3794 turbo braking

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
I didn’t realize there was different options on that charger. Is that a Garrett option? I definitely wasn’t given any options when I purchased the turbo. Wonder if there is any way to identify the vanes that are in it? It gets all the rpm, I really hate using my brakes. I use the tap shifter and tow haul even unloaded.

3500-4k rpm?
 

darkness

Active member
Jul 15, 2009
950
65
28
45
vegas
Have you logged your vane position during turbo braking? You should be seeing 100% vanes during braking. And make sure all the tables were done. I set mine up from 1600 rpm all the way to the end of the table in the 0 and 5 mm3 rows.

I know when I had my ‘07 and was screwing around writing tunes I forgot to do the last few vane tables (b2222-b2224) I was only getting 60% vane and the turbo braking sucked. Quickly changed it when I got home from a trip in the mountains lol.
 

Bdsankey

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Feb 1, 2018
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I didn’t realize there was different options on that charger. Is that a Garrett option? I definitely wasn’t given any options when I purchased the turbo. Wonder if there is any way to identify the vanes that are in it? It gets all the rpm, I really hate using my brakes. I use the tap shifter and tow haul even unloaded.
Not without disassembling the turbo. I like the guys at SDP but I doubt I'd buy a turbo from them as there are far more qualified turbo builds for the same or less money. For example, if that turbo truely does have a stock turbine/vane setup and a 68mm compressor then it is extremely overpriced and will never perform as good as something with a properly spec'd turbine/vane package.


Have you logged your vane position during turbo braking? You should be seeing 100% vanes during braking. And make sure all the tables were done. I set mine up from 1600 rpm all the way to the end of the table in the 0 and 5 mm3 rows.

I know when I had my ‘07 and was screwing around writing tunes I forgot to do the last few vane tables (b2222-b2224) I was only getting 60% vane and the turbo braking sucked. Quickly changed it when I got home from a trip in the mountains lol.
Pretty sure this guy doesn't write his own files (I certainly could be wrong).
 

boostwhore

Drag racer wannabe
Feb 12, 2015
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Goodlow, B.C.
Yes when braking heavily I would be in that rpm range. Vanes are definitely right around 99-%100 when braking. I’m sure if I looked I probably have a data log with braking in it but it’d be finding a needle in a needle stack lol I’ve got the turbo on my bench, I’ll split it and see what the vanes look like. Ya knowing what I know now I definitely would’ve gone with a more reputable turbo specific builder. But Scott has always treated me well and I’ve been working with him on this truck for a long time. No I definitely do not do my own programming, but I have a very reputable tuner that I use for everything. Programming is not the issue here guys. I am not against buying another charger if there is something that would suit my needs better. The truck was capable of 10’s with the current turbo setup having trapped 128 multiple times. Just wondering if there is a way to maintain that or improve upon it while getting some better towing characteristics. I understand that those two things often contradict each other.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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i would drop to the 65 and change the big turbo to a modded 83mm. That will keep you around the same or give you more hp. you are probably going to want more injector though. shrinking your uS to 1500-1600 or less will give you a decent little bump in power as well IF you are running over that to get that power goal.
 

Bdsankey

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i would drop to the 65 and change the big turbo to a modded 83mm. That will keep you around the same or give you more hp. you are probably going to want more injector though. shrinking your uS to 1500-1600 or less will give you a decent little bump in power as well IF you are running over that to get that power goal.
^ solid advice here.
 

boostwhore

Drag racer wannabe
Feb 12, 2015
301
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Goodlow, B.C.
Yep I just got off the phone with ddp and was recommended the 66mm stage 3 and to jump up to a 88mm atmosphere charger. I am a little skeptical about the stage 3 as it has a 76mm inducer turbine.
 

OleBlackyLBZ

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May 22, 2020
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I hotshot with a danville 65, the turbo braking is EXCELLENT, usually all I need is 2500-3,000 rpms to get slowed down loaded. From what I understand and remember off the top of my head the 66 stg 3 has a larger turbine and the high flow vanes, your not gonna like that for what your trying to do. Someone correct me if I'm wrong.
 

boostwhore

Drag racer wannabe
Feb 12, 2015
301
3
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Goodlow, B.C.
Ya that was my thoughts as well, was a little surprised by their answer with the big turbine for what I’m after. The 3794 from sdp is just a bigger comp wheel, nothing done to the exhaust side.
 

Bdsankey

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i dont agree but its your rig and money
I agree.



I hotshot with a danville 65, the turbo braking is EXCELLENT, usually all I need is 2500-3,000 rpms to get slowed down loaded. From what I understand and remember off the top of my head the 66 stg 3 has a larger turbine and the high flow vanes, your not gonna like that for what your trying to do. Someone correct me if I'm wrong.
You are correct, the stage 3 stuff from Dan's is aimed at guys with compounds to really help move some air through the turbine to get to the atmospheric charger. I've used a few of them, for the OP's goals I personally wouldn't use it (stage 3) on his truck. It'll make the power he's after but I think it won't drive/turbine brake anywhere near what he wants.
 

OleBlackyLBZ

Active member
May 22, 2020
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Mark's 3794 65mm has made 980 iirc with a S483. Can't imagine needing more than that, and still be able to tow and brake without issue.
 
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