tapped in the passenger side header. those were only 3/4 throttle runs, I run closer to 50lbs boost at wot, I just didn't have the room to run full out this morning.
Gateing stock VGT
- Thread starter Redbowties88
- Start date
I've seen over 20psi with the vanes at 5% or less on a 2700PW tune. I was going to get a BP gauge but kind of think its a wast unless your going for max effort. I did a lot of logging and testing boost tables and vane tables and think the vane % is a pretty good indicator of how much BP you have.
I think to many people try and push their turbos to hard. More then a few guys I have talked to have made there fastest passes only running 28psi.
I have been doing some more *finer* vane tweaking now that I can actually log it :thumb:
Here is what I have noticed so far (LBZ stock turbo)
At my altitude I seem to need a fair amount of vane position (6700ft)
Working with about a 2250 pulse (stock trans) and a tiny bit of meth mixed in to keep my water injection tank from freezing.
As I increased vane position I am seeing higher flow across the maf. I stopped testing at 42% vane (3000rpms up to 3600, then tapering off a bit).
Down at 25% vane my boost drops, maf drops, and smoke is way too heavy. At 42% I still have a little too much smoke but it's not out of control. The difference in flow from 35% to 40-42% was not real great so I settled at 35% on the big end.
With that kind of vane position I can keep egt's manageable if I dont rev it higher than 3500ish (only do this to avoid 5th). I'm sure my drive pressure is up there, but it just doesn't want to build much boost and smokes pretty bad. I threw lots of fuel at it, with lower vanes and it just smoked worse... no more real flow.
I can hold 25psi up to around 3500. (It will make more boost below 3000 but overall maf numbers are still quite a bit lower there.) Turbo feels tight, and is responsive but I have never inspected the turbine side. I just chalked it up to being the high altitude (though IMO it shouldn't make that much difference).
Here is what I have noticed so far (LBZ stock turbo)
At my altitude I seem to need a fair amount of vane position (6700ft)
Working with about a 2250 pulse (stock trans) and a tiny bit of meth mixed in to keep my water injection tank from freezing.
As I increased vane position I am seeing higher flow across the maf. I stopped testing at 42% vane (3000rpms up to 3600, then tapering off a bit).
Down at 25% vane my boost drops, maf drops, and smoke is way too heavy. At 42% I still have a little too much smoke but it's not out of control. The difference in flow from 35% to 40-42% was not real great so I settled at 35% on the big end.
With that kind of vane position I can keep egt's manageable if I dont rev it higher than 3500ish (only do this to avoid 5th). I'm sure my drive pressure is up there, but it just doesn't want to build much boost and smokes pretty bad. I threw lots of fuel at it, with lower vanes and it just smoked worse... no more real flow.
I can hold 25psi up to around 3500. (It will make more boost below 3000 but overall maf numbers are still quite a bit lower there.) Turbo feels tight, and is responsive but I have never inspected the turbine side. I just chalked it up to being the high altitude (though IMO it shouldn't make that much difference).
What I would like to do is figure how to get more boost out of the big turbo (gauge on the far right) while keeping the drive pressure low (gauge on far left) and keep total boost (middle gauge) about where it is..............any ideas
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What I would like to do is figure how to get more boost out of the big turbo (gauge on the far right) while keeping the drive pressure low (gauge on far left) and keep total boost (middle gauge) about where it is..............any ideas
You're actually pretty good already, not even up to 1:1 right?
yea, i'm satisfied with the drive pressure vs. the total boost, i would like to see more boost out of the bigger turbo though, say at 50lbs total boost, I'd like to have 35lbs out of the big turbo.
Larry, I know you have Cheetah and Mpi but what are they? 71.5 Cheetah and a 75mm/96 1.32a/r for the atmosphere turbo? You may look into upgrading the big turbo.
I'm no expert by any means but I would think a 80 would be bare minimum would want under a 71.am I far off in my thinking that something in the area of high 80's would be close to ideal?