CAMJAG

iTrader: (34)

I dont know if this is the place to ask this but my local sunoco has 103 octane unleaded and I was not sure if it would do any harm to my car to sensors injectors plugs whatever.. Also would it be back to fill the whole tank or just put in a a few gallons someone let me know about it. Thanks

SLowETz

iTrader: (12)

Unless you're running a big shot, you don't need race gas on a stock motor. Ever. Won't hurt it.... won't gain anything either.

BlackFormula01

Doesn't the stock computer only read up to 94 octane anyways? Anything higher would just be a waste of money.
Ed

Beast96Z

iTrader: (21)

What some people don't understand about fuel, is that more octane dosen't mean more power. You only need more octane to overcome detonation. Computers don't read octane either. Computers monitor knock retard, which is a sign of detonation. If your car is not detonating/pinging in any way, there is no need to up the octane. It will actually hurt your performance because the higher octane dosen't burn as fast. Motors perform the best on the verge of detonation. If you can run 89 octane in your car and not ping, then you will make more power with 89 vs. 93 or 103. Bottom line, don't use a higher octane than you have to, you will just be wasting money and power. I wouldn't run 87 though. I've seen some of the trash that comes out of those tanks, but that's another story......

SSEUL8R

If you run leaded race gas in a car with o2 sensors, you're going to end up with problems. Maybe not right away, but over time, the lead in the exhaust will coat the sensor, making it unable to read. You will get a check engine light, poor throttle response, jerky throttle, and poor mileage. Don't ask how i know. Also, like someone above said, the engine only needs enough octane rating to keep it just above knocking, detonation, and preignition. Anything more than that is overkill and waste.

8GTOKLR

iTrader: (6)

if your in california than race fuel will help alot since we have only 91oct 89 and 87 so 107 Unleaded will help and wont hurt anything also 91 or better with any computer tuning is a must. I have never heard a ls1 running on 87 poor car

Beast96Z

iTrader: (21)

This is where you are completly wrong. 107 octane will make you car slower than the 91. Read my above post more thouroughly. If you do not ping/detonate at 91, then there is no need for any more octane. Any more will only degrade performance, wether it is 1hp or 10. I also don't know of anyone running 87 octane in a LS-1. What I said was, if your car did not detonate with 87, then you would make more power. I would never put 87 in my car due to the fact that I know what is in most of the tanks, and it's not nice. Like I said earlier, you make the most power on the brink of detonation, anything other than that is for saftey or a waste.

Nasty Hawk

Would it be Good or not even worth it for myself to run 100 octane, when i know i am going to be spraying.

Nasty Hawk

Would it be Good or not even worth it for myself to run 100 octane, when i know i am going to be spraying. My friend has a 02 WS6 almost stock with 65,000 miles and the car ran great until about 3 weeks ago he started running 100 octane every time he needed gas then his SES light came on and he had 2 replace a catalitic convertor. Think that was from the gas or just time??

Jassick

iTrader: (1)

i run 93 octane just cuz it's that or 89, i also put in a tank of 95 once just to see. Maybe it was my mind playing tricks but it did seem to run a little stronger, emphasize little.

8GTOKLR

iTrader: (6)

never did i say it will make more power. you didnt read what i posted

Project_87

wouldnt running 100 octane when the engine doesnt need it, cause some of the gas left unburnt? then causing the cats to heat up while trying burn up the excess gas coming out in the exhaust? making them melt/go bad and therefore needing to be replaced? just a thought..

adillhoff

Actually, there was a study done fuels. If you put another octane in, the computer will adjust to it. So you could run the same with 87 octane as you would 93. The computer will adjust to it. The only time you need different octanes is with engines where you have to manually adjust the knock/retard.

BOONE

iTrader: (4)

If i run too high of octane in anything performance that i have ever owned, i notice a definite lessening in power. In my bikes that have stock comp ratio, if i run over 92 which is the highest we have at the pump here, it has noticeably less power. Dont use less than premium though. When you mod it, your tuner will tune for pump premium, or tell you what to use. There are other fuels that have huge hp gains if tuned for, but are hard for reg joes to use feasibly, this might have confused your information gathering. Unleaded gas will not hurt sensors, but too much octane will weaken power. Additives for octane will often hurt sensors and boost octane 10 times less than they say, but there are a couple that work ok, I would stick with 92 or 93.

SUPRYZE

True "race gas" contains lead, which will lead to an early death of the O2 sensors and catalytic converters.

Beast96Z is absolutely correct. Octane rating is the fuels ability to resist detonation. In order to make a fuel more capable of resisting detonation, they make it harder to burn. Do you really think that a fuel that is harder to burn would make more power? If your car does not detonate with a lower octane fuel, then you will gain nothing from a higher octane and may actually hurt performance and drivability. When I worked at the dealer, we would see passenger cars (Buicks) come in with 93 octane in the tank and the customers would complain of hard starts and extended cranks when cold. After we made them switch back to the ocatne rating suggested in the owners manual (87) they never had another issue.

CAMJAG

iTrader: (34)

Thanks for the info... Ill just stick to 93

Muffracing

I put a couple tanks of 92 in my '99 3.8 and it seemed like it lost power. I went back to 89 and it ran great. I think my brother now puts 87 in it.

Beast96Z

iTrader: (21)

Not trying to start a battle with you, but things like,"race fuel will help alot", and "107 will help and won't hurt anything" are not true. They could indeed hurt performance and are not needed if you car is not pinging.

Beast96Z

iTrader: (21)

Yes, the car will adjust, but it's the knock sensors that adjust it. If you put in 87 and you knock sensor pulls 5 degrees of timing, your not getting optimum performance. You want the least octane with no pinging and no knock retard. The best thing to do is to tune your car with the highest octane at the pump in your area. Usaully 91-93. Then there would be no confusion as to which octane you should run.

Pro Stock John

iTrader: (34)

1) You can use 100-104 unleaded gas with your LS1 cars.

2) Higher 100-104 gas has more octane, which basically has a cooling effect. So you definitely don't want to use it unless you need it. It will suppress pre-ignition, ie. ignition before the piston at at TDC.

3) There are many situations where you would want to use higher octane gas:
-high compression engine (over 11.75:1)
-lots of nitrous (150 shot or more) with stock timing tables
-high boost FI setup with stock or almost stock timing tables

4) My car is currently tuned to make 680-754rwhp with C16. That is leaded gas, around 116 octane. I have a BS3 SEFI system. But leaded gas will even deaden my Bosch 02 sensors that come with the BS3 (over time).

5) If you live in CA, and have to use 91 all the time, mixing in some 100 might help on a hot day at the track, but you would have to experiment. Racing on a 90F day is problematic on many levels anyway.