50/50 Efective octane

first/thridgen · 02-15-2007

From my reading if you were to take 87 0ctane (ron2 + mon2) at a lamba 1

and add 100% meth to make a lamba .85

you would end up with 104 (ron2 + mon2)

Does this sound correct?

If you were to use 50/50 meth/water instead and increase the boost fluid amount to still see .85 lamba on the wide band

What would the octane (ron2+mon2) equliviant be?

As well what % of hp would you lose by adding water ? (compresion ratio and timing staying the same over 100% Meth)

I am running a na 13 to 1 small block chevy with stock roller cam - 260 psi cranking pressure

VR6T · 02-17-2007

You're a little to smart to be in this forum. :D

first/thridgen · 02-17-2007

Check out this online calculator:

Dynamic Compression Ratio Calculator
with Volumetric Efficiency

This is on the Hot Rodders Auction site

If I was smart I would of been able to post a link but I could not figure it out.

This calculator seems to be a acurate way of telling the Octane rating require ment needed at diferent loads - Try it out, if U are running boost OR Nat. Asp. only put in a max of 100% Ve. For part throttle openings, put in the difference of pressure from atmosphere as it calculates from there.

Example Nat. Asp. running at 15 in of merc. (part throttle) put in negetive 7.35 psi and a ve of let say 85%

Boosted - ve 85% - pressure diference from atmosphere - positive your boost presure in psi

You will be suprised at what little octane that is required under low load conditions.

My point is U can run poor gas crusing and inject alchol under load and run very high compresion ratios. Boosted Or Nat. Asp.

At least I hope the theory is correct, as my heads are cut and the engine is assembled with a very Unstreetable (Alcohol Dependant) 13plus 1 compresion ratio.

You ever get the feeling "why isn't everyone doing this", what am I missing.

02-15-2007	#1 (permalink)
first/thridgen Alcohol Injection Year: 1968 Make: Chevy Model: Camaro Join Date: Dec 2006 Posts: 32	50/50 Efective octane From my reading if you were to take 87 0ctane (ron2 + mon2) at a lamba 1 and add 100% meth to make a lamba .85 you would end up with 104 (ron2 + mon2) Does this sound correct? If you were to use 50/50 meth/water instead and increase the boost fluid amount to still see .85 lamba on the wide band What would the octane (ron2+mon2) equliviant be? As well what % of hp would you lose by adding water ? (compresion ratio and timing staying the same over 100% Meth) I am running a na 13 to 1 small block chevy with stock roller cam - 260 psi cranking pressure

02-17-2007	#2 (permalink)
VR6T Water Injection Year: 1999 Make: VW Model: GTI Join Date: Dec 2006 Posts: 23	Re: 50/50 Efective octane You're a little to smart to be in this forum. :D

02-17-2007	#3 (permalink)
first/thridgen Alcohol Injection Year: 1968 Make: Chevy Model: Camaro Join Date: Dec 2006 Posts: 32	Re: 50/50 Efective octane Check out this online calculator: Dynamic Compression Ratio Calculator with Volumetric Efficiency This is on the Hot Rodders Auction site If I was smart I would of been able to post a link but I could not figure it out. This calculator seems to be a acurate way of telling the Octane rating require ment needed at diferent loads - Try it out, if U are running boost OR Nat. Asp. only put in a max of 100% Ve. For part throttle openings, put in the difference of pressure from atmosphere as it calculates from there. Example Nat. Asp. running at 15 in of merc. (part throttle) put in negetive 7.35 psi and a ve of let say 85% Boosted - ve 85% - pressure diference from atmosphere - positive your boost presure in psi You will be suprised at what little octane that is required under low load conditions. My point is U can run poor gas crusing and inject alchol under load and run very high compresion ratios. Boosted Or Nat. Asp. At least I hope the theory is correct, as my heads are cut and the engine is assembled with a very Unstreetable (Alcohol Dependant) 13plus 1 compresion ratio. You ever get the feeling "why isn't everyone doing this", what am I missing.