help needed please guys - all suggestions welcome.

 

on full throttle the boost rises to a tadge over 1 bar and then falls back to .8 of a bar. I cannot get a constant 1 bar boost.

 

i thought it might be a problem with the boost controller (profec e-01) so tried setting up the boost manually. Even on 100% duty cycle it still couldnt hold 1 bar.

 

Disconnected all inputs to the wastegates (done under very controlled conditions) and still not a constant 1 bar.

 

1 more symptom - the above boost characteristics are in 3 gear the boost pick up is smooth it just cannot hold 1 bar. boost in 1st and 2nd gear is much worse it feels like it is holding back all the time and barely reaches .5 bar - i thought this might be a rev related thing but not sure.

 

help me obi one your my only hope

 

seriously guys all any ideas welcome.

 

Regards,

 

alex

boost leak? I know on another members Z he had the same problem and if I remember rightly his intercooler had a split in it.

 

Vijay

could be a boost leak, but hasnt the profec got a boost limiter on it, make sure thats not set too low, ive got mine set to around 50 odd % and i get over a bar.

ok boost leak sounds plausible - how do i check for that

 

scoops it isnt the profec because we disconnected all the inputs to the wastgates

You never will hold 1 bar to the redline if that's what you're trying to do.

I'd start over with the controller setup, it sounds like the gain is too high (erratic response in low gears).

 

To start, set the start boost very low (about 5 psi) and make sure all the RPM offset points are at 0.

Next, set the gain to about 7 and sp to around 70 (maybe less, depends on what wastegates you have). Do a flat run in 4th up to about 6.5k and record the run, logging boost and rpm.

Play it back and see what peak value you get and how the response looks where it starts to control.

Play with the gain until you get a nice approach to whatever boost that SP will produce. Keep doing runs until it looks good. It'll never be perfectly flat, but you shouldn't FEEL it noticably surge up/down.

Now adjust the set until you get the boost value you want (best to set the peak monitor to record constant rather than peak) and set start boost about 3psi below the peak value - that should give very good spoolup.

Once you've got that then start adjusting the RPM offset points where the boost starts to drop away, you should be able to pull some back.

Err, oops just read the bit about having the wastegates disconnected!!

Probably is a boost leak then.

Alex I used to have the same , would boost to 14psi then fade down to 11psi untill the gearchange when it would boost to 14 and again drop down to 11psi I had two boost leaks , once fixed it boosted to 14psi and held between 13.8-14 all the time , I used a boost leak detector that i bought of Vijay ages ago , great bit off kit and works a treat

I get the impression from mine (AVC) that boost leaks not only, erm, leak, but they cock up the boost controller logic because the air isn't behaving quite the way it expects!

 

You'll need a private test track for an open run to the top of 4th. ;) 6500 is 129mph! :eek:

ok if this is my problem i'll be a happpy man

 

anyone got any ideas if it isnt a boost leak??

 

Regards,

 

alex