Power loss after 5000rpm 88' Turbo 2 on S5 turbo
 

Hey guys,

So I am collecting my car from my tuner this friday. I should note that they do not tune rotaries normally but supplied and installedy EMU Black ECU and supply ECUs to a rotary tuner with whom they consulted. They have not wanted to finish tuning because they found that my car was performing perfectly fine upto 5000 rpm and making good healthy power at 195whp which is around 230bhp, however, after this point they have noted that the car makes an almost metallic resonating noise and the car begins to lose power and torque, the biggest losses being 20hp and 40lbfts. They have said that the power drop wasnt sudden but rather somewhat progressive to redline. The car still uses its factory injectors, is decated and was rebuilt and street ported prior to my ownership however I am the one who has broken the engine in. It may also be worth nothing that I do premix my fuel as the engine was rebuild without the OMP. They have yet to send me the Dyno sheet so I cannot confirm exactly how the car behaves but my first assumption is the waste gate giving out?

I thought it best to maybe get some more experienced opinions before I start tearing it down and examining everything.

Thankyou in advance :)

welcome to the board, Dan. :)

aside from removing the cat, what is your exhaust system like?

Thankyou Diabolical :)

from what i was told it is was a custom built single exit system but have yet to get it high enough to get underneath it. The build quality/assembly of the system might also be causing the noise im experiencing but when i pick her up on Friday i shall put my engineering cap on!

what engine management and can you post a screenshot of leading and trailing timing maps. what afr was it tuned to in upper rpms

Hi there!

So Im waiting on some more details from their logs although I might go a long the car myself later tonight. The graph blow shows the cars power curve and does start to plateau prematurely the car feels fast and the engine seems responsive enough but in going to get the engine tested for compression aswell as the actuator and conduct a smoke test.
https://cimg5.ibsrv.net/gimg/www.rx7...df61ad893a.jpg

what turbo is on there? it looks like a dyno sheet for a stock turbo

OEM S5 Turbo ....