Higher octane?

xXx=BioHazard=xXx · 07-18-2005, 04:27 AM

If you would use a boost or spray at all would you pretty much have to use a higher octane gas?

mason_RsX · 07-18-2005, 07:57 AM

just spray, im not sure but I would assume so...Boost definately yes, high compression definately yes

but newer engines can have sensors to gague the amount of knock, so if your running low octane gas the engine will read the higher levels of knocking and retard spark timing and lower amount of fuel injected so you will lose alot of performance...and damage to your engine is a major possibility

http://auto.howstuffworks.com/gasoline3.htm
this explains octane and knocking

drftk1d · 07-18-2005, 06:16 PM

knock sucks, to avoid it just do 2 things, dont live in california and buy higher octane gas

-The Stig- · 07-18-2005, 07:15 PM

Quote:

Originally Posted by drftk1d

knock sucks, to avoid it just do 2 things, dont live in california and buy higher octane gas

Our cars run just fine on 91 octane.

-Josh- · 07-18-2005, 07:26 PM

Quote:

Originally Posted by RedNeck383

Our cars run just fine on 91 octane.

Your standards just suck is all.

CassiesMan · 07-19-2005, 01:38 AM

Pfft, 91? I use 93.

JekylandHyde · 07-19-2005, 11:01 AM

Who wants a car that runs "fine" ... I rather have one that runs great

I run 94 octane at the pump here in PA

Seriously though, cars run best on the lowest octane they can get away with without seeing detonation. Octane is a fuels resistance to blowing up ... you want it to explode! That's what makes power. If it is too ready to explode it will ignite when it shouldn't (knock/detonation) so you need a higher oct.

In the 88, the Suburban and Jekyl I run 87 octane.
Hyde, with the turbo, gets the best I can find.
I am almost always running 110 leaded now.

nissanfanatic · 07-19-2005, 06:09 PM

Fuel octane is as mentioned resistance to the fuel burning. Higher octane fuel burns slower.

I run 9.5:1 CR with 10.5psi of boost on 93 octane everyday. I boost on hot, cold, ect days with no problems. Basically, when you encounter detonation on a certian grade of fuel, you can do these things:

1) Lower the compression ratio
2) Run higher octane fuel
3) Retard timing
4) Cool the intake charge better(AKA alky/water injection)

Water/alky injection is a very good solution to running expensive racing gas while still having the power of it.

And as jekylandhyde was touching on:

Quote:

Seriously though, cars run best on the lowest octane they can get away with without seeing detonation. Octane is a fuels resistance to blowing up ... you want it to explode! That's what makes power. If it is too ready to explode it will ignite when it shouldn't (knock/detonation) so you need a higher oct.

IMO you should run a known safe octane fuel/AF ratio and play with timing to get maximum power. BTW, if you end up having to retard timing lower than 20* Total timing BTDC, you should seriously consider #1, #2, or #4 that I listed above. WI/AI is what I would recommend.

We over on the KA-T boards tend to stay away from anything past 18:1 dynamic CR on pump gas. We end up running insanely low total timing and it is just not in any way better to run more boost with less timing.

And on every grade of fuel, there is a knock limit. Or "the maximum and mean cylinder pressures that can be achieved,"

SDSEFI Tech: Pushing it too far.

Very good read on everything engine destruction related.

CBFryman · 07-19-2005, 06:10 PM

ptshhh.... octane= HP =...duh. thats why i run 93 with NAWZ octane booster in my civic dawg.... i even put some pencil lead in there..

-The Stig- · 07-19-2005, 07:27 PM

Good post nissanfanatic.

Informative... indeed.

CivRacer95 · 07-19-2005, 08:59 PM

Quote:

Originally Posted by CBFryman

ptshhh.... octane= HP =...duh. thats why i run 93 with NAWZ octane booster in my civic dawg.... i even put some pencil lead in there..

Shit my secret is out!!

nissanfanatic · 07-19-2005, 10:32 PM

Quote:

Originally Posted by RedNeck383

Good post nissanfanatic.

Informative... indeed.

Thanks.

Zgringo · 07-20-2005, 03:07 AM

NissanFanatic, You hit the hail right on the head. Very good post, and I'd like to add #5 to it if I may.
For the hard core boost freaks or the ones running big spray numbers, TOLUENE.
With the price of gas, toluene is as cheap as gasoline, and a 4:1 mix we'll make about 98 octane gasoline.
Go to Sherman Williams paint store and ask for toluene paint thinner. It comes from crude oil and is what's used to boost the octane in gasoline by the oil companys.
Also it's legal and will pass fuel tests at the races.

-Josh- · 07-20-2005, 11:48 AM

Quote:

Originally Posted by Zgringo

NissanFanatic, You hit the hail right on the head. Very good post, and I'd like to add #5 to it if I may.
For the hard core boost freaks or the ones running big spray numbers, TOLUENE.
With the price of gas, toluene is as cheap as gasoline, and a 4:1 mix we'll make about 98 octane gasoline.
Go to Sherman Williams paint store and ask for toluene paint thinner. It comes from crude oil and is what's used to boost the octane in gasoline by the oil companys.
Also it's legal and will pass fuel tests at the races.

So that's what it's come to for you west coasters eh? Having to make your own fuel cause you got nothin but crap....

drftk1d · 07-20-2005, 12:26 PM

Quote:

Originally Posted by Z28Josh

Your standards just suck is all.

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