Infor on running gas or alky

hi guys want to know the pros and cons of running gas vs alky on a blown 526 hemi witth either std or high helix 14-71 blower with bird catcher injection. besides using alky which you will burn 2.5 more of alky than gas. also what you have to do for service on the engine and fuel systems for each each set up. thx

 

alky will have a lot cooler temps on the motor i guess if you run water and radiator you could keep it cool i would think the performance level would be a lot better on alky you will just burn more of it and alky smells better ( lol )why would you want to run gas just curious

 

motor

thanx jim it is because got a motor with older venny heads, flat top nitro fuel pistons. so i am thinking it was going to be used for nitro. so rather than change to exspensive pistons maybe run it on gas. not sure of comp for sure just want to run 7.50s in an altered. unless some 1 can tell me what to do to find out the comp of it. dont know the cc of older venny heards heads serial number is 524 525. was told they are old alky for smaller dragster ci motor 440 to 480 ci.

 

Rob,
I used to tune Jeff Bennetts cifca funny car in the 90's. His engine was an older nitro engine with only about 6.1-1. We ran alky in it but the key to getting a low compression engine like that to run on alky is timing and boost. As the high compression cars run 30 to 34 deg timing and 20 to 25 lbs of boost (spinning a 14-71 at 8 %) to run a 7.50 The lower compression engines need 40 deg timing and 30 to 35 lbs of boost. We never had any engine problems other than blower ware. You can make it work. I would stay with alky as it is more forgiving that gas as is way hot like nitro. Alky is also cheaper than gas even burning more. Thats my experiance.

 

thats good advice learn how to put whites in the blower and just spin the shit out of it i dont think it would be hard to run 7.50s with a blower at all you might be able to put a thinner head gasket on it to up the compression ratio that will help but i for sure would stick to running the alky there shouldnt be any problems with turning the timing up and you could always put some pop in ( lol ) but really 7.50 you should be able to do that pretty easily without hurting any thing good luck

 

alky

thx guys this a great site for infor and good guys who take the time to help us little guys. but i am a newbe at all of this. need to know the dos and donts of alky. does anybody know the ccs of older venney heads think i heard 180 to 190. have a jp1 block, di they make a tall deck version because with my heads and venny manifold i have alum front and back spacers. 4.5 stroke rods in lenght is 7.045, has flat top coated pistons with valve notch on 1 side. pin height thinking 1.500 not sure have to go and measure so maybe the comp is higher than 6 to 1 can you guys let me know thx

 

Rob, I've never cc'd mine, #623-624, but I'm pretty sure all of the old heads are 168-170cc. I'm actually in the process of freshening up my heads today, hadn't really planned to but I could cc a chamber if that will help. Not sure if JP made a tall deck, but with your rod length and stroke I think you've got a std deck. I'm running a 1/2" KB tall with a 4.625 crank, 1.428 pin height and 7.445" rod. I have found out (the hard way) that you have to use some Veney specific stuff, not sure about your end spacers but if your manifold/head doesn't have an approx 3/8" spacer between head and manifold, it's probably a std deck.

As far as running low compression, think you gotten good advice and for what you're doing you should have a tuning window wide enough to drive a truck through. I ran a similar combination although not quite as low compression-wise (8.5-1 Milodon block/heads) in a drag boat years ago, was planning to run blown gas, found out after engine was in boat and rigged it wouldn't hold water. Being a bucks down newbie 2 weeks before 1st race, scrapped the new gas nozzles and barrel valve and put the alky's that came with the hat back in and ran it dry-block. Was running index classes so fuel didn't matter, ran that combo for 3 years, quickest was 7.02 @ 157+ (on 7.00index, remember that tuning window I was talking about... ) this with 454" and a well used 8-71 Ed Pink. Your deal in a light car should have no problem and between round maintenance should be a breeze.

 

What Bore Is Your Motor I Have A Brand New Set Of 10 4.25 Alky Pistons I Would Sell Cheap And I Have Some Good Rods And Rings That Will Bump The Compression Up If You Decide To Go Up On Compression

 

bore size

the piston bore size is 4.186 they are coated pistons most look like they are new along with rings. have to check they came with grp alum. rods too. if you guys like can you please send me a pm with your email addresses so i can give you more details thx again guys

 

alky

hi jim, send me a message with your email for your pistons, have a set of top fuel pistons 6 are new and 2 are used if anybody wants to swap they have rings too also coated thx

 

more on gas vs. alky

hi guys want to know the pros and cons of running gas vs alky on a blown 526 hemi witth either std or high helix 14-71 blower with bird catcher injection. besides using alky which you will burn 2.5 more of alky than gas. also what you have to do for service on the engine and fuel systems for each each set up. thx
in answer to the original questions, usually 2 to 2.5 times more alky than gas. After we run ours, we drain the fuel system, reverse rotate the engine with the fuel pump full of lub, and blow out the tank and lines. Several are now having good success with upper end lubs discussed elsewhere on this forum. Search lubs. Somepros and cons: alky tuniing window about 3 times bigger than gas tuning window. If you found either, than it is less important, however getting there on gas is a lot more difficult. Methanol has some bad stuff in the exhaust. While some will siphon gas with a deep inhale, that is really bad to do on methanol. Both the fumes and the liquid are poison in any quantity.
Roots Blown gas compression and boost should top out not over about 24 to one with 118 gas. That compression is static compression ratio times blower/engine pumping ratio. With 6 to 1, you could go to 4 atmospheres which would be real hard to do with a Rootes. So you would be safe probable at any reasonable overdrive. Unfortunately intake manifold temperature limit would raise its ugly head. If too hot, the engine will have problems. That says keep the overdrive reasonable.
Alky compression can go real high if engine temperature is controlled with enrichment. There is a window and too much fuel can be just as bad a too little. There is a lot to the temperature issue for both fuels.
Bob Szabo, author of: "5000 Horsepower on Methanol" and "Fuel Injection Racing Secrets"
www.racecarbook.com