After getting the car dyno tuned the hp was 457 and the torque was 427. Since that dyno I have gotten a strange 12 bolt, twin disk clutch, large steel driveshaft, and I ran cut outs on the dyno, because I have FLP headers with removable cats. My new dyno was 426 HP and 408 TQ. The first dyno was pulled to 6200, and the one I just took was taken to 6100. They both were about the same temperature, 83 degrees, and my clutch and rear end have been broken in with 1500 miles. I just changed the oil will full synthetic the day before the new dyno. The dynos were dynojets, but at two different places. The higher number was at FLPs new dyno, and the other looks to be a older dyno built into the floor. Why did I lose that much HP, I was looking for something in the 460s or more? Is every dyno different?

 

I think the 12 bolt will probably eat up around 15 or so rwhp. Also the steel driveshaft is sure to eat up some as well. There could also be slight differences/calibration's between the two dyno's.

 

Your loss lyes in the 12-bolt, twin disk clutch, and the steel driveshaft. All 3 add a large amount of rotating mass to the drivetrain which in turn makes you loose HP.

 

exactly.

CamaroSS1618: where did you hear that the addition of such mods would increase HP/TQ

 

I had done a few little engine bolt ons along with the drivetrain stuff, so I was expecting a small power gain, I also have drag welds, which would lower the rotational mass. I was thinking that since the clutch would grab better that it would transfer power better and I would not lose as much power to the rear. But I never thought about how much rotational mass would be added with the rear and driveshaft.