I have. There wasn't a noticable difference. My launches were not very good back then, but I was still running very similar times to the 93 octane runs. The worse was still within .5 sec of the highest ET. This was also in the middle of summer, hot lapping.

 

When I bought my LT1, it ran like complete and utter crap (not to mention it was wrecked), the owners though it had serious issues. It hesitated a ton, pulled timing like crazy, and just wouldn't drive well over 2500 rpm. Plugs/wires/coil helped a bit, fuel injector cleaner through the tank helped a bit, but it still wasn't reliable. I ran the tank dry and filled her up with 91 octane and a can of seafoam and she's run damn near perfect ever since (except false knock from an exhaust leak, but I recently fixed that.)


All in all, running 87 in my case was the culprit of terrible gas mileage, hesitation, and a loss of obvious power. Of course, it's an LT1 so it might be slightly different.

 

Does anyone actually read their owner's manual? LOL. The fear mongering and scare tactics are unbelievable.

Unless you're going to be street racing every day (like that doesn't affect the longevity of your car) you can use 89 or even 87 octane gas.

From my 2001 Pontiac Firebird owners manual, and I quote:

"If you have the 5.7L V8 engine (VIN Code G), use premium unleaded gasoline rated at 91 octane or higher FOR BEST PERFORMANCE.

YOU MAY USE MIDDLE GRADE OR REGULAR UNLEADED GASOLINES, BUT YOUR VEHICLES ACCELERATION MAY BE SLIGHTLY REDUCED."

Case closed. End of story. I have occasionally run 89 octane in my Firebird since gas prices are sky high and have noticed no discernible difference in most driving conditions.

Besides, the GM owners manual says you can do it!

 

That's all fine and dandy for you. But for me this line is everything ''BUT YOUR VEHICLES ACCELERATION MAY BE SLIGHTLY REDUCED. Why would I want to intentionally make my muscle/sports car slower to save $1.50 per tank of fuel? If my money ever gets that tight where $1.50 is going to make or break me then I'll sell them all and buy a econobox.

 

Besides, you may get worse fuel mileage with reg or mid grade due to reduced timing. negating ANY savings. Which will be - at most - a couple of bucks.

AND if (heaven forbid), you have a problem that doesn't allow the car to react to that reduced octane in the tank and you hurt it due to detonation; what does it save then? certainly not the motor.

Fill your high performance cars with premium. they were designed for it.

and Ill admit, in the dead cold of winter where you see temps below 20 degrees f; you might get away with it. and Ive thought about it. BUT for a buck or 2, again, why bother.

Heck, Ill make it simple for you. IF you drive the car all year round, at an above average 20k miles a year. you might fill the tank 80 times, at 250 miles per tank. (low side estimate for those who drive a lot of city.) at 2 dollars more per tank, thats a whopping 160 bucks a year saved. You'd save more by not paying insurance and maint costs on a vehicle that gets classified as a performance vehicle.

 

I always love reading all the fear posts about this topic. It is pretty funny usually.

I will say this...my Corvettes always get 91.

My wife's beetle turbo is 91+ ONLY...not recommended...ONLY. Her friend has owned it since new and ran 87 octane in it for the first 106,000 miles. It now has 132,000 and hasn't managed to blow up yet.

If you want to run 87 go for it, just realize you might lose a FEW HP. As for your engine exploding I think you might just be ok.

The person who drained their tank and filled with 91 probably just had a tank of bad gas...which will cause hell with the car in every way possible.

 

Buy a honda civic if you want to be cheap and detune the crap out of a V8 muscle car. Enjoy your detonation.

 

lmao... i have 185,xxx miles on my 98 LS1 since i just use it as a work car i put 87 in it and can still outrun any car at work... not much of a struggle either... and it gets 100 degrees here in alabama... the trans went but not the motor... the LS1's are very strong cars... i know mines been put through the ringer quite a few times and still pulls like a champ!!! so 87 isnt gonna do anything that your gonna notice by the seat of your pants... just my 2 cents

 

If you race your car/if you're all about getting the absolute most out of it at all times (as we all should be imo), run 93. If you wanna save a few bucks due to outrageous gas prices and take that over the overall performance of your car, run 87. There, problem solved.

 

That is just silly. With this logic you'd be tuned to run 110 octane racing fuel at $10-15 a gallon.

Why if you race your car and want every last bit of performance are you doing things half-assed and running pump fuel at all?

 

Been running 87 in 204000 mile 98 LS1, no probs. Little pinging on hills in hot weather. Seems to work for me

 

Why, Oh why would you run 87 in your Big V8 Engine.

 

I was referring more to street driving than all out racing. If the car in question is an all out track machine, then yes, I agree, I doubt the owner would use regular pump fuel.

The "logic" you're speaking of isn't mine (at least not when it comes to my Z, she ALWAYS gets 93, so none of this really even applies to me). I was just raising the point that people in general with this mindset are more concerned with saving a little money over getting the most out of their cars. Call it silly, call it what you will, I was just stating a fact.

 

There is a performance difference between 87 and 91/93. This is documented by both GM and the end user. There is NO BENEFIT to running 110 in a stock LS1.

To those of you who think 87 is OK... it is. Just keep in mind that you justifying it by difference in fuel prices is foolish at best. If that small difference in cost means that much, imagine when you find out you're not getting all the power you PAID FOR. If you don't want the full 330-340hp GM provides for you, maybe you should have saved some money and bought an LT1 or even a V6.

 

Why would you buy a V8 muscle car and run 87 in it??? To save $1 or so a fillup?

Change your lingerie and go buy a Corolla for crying out loud.