Premium Fuel In Ultra?

[armyman06]

I am looking at a late model Park Ultra. I am a big fan of the 3800. It has good power but its no power wagon by any means. I especically like the gas milage and the regular fuel. I read where the supercharged 3800 requires premium fuel. Just wondering if everyone runs premium in theirs? Any additional info would be helpful. Thanks.

[tomeeg]

I typically use 93 octane, but when the prices skyrocketed, I dropped back to 87 and 89. I don't see much of a difference in mileage or performance with different fuel grades, but I'm sure the engine was designed to burn the higher octane, especially with the SC, so it's probably best to stick to the premium fuel.

[parkav93]

When gas prices are out of this world I have had to use 89 and even 87 octane fuel in my 93 ultra but that was only when 93 octane fuel went to $2.00 a gallon where I live. It is not a good idea at all to do that if you are going to have to excellerate in such a way that the supercharger has to work, like on a highway or an interstate. The reason is that that supercharger is trying to pump a heck of alot of air into the cylinders and the pistons can't speed up as fast as the incoming air is trying to get them to do because of the slower firing time of the low octane fuel. Therefore the engine has to work too hard to meet the demands of the supercharger and that causes stress on all of the moving parts of the engine. The valves will chatter very loudly in this kind of excelleration which causes alot of wear on them. Basicly you will damage the engine if you do that alot. Also the engine is disigned for the premioum fuel so the fuel injectors would become clogged alot faster. Easy excelleration is ok but don't gun it! Gas mileage of the 3.8L supercharged is raited only one gallen below the regular 3.8L about 29 for sc and about 30 for none sc. Your best bet would be not to buy a sc park avenue if you can't afford the gas for one or only use lower graded of fuel when you only have to.

[mojodojo2k]

I agree with ParkAve93...gunning the engine with anything less than 91 octane makes a serious disturbing noise under your hood. Actually i think premium fuel is rated at '93 now....i haven't found any gas station that sells '91 octane, well maybe those 'mom & pop' gas stations in Hicksville might, but i'm a city folk so i haven't seen any gas station that carries it myself. I'm a broke college student but i ALWAYS put '93 octane in the tank and I try not to gun it when some punk kid with a "tripped out" Kia is revving his engine next to me at a red light thinking his .8 liter is gonna blow my doors off.....grrr, when will kids learn!!!!!! I own a '94 PA Ultra and compared to my last car which was a Chevy Caprice, this car sucks down gas. I just bought the car last week so i'm still trying to adjust to the smaller gas tank...lol. But the point of this lame reply is that when i first bought my car i put 89 octane in it and the engine seemed to idle rougher and acceleration wasn't that good. So then i read the car manual and learned that premium fuel is needed because of the supercharger. So i have been using premium fuel ever since and have noticed a considerable change in engine quietness and speed (mainly on highway).
Thank you!

[parkavenuechrome]

the Super charged Parks need 93 octane.. Best thing for the motor.. 87 will detinate like crazy and kill your motor.

[aarcuda]

Originally Posted by parkav93

The reason is that that supercharger is trying to pump a heck of alot of air into the cylinders and the pistons can't speed up as fast as the incoming air is trying to get them to do because of the slower firing time of the low octane fuel. Therefore the engine has to work too hard to meet the demands of the supercharger and that causes stress on all of the moving parts of the engine. The valves will chatter very loudly in this kind of excelleration which causes alot of wear on them. Basicly you will damage the engine if you do that alot. Also the engine is disigned for the premioum fuel so the fuel injectors would become clogged alot faster.

Low Octane gas burns faster that high octane gas. octane is the gas ability of the gas to resist combustion (or self combustion , ie, detonation). Higher octane gas combusts slower and can be squeezed more before it self detonates. Thats why higher compression engines (or engines which squeeze more gas into the cylinders-higher cylinder pressure) needs high octane gas. to prevent the gas from self combusting before the spark plug fires it off.

octane has nothing to do with valve chatter (valve chatter is more than likely detonation which sonds like a bunch of marbles in a tin can) and higher octane gas does not keep injectors cleaner unless the gas company puts some sort of injector cleaner into the gas.

[GSteven]

I have been running 87 octane in my 94 PAU with no detonation or other noticable ill effects.

[mojodojo2k]

...yeah you're right. I just started using 87 octane in my '94 Ultra and the only thing i noticed was a horsepower loss on the highway. I'm with GSteven...nothing wrong with 87....that is, if you're engine is running smoothly!

[aarcuda]

the reason for the horsepower loss is most likely the detonation. but you dont hear the detonation because the engine has knock sensors on it and as soon as the knock sensors pick up the detonation, they retard the timing so it stops detonating. when the timing gets retarded, the power does down.

[vljenewein]

I put 93 onctane in most of the time, and when it's about 1/2 empty I will fill up with 89 octate (regular PLUS) which is the same price as regular at our local station. I figure that the combination of 93 and 89 will get close to the 91 needed for this engine.