yet another leak topic.... [YALT]

[greg_p]

Hi all,
I need some help from you guys ...

I probably have a leak problem, but I'd like to check everything possible, because finding a leak on a fmic piping is a pain in the ass...
I explain:
I can easily set the boost (with a bren device) between 7 and 12 psi, with about a turn for 1 psi, but once coming to 12~13, the boost doesn't go farther...
I checked the boost controller, but the spring may not be stiff enough... How to know?

Otherwise, I suspect a leak in the piping, or a fecked boost gauge, but it is an autometer, and I double checked the connections. And the gauge values doesn't seem strange (-20 when I lift the foot from the accelerator, -16~18 at idle). If there is a leak, it can be on the solipe pipe.
I'm still using the factory bov, but I did the modification, and it didn't make a difference when I removed it.
When driving fast, I can hear the turbo noise from the intercooler, and the blowing sound from the filter (a conic Jim wolf Tech of Z32).

So can it come from the exhaust part, like an exaust leak, a problem between engine and the tubby (like a leaky gasket) ???

[Jon]

the gauge values doesn't seem strange (-20 when I lift the foot from the accelerator, -16~18 at idle).

I think most folks are looking at -20mmHg at idle, and up to -30mmHg when lifting off the throttle. I'd look at the boost gauge connections if it's recently fitted.

EDIT - you said you already double checked them. Next idea is to start at the plenum and work upstream, checking clips and stuff. -18mmHg could indicate a worn engine, but you should still see more than 20 when lifting off.

[greg_p]

it's not mmHG, it's in PSI... It's always been like that since fitted (8 monthes ago).

[Jon]

it's not mmHG, it's in PSI.

The boost/positive numbers are psi, vacuum side is mmHg. Wierd but true. -20psi is impossible.

[greg_p]

i'm going to check rightnow :P

[greg_p]

Ok, it's in in.HG, so (can't find a conversion table for vacuum...).

After a search on this, found that -20~22 inHg when foot is off, and -18 at idle seems correct. Usually vaccum goes to -20 then goes back to -17~18 (figures and lines are small) in idling regulation.

[Jon]

oh shit yes, inches. I remember those

[greg_p]

You almost made me have an heart attack saying about worn engine !!!

[Mr OCD]

Ok, it's in in.HG, so (can't find a conversion table for vacuum...).

After a search on this, found that -20~22 inHg when foot is off, and -18 at idle seems correct. Usually vaccum goes to -20 then goes back to -17~18 (figures and lines are small) in idling regulation.

Thats fine mate - exactly what my also reads on guage and trust me there is nothing wrong with my engine

I did notice when I had only fitted boost controller and induction that the figures were a little higher... like nearer 30inHg when coming off then settling down to 20inHg idle... bt since the exhaust, decat, etc has all gone on it has dropped marginally to the figures you describe.

I honestly wouldnt read into it too much

[Jon]

You almost made me have an heart attack saying about worn engine !!!

I even rewrote that bit a couple of times trying not to create panic.


For the low boost issue, I'd suggest swapping Bren devices with someone local, but that's not easy in France.
Maybe, remove the Bren device and put the solenoid back to standard operation. If you then get about 9psi then the spring in the Bren device is suspect.

[zenkis14]

Hi Greg,

I have just fit my Blitz DSBC today, so i have a spare Bren device.
Let me know if you would like to give it a try.

NB: Just seen your car today parked in Rue Dautheville. Nice car btw

[Jon]

I'm just so wrong about everything today

[greg_p]

Hi Greg,

I have just fit my Blitz DSBC today, so i have a spare Bren device.
Let me know if you would like to give it a try.

NB: Just seen your car today parked in Rue Dautheville. Nice car btw

Laughing out loud :P... So close but posting on a so far forum... :P

Thx!

[OdEssA]

I got also a "autometer" boost gauge, 25inHg when lifting off the throttle and Idle = 20inHg

[greg_p]

Odessa?
Do yu have a free flow admission, or something like an induction kit?? (apex filter, or anithing conical :P).


Otherwise, we had a ride with zenki this afternoon, looks like his bren device set at 0.9b gave only 10~11psi on my gauge... So The bren device I have should be okey, there a leak somewhere...

I'll have a look on the fmic piping... I'm also afraid with the tubby gasket

[OdEssA]

not for the moment, i drive with my standard airbox. But it seems like you got a boost leak . Good luck with searching

[greg_p]

Thx!
It sounds normal to have such a vacuum with the standard box (-25inHG the foot off, and -20 at idle). With an induction kit, which is less restrictive, the vacuum seems a bit less.