E55 always @ 11.5psi (0.8 bar)
 

Hi all. Got boost problem. Cant figure out why the boost is always 0.8 bar 1500-7000rpm.
The car has following mods:
77mm clutch pulley
82mm tb
Longtubes
Cooling
Ecu
Custom cai with no filters through high beams.

On 81mm pulley i was seeing 13.5 psi with these mods.
At one point i saw 14.5 psi @ 4000rpm falling to 12psi @ 7000rpm, but the belt was slipping. It had completely eaten away the pk.
Not long after that boost is always 0.7-0.8 bar in any gear, at any rpm.
Here is what we tried:
Stock tune
Changed bypass
Checked for boost leak
Chamged clutch on the pulley
Went back to 81mm
Went for 77
Went for 76
Changed blower oil
Took blower appart, wings did apear scratched but i doubt to the level that blower can loose its capacity to blow.
Changed map sensor
Changed gas pedal
Few other tunes.

Today, i officially declared dead end. Please help...

Ps. The funny thing is the car pulls good. Real good. Considering its stock boost...

Just as a way of eliminating your intake, take off the intake and do a run without any intake just bare tb

I know for a fact that on the night that i saw 14.5psi i had the cai. Should i still check it?

Yes just to eliminate that out of the equation

0.87 at some point. A bit more.

So you went up a pound of boost without intake

Do you mine me asking what you are using to check boost levels?

If you are not down on power, you could have had restriction that elevated your boost levels and now its not there.

You running catted longtubes? Check the cats.

I check both with a boost gauge as well as obd. They slways same.
Got 1 psi. But i m still far from desired boost level.
Also. Just dynoed the car.
3rd gear 450 whp 680 wnm
4 th gear 470 whp 480 wnm @5200rpm.
My torque is horrible. Mustang dyno.

1 psi is a lot so that means that the cai was not working as well as you thought. Remember that cold air going in the tb can add another .5psi so you would be at 13psi

What is your afr?

Dipping into high 10s or low 11s

If iats are in check then you can go mid 11s on 93oct

What else can i do to get the boost back? I really dnt think its in the pulley... Otherwise i d just go for 74 or lower.

Since you said you did a boost leak test, do a leak down test to make sure everything has proper seal.

What is your elevation in Tbilisi?

Is your belt slipping? If you still have the engine cover on, check underneath to see if there is some rubber "dust" building up. One member here claims to have picked up 2 psi by adding the belt wrap kit.

He said that he had the boost before, so elevation is not the issue. I doubt it's belt slip because it would show spikes which he is not claiming. Do a leak down test demetak

Whats a leak down test? Please elaborate.

Also. I m being told that it can be torque converter. To prevent slipping ecu pulls boost via bypass. On the dyno graph it can be seen be a spike in torque and hp curve and then a suden drop followed by a gradual rise

Here you go

Suction is clean.
What do u think of the torqu converter. Could explain me making 600nm at stock boost while it should be 700. And boost being limited from ecu to protect tranny

No not tq converter, very very unlikely since you take off the intake and you gain over 1 psi
Do a leak down test, it will show if everything is sealed because air has to be going some where..

The TCU has a torque limiter in it. Mine was cutting power until Jerry reflashed it and raised the limiter.

Exactly.... Mine did the Same thing...

He has a tcu tune
This is something mechanical not Sw issue imo because when he took off the intake he gained over 1 psi of boost

Tomorrow i will put back stock tcu.
The torque limiter is removed on my weistec tcu tune and i showed 700 wnm in 4th with 81mm pulley.

If no change. I ll do the leak down test.
The reason tc sounds logical to me is that coz of the dyno graph. This is in one geat, it wont downshift when on wot at 2k rpm and still this happens.
At the beginning of the run, the car literally tries to jump off the dyno, but then for some time the rpm gets stuck at the same point and power starts to gradually increase.
https://cimg5.ibsrv.net/gimg/www.mbw...a8c130ff08.jpg