Fuel octane required running 9:1 engine. RON V MON

[Howieau]

Hey I understand that when making big power out of a higher compression you have to use a higher octane fuel to cope with detonation issues etc.

Is there anybody here running 9:1 on a turbo engine, what fuel are you using and what power are you making? Can you make good power out of BP 98 octane fuel or shells higher octane fuel? Or do you have to move up to some more hardcore shit.

I dont want to jump into building a 9:1 engine I can't afford to run haha.

[legend]

the 4agze runs 8.9-1 and a lot are converted to turbo and run fine the std ecu with moderate boost and 98 ron fuel
but what ecu will u be using and what boost are u planning to run

[pisso001]

My dads old race car had a compression ratio of 11:1 and he ran it on the 98 stuff went well.. Made about 200BHP out of a 2L.. It wasnt turbo though...

Probably not that helpful but you never know...

Thanks,

Pisso.

[Howieau]

Cheers guys.

Ill be running an EMS computer, and was hoping for over 20psi but now that im going a higher compression ratio im not sure what I can run. I want to run as much as possible down the track a bit. I hear guys are putting 20psi into 3sgtes on 9:1.

[JustCallMeOrlando]

So long as it's tuned right and preferably intercooled it's entirely possible. There is a S2000 getting around Perth with turbo and 11:1+ compression.

It's all in the tuning. Don't get fixated on a boost pressure either, remember, every psi of boost at a higher compression = more power and more compression gives better driveability off boost.

[Norbie]

There's no direct relationship between static compression ratio and fuel octane requirement - there are too many other variables which influence the engine's detonation threshold. Cam timing, combustion chamber design, even the position of the spark plugs have an effect.

Generally speaking though, a modern engine with 9:1 compression will have no problems running plenty of boost. FWIW the late-model 2JZ-GTE (the VVTi version) has 9:1 compression from the factory and people have no problems cranking up the boost on 98RON pump fuel.

[The Real Roadrunner]

on the money norbie, vvti 1jz 9.5:1 according to some spec cheet not sure if they are correct though.
the engines VE has alot to do with how much timing you can run ie: more efficient=less timing and vise versa.

in theory you could build a 13:1 motor and then change cam overlap/timing to bring the static comp down (psi on comp tester). some big turbo drag engines are built this way by various builders to bring boost in earlier.

talk to an engine builder or others that have played with your intended engine and see what they would use.