Help Lost Power

[lstef11]

Hi guys having an issue that's got me stumped so just after some advice or ideas. Motor is basically stock besides the greedy front facing manifold and a front mount, over the past week we installed a after market exhaust manifold, hi-flow cat with a 3 inch system from the turbo back and a 2 way diff now we have lost power dramatically the car was running 10psi fine before on the standard ecu now it won't go over 8psi and it drives like the timing is out or something could it just be in need of a tune after the upgrades or would it more likely be another issue somewhere? Any advice is appreciated thanks

[KiwiRS4T]

Have you got an aftermarket ecu? How you going to tune it? You can' t really call changing your inlet and exhaust manifolds an upgrade. A bigger turbo is an upgrade. Having said that you shouldn't have lost much power. Have you moved the CAS at all? No 1 suspect is boost leak. See if you can test the system by pressurizing it and look for leaks.

[lstef11]

Hi mate thanks for the reply I do have one but we haven't installed it yet we are still running the stock ecu I didn't think that was the issue but I was just throwing it out there as it was the only thing that would make the slightest sense I know none of what we did should of made much difference no we didn't touch the CAS and yer that was my first thought I checked over everything as best I could but didn't have the gear there to pressurize the system

[lstef11]

Though it's not coughing or missing at all like it would with a boost leak just drives like it's severely restricted almost like someone has retarded the CAS almost all the way if you know what I mean

[chiksluvit]

what exhaust manifold is it?

i had an aftermarket exhaust manifold that came in one of my old cars and it cracked at the weld, caused a noticeable power loss- went back to stock exhaust manifold which also helped with boost response

stainless exhaust manifolds crack easily

and what dump pipe have you got?

some short hks style split dumps may also catch the wastegate flap. though i've had two of those split dumps before and never experienced that problem