Using 98 through an LS1

[akust0m]

I picked up an SS the other day and have been running it on 98. I'm curious as to peoples experiences between 91, 95, 98 on an untuned/tunes LS1 with/without performance modications.

[Bravotwozero]

In my experience it made no difference performance wise between 91 and 98. And this was in a VY SS.

[edals]

THe Old Mans VY SS use to Run a bit smoother on 95 to 91, and had better fuel economy. But Why not just run 95, keep the injectors running clean

[bazza13]

98 makes a definite difference for my ss a hell of a lot smoother and better performance, 95 not to bad but 91 is crap here in nz I wouldn't use it in any car! lol

[GM GEN3]

i only run bp 98 when i run 91 the car runs like shit and get #### all kays out of it 98 is the way to go it cost more but way better for the car!!!!

[TonyJZX]

on a standard LS1 with the 10:1 ratio it hardly matters

[QldKev]

98 is a waste untuned, unless you are just using it to clean the injectors.

but why would you have a LS1 that was not tuned? Get it tuned for 98 and enjoy all the extra ponies, and the better fuel economy.

QldKev

[2DIE]

I know for the ecotecs and buicks, 98 is a lot better because of the higher compression, I always ran my car on 98, filled up with 91 once and felt like it was running on 3 cylinders. (E10 is even worse even though its ment to be higher octane)

Everyone thinks the higher the octane the better it will run but thats not the case, if the compression is too low it wont ignite all the fuel, or ignite it late ect.

I tried to find some info that I was looking at a while ago but I couldnt find it, this one though is kind of along the same lines without going in to as much detail as the one I was trying to find.

Car Bibles : The Fuel and Engine Bible: page 3 of 6

[goose202]

91 is all that is officially required for the LS1.
Until you do the sensible thing and go get it tuned for 98.

E10 has other factors than octane rating. Different energy density is a big part of it.

[crazybiker]

I know for the ecotecs and buicks, 98 is a lot better because of the higher compression, I always ran my car on 98, filled up with 91 once and felt like it was running on 3 cylinders. (E10 is even worse even though its ment to be higher octane)

Everyone thinks the higher the octane the better it will run but thats not the case, if the compression is too low it wont ignite all the fuel, or ignite it late ect.

I tried to find some info that I was looking at a while ago but I couldnt find it, this one though is kind of along the same lines without going in to as much detail as the one I was trying to find.

Car Bibles : The Fuel and Engine Bible: page 3 of 6

I'm sorry, but are you mistaken? Buick? High CR? The buick has a compression ratio of 8.5:1. That's quite low. I could destroy the hell out of my 2 stroke motorcycle, not replace the rings in it for 200 hours, and still have a better CR than that.

Ecotecs, not sure though.

But as everyone else has said, 98 will not make a difference unless tuned for it.

[Cúl-Báire]

The 98RON has a real placebo effect more than anything I believe; sure some say your car runs better, and it might get 0.2kms more out of a tank of fuel but really it will make a shit of difference unless your car is tuned for it. I am a firm believer of it's where you get your fuel that makes a difference; for example even running 98RON from a Woolies branded Caltex will make my car cough and splutter like a sick pig; however it will run fine on 95RON from Shell, BP and Caltex branded service stations (even though it's tuned for 98RON).

My opinion of course, your milage may vary!

[2DIE]

I'm sorry, but are you mistaken? Buick? High CR? The buick has a compression ratio of 8.5:1. That's quite low.

You are probably right, I never ran 98 in my Buick.

Ecotec is a different story though, when I filled up with 91 for the first time I thought "wtf is wrong with my car?", it didn't click for about half a hour and I thought it was the fuel. Ran it near empty and filled up with 98 and got the power back.

From these forums I have read that most people don't notice any gains in a standard V8 though, a few have said they do but the majority dont. With Ecotecs you will find it the other way around.

[crazybiker]

You are probably right, I never ran 98 in my Buick.

Ecotec is a different story though, when I filled up with 91 for the first time I thought "wtf is wrong with my car?", it didn't click for about half a hour and I thought it was the fuel. Ran it near empty and filled up with 98 and got the power back.

From these forums I have read that most people don't notice any gains in a standard V8 though, a few have said they do but the majority dont. With Ecotecs you will find it the other way around.

It's all in the tune.

I'm not sure what car/engine it is, but I'm sure one of them is designed with two maps in the computer. One for lower octane and one for higher octane. Either way, it's just better to get it tuned properly to run on 98, and then always run it on 98.