dyno flat at 6000-6500 rpms?

**CactusG8** · 10-03-2018

Hellcat 426 stroker. It is struggling in the high rpm range. I have a dual livernois fuel pump, boost a pump, 1300ix injectors. With a 10 percent lower and 2.65 upper it is only seeing 15 psi. It has a modern muscle ported throttle body. The engine builder thinks it is the throttle body. The tuner thinks maybe the stock supercharger is just too small for the stroker. It was tuned with Diablo. The car has 3.09s and a slightly shorter tire than stock. It was done in 5th. It should of been done in 6th gear. Automatic. Next week my friend is going to put it on the dyno and scan it with hp tuners.

**JoshCP527** · 10-03-2018

looks like you are hitting a limit in the curve and that boost is well a bigger motor on small supercharger. 2.65 and lower is around 18psi in good weather on a 6.2. Just FYI you spin it faster and up the shift rpm it is know to come apart the rotors dont like 25k to 26k blower speed.

**1bh** · 10-03-2018

15psi on that stroker and hellcat blower with those pullies is correct.

**[email protected]** · 10-12-2018

We've done numerous 426 combo's in the Hellcats. Stock fuel pump, ID1050's, upper and lower, stock TB, our custom "Demon Plus" cam, stock SC - no issues. We always run them on the dyno in 5th since none of our customers are going to be trapping at 200mph. I would guess that it is going flat due to a tuning issue.