Guest]

Hesperus,

I dont know if I got this right. But if you installed an Apexi AVC-R as your boost controller, you might need to have it relearn your boost curve. Put it in learn mode and accelerate your car through its gears. If you need more help, call Raymond on his cell and he can help you.

Good Luck!

 

[Guest]

TurboAWD,

Thought about that actually, and have been getting the AVC-R to relearn. I downloaded the english manual off the Apex'i site, and the procedure seems pretty straightforward. My butt-o-meter dyno still suggests something's off however... Will experiment more over the weekend.

If things still don't feel sorted, I'll drop by the shop this week. Your car hasn't broken your dyno again, has it? |EQU|)

Many thanks for your input. Cheers!

 

[Guest]

hesperus,

FYI, I had a similar experience. My Evo 6 had a Ralliart panel filter as the only change before putting on a Cat-back HKS Hyper exhaust (no dump pipe change). Torque dropped off noticeably (although, also measured just by using butt-o-meter dyno) after the exhaust was fitted. There seemed to be no change for better or worse at the top end (result may be due to dyno problems http://www.ltregister.f9.co.uk/graphics/Happy.gif border|EQU| 0 align|EQU| middle > ).

In my opinion, the car is set up very well from the factory, i.e. as far as the matching combination of intake / ECU mapping / exhaust is concerned. If one component is changed, there may not be much benefit, indeed performance on the whole may be reduced. Some amount of exhaust backpressure is a good thing for a turbo engine and reducing that (and that only) by freeing up the exhaust will stuff up the whole system.

I have since fitted a Ralliart Sports ECU and played with the boost. I now believe I have got a "good match" (not as perfect as what I would have with a programmable ECU) of intake / ECU mapping / exhaust back again. Torque has increased to a lot more then I had before when the car was standard and the car pulls stronger all the way up the rev range. It's also just as smooth and easy to drive as it was standard.

IMHO, it's no benefit to change an exhaust without having the ECU mapping to match it…..

 

[Guest]

I have to disagree with Matthew.I had a new exhaust(magnex downpipe and cat replacement,HKS Hyper rear) and HKS air filter and my car goes alot better.It pulls so much better through all gears.This is with the ECU unchanged on an EVO 6

 

[Guest]

If you have 1,1 bars boost on the standard turbo, you cannot seriously be expecting it to be fast!?