schapeshag

iTrader: (1)

Title's pretty straight forward. i have a few ideas what the problem might be but I'd like some educated input as where to start first. the 1.6 is pretty wore out and compression is suffering. Using a gt2554r, turbosmart bov and manual controller. 550 injectors and a megasquirt. Homemade log manifold with full 3" exhaust no cat. 2.5" piping with intercooler.
Ran it on the dyno a few days ago and made 203hp. What i know is that my bov is not leaking and that when i hit 10psi at around 3800rpms it holds it nicely throughout the rest of the rpm range. BUT, no matter how much boost i try to dial in i can't make anymore.
My initial thought is that i might have too much backpressure on the turbo. Despite having 3" exhaust my downpipe does not make a curved 90 degree bend but rather a straight right angle 90 degree bend like an "L".
Maybe i've given enough info to stir up some theories. Thanks.

adamvanxxx

Sounds dumb, but all the couplers good and tight?

schapeshag

iTrader: (1)

Yes. Everything after the turbo has been checked and monitored thoroughly. And just to throw it out there, when i crank the boost controller way up i get a spike up to 12-13lbs but quickly drops back down to 10. Datalogging confirms my autometer gauge btw.

skidude

iTrader: (3)

Does the wastegate stay closed? It's possible the spring is tired/weak so the pressure is forcing the wastegate to open a little even though it is not getting the signal to open.

duffbuster243

iTrader: (1)

Not hitting 10psi until 3800rpm sounds laggy for a 2554r. Sounds like there is not a proper preload on the wastegate.

schapeshag

iTrader: (1)

Definetly seems to be the next obvious solution. The one i completely failed to check.......gun barrell in mouth....pull trigger.

schapeshag

iTrader: (1)

It might be kinda laggy, but i have no basis for comparison on this old wore out motor. Aside from it''s dying compression i could think of a handful of reasons why it might be slow to spool. But i don't think any of those reasons are related to my current problem.

94mx5red

iTrader: (14)

Try disconnecting the wastegate, and securing the flapper closed. Be careful, obviously, for a boost overshoot.

schapeshag

iTrader: (1)

I like that idea.

schapeshag

iTrader: (1)

A lot.

schapeshag

iTrader: (1)

Well we can go ahead and bring this thread to a close. Close hangar wrapped around wastegate, simply put, freakin' rocked my world. Last time i had a hardon like this was when i was watching justin bieber play the flute.

94mx5red

iTrader: (14)

94mx5red

iTrader: (14)

5.5 years on mt and I finally help someone.

:blushing:

schapeshag

iTrader: (1)

Your checks in the mail. Skidude's also.

skidude

iTrader: (3)

Yay, I have 2 props!