87, 89, 91, or 94 oct

Frequently asked questions about the Lesabre T-type.

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91Sabre
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87, 89, 91, or 94 oct

Post by 91Sabre » Wed Apr 27, 2005 2:09 am

I did a search and didnt find much on what kind of gas anybody uses. I was wondering if 91 and up would hurt the engine?? or if it would even clean a bit of the fuel tank, lines, injectors. I sometimes stumble upon a gas station thats giving out 91 at 87 prices because they ran out of the 87 :lol

BTW this is for an '87 PA

2seater
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Post by 2seater » Wed Apr 27, 2005 2:25 am

If you have any knock problems and you have a knock sensor, it may improve performance somewhat. If knock retard of the spark is not a problem, the car will likely be slower running more octane than you need. It may feel smoother but usually hurts engine responsiveness. If you want to clean the fuel system, add a bottle of Techron to the fuel.
Hal twoseater@tds.net 1990 Buick Reatta, turbocharged, Dynomax s/s UltraFlow, hand made turbo manifolds, ceramic coated, 160* t'stat, GM Tuners chip, larger throttle body, relocated MAF, 30# injectors.

T
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Post by T » Wed Apr 27, 2005 2:28 am

87 is all that our cars need. Higher octane will not make your car run any better. Some premium fuels have more detergents, but it's more effecient to add it yourself, in a form like TECHRON.
-T

'87 Lesabre T-type
L67 swap, CAI, STB, 180deg stat, Walbro 307 fuel pump, tranny cooler, Michelin XGT H4s, ZZP 3.4 MPS, AC 41-601 plugs.
PB: 14.447@95.08 (2.299 60ft.)

'88 Lesabre T-type
RIP

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Post by Nathaniel Gjr. » Wed Apr 27, 2005 2:36 am

Out of habit i have always run premium gas in my car. i sometimes put 87 when i do not feel like paying these stupid prices. i guess that myth i always hear about " put the good gas in that car." is just that. i think sometimes people forget these cars are computerized and run on the 87 fuel by design. withte the price going up, i might switch to 87 on a permanent basis with a bottle of techron or stp gas treatment this summer. not trying to get a political thing started, but anyone else wonder why the oil reserves for emergencies in this country have not been opened up yet? gas should hit a high of $5.00 a gallon soon.

Nat Gjr. :mtt:
Negative people are fuel for your positivity. 1989 Buick lesabre T-type Garnet Red Red,Black leather Interior, all power, repro rear spoiler,Pontiac Bonneville dual outlet exhaust muffler,new timing gears,kyb GR-2's. One of GM's last great cars. 1998 Buick regal GS sedan Green/Grey, supercharged.
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2seater
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Post by 2seater » Thu Apr 28, 2005 12:44 am

Not to start a rant about fuel prices either, but I blame the news media and the public for a lot of this problem. Have you ever noticed on your local news and the newspapers when there is a spike in prices they take pic's of people filling up their motorhomes, trucks, sport ute's, whatever and then they put it in the news. They ask people what how they feel and you see macho responses about not changing their habits and such. They may as well call the oil company and tell them the public isn't at their limit yet and just keep running the prices up. This type of reporting started last year when fuel took it's first large jump after a few years of relative stability. Just an observation.
Hal twoseater@tds.net 1990 Buick Reatta, turbocharged, Dynomax s/s UltraFlow, hand made turbo manifolds, ceramic coated, 160* t'stat, GM Tuners chip, larger throttle body, relocated MAF, 30# injectors.

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Post by Nathaniel Gjr. » Thu Apr 28, 2005 4:33 am

:D i got too agree with you 2seater. today i saw a program on cnn where they weretalking about the large drop(roughly 18%) sales have taken on suv's. now whether you are a truck guy or not, those things do drink more gas than a regular full sized car. and around my way, alot of the big suv's have been disappearing and alot of newer cars or older good conditioned cars are returning. i also noticed they ask these macho guys who drive navigators like porshces and cut people off the questions about fuel economy. they always seem to give the oil nations reason to spike the fuel with " i love my truck, 5 miles on the highway aint so bad. i just fill her up." the shame is not too long ago someone told me my car was one of those huge 80's guzzlers. what a misinformed moron.

Nat Gjr. :mtt:
Negative people are fuel for your positivity. 1989 Buick lesabre T-type Garnet Red Red,Black leather Interior, all power, repro rear spoiler,Pontiac Bonneville dual outlet exhaust muffler,new timing gears,kyb GR-2's. One of GM's last great cars. 1998 Buick regal GS sedan Green/Grey, supercharged.
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Post by Whitelion-89-T » Tue Jun 27, 2006 5:18 am

Yes, I was just reading something about gas prices going crazy. This person said that if every one would only put $10-$15 worth of gas each time, not fill your tank. After a stort time the gas company would have all this extra gas.They would have to put it down.lol


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Post by Dirtracr95 » Mon Aug 13, 2007 8:13 pm

I know 87 gas is the norm but i was wondering about 85 octane I used it when i drove Dave G's old T back to chicago. Infact i got the best gas milage on it 31mpg but that was also at 7000 ft and 55-65mph because of the snow and construction speedlimits.
~~~Freddy~~~
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Post by Henry » Wed Aug 15, 2007 11:00 pm

I found this from previous thread that was about Spark Plugs and the Fuel Octane, it may help here.
Henry wrote:
Whitelion-89-T wrote: The (AC-Del-Co) sounds like the best plug.A lot of HP cars I had I would change the plugs every 3 maybe 4-K miles or every spring. How often do you guys change the plugs on the 3800. 8-) Plus do you run a hotter plug?

Hey Viking 94 octane fuel, well that not hurt the motor? I was running 89-octane until T said that we should only run 87-octane. I also read that in the manual. The computer is set up to run on 87-octane.She still runs as good with the 87. But I always ran my older HP cars on 91+ octane. Do you feel a diffance in performance :-?
Thanks. 8-)
Our cars are designed to work Best with 87 Octane. Running a higher Octane will not hurt the engine, but you will not gain anything from it other than paying more for gas.

All octane is, is Resistance to detonation. The way thats achieved is by SLOWING DOWN the burning process.

Older cars NEEDED that higher Octane to help Reduce Detonation and since the engines are designed for that Slower burning Higher octane fuel.


In short, Higher Octanes burn SLOWER and COOLER than lower Octanes.

Another words, 87 Octane burns HOTTER and FASTER than Higher Octane.
:cheers:
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T
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Post by T » Thu Aug 16, 2007 1:28 am

Dirtracr95 wrote:I know 87 gas is the norm but i was wondering about 85 octane I used it when i drove Dave G's old T back to chicago. Infact i got the best gas milage on it 31mpg but that was also at 7000 ft and 55-65mph because of the snow and construction speedlimits.
Places in high elevation usually have lower octane fuels, simply because less octane is needed because there is less atmospheric pressure. Your compression ratio is effectively lowered, reducing your octane requirement.
-T

'87 Lesabre T-type
L67 swap, CAI, STB, 180deg stat, Walbro 307 fuel pump, tranny cooler, Michelin XGT H4s, ZZP 3.4 MPS, AC 41-601 plugs.
PB: 14.447@95.08 (2.299 60ft.)

'88 Lesabre T-type
RIP

For questions concerning Lesabret.com, please e-mail me at lesabret@gmail.com

Dirtracr95
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Post by Dirtracr95 » Thu Aug 16, 2007 1:47 am

ok that would be why i could only get it while i was in the mountains
~~~Freddy~~~
Pandora 1988 :wtt: 255650 miles COTM Nov 2007
Darlington 1987 :btt: 115000 miles
Cream Puff 1988 :wtt: 194500 miles
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Re:

Post by tronporsche » Thu Jun 26, 2008 11:17 am

[quote="Henry"]I found this from previous thread that was about Spark Plugs and the Fuel Octane, it may help here.

[quote="Henry"][quote="Whitelion-89-T"][b] The (AC-Del-Co) sounds like the best plug.A lot of HP cars I had I would change the plugs every 3 maybe 4-K miles or every spring. How often do you guys change the plugs on the 3800. 8-) Plus do you run a hotter plug?

Hey Viking 94 octane fuel, well that not hurt the motor? I was running 89-octane until T said that we should only run 87-octane. I also read that in the manual. The computer is set up to run on 87-octane.She still runs as good with the 87. But I always ran my older HP cars on 91+ octane. Do you feel a diffance in performance :-?
Thanks. 8-) [/b][/quote]

[color=black][b]Our cars are designed to work Best with 87 Octane. Running a higher Octane will not hurt the engine, but you will not gain anything from it other than paying more for gas.

All octane is, is Resistance to detonation. The way thats achieved is by SLOWING DOWN the burning process.

Older cars NEEDED that higher Octane to help Reduce Detonation and since the engines are designed for that Slower burning Higher octane fuel.


In short, Higher Octanes burn SLOWER and COOLER than lower Octanes.

Another words, 87 Octane burns HOTTER and FASTER than Higher Octane.[/b][/color][/quote]

:cheers:[/quote]O.K. So higher octane burning slower and cooler than lower octanes means saving gas ? Or still no difference? and how often add the fuel cleaner if I go from 91 to 87 for my 3800 ?

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Re: 87, 89, 91, or 94 oct

Post by Alibi » Thu Jun 26, 2008 1:07 pm

Theres no point in running anything other than 87 in a stock LN3 Vin C 3800. Thats what the motor was built with in mind from GM.

However, dumping in a bottle of injector cleaner every 3000 miles or so is recommended and a bottle of Heet (or similar alcohol-based additive to help remove water from the fuel system) periodically.

Suggested brands of injector cleaner:

-Chevron Techron, $7-12 depending on size. Black bottle, my highest recommended product for this application.
-Seafoam. $8 a can or so. The can says to use 1/3 but you can get away with a full can in a half tank of gas for an extra concentrated clean...
-Lucas. $3 a bottle or so. Its basically a bottle of Kerosene with some detergents in it but its OK. Not nearly as impressive as the Techron though IMO.

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Re: 87, 89, 91, or 94 oct

Post by tronporsche » Thu Jun 26, 2008 8:40 pm

Hooray ! I've been putting in 91 to give my engine the best performance. no more of that !! (although by the time you fill up the tank, you may only pay another 3-4 dollars for the good stuff.) Does AMPM have good enough gas, compared to 76, mobil, and all of them?
Interesting.....I was putting Shell in my car at first, I had back fire. I went to 76 gas, and no more backfire.
I brought Platinum Fusion spark plugs for my 3800 when I did the conversion, and after reading more information, A book says the engine likes copper spark plugs, however that book was from the same year as the engine, (89) or older, and wouldn't up to date technology make this o.k.? (Autozone sells me the sparkplug according to their computer order).
One last Question, doesn't really have to do with octane though....I notice lately my car is not starting up sometimes after parking for a few minuites. A guy told me Buick starters are known to get stuck. Is this true ?
I notice usually when I "step on it" or do a "rocket launch", the car cuts off at the light, and I have to re -start it. Will a fuel cell tank correct this ?

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Re: 87, 89, 91, or 94 oct

Post by Alibi » Thu Jun 26, 2008 9:16 pm

[quote="tronporsche"]Hooray ! I've been putting in 91 to give my engine the best performance. no more of that !! (although by the time you fill up the tank, you may only pay another 3-4 dollars for the good stuff.) Does AMPM have good enough gas, compared to 76, mobil, and all of them?
Interesting.....I was putting Shell in my car at first, I had back fire. I went to 76 gas, and no more backfire.
I brought Platinum Fusion spark plugs for my 3800 when I did the conversion, and after reading more information, A book says the engine likes copper spark plugs, however that book was from the same year as the engine, (89) or older, and wouldn't up to date technology make this o.k.? (Autozone sells me the sparkplug according to their computer order).
One last Question, doesn't really have to do with octane though....I notice lately my car is not starting up sometimes after parking for a few minuites. A guy told me Buick starters are known to get stuck. Is this true ?
I notice usually when I "step on it" or do a "rocket launch", the car cuts off at the light, and I have to re -start it. Will a fuel cell tank correct this ?[/quote]

I believe the backfiring is being caused, in part, to the higher octane.

No clue on what brands of fuel are better than others as I've got totally different stations in my area (Conoco, FastTrip, Caseys, etc). In general, I just stay away from the no-name stations and leave it at that.

DO NOT USE BOSCH PLUGS. DO NOT USE PLATINUM PLUGS. Just use the basic cheapy $3 AC Delco spark plug and you'll be golden. Other plugs just do not work correctly with the GM DIS (distributorless ignition system). Just because a parts store lists it, it doesn't mean it will work right.... it just means it'll fit in the hole ;)

On the no-start issue, you ought to start a new thread in "General" so we can go step by step to eliminate other possible issues.

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