: What gas grades do you guys use?



ocmdiaz714
07-29-09, 02:53 AM
I was on this website that gives you information on how to maintain a good MPG, what gas grade to use and etc. I saw my 1994 would run best with premium gas. I was using 89 and the previous owner used 87 and it failed smog due to high NOx. I'll be using Shell premium from now on.

Stingroo
07-29-09, 03:23 AM
I'm curious, but why Shell?

CTSV OWNER
07-29-09, 11:41 AM
In my 1995 Fleetwood I use 87 octane all the time. It just passed NJ state inspection just fine. Last tankfull I went 330 miles and took 16.2 gallons to fill. Thats just barely over 20 mpg


Dave

dirt_cheap_fleetwood
07-29-09, 01:25 PM
I use BP 87 octane. BP because its has less foreign oil and more domestic oil compared to other stations that use nothing but imported oil.

jayoldschool
07-29-09, 03:56 PM
I believe the only 80s/90s RWD Cads that are spec'd to use high octane are the 4100 cars.

dirt_cheap_fleetwood
07-29-09, 04:13 PM
Even the 4100 can run on regular, but it doesn't have a knock sensor so if it starts to detonate you can damage the engine. That's how it is in all the 4.x engines.

drmenard
07-29-09, 04:17 PM
I use 87 octane... these cars were made to run on 87...If you could retune your ECM to run on 93 octane, you would get more power... but without the retune, your wasting your money...

jayoldschool
07-29-09, 04:34 PM
Even the 4100 can run on regular, but it doesn't have a knock sensor so if it starts to detonate you can damage the engine. That's how it is in all the 4.x engines.

I wouldn't. The manual specifically calls for high octane. Running lower octane at best means less power, and that is not a good thing with the 4100 cars. At worst, detonation, and the 4100 does not need anything that can exploit its fragility...

csbuckn
07-29-09, 04:55 PM
So is this probably the reason that my built 350 is throwing a knock sensor code. I use 92. Should I go back to 87 or maybe 89

ocmdiaz714
07-29-09, 06:46 PM
The 94 FWB is 4100?

sven914
07-29-09, 06:55 PM
The 94 FWB is 4100?

No. It has a Chevrolet 350, if I'm not mistaken.

The owner's manual should tell you what grade to use. I'm not sure what options the FWB had in the engine department, but I know other vehicle manufactures require different fuel grades, based on the vehicle's options.

What ever the recommended grade is, you should use the next highest grade, once a month, to improve engine performance.

Stingroo
07-29-09, 06:56 PM
No the '94 FWB has an LT1.

sven914
07-29-09, 07:04 PM
No the '94 FWB has an LT1.



a.k.a: the 5.7 Liter, 350 cubic inch engine built by the Chevrolet motors corporation.

DerMann
07-29-09, 07:22 PM
I use 87 octane exclusively. Every other month or so, I like to put 93 in with some of that fuel injection cleaning stuff.

dirt_cheap_fleetwood
07-29-09, 07:35 PM
a.k.a: the 5.7 Liter, 350 cubic inch engine built by the Chevrolet motors corporation.

Actually, they are different. The LT1 has reverse cooling and a a different ignition set up as well as other differences. My car (and others up through '93) has the standard "350" that is being referred to. The LT1 is a different engine. An LS1 is a 350 CI engine as well, but nobody calls it a 350 because it is a different engine.



I wouldn't. The manual specifically calls for high octane. Running lower octane at best means less power, and that is not a good thing with the 4100 cars. At worst, detonation, and the 4100 does not need anything that can exploit its fragility...

Oh, I know that. I used to run nothing but premium in my old '88 FWD Fleetwood with the 4.5. I just said it could be done but you risk a lot in doing it.

sven914
07-29-09, 08:10 PM
Actually, they are different. The LT1 has reverse cooling and a a different ignition set up as well as other differences. My car (and others up through '93) has the standard "350" that is being referred to. The LT1 is a different engine. An LS1 is a 350 CI engine as well, but nobody calls it a 350 because it is a different engine.

The LT1 is the second generation engine, designed to replace the LT-1, 350 cubic inch Chevrolet small block (originally designed in 1970). Though the block was replaced and everything about the engine is different, it still displaces 5.7 liters, which makes it a 350. The Olds 307 isn't know solely by it's three digit RPO designation (LV2) and nor should the LT1.

Bro-Ham
07-29-09, 08:20 PM
Hi, Uh oh, I feel a smart a-double-s comment coming on. My car runs on any gas I put in and the ECM and the check engine light never act up because my car doesn't have either. My smooth running robust old school Cadillac engine is neither fragile nor low on power. It is heavy on the gas and puts out plenty of emissions and I'm proud of that. LIFE FOR CLUNKERS! :)

Stingroo
07-29-09, 09:25 PM
Sven but not all Chevy small blocks are 350ci. Idunno, it's not too important. It's called the LT1 by most people anyway.

And the "standard 350" you're mentioning is the L05 I think. Just a random tidbit.

Warren_R
07-30-09, 05:04 AM
Mine runs very nicely on 87 oct., :bouncy: with 92 used now & then just for the fun of it. I haven't noticed any difference between the two, and GM *does* recommend 87+ for the engine. :caddy:

jayoldschool
07-30-09, 11:42 AM
I'll throw another wrench into the discussion. Around here, we now use 10% Ethanol in our regular (87) gas. 89 is just half 87, half 91. However, there is no ethanol in the 91. I have noticed a significant mileage degradation when using E10 87 in my LT1s and my L05. So, it may be worth the premium price just to get back the mileage by going with 91 IF it is ethanol-free. I know that some US states have ethanol in all grades of gas, so do your homework.

Stingroo
07-30-09, 01:31 PM
I think FL has ethanol in all the gas grades. I never thought about that. Hmm...

Bro-Ham
07-30-09, 05:10 PM
Sting, If I remember correctly I filled up at a gas station here in Sarasota that said the 87 was ethanol free - - I can't remember which place but I will pay attention. I don't like the idea of ethanol in gas. What's the difference in running regular 87 vs midgrade 90 (or 89 some places) vs premium 93 (91 or 92)?? My 425 seems to have a little tick every so often that I don't notice when I throw in the premium on trips sometimes.

DerMann
07-30-09, 08:11 PM
Yeah, most fuels around here and in Indiana are E10. Didn't know that ethanol wasn't present in higher octanes.

They really should get rid of E10, all it is a 'safe' filler for gasoline so they don't have to use water to water it down.

dirt_cheap_fleetwood
07-30-09, 08:15 PM
I have mixed experiences with ethanol free gas. My Dad's Ford Van and my grandparent's Crown Victoria will run almost 100 miles more on a tank of ethanol free gas. However, it makes no difference in either my Caddy or my Mom's Blazer.

brougham
07-30-09, 11:37 PM
I always use regular 87 and I usually get it at shell because its close. It used to mainly just be Sunoco that had ethanol gas but since they closed most of the Sunoco stations around here I haven't gone there in a long time.