LBZ-Overboost and vane indexing

[killerbee]

This truck will make 30 psi of MAP with zero vane at high rpm. (this pic shows 37 psi). Does everyone else have this same problem?

IMO, GM goofed on vane indexing, or they really did something that improved turbine effectiveness or ??? This sucker really needs a wastegate.

[bballer182]

holy S! how does that work? I would have thought that there was an error in the MAP sensor, but the MAF matches what the MAP is saying too? And only @ 3000 RPM with only a 1300us pulse it making 30psi??? I'm assuming you are subtracting out the BARO to get 30 from 37? Is your density altitude really that high, only 7psi? I would need about 10-20% vane to get that boost...

[killerbee]

we are at 14.0 psi baro.

I can make 26 psi of boost with zero vane.

Set min and max vane to 0% and run an experiment in first gear, with foot riding the brake for load (fuel). I just want to be sure this is an LBZ thing across the board, and not something unusual about this vehicle.

[killerbee]

MAP=boost+baro

It is labeled boost on the readout, but that is MAP

[joecar]

Is this a calc pid you guys can use (post #9): showthread.php?p=104303#post104303 (http://forum.efilive.com/showthread.php?p=104303#post104303)

[killerbee]

The table is in MAP, so I have just become used to referencing that.

[bballer182]

The table is in MAP, so I have just become used to referencing that.

me too...

I'm all out of daylight for the day but i'll give it a shot tomorrow.

Stock PW, pressure and timing or what?

[killerbee]

whatever tune you like. If I am right, it won't matter. :)

[GMC-2002-Dmax]

holy S! how does that work? I would have thought that there was an error in the MAP sensor, but the MAF matches what the MAP is saying too? And only @ 3000 RPM with only a 1300us pulse it making 30psi??? I'm assuming you are subtracting out the BARO to get 30 from 37? Is your density altitude really that high, only 7psi? I would need about 10-20% vane to get that boost...

The log shows 36% TPS, I would like to see the log just before the lift off the pedal at WOT.

:angel_innocent:

[killerbee]

me too...

I'm all out of daylight for the day but i'll give it a shot tomorrow.

Stock PW, pressure and timing or what?


I am almost afraid to try a 4000rpm tune. :)

[JoshH]

Holy cow, I guess I was right on the cause of your smoke, huh? I just noticed your pulse width at 55 mm3 of fuel. That's equivalent to 90 mm3 on the stock pulse width table! :eek:

[vortecfcar]

The turbine/vane setup is a lot tighter on the newer trucks ('06 and up). It's not uncommon to run 0% vane where the LLY would run ~40%.

Nick

[Dozerboy]

The turbine/vane setup is a lot tighter on the newer trucks ('06 and up).

X2 I have seen boost in the mid 20s with the vanes at 0

[bballer182]

I wish i had an LLY exhaust housing. The danville turbos are all built using the LLY housing to flow more exhaust than the LBZ or even worse the LMM turbo.

[killerbee]

I am wondering if anyone has tried using an LBZ turbo on an LLY. I have no real explanation why, but the LBZ is looser and just seems to want to make boost. The MAF numbers seem to support this also.

[killerbee]

Has anyone tried actually increasing min vane table, to determine if the lowest values are actually more boost producing than say, 15 degrees?

[bballer182]

I am wondering if anyone has tried using an LBZ turbo on an LLY. I have no real explanation why, but the LBZ is looser and just seems to want to make boost. The MAF numbers seem to support this also.
I would think that it would be an upgrade for the LBZ's to use the LLY turbo because the exhaust housing is bigger and flows more that the LBZ, which can make it more efficient in the higher RPM and higher boost numbers. I've considered swapping mine out.


Has anyone tried actually increasing min vane table, to determine if the lowest values are actually more boost producing than say, 15 degrees?

I've played with mine but it's so difficult to do because you would have to do it in a DSP tune, because the DVT's don't work like they are supposed to. So i gave up on it. but i did do a little experimenting and found that are cruise range changing the vanes from 0% all the way to 30% did nothing as far as boost is concerned. And thats as far as i got when i gave up.

[LBZRCKS]

I am wondering if anyone has tried using an LBZ turbo on an LLY. I have no real explanation why, but the LBZ is looser and just seems to want to make boost. The MAF numbers seem to support this also.

It's been done a couple of years ago. IIRC it didn't make any difference really. LBZ looser?? Think you've got it backwards...

[killerbee]

"looser". Not loser.