so we have a few stations in town with 100 unleaded on pump. I've been wasting some money lately on a few tankful's!!!

Is there any real advantage to running this without a tune to match it? i.e cleaning the fuel system, cleaning the injectors.. increasing gas mileage?.... please tell me it does something....

(all on stock ecu)..

 

since.. if you think about it, It would be worth the 6 bux a gallon if you get a few more miles out of a tank of gas right?????

 

I think sideways did a test years ago on a stock car, it helps with the consistency of the power.

 

it helps my stock in the shell corp.

 

A stock (not FI) S2000 will really only benefit from octane numbers up to ~96 octane (U.S.). I tested a listed unleaded 101 octane (which means there were additives to boost the numbers) gasoline that was available in Oklahoma City in 2002-2006. I tested varying mixtures throughout 2004 and came to the conclusion that octane levels above approximately 96 (AKI) had absolutely no benefit (in my 2003 S2000). The compression ratio of AP2s is essentially the same (deposits from car to car make a bigger difference) and wouldn't benefit from any real increase in octane above ~96 AKI either.

You need to check the pump to see how they measure the "octane number" for the fuel you're using. If it's measured using the "RON" (Research Octane Number - as used in Europe, Middle East, and some far Eastern Asian countries) method, your basically paying $6 a gallon for 94-95 AKI (U.S. octane measurement [R+M]/2) equivalent. Definitely NOT worth the expense.
Otherwise, if the pump reads "(R+M)/2" or "AKI" for the octane rating, I'd suggest using a mixture of 91-93 AKI pump super unleaded with the 100 octane gas. The ratio is easy to calculate from there (50/50 mix of 91 and 100 octane will yield ~95.5 octane mix). Once again - if the pump says the 100 octane is measured using the "Research" or "RON" method - you're pissing away your money... or you could see it as helping jeggy's stock value.

The other issue at hand is WHAT they're using to bump the octane number up.
There are several additives that can inflate the "effective" or "equivalent" octane number (to include alcohols and lead) that are anything BUT a good idea for your car. Alcohol(s) have a lower energy content and tend to gum up fuel systems, and lead (TEL) will wreak havoc (expensive mistake) on your emission control system.

Once you resolve that you're dealing with an unleaded, high quality 100 octane fuel rated using the AKI or [(R+M)/2] method, and not artificially boosted with lots of "alcohol", I would run it in a mixture ratio that yields the best bang for the buck for you.

Final note: If you're running forced induction - I WOULD run unleaded 100 octane (AKI) fuel - consider it insurance for your considerable investment.

 

i've had cars loose power on the dyno just by putting race gas in the car while dynoing.

 

wow...

 

I have always thought you should run the lowest octane that you can without detonation. This is coming from high compression B series background.

I am pretty confident that race gas in a stock engine/ECU is a waste of money.

 

From the factory, a s2k is tuned for 91 octane, NOTHING higher.

 

if you have standalone, you can bump the timing to take advantage of the higher octane, but stock ecu will not care. i suppose you can make one map for race gas, and one for pump 93. but i dont know how much power you would pick up from the timing bump, nor do i know how much timing you could add.

my only experience was with my 2002 jetta. had an apr chip in it, and on the race gas mode, htye bumped timing by 10 degrees everywhere. you felt it and the car pulled way harder. but it was boosted, so not sure if the 10 degrees advance was beign amplified by boost. the apr 100 race program did not run higher boost though. just more timing.