Hell yeah!
Who has a VMP Gen3 TVS
- Thread starter 2011 gtcs
- Start date
Hell yeah!
Steve’s going to love dat torque! Very interested to see his comparison to the KB 3.6. Still love that whistle, but this will give him the silent but deadly vibe 
-J
-J
Here’s a look at the gen3 I just finished up. One spot I have to fix but came out good.
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I would have like to have seen results with a 2.7 or 2.8 pulley on the VMP Gen3. I think you would have been a whole lot happier. The 2.65 has a different boost curve than the 2.3...the 2.3l is actually done around 3-4k, it hits pretty hard right there, boost falls off, and comes back. The 2.65, when spun just a little bit hard, comes on strong and then just keeps pulling with no boost drop off. It's hard to compare peak vs peak when the curve shape is different. If poor quality fuel is an issue I actually like the gen3 better because it does not hit peak boost at torque peak where you are most likely to knock. A 3.6l KB that is under-spun to deal with boost/timing limits on 91 oct will have the same loss of average power that you complained about with our gen3, but you went E85 with the KB, so its hard to draw any true comparison IMO.
Agreed on the different boost curve. The Gen3 fixed my boost falling off with the Gen2R.
Looking forward to making 1000+ on the Dyno in a few weeks!
Gen3 still has my vote for the best street/strip blower for GT500
Looking forward to what’s next from VMP
-J
Though I believe this question to be solved, for what its worth, we now recommend a 2.7 on 93 and a 2.8 on 91, for the VMP Gen3, on the 5.4l. On the 5.8l you can go down one size to a 2.6 and a 2.7. This will get you into the high teens boost wise with a stock lower.
Our 2.3l and our 2.65l use the same pulleys, but the 2.3l was commonly run with the 2.4 and 2.5 to make 17-18psi. The 2.65l will make similar boost with 3-4 pulley sizes larger, and when in doubt, err to the smaller size. We've had 2.8 and 3.0 pulleys for a long time, but nobody bought them. With the introduction of the 2.65l those sizes became a little more popular, and we also came out with a 2.7 to bridge the gap between 2.6 and 2.8. There is also a 3.2 and 3.3, but thats more for the 5.0l cars with our blower, and anyone class racing with the 2.65l, most GT500s won't need them.
I'll also throw out there that most stock-motor builds no longer need a 10% or 15% OD lower with the Gen3, you can hit 800+rwhp with the stock sized balancer. That saves you $600-$700 not counting installation.
I agree, it would have been nice to compare 3.6 to gen 3 with built motor. Regardless, both are very capable of generating >1000 whp with proper set up. Had you had the TB sorted out when I bought my gen 3 I would have been a little more willing to give VMP the benefit of the doubt. Your points on gen 2r vs. gen 3 are valid but the differences are marginal if you are running pump gas and really not worth a $4k upgrade to get results that are essentially interchangeable IMO. My IATs were better on the gen 3 for sure and no doubt it is running more efficiently. But these differences are too minute to matter for my (and probably most other's) application of mostly street and occasional strip duty.
A look at the finish product. Let me know if you’re interested in anything being done.
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Justin, what upper do you recommend for a cammed 5.8 with a 10% lower? I went with the 3.0” upper and thinking it might be borderline too much for the 93 octane tune.
The cams drop 2-3psi and the 5.8 drops 1-2psi, the 3.0 with a 10% is equivalent to a 2.8 upper pulley only...which is incredibly mild. Assuming your compression ratio is around 8.5-9, I would not be afraid to drop to a 2.8 or 2.7 with your 10% lower. The cams bleed off quite a bit of cylinder pressure at the TQ peak where you are most likely to knock. I don't know what kind of power you are making now, but the builds we have done like yours, made 1000+rwhp on E85 with a 2.4/10% on a box stock VMP Gen3. Given you are on pump gas, that thing should still be a monster.
I made 770 on this build with a bone stock Trinity TVS last spring. Started with a 2.5 upper, but went back to a stock upper for a little more margin for error. As you were saying, due to the different curve on the 2.3 TVS, boost was peaking at over 19psi at 4K rpm, but falling off to 16psi by the end of the pulls. Saw a little knock on the logs and that’s why I swapped back to the stock upper for street duty.
I expect I’ll be well over 800 on 93 with the addition of the Gen3/KB168/DD149. Also doing a Mach 116 tune for track duty. We’ll give it all the boost on that one, should be over 1K. Thanks for the reply.
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