Rb26 Boost Spike...

[BrynDETT]

just had a look on google but didnt come up with anything interesting...

when gettin up the car it has hit boost as high as 21psi, im pretty sure it only happens on the limiter ( to scary to look at ebc to check boost when it happens), possible even at high rpm's...

first i thought it was the evc 6, but i just disconnected the control lines and ran straight from source to actuator and on limiter in 2nd it hit 19.8psi.... just wondering wat u guys and gals think could be causing this..

i seem to remember over on gtr uk reading something about r34 gtrs spiking when u put an exhaust on them and u need to make a restrictor before the cat?? make any sense?

peak boost readings are from my evc

r34 rb26

standard turbos

2.75" front pipes

3" cat back with 3" decat

and also i might just be misunderstanding but my boost ramps nothing like it does on the dyno sheet,

on the sheet the boost whent straight up to 16psi at 3800.. but on the street i dont see full boost untill high up in the rpms... maybe 5 or 6k (guessing) but it is late......

it goes up to 9 fast then slowly climbs the rest of the way....

[BrynDETT]

anyone???

[TwentySix]

maybe your wastegates are getting stuck ? =/

or you have a leak in your wastegate signal line, check vacuum hoses around turbo??

with ebc removed, boost should run slightly higher then what the wastegate actuator is ( stock with exhaust ? 11 - 12 psi? )

issues ussually more common on boost T setups spiking .... not ebc setup. does same thing with ebc removed? =/

[TwentySix]

your turbos are still alive .... r34gtr stock turbos are gangster shit

[BrynDETT]

maybe your wastegates are getting stuck ? =/

or you have a leak in your wastegate signal line, check vacuum hoses around turbo??

with ebc removed, boost should run slightly higher then what the wastegate actuator is ( stock with exhaust ? 11 - 12 psi? )

issues ussually more common on boost T setups spiking .... not ebc setup. does same thing with ebc removed? =/

hmmm wastegates shouldent bt hitting anything as i have stock r34 dumps... and yeah still does it with ebc disconnected...

hmmmm... anything else u can think off?

and lol... should they have died allready?

[GTRNUR]

Yes the turbo's shouldnt have survived that kind of boost. You have been very lucky, or you might have steel wheel N1 turbo's which is why they have held together.

1. Replace the pressure line from your plenum to your turbo's. Don't inspect it, just replace it.

2. Get an air compressor. Dial the regulator down to 0.6 bar (10psi), and blow pump up the line from your plenum to the turbo's. Your acutuators should be just starting to move at 0.6 bar. Increase the regulator to 0.8 bar (12lb), and check the actuators have moved identically, and again at 1 bar.

This will either fix the problem, or it will show you where the problem exists.

It could be:

a split or blockage on the wastegate supply line somewhere.

a stuck wastegate actuator

way too much preload on the wastegate actuators

a stuffed diaphram inside one or both of the actuators

or... you have it all connected up incorrectly.

Plenum boost source - > T-piece = 1 line to each turbo actuator.

or

Plenum boost source -> evc solenoid -> tpiece = 1 line to each turbo actuator. (make sure your solenoid port hookup is correct too)

R34's dont over boost when you put big exhausts on them. It sounds like you read some technical advice that was posted by some 2JZ supra owner...

Edited July 29, 2011 by GTRNUR