GASOLINE

[1988GTU]

I hafta self serve 110 to my one beater, but that's only due to a snail living in the engine bay...
My other beater (quad) actually will have kr with 91 or less. I am forced to run 92 in it if I am going to partake in spirited driving.

[3X00-Modified]

..........
And IIRC the quad actually only needs 91... now my Legacy needs 93...

You're both wrong (You and Speedy). The Quad was built to run on a MINIMUM of 90 octane. As you go up the Quads behave better.

ORLY?

2.3 L Quad 4 LG0 engine
The High Output 2.3 L LG0 was rated at 180 hp (130 kW) from 1989 to 1992, 175 hp (130 kW) in 1993 and 170 hp (130 kW) in 1994; both the 1993 and 1994 power reductions were a direct result of the first two rounds of the Quad4's NVH reductions; both being exhaust port size reductions. Changes that differentiated the LG0 from the LD2 engine were more aggressive camshafts and an extra half point of compression; 9.5:1 to 10.0:1. These engines were recommended to run exclusively on premium fuel of 91 octane rating or higher due to the compression ratio.

The High Output engine was introduced with both a special production run of 200 Cutlass Calais International Series coupes, as well as 200 Grand Am SE coupes — all featuring Bright Red paint, and grey interiors. The LG0 engine was only available with the heavy-duty (for its time) Getrag designed HM-282/NVG-T550 five-speed transmissions.[3]

From 1989 to 2009, the Quad 4 held the title of being General Motors most powerful naturally aspirated regular production four-cylinder engine. Only recently was the LG0's 180 bhp (130 kW) rating eclipsed when the 2010 model year 2.4 L Ecotec LAF launched in the Buick Lacrosse and Chevrolet Equinox. The LAF has a rated output of 182 hp (136 kW) but does so with 11.4:1 compression ratio, gasoline direct injection and variable valve timing.

There was a limited production version of the LG0 engine offered in select Oldsmobiles which used the designation W41 (listed below).

LG0 applications:
1990–1993 Chevrolet Beretta GTZ
1994 Chevrolet Beretta Z26
1989–1991 Pontiac Grand Am SE
1990–1991 Pontiac Grand Am LE with "Sport Performance Package" (RPO: W32)
1992–1994 Pontiac Grand Am GT
1989–1991 Oldsmobile Cutlass Calais International Series
1992–1994 Oldsmobile Achieva SC
1990 Oldsmobile Cutlass Supreme International Series

And the W41 had the same compression ratio so that would also fit into the same category.

But as always, what do I know over you...

And if your going off your "premium" being 90 out west, then that may be the confusion, but out here Premium is 93... we don't carry 91 unless you find a station that mixes. Our choices are regular, midgrade and premium, 87, 89, 93.

SO if you wanted to get techincal, I could say the dash says "premium fuel" so that means its rated to use 93!

Bottom line anything over 87 in a V6 is wasteful and if your getting a ping noise you either have the timing set too high for that fuel if your tuning, or there are some other internal issues causing a bump in compression which would require a higher octane fuel. MPG should and typically will not improve with higher octane fuel since it burns slower and doesn't contain any more energy than the 87 octane fuel, its been tested over and over and proven so if you experience variation when using different fuel it could simply be errors in your math, or driving style. And as I've said in other threads we started racing a GM crate engine which is stated to run on 92 octane fuel min, they made us run 110 and we lost a significant amount of power due to that... Same goes for the open engine, we found that if you would mix 93 and 110, 2 to 1 and bring the octane rating down you would make more power over running the straight race fuel, as well as save a significant amount of money.

[woody90gtz]

I tell people all the time that higher octane than you need actually doesn't burn as well as the proper octane...but some just don't get it. Some of the guys around here run race gas in derby cars for christ sake.

[woody90gtz]

I hafta self serve 110 to my one beater, but that's only due to a snail living in the engine bay...
My other beater (quad) actually will have kr with 91 or less. I am forced to run 92 in it if I am going to partake in spirited driving.

I'm surprised the quad is that sensitive, the CR is not all that high at 10:1...and they were in relatively light cars. I wonder if it is the combustion chamber shape.

My 5000lb truck is at 9.72:1 and zero knock counts when pulling a 5000lb trailer on 87.

[3X00-Modified]

Some of the guys around here run race gas in derby cars for christ sake.

It gives them the extra power to reverse into the next guy!!! LOLZ

[DTMAce]

If anyone should have an idea of how wasteful higher octane is, its me.

I ran premium fuel in the Z for 210 thousand miles. The only reason I stopped is all you guys. LOL

But I haven't noticed a difference running 87 vs 93 either. I remember even running 96 a few times. (some stations have like 6 grades of octane in Ohio)

Anyway. Only run higher octane fuel if you need it.

[Chazzman]

I hafta self serve 110 to my one beater, but that's only due to a snail living in the engine bay...
My other beater (quad) actually will have kr with 91 or less. I am forced to run 92 in it if I am going to partake in spirited driving.

You still got the Garnet Z?

[1988GTU]

I hafta self serve 110 to my one beater, but that's only due to a snail living in the engine bay...
My other beater (quad) actually will have kr with 91 or less. I am forced to run 92 in it if I am going to partake in spirited driving.

You still got the Garnet Z?

Yes, and it's since have had a motor swap and some minor mods.

[1988GTU]

I hafta self serve 110 to my one beater, but that's only due to a snail living in the engine bay...
My other beater (quad) actually will have kr with 91 or less. I am forced to run 92 in it if I am going to partake in spirited driving.

I'm surprised the quad is that sensitive, the CR is not all that high at 10:1...and they were in relatively light cars. I wonder if it is the combustion chamber shape.

My 5000lb truck is at 9.72:1 and zero knock counts when pulling a 5000lb trailer on 87.

I think the engine I bought was a decked head reman, it would only explain the octane issue with the light modifications. I'll make the effort to measure that out when I put it under the knife the next time I get a chance.

[SuzukiGhostRider]

I'm not saying a Quad will gain power or speed with higher octane, but you notice less FK and better throttle response. And yes, unfortunately , 90 octane is "premium" out here, but recall.... I grew up in the midwest where octanes went 89 , 91, 93.