Installed a Corksport Downpipe today...

[AutoEuphoria]

I honestly can't tell. Weather has been so cold lately that I haven't had a chance to really test that.

 

[mazdaspeed32007]

i know right now running the stock map i get a spike at around 16-17 and it holds around 15.5 until the inevitable rpm/up boost/down. once i get my fuel pump and run the stage 2 map ill see what my true boost spike will be. i hope my wg isnt hitting the dp ill be pissed if i need to take it off again. not that its all that difficult....i just dont want to do it a 2nd time. i wonder if that was the problem in the tock dp? has anyone ever checked it? i know i used to get crazy boost spike when i ran close to stock.

 

[ChrisK]

Honestly, I haven't looked at the stock pipe, just took it off and put it in storage.

But my spike was up to 21psi at times.

And everyone I asked about it on the forums said it was just because I had free flowing exhaust, but I just felt like there was more to it. I've owned 4 turbo cars, and none of them did that when I added exhaust and DPs.

 

[kgb]

I called corksport before I bought my dp and they chuckled and said that is not a problem and sent me to this link...


http://www.msprotege.com/forum/showthread.php?t=123727433

 

[AutoEuphoria]

EDIT...nevermind LOL. I guess there wasn't an issue afterall. Strange :\

 

[destrux]

Going from a non-divorced style downpipe to a divorced style can cause boost creep like that... not because the flapper hits the wall.... but because the exhaust coming out of the wastegate does. Look at the picture corksport posted of the turbo without the downpipe bolted on. The exhaust has the most open flow path out of the wastegate on the side that's wide open where it merges with the main exhaust path. If you put a wall right there to divorce the wastegate flow, it is going to somewhat block the wastegate flow. It's common on mitsubishi turbo's that have divorced wastegate flow from the factory to port out the turbine housing around the wastegate flap, and to slightly open the wategate hole (not too much!) to improve wastegate flow to prevent boost creep. When I first ditched the tiny stock 2 1/8" exhaust on my eclipse for a 2.5" system I couldn't get the car to run less than 16psi of boost above 5000 rpm at WOT (which normally isn't a problem, but I had a variable boost setup to run 11psi in first and second gear and this boost creep prevented that from working).

Divorced downpipes are better for power though... the wastegate flow bumping into the main flow causes turbulence (which is usually bad for power). Not a big gain... but maybe 4hp over a poorly designed non-divorced DP.

 

[ChrisK]

Well I can 100% guarantee that my wastegate flapper was hitting the dp. Also 2 of the bolt holes on my dp were not drilled big enough. Causing another issue.

 

[martyxcore]

just bought a used cs dp. can i just cut the wall off where the the flapper is hitting for people with issues. dont see how this would cause any problems.