Quote:

---

I finally got my new 572 B1 motor on the dyno. Made several pulls on 116 Maximal,(5) to 7600, and it made 1034HP at 7200RPM, and 810FP at 6200RPM. Then we put the E85 APD on and made 1 pull, made 75 less HP, and killed the rings. My combo is 4.500x4.500, B1 original heads, 16-1 compression, cam is [Email]286@50Int[/Email] [Email]296@50Ex[/Email], 112 lobe center, 1150 APD dominator gas, 1250 dominator E85. I mix Sonoco 112 with Sonoco Maximal 116 50/50 and add that 10% to 90% pure Ethonol. A/F on E85 was 9.6-1, and gas was 14.50-1.
Any ideas? Engine builder sited excessive detonation.

---

I don't know what AFR the E85 wants so it won't detonate but the race gas AFR are way to lean for that kind of compression, IMO. Did you fatten the jetting up at all on the first 5 pulls on gasoline? I have seen AFR sensors read goofy on a engine dyno that had a lot of race fuel as well as pure methanol ran on them, my last motor was reading lean AFR on race gas but lost power when we fatten the jets up two sizes. It regained the lost power when we jetted it back down I switch intakes and carbs(single 9375-2 Dominator on a 440-2 intake with a tapered two inch adapter and a one inch phenolic spacer(AFR read 14.2to 14.3) to a pair of early 9375 non HP carbs on a Indy tunnel ram, AFR read 10.2 on the first pulls and the motor lost a bunch of power so we ended up jetting it down 12 jet sizes and stopped testing due to running out of time on the dyno. That jetting ended up making around 30 more HP than the first set up did, we did not jet the tunnel ram carbs down enough to loose power when we quit so it may need leaner jets jet on the tunnel ram combination. I am going to test it agagin soon and see if one or both of the tunnel ram carbs has a stuck or leaking needle and seat. I'm sorry you hurt your motor, it sounds like it is a good one, let us know how bad it is hurt and what it takes to fix it Are you going to retest it after it is back together? I hope so I have seen a loss of power on a 452 C.I. motor that had 14.7 to 1 comp. ratio going from VP C114+ to VP C12, around 30 HP on a 640 HP reading going down to 612 HP with no jetting or timing changes