High Octane Gas?

[ViperJames]

There is a Sunoco station pretty close to my house that gets 100 Octane gas around this time of year...NOT cheap I think it will be around $8.00 per gallon. My buddy buys this to put in his 500HP 300z TT when he tracks the car. He says the difference is amazing. I was wondering if anyone here has done this with their Vipers for track time? I have a few up and coming track events and i am considering it...what are all your thoughts?

Thanks

 

[Rizzo]

I think if you put 100 octane in a car designed for 91 octane you will loose hp. If you are running a high compression engine or a turbo or super charger that is a different story as you can take advantage of the higher octane. Putting that in your Viper wont hurt anything but it will not make you any more hp.

 

[Purdue_Boiler_Viper]

Today's engines are engineered for a given octane of gasoline. Unless you change that engineering, e.g. the ECU program, etc., using a higher octane gas will only burn the dollars in your wallet faster.

So, your friend is mistaken, unless he is reprogramming his ECU for the 100 octane gas.

 

[Joseph Dell]

I _thought_ (and we are talking rice so i don't know for sure) that some of the ricer engines a) have knock sensors, and b) are self-optimizing based on octane. put another way, the car will auto-detect some of its limits and correct accordingly.

I don't know this for sure, but i was pretty sure that _some_ cars do this. Again, not sure about this one in particular...

JD

 

[snampro]

ditto, your friend is ******** if he thinks higher octane is increasing horsepower without reprogramming. What he's doing is ******* $8.00/gallon out his exhaust system.

I thought knock sensors only pulled the car back, not turned it up.

 

[ViperJames]

ditto, your friend is ******** if he thinks higher octane is increasing horsepower without reprogramming. What he's doing is ******* $8.00/gallon out his exhaust system.

I thought knock sensors only pulled the car back, not turned it up.

I apologize if my inital post was misunerstood, i never stated that my friend said it would increase horsepower. What he said it would do is make the car run smoother under very high stress (racing) or beating the crap out of it to maximize results in other words. He has been racing for 20 years and builds race engines for a living. So I would like to think he is not ********. The only thing I can say is that he races and builds 300z's not Vipers. So that is where the difference may be.

 

[snampro]

yeah, sorry, that sounded a little harsh, just kidding and it came across rough.

bottom line: don't run 100 octane in your stock VIPER unless you get it tuned, its just a waste of money.

 

[banton]

Your friend may be running higher octane for a couple of reasons:

- Slower/cooler burning to avoid detonation or pulling timing (reducing power) from prolonged and increased cylinder heat generated from the FI set-up.
- Being he is running a TT set-up, he is likely running a stand alone EMS, so he uses the higher octane to be able to increase boost from normal street/pump gas levels when he races the car.

As noted by others, unless you have modded your car to take advantage or that requires higher octane, you will be basically wasting your money.

 

[FE 065]

Everyone's right so far..the 100 octane is leaded fuel isn't it?

 

[Mccarlin]

No the 100 is UNLEADED! the highest octane unleaded is 104, after that its all leaded

 

[banton]

No the 100 is UNLEADED! the highest octane unleaded is 104, after that its all leaded

Whatever you do, don't get us starting on MON vs. RON ratings or the impact of leaded vs. unleaded when mixing to get a certain octane mix, Mike

 

[Purdue_Boiler_Viper]

Hey wait a minute! You weren't talking leaded RON were you? That changes everything!

 

[ViperJames]

Yes we were talking UNLEADED. Okay so I guess I will be keeping my money in my pocket! Thanks guys.

 

[dyeguy]

I live in Arizona and the highest octane gas we can get at normal stations is 91 so I do like to put a couple gallons of 100 octane in with the 91 when I go to the track just in case I got some bad 91 and could be running a little lean at the upper rpm range. It's for peace of mind, not extra hp.

 

[kwkshift]

No the 100 is UNLEADED! the highest octane unleaded is 104, after that its all leaded

Actually, my buddy just got his race gas delivered yesterday. He's going to be using Sunoco 109 unleaded. The fuel guy said that if that wasn't enough, he also has some new 114 and 120 unleaded! (This is for his Ford GT with a 3.3L Whipple with lots of boost.)

My car has an 11:1 510 stroker and it runs just fine on 91. On the dyno, we were making timing adjustments when I had some race gas in there and we couldn't get any more power with the more agressive timing curve than the 91 octane tune. So, I just put it back to the 91 tune and that was that.

 

[YouWish]

yeah, sorry, that sounded a little harsh, just kidding and it came across rough.

bottom line: don't run 100 octane in your stock VIPER unless you get it tuned, its just a waste of money.

How about running 94 octane in my Viper is it better than 91? I'm just talking about daily driving.

 

[CROM]

Nope, save yourself the 20 cents/gal and run 91.

 

[banton]

No the 100 is UNLEADED! the highest octane unleaded is 104, after that its all leaded

Actually, my buddy just got his race gas delivered yesterday. He's going to be using Sunoco 109 unleaded. The fuel guy said that if that wasn't enough, he also has some new 114 and 120 unleaded! (This is for his Ford GT with a 3.3L Whipple with lots of boost.)

Sunoco 109 unlead is only 99 MON.
Sunoco 110 leaded is 105 MON.

That is why you can't go by the RON figures when it comes to fuels. Even the same 109 RON figures between fuel companies can have different MON ratings. I believe the VP 109 unleaded has a MON of 101 vs. Sunoco's 99 MON. When you start getting to these types of octane requirements, my guess is the leaded is probably more cost effective and will provide better performance/protection too if the 109 unleaded isn't enough. Unless one is still running cats or depending on the 02 senors being used, the leaded would be my choice or a mix of leaded and unleaded to get to the desired MON rating for a particular tune.