Wassup guys!!! I have a stock '05 Evo VIII. I was wondering if it's okay for me to put 100 octane on a stock car. It there any difference in horsepower?? Any future engine damage that I will encounter?? Your thoughts and reply are greatly appreciated.

 

It will most likely be slower due to the car running much richer, you need a tune to take advantage of it

 

I doubt 100octane will slow the car down as much as it will just do nothing. Unless the car is knocking (which yours most definitely is probably not since its stock) the added octane wont do anything unless you turn up the boost.

Putting leaded in will cause the car to become slower in your case more so than the 100. But regardless, dont waste your money. When y ou get some mods and have an MBC, throw some 100 in there and crank the boost to 24 or so.

 

as long as it's UNLEADED, you're ok. leaded race fuel will destroy your cat & throw a code. i only use 101 unleaded in the '03. it's $6/gallon, but that's cheaper than a new motor...

u might "feel" a little more pull, get almost no detonation, & attain better fuel mileage, but you will not benefit the most until u get a tune. an Ecutek flash allows u to run 2 fuel maps which would work perfect for daily driving & track days. or standalone ECU of course would do well also.

 

I actually ran slower with 100 octane compared to just straight 91 octane when I was completely stock. Our cars run way too rich in stock form. You need to pull some fuel out in order to take advantage of that 100 octane, otherwise it's a waste of money.

 

Thanks for your quick response guys. Now, i have an idea. Thanks again.

 

i have run 100 octane exclusively from day one. Crank up the boost to 25 add 100 VP unleaded and let her rip.....

 

Yeh, leaded will also damage the O2 sensors.

 

As they said, you won't see any difference unless you have a tune to support it.

 

No difference unless you pull some fuel. But the car run will actually smoother and knock free

 

What kind of gas are you running now 91 or 93 ? If your running 91 , I think 100 would make more power , but I dont think it will make more than 93 (on a stock car) . I think Shiv (Vishnu) tested this and got like 6-7 more hp on 93 vs 91

 

I don't run quite a full tank of 100, but it's pretty darn close. So far the acceleration has been smoother and I have more pull in the 4 to 6k range.

m~

 

He lives in California, so he would running 91 octane like myself. If he is completely stock, adding 100 octane will not help him. The only exception that I would see is if he added very little, just enough to make about 93/94 octane. I added 5 gallons of 100 octane to my 91 octane and lost about 2 MPH's and about 2/10ths at the dragstrip. I did this when my car was stock and when I had a 91 octane flash. It was only when I had my Xede with a 100 octane map that I gained alot of power over 91 octane by itself .

 

Running 100 will help you. The Evo has two timing maps. As soon as you get a certain amount of knock, the ECU will revert to the less agressive map. With 91, we are all on the secondary ignition map. 100 octane will prevent this. Reset your ECU, put in 100, crank the boost up to 25 psi and then tell me if you dont feel the difference.......ive done it, and my car rips...........

 

^His car is stock, he will NOT feel a difference...