Depends on the engine limits (blower limits on the Allison) and weight limits.
According to the flow test we did (with a f...ing V8 Mercedes Bi-turbo chopper engine that had to be chipped over its original 650 hp to even spin the blower that fast) the original Allison blower wheel runs into stall speed at app. 36,500 rpm.
At that point, it already creates VERY hot air and above that even more heat and less flow.
As long as that blower has to be used, you're kinda stuck at 2700 hp per engine. You can play a little with compression - but air that doesn't move through the blower won't make it through your cylinder heads either.
Whether you run with the 8.1 or 9.6 blower ratio only determines at what engine rpm that power will be made (3800 or 4500rpm).
With better blowers you can then can create more flow and less heat = more power.
If my old team would use the technology they have used on the rear-end, brakes, driveline, their hmd superchargers, etc ..of their 5500lbs twin Allison (with by now 100 lbs of moveable weight) they could run a three-engine tractor at under 7000 lbs.
Above that, it would get complicated placing the engines forward enough on one chassis due to their size.
[youtu.be] this was the last pull off vs Boers and Heuvelen in light mod in January. The Allison still needs it's crossbox and blower wheels changed to counter rotating so it will run straight. The two Hemi guys already run counter-rotating engines.
Floating Finish - the German Tractor Pulling Web Show and EU Live Streams: [www.youtube.com]
Edited 2 time(s). Last edit at 04/28/2020 11:23PM by Sascha.
