sonix7

I came across a place that has Sunoco fuels, I found the Sunoco GT plus 104 octane unleaded. here is the link, anyone see any problem with me using this fuel? I have basic reliabiltiy mods , intake, DP, stock twins. let me know why or why not? all opinions and especially technical answers welcomed.
http://www.racegas.com/fuelspecs/default.asp

quicksilver_rx7

Does it hurt to run 93 octane?

nopistons94

104 can clog your cat even if it is unleaded

sonix7

I am going to order a high flow cat and get to the CPU and fuel system over the winter. What did you mean by "Does it hurt to run 93 octane?" ? I am just trying to get some higher octane gas, since all I can get is 91 oct. pump crack, I know that the RON and MON are actually lower than advertised and want to avoid that range of octane. I am running 80/20 mix of 111 leaded and 91 pump crack and MMO. It likes it. I just don't like putting the leaded in there. I am replacing the cat anyway, so no big loss if it does start to clog, plus I put like 25 miles a week maybe on it. I got some boost creep going on a couple of days ago for the first time I noticed it. I just want a piece of mind that my **** isn't in the danger range of knock and detonation, can someone shed some light on this as I have not quite grasped all factors in this. just checking my list and checking it twice.

quicksilver_rx7

Octane rating is a number that is calculated to describe a fuel's ability to resist detonation. In other words, the higher the octane, the less you have to worry about detonation.

Leaded fuel is actually more explosive than unleaded fuel. Therefore, more complete combustion and better performance. The major problem with leaded fuel is the health issues associated with it.

sonix7

BTW, that is the only thing I am concerned with is resist detonation and have the car run better, not any hp increase or anything like that. Am I wasting my time or will it achieve what I want?

FLA94FD

94 vs 93 would have little impact either way. If your tuned that close to edge you need to back off the tuning at bit.

Leaded fuel was replaced because of polution, cats wont work with it.

sonix7

I am not even tuning it yet. I am running stock except for DP, intake. I just want a higher octane because I am only able to get 91 octane, I had a rep from VP racinf fuels contact me for a location out here. I also came across a place that has 104 sunoco racing unleaded fuel. I was just wondering if it is a waste of my time if I want to get into a less chance of det. situation. I just am scared about the effects of a low octane pump crack on my stock engine, I get gas from hugh retail outlets, costco, safeways, i.e., I just don't trust the octane rating and the real RON+MON is probably like in the high 80's, **** that. thats where my worries come in. I just want to know what I should expect from this type of fuel on my nearly stock setup (for now)

Bacon

iTrader: (12)

Mix it!, if the best you can get is 91 you definitely want to feed her more octane, especially if you’re looking to do any mods, And with winter coming cold air+boost+91 octane= not the best combination. If you do any track days try to run all 104, your rex will love you for it. So if the 104 is a close drive mix it with the 91, 50/50 should be more than enough.

I wish I had a place that sold 104 locally, I have to go to the track, fill up with C12, and get 15gal of C16 in jugs to take with me(then again I run 17+psi on a regular basis)

KyleH

My only suggestion is to stick with the same gas station for all of your fill-ups. For what it's worth, I would suggest a good company like exxon/mobil or Shell. They have superior additives, IMO. The most important thing is to stay consistent and tune on the fuel you always use, to avoid variation of characteristics as much as possible.

Jesuscookies

iTrader: (1)

For what you have on the car, it is a complete waste of money.

sonix7

even the reassurance of not using a low octane gas, still not worth it? I think I understand what you are saying though, let me guess, if I am not running higher levels of boost then I shouldn't have any worries about my knock or any detonation, right? I plan to up the fuel and exhaust and get a p-FC for the car over the winter, which is real soon. I have all reliabilty taken care of, now working on mods. I do have cold *** air in the winter and low octane gas, best supplier retail is texaco. I like the 50/50 mix idea. I just don't trust the octane level of the gas, I guess if its not going to damage anything then the 104 is what I will get and 50/50 mix it up. I just love my ride like that, plus I get to have fun when I want, not drive the thing cause I have to, so gas mileage is not a huge issue. Thanx for all the responses.

rynberg

The first and only logical and accurate response in this entire thread.

What a load of horseshit.

He's got a stock ecu and some bolt-ons. Give me a break. I guess the hundreds of FD owners in Cali are all screwed running 91 then.

I do run 100 unleaded when I road race the car but only as insurance and only because the motor runs so hot for extended periods. If you are running 17 psi on a single turbo, I would agree with you, but this octane obsession for cars running on the street with a few bolt-ons is equal to the oil obsession so many people here seem to have.

sonix7

I am not saying Cali people or anyone else for that matter are screwed, but more so that you don't have to worry as much. No? So the only reason to run higher octane fuel is if you are running more boost, period! correct? Otherwise it is a waste. No other benefits at all? Thats all I want to know. If so then your right complete waste, if I can help prevent detonation and knock with a higher octane gas then I find it valuable. If you tell me it does not do this then I am satisfied. I am getting confused as to what the purpose of higher octane fuel is, sounds like an opinion based issue. Where is the proof? What does higher octane gas do in relation to the FD at any level, stock or modded?

rynberg

Higher octane fuel resists being ignited as easily -- resists pre-ignition and detonation. It is completely unnecessary, no matter the ecu or bolt-on mods, up to 15 psi or so for street use. Like I've said before, I do run 100 octane as insurance when road racing, but it's impossible to drive your car anywhere near that hard on the street.

Anything higher than pump gas on a car with bolt-ons is an absolute waste of money for street driving. Guys running very high boost on modified/stock twins or who are running single turbos are in a different category IMO.

sonix7

there we go. alright then. point well said.