mariognutti

good morning,
last week I installed an evolution race line exhaust system on my porsche gt3 rs 4.0

after that I did a dyno test and the result was 4hp power increase only compared to a one day before dyno test with the original exhaust system.
why a so poore improvement?
is there something wrong? I haven't remapped the ECU yet... do you know if the akrapovic hp improvement declared is with a new ECU setup?

thanks a lot for your help!
mario

M3EvoBR

Hello Mario,

By Evo race line, did you also installed the headers ?
Please also take in consideration that by not testing same day, minimal temperature difference could easily impact the result, which had a delta of about 1% per your statement. This could easily vary.
Akrapovic doesn't use long tube headers, and also their exhaust systems doesn't have any improvement in diameter over stock.
I did several tests with different exhausts, and also different designs and diameters. You most likely had some mid range improvement in power and slightly torque.
Also the 4.0 uses a smaller count cat cell unit which improves flow over a 3.8 car leaving less room for improvement.

Here is a same day, same dyno test on a 4.0 RS ONLY with rear muffler replacement and side muffler delete. No ECU re-mapping.

Nizer

16hp w/o a header change? Nice.

mariognutti

hello M3evoBR,
thank you for your answer.
yes, I installed also the headers.
I'd like to know if it's normal and if akrapovic specs are with ECU remapping included.
this evening I'll post the graph with new ECU.... we'll see...

please consider that my 4.0 output in original configuration is 501 hp, with the complete akrapovic evolution race is 506 hp (same dyno with controlled atmosphere).

M3EvoBR

It's quite normal, and no the Akrapovic specs are without ECU tune.

Please post your dyno sheet. Also please note that you should make at least 3 runs in each configuration, to give a little bit of time for the ECU to adapt.
The graph above shows the best runs of both set up (stock and M&M exhaust) which were about 3 runs each give or take.
What kind of dyno did you use ?

Regards,

Eddie.

M3EvoBR

Tks. Yes this is Trakcar same day test we did a few months ago.
There are some decent gains once you install a less restrictive set up.

mariognutti

this is the dyno:

http://www.facebook.com/pages/edit/?...e/279042017853

basically I have 10hp lack by akrapovic specs! might be because it's a 4.0 and its stock exhaust system is more powerfull than the 3.8 one?

this evening I'll post dyno sheet

M3EvoBR

Mario,

The exhaust is the same as the 3.8 RS, although the headers have different catalyst converter cell counts, being less restrictive.
Those cars really benefit from a less restrictive system as you could see on the dyno sheet above.

mariognutti

this is my last dyno sheet:
test 8 is the original car condition (501 hp)
test 22 is with complete akrapovic evolution race + remapped ECU. now the output is hp 527 (+ 26 hp).
what do you think about that?

thanks a lot for your comments...

M3EvoBR

Any sheet from the exhaust change alone ?

M3EvoBR

Gains are solid, all across the board, but if you didn't have any gains with the exhaust alone, you're leaving something on the table, specially after replacing headers and exhaust.

mariognutti

M3EvoBR,
you are right.... tomorrow I'll post a sheet with original condition vs exhaust change alone...
have you seen the big dip between 2000 and 3000 rpm?

M3EvoBR

Ok, sounds good. Don't even consider anything below 3500-4000 RPM in those cars, as you will never drive them in this range. Specially the RS cars with short gearing, you're always 4000RPM or higher.
Look past 3500 RPM how much gain in torque and power you have.

On a side joke - This is not a Diesel VW...

mdrums

M3EvoBR, didn't you find that the M&M system to have the best gain in power all over?

mariognutti

this is the original condition vs exhaust change alone: