Valley turbo upgrade - compounds - built engine
- Thread starter NevadaLLY
- Start date
I just spoke to a reputable builder who think's I'm crazy to tow with 100 overs and the turbo I selected. Said that since I didn't port the heads, my drive pressure will be through the roof. Anyone agree/disagree? I had thought I took care of all of the issues you can and that Duramax heads already flow quite well for <800HP?? I've done manifolds, up-pipes, the stage 3 turbo, compound (albeit a tighter 1.15 housing), 4" exhaust all the way back. 
I just spoke to a reputable builder who think's I'm crazy to tow with 100 overs and the turbo I selected. Said that since I didn't port the heads, my drive pressure will be through the roof. Anyone agree/disagree? I had thought I took care of all of the issues you can and that Duramax heads already flow quite well for <800HP?? I've done manifolds, up-pipes, the stage 3 turbo, compound (albeit a tighter 1.15 housing), 4" exhaust all the way back.
he may have missed something. drivepressure was never my issue and my exhaust side flowed less than yours. maybe he was thinking you wanted to tow AT 7-800hp?
I'm curious why more guys don't install a smaller sized gated fixed vane in the valley? I just put on a 68mm stg2r a few days ago and it's very interesting seeing the difference in drive pressure vs boost at all stages (comparing s300sxe vs 68mm stg2r). The stg2r so far is between 1.5:1 to 2:1 drive pressure almost all the time. I can get real close to 1:1 at lower boost pressures but then things get a bit lazy. The 69sxe I was running ran right near 1:1 until I got around 2500rpms at full power.
These findings would make myself consider doing a fixed vane in the valley with a gated housing. I would think things could be a bit more efficient?
These findings would make myself consider doing a fixed vane in the valley with a gated housing. I would think things could be a bit more efficient?
I told him at 450-500. Said towing on that setup with 100overs... “woooow”. I was kind of surprised. This shop is well known around the ranch and no stranger to the duramax and its capabilities. Maybe just the individual but it made me question what I’m missing. Are the heads that restrictive. The convo definitely has me putting in a new drive pressure gauge.. I’m just running out of room for gauges
I tow with 100's and got no complaints other than my valley turbo is to big so it's more work to clean up the lower rpm low boost areas. Only good thing is drive pressure is usually less than the boost or barely over like 2-4 psi in the higher 34-3600rpms but I have a gated charger.
You also have the ported heads as this builder mentioned - -
Did you notice a drive pressure difference before/after heads? I have the same exhaust housing as your 67 (i think) with the stage 3, 64mm. it has a 76x68 in the GT40 housing.
It's hard to say mine was parked for 3 years with a cracked piston before I decided to build a motor for it. Doubtful they did anything for drive pressure I would imagine.
I’ve been towing 15k 5 hour trips with 200s in my lml with bigger turbos on a 800hp tune stock heads and studs no issues. I’d run it
I'm definitely going to run it and provide feedback on my setup. Many of you all on this forum helped me select the components for this build so can't leave out the best part. My gut is this is going to be a very well performing, fun, reliable build which has great towing characteristics balanced with some pep unloaded with the max effort tune (every once and a while
)You are not going to have a problem with this setup unless it is a tune related created issue. It does take drive pressure to spool a turbo. Getting it in a acceptable place is where the tuning comes in. Don’t worry much about the turbo selection.
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Sweeet! Post some videos. I did a launch with mine finally the other day and got a good video of it. How big of tune you running?
