compression ratio....what gas to use?

i was wondering if u have 13.1 compression can you use 108 octane or do i need 114 or 116 , out in ma we got vp
or if i was to do nitrous like 12.1 with a 200 shot do i need all out c116 ? just trying to figuare expenses with fuel feeding these giants

thanks guys

What heads do you have and what's your cam spec's?

havnt bought cam or heads yet doing a 545 but lookin at scj heads but want an idea before i do anything , feeding a 545 with high compression with c116 is gonna get expensive i think its 16$ a gallon here in ma ........id like to run 108vp it would be cheaper even if i had to run 10.5.1 or 11.1 and run a nice shot of the juice

It's kind of hard to have it both ways, not impossible, but not easy either. High compression=high octane. If you can't afford the right fuel, don't build it that way. But don't be disappointed when it doesn't perform the way you wanted it to.

i was gonna do a 13.1-14.1 545 but then i was figuaring 116vp is around 16$ a gallon and feeding this motor is gonna get costly any idea
how much fuel a motor like this prob with a 1250 dommy on top will eat in a pass are we talking a gallon? 1/4 mile ........an idea obviously theres a lot of variables to putin

or i was thinkin nitrous but ....want to figuare out before i buy any heads or internals

just coming from efi vortech stang running 10.30s on 108vp and now figuaring the 116 is gonna be costly ...we also have 114 and i think 112

just trying to figuare what would work with that kind of compression or best route

thanks again guys......i know im posting a lot of questions and maybe stupid ones , but you guys are a huge help and i appreciate your guys knowledge and help.......i live in ma and up at new england dragway in epping NH ,theres very few bbf running up there that i have seen but this forum is the balls!

Methanol is two bucks a gallon............

richter69 wrote:Methanol is two bucks a gallon............

There's a thought, I'm not an alky guy, but it might be the answer to your prayers...

You said your looking at SCJ heads, so I'd guess it's safe that whatever head you end up with will be of aluminum. That helps! O.k. ..... give us an idea of which cam your considering. The intake valve closing point on the cam will be very important in determining what octane fuel you'll need.

not sure on cam was gonna talk to lem when time comes , its a track only car so im sure it pretty big but obviously dont have specs

5pointslow wrote:not sure on cam was gonna talk to lem when time comes......

It's time!

Yor build up is just like the one I am putting together now. I have been there and checked about the fuel. I was told by Lem's fuel guy that it also possible to get to much octane when it is not needed. My compression is 13.2:1 with the SCJ heads on a scat 521 kit. I am either going to run 110 or 114 in mine, or like Jon said alky probaly would be better since yours is a track only car, but it's what you feel good at dealing with.

i also realy hope this motor make sthe power .... i mean car is setup now with chute and wheelie bars , id look like a tool runnin high 9s with a chute lol


yeah 108-114 is good , that 116 shit up here in new england isnt cheap

my deal was dynoed with 112 but i use 118 in the tank for the spray .......... the last outing i used some monster 114 and it worked great also on the spray

5pointslow wrote:i was wondering if u have 13.1 compression can you use 108 octane or do i need 114 or 116 , out in ma we got vp
or if i was to do nitrous like 12.1 with a 200 shot do i need all out c116 ? just trying to figuare expenses with fuel feeding these giants

thanks guys

13.1 needs minimum of 110, possibly more if your gonna spray it. Sounds like you haven't bought pistons yet. I would do the 13.1 nitrous deal and run Q16 as opposed to C16. We will be out with a 14 1/2 .1 nitrous deal and will run Q16. Expensive but it is oxygenated and you will pick up power

i havnt got pistons yet or heads trying to figuare my combo ...i know i m gonna do a 545, i haver 4bolt caps on a d1ve block and a partial fill

obviously gonna get pistons and then bore and fit to them with rings ........not sure on if im gonna need nitrous ......basicaly car is setup with a chute and wheelie bars and its gonna be embarissing to go up there and run a high 9 ........was gonna do 13.1-14.1 scj or a460 heads
prob scj for money but not sure , i made this thread to get an idea on what fuel u guys are using with your combos ......car is gonna use a glide (i realy dont want to relie on the bottle to get there but trying to figuare cost of nitorus ect...vs all motor combo)

coming from 10.30s efi with vortech t trim ....this big block stuff u have a lot more options ...to me at least it will be my first bigblock
but hopefully be happy in the end

5pointslow wrote:i havnt got pistons yet or heads trying to figuare my combo ...i know i m gonna do a 545, i haver 4bolt caps on a d1ve block and a partial fill

obviously gonna get pistons and then bore and fit to them with rings ........not sure on if im gonna need nitrous ......basicaly car is setup with a chute and wheelie bars and its gonna be embarissing to go up there and run a high 9 ........was gonna do 13.1-14.1 scj or a460 heads
prob scj for money but not sure , i made this thread to get an idea on what fuel u guys are using with your combos ......car is gonna use a glide (i realy dont want to relie on the bottle to get there but trying to figuare cost of nitorus ect...vs all motor combo)

coming from 10.30s efi with vortech t trim ....this big block stuff u have a lot more options ...to me at least it will be my first bigblock
but hopefully be happy in the end

Well nitrous will always win the consistency battle, especially when it gets hot out

Tell us more about the car, you might not need all that power to get where you want if she is a light wait

[/quote]

13.1 needs minimum of 110, possibly more if your gonna spray it. Sounds like you haven't bought pistons yet. I would do the 13.1 nitrous deal and run Q16 as opposed to C16. We will be out with a 14 1/2 .1 nitrous deal and will run Q16. Expensive but it is oxygenated and you will pick up power[/quote]

I know a fellow mud racer running 14-1 comp and was using Q16 with Nitrous and he had nothing but trouble with the extra O2 of the fuel. I think he burned up 5 or 6 pistons in one short season. I quized another buddy who is a successful Nitrous racer (598" & 16-1) and he recommended for my mud race buddy to only use C16 with nitrous as it is much easier to tune and safe. If Nitrous gives more O2 do you really need more with the oxygenated fuel ? Just wondering ?

On another note I will be running 13.8 - 1 on my iron headed 557" engine this coming season and was going to run the VP113 oxygenated in a non-nitrous application ? If that is not enough I guess the 114 is what I will go with.

FWIW Mark

car has a 25.5 chromoloy cage, 1 kirkey seat , mini tubbed stock supension 9 inch
powerglide , all bumper renforcment taken out
chute, wheelie bars
tubular k member aje
motor plates
qa1 coilovers

5 1/2 lift off hood cervinis fiberglass

should be aroound 2800-3000lbs with aluminum headed bbf .....id think

5pointslow wrote:car has a 25.5 chromoloy cage, 1 kirkey seat , mini tubbed stock supension 9 inch
powerglide , all bumper renforcment taken out
chute, wheelie bars
tubular k member aje
motor plates
qa1 coilovers

5 1/2 lift off hood cervinis fiberglass

should be aroound 2800
-3000lbs with aluminum headed bbf .....id think

Im only going by on your first post, the expenece of fuel. I run the Q16 75$ for 5 gallon's, without a golf cart (and i do have one) it can get very expensive. If fuel cost is a concern, re think your combo. Bigger might be better, talk to Lem they built some pretty stout combo's that run on pump gas.. and the wear and tear should be at a minimal

how many gallons u go thru on a weekend ?.....no i understand the costs , im just trying to get an idea what its gonna take to feed the pig lol


any info woud help thanks

5pointslow wrote:how many gallons u go thru on a weekend ?.....no i understand the costs , im just trying to get an idea what its gonna take to feed the pig lol


any info woud help thanks

I bring 15 gallons with me for the day, most of the time that's plenty, But im also pulling the car up to staging lanes and pulling it back to the pit's.