do supras need premium gas???

Bigdough666

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My Supra runs like shit when I put anything less than 93. She runs on 100+ from now on though, not about to risk losing the motor for a few dollars savings at a time.
 

CyFi6

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Most people have done a head gasket job sometime sooner than 20 years ago, and in that time they (probably) cleaned up the combustion chamber and pistons etc. so saying the combustion chamber carbon and all is 25 years of build us isn't all that accurate for at least many of the people here.
 

7M-GTEric

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Best case, assuming it's stock or close, is you drive it for 21 years on 87 and nothing happens...just as it shouldn't.
The way I look at it is, if my motor's got 212k on it, and it's been run on 87 it's entire life, and it runs no differently the couple times I've put premium in it, I'm not gonna spend the extra cash for premium. Every car I've ever owned called for premium and I've never once had a fuel-related problem on any of them. Just my .02
 

speed

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I don't see the big deal about a $2 difference on a fill up between gas choices.
Exactly. Its like people driving an extra couple of miles cause one station is 5cents cheaper. if you put 15 gallons in, thats not even a dollar more.


....people.......
 

IJ.

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For me it came down to I can make xxxrwhp safely before I'm skirting detonation issues on xx octane fuel.

I want more power than this so I step up to the best available pump fuel and will dyno again to find it's threshold.

You will make the MOST power using the lowest octane fuel that will run without detonation in your particular combination.

Running higher octane WILL cost you power if the car isn't tuned to make use of it.
 

Supra-K

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correct me if im wrong, but the higher the octane the slower the burn right? All higher octane does is prevent high compression engines, or a turboed engine from pre detonation, or in easier terms exploding before its suppose to, the higher octane prevents that by burning slower, if your car isnt pinging on 87 then pre det. isnt happening so you should be all good esp. since you a NA, well that is if your stock, just depends on your setup and compression really, so I guess all you can do is listen for a ping, I think spark plug wear can tell a good story on what to do, not to sure about that but just my 2 cents yo.

o and ill agree with everyone else, the extra 2 bucks it takes to put 91 in is worth it, it could potentially save your engine and run better but only if the engine doesnt call for 91, a big misconception is putting premium in any car= better gas mileage and better performance, as of HC engines and turboed cars in performance area, yes, in gas mileage on any car, in LC engine putting premium may cause worse performance, its just redundant really, hope this helpe haha sorry for my crappy spelling little out of it
 

xarewhyayen

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correct me if im wrong, but the higher the octane the slower the burn right? All higher octane does is prevent high compression engines, or a turboed engine from pre detonation, or in easier terms exploding before its suppose to, the higher octane prevents that by burning slower,
You're wrong. Do more research on octane and its purpose.

http://www.howstuffworks.com/question90.htm

^octane for dummies.
 

Supra-K

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dude that basically just restated what I said in a different way, burning slower meaning detonation later, potato potato situation
 

Poodles

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umm... no, octane raises the detonation threshold, it does NOT burn slower
 

Supra-K

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omg forget it im trying to make it easier to understand but welcome to supramania where everyone knows everything
 

Guyana00

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You need to let it go, it just doesn't burn slower. You're stuck on that idea, people are trying to correct you, point you in the right direction and give you correct information for YOUR benefit as well as the community's.

Take a breath, no need to snap.
 

webbs7mgte

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my solution to aruging about who is right is run the gas you think you can run safely or what you thinkt eh car shoudl run and lets see whos lasts longer they dont put it on their for no reason if it coudl run unleaded than they woudl say its remocomended for a reason
 

All_star

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ive been putting n 91 my shit is running like a champ but i have a fuel cut nd my supra is n/a wit a rebuild engine nd new fuel pump nd a new head gasket after running it for awhile i cant go past 3rpm it suck cuz i have to shift all the way to 5th wat u guys think it is
 

IJ.

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ive been putting n 91 my shit is running like a champ but i have a fuel cut nd my supra is n/a wit a rebuild engine nd new fuel pump nd a new head gasket after running it for awhile i cant go past 3rpm it suck cuz i have to shift all the way to 5th wat u guys think it is
English subtitles please?
 

All_star

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ummm just recently ive been putting n 91 octane runs like a champ but after a long time of driving it starts to bog out around 3 thousand rpm nd i have to shift early so it wont bog out . i think i need to get new injector cuz i bought my car when it was just sitting for four years n a drive way lol
 

IJ.

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Ok that was a bit better ;)

Define "long time" 30 minutes? 3 hours?

Also "bogs out"???

Is it blowing any smoke you can see when it does this "bogs out" thing?
 

All_star

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ill say about nd hour of driving but no smoke doesnt come out feels like it want ot turn off the whole engine is rebuilt i upgraded the piping to 2 and half nd i put in a kone filter should i change my injectors to 550cc
 

Figit090

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Running higher octane WILL cost you power if the car isn't tuned to make use of it.
That line was enough to make me stop reading the rest of the thread. I'll look over it just to see and not miss things but, anyway... :p

I run 87 without problems in my n/a. it's stock (duh?) and i've tried 89 and 91, no really apparent differences. i wanted to think 'premium' was helpin but i don't really know, and doubt it did. dont know what my timing is, i need to check it actually....it was fine last i checked though.
 

Poodles

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Premium gasolines USED to have more cleaning additives as well, but these days even the regular has the same amount...
 

CaptMKIII

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Does the owners manual say what to run? I haven't had my Supra but for 2 weeks now and I don't really know what to put in it. Filled half the tank with mid and it seems to run fine, but if the owners manual says to use prem. then I want to run prem.
 

Figit090

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Does the owners manual say what to run? I haven't had my Supra but for 2 weeks now and I don't really know what to put in it. Filled half the tank with mid and it seems to run fine, but if the owners manual says to use prem. then I want to run prem.
I THOUGHT my owners manual (N/A supra) said premium, but it actually said not to run premium and I just read it wrong.

Dunno about turbo owners manuals. Unless they're the same?

hmmmm
 

got_boosted

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I don't see the big deal about a $2 difference on a fill up between gas choices.
EXACTLY!! :3d_frown:

My N/A ran great on 87. I'll never run less than premium in my turbo. I wish I had 93 pump gas here in CA because if I did, I'd still spend the extra penny(s).

Collin
 

Poodles

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Back of my 89 turbo owner's manual:

Fuel: Use only UNLEADED fuel, Research Octane No. 91 (Octane Rating 87) or higher. For improved vehicle performance, the use of Premium unleaded gasoline with a Research Octane No. of 96 (Octane Rating 91) or higher is recommended.



(The bold parts are bold because they're bold on the back of my manual)
 

TooRandom

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I've used regular petrol at shells gas stations only and never had a problem. Btw i drive a 86.5 turbo.
 

supraguru05

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Why would an EGR system affect octane necessity?
egr is a knock deterent in that it dilutes the oxygen fraction in the combustion chamber

now that i think about that that feature just slows the flame rate but i know it gives some more buffer room before autoignition.