feels like i lose power when ext wg opens up

[FASTSPOOLINGST]

When i am boosting, my car pulls hard until my wg opens up then it feels like it loses power for some reason.

I can hold the boost at around 15 psi and it pulls hard as hell, but when i make a pull where i floor it and the wg opens up at 17psi, it feels like the pwr just isn't even as strong as the power is at 15psi at 3/4 throttle.

Why does it feel this way?

 

[Pj97GST]

It's very possible that your knock sensor getting overly sensitive and "seeing" the additional noise as knock.

Then again, it's all relative to your mods.. What's your setup? Haved you datalogged the car to watch your knock count or timing? Go more indepth and it will be easier for people to help you out

 

[djpast]

maybe cuz its losing alot of backpressure that the engine needs that is preturbo? i notice that my car feels slightly slower with a external dump then it did with the stock o2 housing.... but then again... alot of ppl report 10-15 hp gains with externals and dumps... hmmm.

 

[Pj97GST]

A turbo motor does not rely on backpressure as much as a normal car does. Backpressure on a N/A car assists in exhaust scavenging and efficiency of the combustion chamber.

The less backpressure the better on a turbo motor.. The senstaion of your car being slower can be attributed to many other things... Like I mentioned, what are your mods? You may be having other issues that you are completely unaware of, but attribute them to the addition of the dump.

Don't rely on the "assometer"

 

[djpast]

like i said....the exhaust on the wastegate comes up BEFORE the turbo. in which case, backpressure DOES make a difference. So if your wastegate is too big, it can theoretically hurt your performance... what do you think spins the turbo?

what you said is like saying having cracks in your manifold is a performance upgrade... which we all know its not. you lose power, as well as spoolup time and top end.

 

[Coldandafraid]

The less backpressure the better on a turbo motor..

Not entirely true. Besides the fact that a little back pressure will help prevent boost creep (not applicable in this situation with external dump) it also creates a condition called boost stacking inside the engine. If the exhaust cant all get out before more air is pushed in, you see more boost and the car is actually faster.

As for your problem, hows your tuning? Maybe you are a little rich and its slowing you down as you hit WOT, and open the WG.

 

[Pj97GST]

Damn, i guess that I didn't pay attention to the fact that his w/g is pre-turbo.. I totally missed it and stand corrected. doh!