Proper Octane For 5.7L TPI?
#1
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Car: 1991 Chevrolet Camaro Z28
Engine: 5.7L TPI L98
Transmission: 700R4
Axle/Gears: 3.23 posi/limited slip
Proper Octane For 5.7L TPI?
I was just curious to know what exact fuel grade i should be putting in my car.... 91 z28 stock? sorry for the stupid question.
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Car: 87 Camaro IROC-Z
Engine: 5.0 LB9 Stock
Transmission: T-5
Axle/Gears: Stock BW 3.45
How about an 87 5.0 TPI? I've been using 87 (as a struggling college student I can't afford too much).
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Car: 1989 GTA
Engine: 350TPI w/ Speed Density
Transmission: 700r4
Axle/Gears: Borg warner 3.27
Normally premium is only 10-20 cents more per gallon so even if you have a 20 gallon tank it only takes 2-4 more dollars to fill it up. My tank size is only 12 gallons from E-F so it only costs 1.20-2.40 more to fill it up with premium as opposed to regular. Just thought I'd point that out.
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Car: 92 trans am/ 93 dodge spirit V6
Engine: L98 V8 - 350
Transmission: TH-700-R4
Axle/Gears: 3.23
i grab the best i can get, which is 91 here in canada...does fine, but i think your suposed to put 91, because it has a higher conpresion ration... i think its like 9.3, so its best to put 91 or 93 for you american drivers, its cleenest, and by the way, 91 or 93 does not give more power, its makes ther engine run cleaner, and in a sence makes it stronger, but not faster.
#16
My L98 gets vastly better milage using Sunoco 94 as opposed to regular octane or even premium 91.
I'm not imagining it either. I've seen what an average 2mpg increase using 94 octane (so long as I'm driving responsibly).
Also, since I advanced the timing on the car aswell, the 94 does a good job at preventing detonation. 92 is alright aswell, but anything less, and I get engine knock, so I don't really have a choice in the matter
I'm not imagining it either. I've seen what an average 2mpg increase using 94 octane (so long as I'm driving responsibly).
Also, since I advanced the timing on the car aswell, the 94 does a good job at preventing detonation. 92 is alright aswell, but anything less, and I get engine knock, so I don't really have a choice in the matter
Last edited by LT1FUN; 08-12-2006 at 07:59 PM.
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Car: '85 Iroc-Z
Engine: 355cu, 11:1, 292H, 750cfm, LT1 head
Transmission: T5 non/wc
Axle/Gears: 3.73, 7.5in 10bolt posi
Here in Quebec gas is cheap, 91 is the top in octane, I have to run on Lucas Octane booster 1 bottle in an half tank or put 50/50 of super whit 100LL(plane fuel), but the plane fuel is about 1.92$/liter!!!
So please don’t tell me it cost tow much to put premium gas in your V8!!
Come on!!!
At least, relaxe on gaz pedal!!
So please don’t tell me it cost tow much to put premium gas in your V8!!
Come on!!!
At least, relaxe on gaz pedal!!
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Car: Formula
Engine: 6.0 LSX
Transmission: 4L60E
Axle/Gears: 9 Bolt 3:27
I'd love to see some dyno graphs of people claiming they feel more power with higher octane. If your stock timing is at 6* the octane in the manual whether is be 87 or 91 should be sufficiant. I think most of it is a head game. Car Craft did a report one issue with a stang and the higher the octane the less power it made , unless they cranked the timing up. I think it was 0* with 87 made like 300 HP and then they used 94 octane and made 288. They had to move the timing up a few degrees to like 8 to achieve the 300 again.
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Car: 1985 Z28
Engine: 85 L98
Transmission: 700r4
Axle/Gears: stock 10 bolt-3.73 eaten posi
octane is just the rating of fast the fuel burns.
so in a high comp motor running low octane can cause spark knock, which in a efi motor the knock sen. reads and retards the timeing making less power.
now a stock L98 is not a high comp motor at 9-9.5 to one. so there is little diff between the two. how "clean" your motor is depends on wheither you use Shell or 711 gas. most high-end gas manuf. put detrugence in the gas which will clean your motor.
the idea is to go as low as possible with your octane and still be in the limits of your comp. in other words without making knock.
so in a high comp motor running low octane can cause spark knock, which in a efi motor the knock sen. reads and retards the timeing making less power.
now a stock L98 is not a high comp motor at 9-9.5 to one. so there is little diff between the two. how "clean" your motor is depends on wheither you use Shell or 711 gas. most high-end gas manuf. put detrugence in the gas which will clean your motor.
the idea is to go as low as possible with your octane and still be in the limits of your comp. in other words without making knock.
Last edited by 3rdgenZ; 08-13-2006 at 02:14 AM.
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Car: '85 Iroc-Z
Engine: 355cu, 11:1, 292H, 750cfm, LT1 head
Transmission: T5 non/wc
Axle/Gears: 3.73, 7.5in 10bolt posi
octane is just the rating of fast the fuel burns.
so in a high comp motor running low octane can cause spark knock, which in a efi motor the knock sen. reads and retards the timeing making less power... ... ...
the idea is to go as low as possible with your octane and still be in the limits of your comp. in other words without making knock.
so in a high comp motor running low octane can cause spark knock, which in a efi motor the knock sen. reads and retards the timeing making less power... ... ...
the idea is to go as low as possible with your octane and still be in the limits of your comp. in other words without making knock.
I ear that you can get some point octane by mixing different brand of fuel because :
Fuel Octane = (Research Octane+Motor octane)/2 , then exemple: sunoco can have 96(R.O.)+92(M.O.)=94 real octane
And a
What is the Highest Octane fuel avaible at the pump in your contry and what is the price!! ??
Here Super(91) is now at 1.28$/litre today
Thanks
#21
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Car: 92 trans am/ 93 dodge spirit V6
Engine: L98 V8 - 350
Transmission: TH-700-R4
Axle/Gears: 3.23
i live in winnipeg canada, its $1.28/litre. question then, if i use 91 octane, what timing should i use to get the most preformance out of a stock L98?
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Car: '85 Iroc-Z
Engine: 355cu, 11:1, 292H, 750cfm, LT1 head
Transmission: T5 non/wc
Axle/Gears: 3.73, 7.5in 10bolt posi
If your motor does'nt knock on high load at and on WOT your maybe able to give em a little more
Try it in third gear at 50km(about 1500rpm) you should be able to do a WOT whitout any knoking, if you ear some , well release pedal and retard your timming a little bit
91 octane should be enough for you'r engine some time carbon accumulation and other does'nt help but,...
And for your timing it depend on your gear, transmission, torque, but the stock timing for your car is about 4-6 at idle, but you can jump to 8-10 by doing some road test it should give you more power!!
I hope my english is not to bad, I just do my best!!! ( but I don't care )
Try it in third gear at 50km(about 1500rpm) you should be able to do a WOT whitout any knoking, if you ear some , well release pedal and retard your timming a little bit
91 octane should be enough for you'r engine some time carbon accumulation and other does'nt help but,...
And for your timing it depend on your gear, transmission, torque, but the stock timing for your car is about 4-6 at idle, but you can jump to 8-10 by doing some road test it should give you more power!!
I hope my english is not to bad, I just do my best!!! ( but I don't care )
#23
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Car: 95 E-150 & 07 Kawasaki ZX-6R
Engine: A slow one & a fast one
Transmission: A bad one & a good one
Axle/Gears: A weak one & a chained one
It's amazing how many people just don't know what octane is all about...
Run the lowest possible without detonation. You will make more power, and the motor will run cleaner. YES, CLEANER. Higher octane is more resistant to spontaneous detonation, but as a side-effect, is also slower-burning. Meaning, running higher octane than your motor requires, can result in an incomplete combustion because the fuel just hasn't had enough time in the chamber to fully burn. This results in carbon buildup on the pistons and valves, which can lead to other issues down the road, including creating a "dependence" on that octane in extreme cases, because the buildup has effectively increased the compression ratio on the cylinder.
If you want to run higher octane, you need to advance your ignition timing. Why? It sparks earlier obviously, and you're giving the combustion event more time before the cycle ends.
My motor will run on 87 octane all day, but I choose to run it on 93 and advance the ignition timing to 15 degrees base (stock is 10.) Makes more power this way, and it can only handle another degree before it starts to ping so it's in the perfect zone.
Run the lowest possible without detonation. You will make more power, and the motor will run cleaner. YES, CLEANER. Higher octane is more resistant to spontaneous detonation, but as a side-effect, is also slower-burning. Meaning, running higher octane than your motor requires, can result in an incomplete combustion because the fuel just hasn't had enough time in the chamber to fully burn. This results in carbon buildup on the pistons and valves, which can lead to other issues down the road, including creating a "dependence" on that octane in extreme cases, because the buildup has effectively increased the compression ratio on the cylinder.
If you want to run higher octane, you need to advance your ignition timing. Why? It sparks earlier obviously, and you're giving the combustion event more time before the cycle ends.
My motor will run on 87 octane all day, but I choose to run it on 93 and advance the ignition timing to 15 degrees base (stock is 10.) Makes more power this way, and it can only handle another degree before it starts to ping so it's in the perfect zone.
#24
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Car: 1985 Z28
Engine: 85 L98
Transmission: 700r4
Axle/Gears: stock 10 bolt-3.73 eaten posi
[quote=Nixon1;3020844]It's amazing how many people just don't know what octane is all about...
nobody here is disputing your statements, so why would you make such a bold statement?
nobody here is disputing your statements, so why would you make such a bold statement?
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Car: 95 E-150 & 07 Kawasaki ZX-6R
Engine: A slow one & a fast one
Transmission: A bad one & a good one
Axle/Gears: A weak one & a chained one
[QUOTE=3rdgenZ;3021094]
Dont take it all personally now.
Im just saying, in my experience, the amount of people who know about cars but are ignorant about octane is amazingly high.
Dont take it all personally now.
Im just saying, in my experience, the amount of people who know about cars but are ignorant about octane is amazingly high.
#26
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Car: 1991 Chevrolet Camaro Z28
Engine: 5.7L TPI L98
Transmission: 700R4
Axle/Gears: 3.23 posi/limited slip
Ive been using 93 about 99 percent of the time since ive had my l98 (since feb. of this year) and recently took a trip and got about 180 on a tank. I use the i think its 87 octane?, and got around 250 miles on that tank so thats why i asked the octane question.
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Car: '85 Iroc-Z
Engine: 355cu, 11:1, 292H, 750cfm, LT1 head
Transmission: T5 non/wc
Axle/Gears: 3.73, 7.5in 10bolt posi
You may see a little difference in consuption but I mostly think that is much more the way you have driven those 180 WOT milles
#28
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Car: 1988 Pontiac GTA
Engine: 305
Transmission: Auto
I'm not sure what scale they use in the US (RON or MON?)
UK gas is rated at 95 Octane (RON) / 85 (MON) and typically costs £0.97/Ltr or $7/Gallon!
You can buy 102 Octane (RON) gas but it costs a fortune:
BP Ultimate UK - 102 octane
UK gas is rated at 95 Octane (RON) / 85 (MON) and typically costs £0.97/Ltr or $7/Gallon!
You can buy 102 Octane (RON) gas but it costs a fortune:
BP Ultimate UK - 102 octane
#29
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Car: '85 Iroc-Z
Engine: 355cu, 11:1, 292H, 750cfm, LT1 head
Transmission: T5 non/wc
Axle/Gears: 3.73, 7.5in 10bolt posi
95 (RON) + 85 (MON)
__________________ = 90 octane!!!
2
Look at :
Octane Information Calculator
#30
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Car: 1988 Pontiac GTA
Engine: 305
Transmission: Auto
It is a standard :
95 (RON) + 85 (MON)
__________________ = 90 octane!!!
2
Look at :
Octane Information Calculator
95 (RON) + 85 (MON)
__________________ = 90 octane!!!
2
Look at :
Octane Information Calculator
I'm running it at the stock 6 degrees, looks like I should be able to run it a little higher.
Matthew
#31
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I use 91 in my 88 LB9. Never a hint of pinging.
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Car: 1985 Iroc Z-28
Engine: 305 TPI
Transmission: 700R4
85-305TPI
I run the cheap stuff in my TPI, 85 octane. No major mods, just flowmaster and K&N to breathe a little better. I do live at a fairly high elevation though, Utah. It seems to run just fine. There is no difference if I run premium, so I stick with the 85 octane.
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Car: 1987 iroc z
Engine: 5.7 tuned port injection
Transmission: Automatic
Re: Proper Octane For 5.7L TPI?
The computer controls the gas the manual says computer is set for 87 octain so put in 91 will not make a diff on power jest cleaner engine
#35
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Car: 89 Iroc
Engine: 305
Transmission: 700r4
Axle/Gears: 3.23
Re: Proper Octane For 5.7L TPI?
Owner's manual states 91+ octane, however, car will run on lower octane at slightly reduced performance. That is straight from the manual. Also, that is part of the reason our cars have a knock sensor.
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