440 fuel

[Steve89x]

im just wondering what everyone else runs as far as fuel for your 440 12:1

Ive read, people still usings 93 octane and others mixing 110 and 93 and another person saying 120 octane and so on

i realize now i should get hd studs but just dont feel like taking the engine back out and apart and was reading that the higher octane burns cooler keeping the engine cooler which is the reason the studs pull out, the aluminum heats up more with lower octane and the studs pull free

does anyone have a 12:1 without hd studs and still run on 93?

also if not anyone running that combo, will running higher octane decrease the chances of the studs pulling out for me at all?

[m36indiana]

i run a 440 stroker and i use VP c12 108 octane 50/50 mix with 93

[REPOMAN]

I USE PUMP GAS.

[red_rider_069]

Originally posted by Steve89x
im just wondering what everyone else runs as far as fuel for your 440 12:1

Ive read, people still usings 93 octane and others mixing 110 and 93 and another person saying 120 octane and so on

i realize now i should get hd studs but just dont feel like taking the engine back out and apart and was reading that the higher octane burns cooler keeping the engine cooler which is the reason the studs pull out, the aluminum heats up more with lower octane and the studs pull free

does anyone have a 12:1 without hd studs and still run on 93?

also if not anyone running that combo, will running higher octane decrease the chances of the studs pulling out for me at all? uhg.. well i had mine on 11:1 before i blew piston and ran on 91 at times.. when i could i mixed with race fuel.. idk if that helps any but the hd studs looked fine..

[red_rider_069]

Originally posted by REPOMAN
I USE PUMP GAS. your not running a bore though!? or stroker?

[Dew2008]

120 On 12.5:1

[GPracer2500]

Originally posted by Dew2008
120 On 12.5:1

Is that 120 MON, RON, or what? What fuel is it?

When discussing octane ratings and racing fuel is involved, we should always specify what rating system we are referring to. Otherwise, who knows what the number actually means. MON and RON could be 10 points apart. If we're talking about pump fuel than a straight-up number is fine since all pump gas sold in North America is rated as RON + MON divided by two.

[Dew2008]

Good Question LOL...The shop that built it for me supplies my racing fuel. Therefore I do not ask any questions. I can find out for ya though

[Wheelie]

I run pump gas everywhere except the sand dunes. At the dunes I run 50/50 premium and 110. My compression ratio is about 11.5:1 and I've been running the stock head studs for 2 complete seasons, this will be my 3rd.

[REPOMAN]

Originally posted by red_rider_069
your not running a bore though!? or stroker?
i most certainly am. 440 big bore with wiseco piston! or else i wouldnt have posted in this thread.

[Dew2008]

Thats not good for your engine. With a high compression you should be running a higher octane fuel.

[red_rider_069]

Originally posted by REPOMAN
i most certainly am. 440 big bore with wiseco piston! or else i wouldnt have posted in this thread. sweet jsut double checking bro =).. cuz you didnt say what you were riding..

[REPOMAN]

Originally posted by Dew2008
Thats not good for your engine. With a high compression you should be running a higher octane fuel.
its not bad at all actually. it has been running strong for a long time now.

[GPracer2500]

Any of you guys performed a compression test to see how many PSI your engine cranks? The 400EX is kinda unique among performance quads in that many EX's aren't using an auto decompression mechanism. I'd venture that the fast majority of 400EX's that have aftermarket pistons installed also have aftermarket cams installed that don't have an auto decomp.

That makes for easy compression readings that actually mean something. A PSI reading doesn't care about what's written on the piston's box. Compression ratios are just a number assigned to a piston based on figures from some "standard" set of engine specs (gasket thickness, deck height, combustion chamber volume, etc). Just because the piston you bought says it's 11:1 doesn't mean that's the compression ratio you've actually got in your fully assembled engine. 400EX's seem especially prone to winding up with a different compression ratio than the one assigned to the installed piston.

[AutoRoc]

VP113 here. It took care of the rich carb jetting...HA!

[440exRider187]

<---100 oc, no less