87 Octane LS Chevy Engine ??

[JEFFTATE]

Would an LS Engine run good and make good power on 87 Octane fuel ??

Scott Parkhurst built a couple of First-Gen Chevy smallblocks a couple of years ago with tight quench areas and around 9.7 to 10.3 compression or so.
With the correct head and combustion chamber combination , they made great power ( around 500hp ) on 87 Octane.

Why couldn't this build style be applied to an LS Chevy Engine ?
Maybe use ceramic coatings on the pistons , combustion chambers , and intake runners.
Then lower the compression just a little.
And still keep a tight quench area ?

I think you could make good power and save gas money.

Anybody ever done this ??

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[Mr. Camaro]

My wife runs 87-octane in her 5.3 Tahoe all the time and it runs great with no signs of knock under any circumstances.

The LQ4 6.0 liter's have just as low compression as the 5.3 so they could run on it also.

I don't think the higher compression LQ9 6.0 liter's or any LS1, LS2 or LS3 would work very well on 87-octane without custom tuning but they can run on it in emergency situations according to the owners manual for my LS1 car. The factory doesn't advise this for long term use so it must be way down on power.

[JEFFTATE]

What I'm suggesting is a custom build with modifications to use 87 Octane fuel.
And still make 500 hp.
And still get in the mid 20mpg range.

I just wonder if it can be done ???

[MastMotorsports]

We have several engines that make over 500 on 87. With Adaptive Octane Learn you can run premium or regular and you are safe with each.

[JEFFTATE]

We have several engines that make over 500 on 87. With Adaptive Octane Learn you can run premium or regular and you are safe with each.

Hmmmm.....
Sounds good.

[Mr.VENGEANCE]

what jeff.. you got a truck engine laying around or something?
gonna put it into the camaro?.... doit!

and i have the 5.3 in my 07 tahoe.. and it runs great on the 87.

[JEFFTATE]

No , I don't have any LS Motors laying around anymore.
I had a 385hp LS6 , but I got stupid and sold it.
So now I'm LS-less.

This is just a theoretical discussion.

[junkman]

I have a 00 silverado that has never seen premium, and a 02 z-28 that has had 87 in it more often than not. Doesn't seem to mind. It's not optimal I'm sure, but the pcm will pull some timing if it picks up some knock, Just put good stuff in it if you're planning on beating on it some that week.

[Vegas69]

You can run any fuel injected engine on 87 octane....but your computer will retard the timing if your knock sensor is alarmed. Your just giving up some ponies.

[JEFFTATE]

What I'm talking about here is changing some of the details of the engine so 87 Octane will work , and make the same or more power , without retarding the timing.
It has been done with first-gen smallblocks , so it should work with LS-based smallblocks.

[DaCajun]

What they did to that small block to run such a low octane with increased compression was to run some very long rods "ford 6 cylinder rods". That was a 400 block with a 283 crank, ford 6 cyl rods and AFR heads with very small combustion chambers. What this did was increase the piston dwell for a complete burn allowing the low octane fuel. It was called the 350 Chevrolet should have made. The same could be acheived with an LS1 based motor but you would need a special crank to decrease the stroke and some longer rods. The benefit of the LS1 based block is the increased deck height.

-Dave