sbc whipple ethanol compression?

I run a efi sbc 400 with a 871 9.1 compression on ethanol (e85) on the street and considering stepping up to a whipple r980 or a980 and compete in a 10.5 class. I want to swich fuel when im at the track and run methanol and i know i should go up in compression then but that wouldnt work on the street when i swich back to ethanol (i have to run the blower 50 under or something like that). How will my sbc work with a big screw blower and 9.1 compression and methanol? 303/310 advertised and 60cc chamber.

 

meth + 9/1CR + higher boost + 400

Regarding detonation: As long as you keep the fuel volume up about 40% from your ethanol combo at the same blower, you should be OK. For the larger blower, increase the fuel proportionately with the increase in air to the engine from the larger blower. However, you may run into mechanical strength limits. The 400 may not have enough clamping around the cylinder head or head gasket width between the cylinders to contain more boost. At higher power levels, stock diameter wrist pins may be a problem. As the power goes up, the weakest link in the engine will start to fail. There is a lot of good info throughout this forum, in the recent past, from some experienced blown small block racers. You may want to provide more info about the parts you are running for comments from other experienced sb racers. In addition, you may have some problems with your injectors on methanol regarding volume issues and corrosion issues.
bob szabo, author of racing tech manuals: 5000 Horsepower on Methanol and Fuel Injection Racing Secrets
www.racecarbook.com

 

Thanks bob for your reply. Regarding the fuel tuning I will benefit from my autronic sm4 ecu. ofcourse i have to be fatter over the whole fuel map and get the injectors and pump that can handle that but the map sensor feels the boost and the ecu automatically correct the fuel to achieve the correct a/f ratio, i got a a/f sensor in each collector. dont think the corrosion will be a prob because i will always run e85 directly after every race. yes you are right there are alot of experiensed people in here and i have spent several hours reading other threads. i currently go with a littlem, brc crank, oliver rods and je inverted dome pistons, cometic headgaskets, pontiac 867 heads, crower shafts and lifters, tit valves, 300 on the seat, 9.1 compression. on this ethanol setup i have 974hp/826lb@7000 with 14 pounds from a stage3 tbs 871. i want 1500hp with the whipple and methanol so i might need 25-30 pounds boost, will my parts stand it? someone hwo can say anything aboat the 9.1 compression-methanol-whipple combination?

 

We run a non-retro 14/71 HH on our 427 SBC. We've made some big changes since we started. The Dart block and Brodix -12 heads have been filled, no water holes in the head gaskets, "O" rings and receiver grooves, 990 wrist pins and 10.75:1 compression. All of this was after we hurt number 4 and 8 cylinders. Runs 6.90's @ 200MPH, with lots more left in it. We run the blower at 30 over. Lots of things change when you "bolt" on a bigger blower. I seriously don't think your EFI will handle the needed fuel volume. Some of the faster TAD's (blown) in NHRA are running 9:1 to 10:1. But that's a hemi, a totally different animal. PSCA has allowed screw blowers this year. But changing to one of these is very costly. I think you have some things to think about. Do you want a race car or street car?

 

Whipple

You will have problems with that on the street. unlike othjer blowers, the whipple actually makes boost at idle and you can have problems with the blower overheating. I have a friend who ran them (yes he had 2 on twin 565 big blocks! and not the weenie whipples, the big ones like you are asking about.) on his lake boat and wound up using a bypass to send the boost back to the top of the blower at idle.

 

ok this bypass, did he had a manual valve to open and close it or did he had an electric valve? was it the same guy that had overheating problems? what fuel did he use? sounds a little strange that you can have overheating problems when theres alot screw kits out there for street cars. ofcourse a 980 is much bigger but its the same blower type and i wont spin it fast when ethanol is the fuel. will also use heatreducing plate between intake and blower so it dont catch heat from the motor.