upcoming dyno day for my twin turbo 12v cummins

12vtwin said:
Video quality is awful, but my top gauge is a 100psi boost, bottom is a 1500* pyro, you can see I reach 70psi pretty quickly.

https://www.youtube.com/watch?v=QHSpAA8Q0TY
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A boost gauge between the stages would tell you a lot. On my current twin set my secondary gate is fully open at 30 psi and the primary takes over most of the load. When I get my primary turbine housing back Ill take a video of overall boost and primary boost.

IIRC that super B's gate is set around 40 PSI from BD
 
12vtwin said:
Thanks man, I hope I hit a nice number. I love the setup, spools very fast (16-1800rpm starts to get boost and has full boost (75psi) by about 2800rpm. Lots of power, I have 3:55 gears and it will smoke the tires in 3rd gear if I stomp on it at 35-40mph. I have about 1000miles on the turbos and I don't have any complaints.



Why 30psi? Right now I am hitting 75psi...
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12vtwin said:
Ok, thanks, I'm looking at some of those threads now. I'm planning on making 3 runs, maybe do a low, medium and high pressure run? 30psi, 50psi, 75psi maybe?
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You are referring to overall boost. The suggestions are referring to wastegate tuning in your high pressure charger. Do some reading on compound tuning. There can be several combinations of primary and secondary boost to achieve the 75psi. Some more right than others.

On a side note, a friend of mine made a very smooth and flat 600hp with r700's on a vp truck. So the air is there. And consider making pulls in OD as well. In my experience direct drive never loads hard enough to get real world boost. Load cell vs inertia dyno will demand two different recommendations on tips for running.
 
94 12valve said:
A boost gauge between the stages would tell you a lot. On my current twin set my secondary gate is fully open at 30 psi and the primary takes over most of the load. When I get my primary turbine housing back Ill take a video of overall boost and primary boost.

IIRC that super B's gate is set around 40 PSI from BD
Click to expand...


What useful info would a boost gauge between the turbo's tell me? I have an internal wastegate on my secondary only. I adjusted the wastegate from 35psi (how it came from BD) to 75psi, I called them and they recommended that my primary would be more efficient at 65psi, so I'm going to set it there for now. Sorry if my questions are redundant, just want to try a few different settings on the dyno and see what's what. Appreciate all the help guys! I'll post video of my runs this weekend.:thankyou2:
 
I guarantee you lose that pos air filter youll spool better and flow way more on top. that pos killed my tow pig
 
12vtwin said:
What useful info would a boost gauge between the turbo's tell me? I have an internal wastegate on my secondary only. I adjusted the wastegate from 35psi (how it came from BD) to 75psi, I called them and they recommended that my primary would be more efficient at 65psi, so I'm going to set it there for now. Sorry if my questions are redundant, just want to try a few different settings on the dyno and see what's what. Appreciate all the help guys! I'll post video of my runs this weekend.:thankyou2:
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I would go back to the original settings from BD. I also second running in the tallest gear you can, it will make the most power.
 
JQmile said:
I would go back to the original settings from BD. I also second running in the tallest gear you can, it will make the most power.
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The only issue running the tallest gear is 5th gear is a known problem in the nv4500's for an auto always dyno in OD. For a 4500 personally I would dyno in 4th
 
Got my truck on the dyno today, a few small hangups but I was overall very happy with the results. It was an inertia dyno and I realized when I got there that my rear brakes are pretty well shot, so I wasn't able to brake boost it at all, but I still ended up with 561/1089. Did that in 5th gear with 65psi of boost, 65psi turned out to be what the truck liked best. I'm not sure if my hp and torque dropoff at higher rpm is due to needing more timing advance (at 22* now) or if it was just do to spinning up the dyno too fast. on my best pull we actually only took it to 3500rpm because the drop off above that was pretty rapid. Thanks for the helpful tips guys!
https://www.youtube.com/watch?v=dNAne4bdUsg
 
Congrats on the numbers man! It sounds about what it should be, although making the power you "should" is still always a pleasant surprise (at least it was for me). I would say your top end is dropping off because the truck is starting to defuel, I'd see if I could adjust them a little to get some more rpm. Adding another 3-4 degrees timing will add another 30hp or so, but it will spool slower, so it just depends on what you're willing to live with. That pyro climbs pretty fast, so I'm thinking you could use some more timing.
 
Since it was an inertia dyno I wasn't sure if i was defueling and maybe need a stronger lift pump or if i was just spinning up the dyno too fast. On the street it doesn't feel like it drops off like that. Thoughts?
 
Where you dynoed is local to me, how do they take to diesels (deal with the smoke) and did they drive or let you. If you are ever in Middleburg stop by my shop on 218 marine services, we are big 12v fans.
 
jasonc said:
Where you dynoed is local to me, how do they take to diesels (deal with the smoke) and did they drive or let you. If you are ever in Middleburg stop by my shop on 218 marine services, we are big 12v fans.
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I told them ahead of time when I scheduled that I had a diesel pickup, they didn't ask any questions. When I got there and they asked if it smoked I said "a little bit", because it's all relative..right?? :lolly: It smoked/sooted the dyno area up pretty good, but they didnt complain. They operated the truck, but I sat in the truck with him and I told him beforehand exactly how I wanted him to run it (what gear, rpm). I wasn't rushed at all. They were really professional and did a great job, I would definitely us them again. And it was only $75 for 3 runs. I'd recommend them for sure. Next time I'm down in middleburg I'll swing by your shop.
http://www.efialchemy.com/index.html
 
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