Premium Gas For GTP

[Markusss]

With the price of gas going sky high, I was wondering if my 2000 GTP could take a lower grade of gas. What would happen if I put regular or midgrade gas?

[BNaylor]

Originally Posted by Markusss

With the price of gas going sky high, I was wondering if my 2000 GTP could take a lower grade of gas. What would happen if I put regular or midgrade gas?

Its possible depending on the circumstances. Even GM says that you can go as low as 87 octane in the SC Series II 3800 but in emergency situations only.

If detonation is sensed due to the lower grade fuel, the knock retard (KR) will kick in which will alter spark advance and timing to compensate. The end result is degraded performance. Extended occurrences may result in engine damage.

I've heard of GTP owners using mid grade unleaded but they put in spark plugs that are a range colder. Personally, I'd stay with 91 octane or better.




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

[ericvrose]

The price difference for a full tank would only be about $2 or less so is it really worth risking engine damage.

[richtazz]

I took a trip with my mother-in-laws 04 Buick P-Ave ultra and she filled it up before we left with 87 octane, we averaged 22mpg on the way there. We filled up for the return trip, with 93 octane, and averaged 28mpg. If your car is affected the same way, I'd stick with premium.

[jimmytroanoke]

Originally Posted by richtazz

I took a trip with my mother-in-laws 04 Buick P-Ave ultra and she filled it up befroe we left with 87 octane, we averaged 22mpg on the way there. We filled up for the return trip, with 93 octane, and averaged 28mpg. If your car is affected the same way, I'd stick with premium.

I've found the same thing with my Toyota Avalon(10.75:1 compression ratio). The improvement in mileage cancels the extra cost of premium. Any engine with high compression, or a super/turbocharger will get better mileage on premium.

[BNaylor]

A lot of GTP owners would probably find the issue of fuel economy and cost of fuel moot because of the performance aspects and many are modded. I pay $5.50/gallon for VP Racing C10 unleaded fuel. However, th GTP is not my primary mode of transportation.




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

[richtazz]

what does that beast of yours run in the 1/4 Bnaylor? Sounds like you're hunting mustangs

[BNaylor]

Originally Posted by richtazz

what does that beast of yours run in the 1/4 Bnaylor? Sounds like you're hunting mustangs

Mustangs??? Hunted and killed. Of course safely at the dragstrip. I only pick on the Cobras. The GTs are a waste of time.

1/4 mile is nothing spectacular. With just bolt on type stage 1 type mods in May 05 she's turned 13.62 @ 102 mph with a 0 -60 ft time of 2.09 seconds. I'm working on a second stage of mods. Just put in a ZZP Stage 1 72mm throttle body and got the cold air tuneable Granatelli MAF tuned in. Working on installing headers and 1.8 ratio rocker arms. I'll try another series of runs in August. I'd be happy with consistent low 13s.

My goal was to keep it fun and fast but within the limitations of the 4T65E-HD tranny and without blowing the engine or supercharger.




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

[dmasjz45]

why use 87 octane in any engine..i have only a gt but with mobil 1 synthetic and 93 mobil octane gas, i bet my heads look pretty damn nice with 86k miles...i've seen how gunky engines that run 87 octane look compared to 93

[richtazz]

There is no reason to use a higher octane than your engine requires. There is no benefit whatsoever. the only time it's advisable to up the octane is if your engine starts developing knock due to carbon build up, but that's rare these days on multiport injected engines. As far as your car bnaylor, a 13.62 is nothing to sneeze at, and you can fit 3 adult friends and their golf clubs in your car. Can a Cobra owner say that?