My 11.0:1 c/r 466 doesn't like the local 91 octane 'premium' (piped over from the Republic of Kalifornia). It does like 12-14 degrees of initial advance and 24 at the crank and runs like crap below 10 degrees of initial advance. 100 octane at $4.70/gal is becoming oppressive at 5-7mpg and I was wondering if anyone has recommendations or comments on using bulk Toluene or Xylene (with proper proportions of mineral spirits and tranny fluid)as an octane booster?

 

George, If you come up with a receipe for this, you'll be sure to share it with us, right?

 

George,
I realize I'm still new here but how did you come to have or even want to try to use 11-1 on the street? I used to run an 11-1 small block, street and strip, and the cheapest gas I could get it to thrive on was 100 low lead av gas. You have to jet up for it as it's specific gravity is less.

You may want to consider dropping the compression. I read an article published by NASCAR and in an effort to slow down the superspeedway cars they did an experiment where the only change they made was to drop the compression from 12.7-1 down to 9-1 and those particular 358" engines only gave up 20 horsepower.

The other way to go may be to buy a few driums of Union 76 110 leaded race gas and blend it with the super to see what will suppress the ping. The Union race gas can be found for 3.50 to $4 a gallon. This is what I use in my 14.5-1 engine only straight.

 

There are still a couple of sources of buying tetra-ethyl lead. Those can really boost your octane level. Of course it's for off-road only (wink, wink). I have heard of people using toluene. I'll seee if I can find how much to raise the compression a given amount.

JJ

 

George,
From what I remember the mix on Toluene is one part in 10, or 1 gal to every 10 gal. of premium. Do a search on the web...there are two sites I remember going to with both sites using Toulene on turbo-charged vehicles.
On my blown Vette I find I can run a half and half mix of Av-gas and premium but require racing fuel when boosting AND injecting NOS at the same time. You have a few other options also:
1. Run water injection (probably your least expensive and easiest "fix" option)
2. Switch over to alcohol (will also pick up 7% more HP on average)
3. Convert to propane or natural-gas.

Deen

 

Here's a website devoted to this. Toluene's octane is 114. It has a linear affect on boosting octane. For mixing fuel the formula is 114 X % of toluene in fuel mix + octane of gas X % of gasoline in fuel mix. Example, for 10 gallons, use 1 gallon of toluene, mixed with 9 gallons of 92 octane. 114 X .10 + 92 X .9 = 94.2 octane.

http://au.geocities.com/ozbrick850/e...taneboost.html

JJ

 

Thanks bigsnag. There are a bunch of them out there, hopefully someone who has used it will tell us of their experiences. Its basically the same thing sold over-the-counter in small, very expensive containers with minimal octane increases.

This one is fron\m the vintage Triump site:

http://www.vtr.org/maintain/gasoline-octane.html

 

Let us know if you try this. Tell us if it works.

JJ

 

Well, it's not going to work because anything that has the word boost in it, automatically becomes a link to Motorhaven. Did I mention I f%(&ing hate that "feature"!!! I will email anyone the address to this page if they want it.

JJ

 

Hired Gun,

These engines were originally designed, in the 429 CJ/SCJ versions, as 11.3:1 c/r. Standard production, low rpm 429/460s were 10.5:1. I decided I'd rather put this engine together at that level than drop down in c/r. Sure has a nice crackle at that c/r with headers. Its not a daily driver, so mileage or fuel cost wasn't a primary consideration. If I can beat $4.70/gallon, that'll make me happy.

I will try the homebrew octane booster, because there are only a few, widely spread places in my local I can buy 100 octane, and report on the outcome.

 

I thought the SCJ was designed at 12.0 cr or 12+?