I have a 97 LT1 and should I put cheap 87 or 93. I heard 87 hurts the LS1 from studies bec it has to run a lower stage ur suttin. Or does this matter if I have ever my computer done then it will take advantage. I always put 93 and I can afford it. I put 87 couple times and the gas peddle feels less responsive sometimes and doesnt feel as hard. I dont know.

 

A minimum of 91 octane, and 93 if you have it.

 

if you get the computer tuned for 93, run 93 or it will hurt performance and MAY blow the motor. stock the manual says to only use 91 or better, but 87 won't blow it. running 93 you won't FEEL an improvment.. but you might gain a few ponies...

 

dont be a cheapazz...run the 93.

 

Technically, if you did run 87 octane and you scanned the car and if no knock is present, then you could get away with it. But it would be easier just to spend the extra couple bucks a week and put in 91 or greater as the owner manual states.

 

ur really not saving much by using 87 anyways, think about it

down the line it will kick ya in the a$$ if u keep using 87

 

I put 87 in my LS1 once & it souned like a diesel.

 

Don't forget about altitude. Higher altitude doesn't require as much octane. Don't know your altitude, but keep that in mind.

Ken R.

 

owners manual says

"if you have a 5.7L engine (VIN Code P), use premium unleaded gasoline rated at 91 octane or higher for best performance. you may use middle grade or regular unleaded gasolines, but your vehicle may not accelerate as well."

but i wouldn't take the chance, i always use 93

 

I have 2 LT1s. The one in my 94 runs awsome on 89 with no knock retard. While the one in the wifes 96 vert has to have 91 or 93 and even then is not totally knock free.

I'd run what your car wants. I wouldn't even bother with 87 as I doubt it would like it.

Re'

 

My aunt has a 97ss w/ 160+k on it she has had it since new, and always runs 87. IT's a F()@*&n Factory freak, barks 4th hard (m6)

 

Final answer: Generaly speaking,high-compression engines need high octane fuel to prevent pre ignition which can ruin your engine. JMHO

 

I could chirp 3rd in a 160hp ranger chirping tires doesn't mean it's a freak.

 

If you use low octane fuel, the PCM will detech knock and reatrd timing. Not only will this decrease performance, as previously noted, but will kill mileage, thus negative any savings. Thus the recommendation to use premium.

Rich

 

4th? If you're shifting out of third at redline, that's close to 100mph. No way a stock LT1, freak or not, barks the tires going into 4th at 100mph.

You're probably letting the revs fall too much, popping the clutch a little too fast, and getting a reverse chirp.