octane

Bucketlist · Bucketlist's Garage

What does the brain trust think about the fuel used in your cars. Do you buy 93+ from the pump or use an additive?
One of the stations in town has started offering 93 and 101 octane fuel from the pump. Since I don't race my car I have felt fairly comfortable with an additive. My current choice is RACE GAS | Racing Fuel Concentrate which I buy in quart cans. Should I change my thinking?

Mick_D · 03-04-2016, 07:47 AM

I like the idea of using methanol and water injection to effectively increase octane and decrease operating temps. How many tanks do you get out of a quart of that? 30 bucks a quart vs 8 bucks a gallon of methanol/water that I can get 2500 miles out of might not be a thing.

Dai · 03-04-2016, 07:53 AM

I would mix some 101 with the 93 to get desired octane for both my car and my wallet. That's a great gas station.

xbmwguy · xbmwguy's Garage

i bet that 101 contains lead. great for our non cat cars, no so good for your o2 sensor for the lm2

krasuskyp · 03-04-2016, 07:18 PM

good point, Frank

tho

wb02 sensors are cheap and quick enough to swap heh heh

I like the blend approach on the rare treat it occurs

kenikh · 03-04-2016, 07:45 PM

100 is typically unleaded. 110 and 118 are leaded.

Alan L · Alan L's Garage

Lead will kill the WBO2 sensor in a matter of a few hrs.
I used to use Aviation fuel in my race car - highly leaded. Had to go to unleaded when I needed AFR.
Alan

Bucketlist · Bucketlist's Garage

Quote:

Originally Posted by Mick_D

I like the idea of using methanol and water injection to effectively increase octane and decrease operating temps. How many tanks do you get out of a quart of that? 30 bucks a quart vs 8 bucks a gallon of methanol/water that I can get 2500 miles out of might not be a thing.

91 octane is the best premium available around here before this source. I usually add about a quart of Race Gas additive to a tank thinking that should equal about 93+. The cost would be about the same as using the 93 from this pump or mixing 5 gal of the 101 with the 91....

I have always liked the idea water/meth. Any recommendations?

kenikh · 03-05-2016, 06:47 AM

Snow performance has a good reputation. I've had a few qualifies sources tell me if you use water meth, keep the mixture under 50% alcohol. Something to do with long term corrosion of Nikasil on cylinders.

Alan L · Alan L's Garage

There are some good threads on water /meth. A well trodden path.
Regards
Alan

lite75 · lite75's Garage

If its sold for street use I bet that 101 is unleaded. I ran the unleaded 100 for a while and you can definitely get more power from it with some tuning. However at $8.50 a gallon it makes E85 very appealing.

Mick_D · 11:50 AM

Quote:

Originally Posted by Hot Euro

I have always liked the idea water/meth. Any recommendations?

The one I have experience with is Snow, I put a stage III system on a 5.7L Challenger that had a Magnusun 2.3L supercharger on it. It was was configurable in many ways, the simplest of which was a simple analog injection curve that followed the throttle, with a kill switch on the whole thing so if the tank ran dry I could just remove it from the loop entirely. If you aren't running an EMS or a computer-controlled EFI this is probably the best way to go. I think the stage III runs about $1K but a stage 1 would do the above for under $500. Instead of paying $16 or more a gallon for their methanol/water mix, I used windshield washer fluid that was rated for -20 degrees Fahrenheit, which has about a 52/48 mix of water/methanol, costs about $8 at Autozone, and ran for about 800 miles a gallon in the above-described configuration. A fun thing was that since I had it plumbed to the windshield washer tank, I even got a little alert on the dash when the tank ran low.

I never did any investigation into how high an octane boost I was experiencing, mostly because I had no idea how to do it, but I can tell you that the difference between having it engaged and not having it engaged was noticeable in terms of power and throttle response, and if it was a hot day the difference was even more noticeable. In a different configuration using the car's ECU and the Snow programmable controller, I got 41 extra horsepower on the dyno on a day of 92 degrees F with 77 percent humidity. This is pretty good, but the weather conditions here change dramatically pretty quickly and I didn't want to have to retune the car every time the weather changed.

I am probably going to use meth/water injection on my '75S, but before I do I need to get it back from the painter and get the motor running.