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Discussion Starter · #1 ·
Will premium gas really improve the performance of my 1991 escort gt?

I notice i do more km with premium gas but is it really better for performance?
 

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Premium fuel CAN be of benefit to your car if you´ve advanced your timing. If you bump the timing up, you have to run premium fuel to avoid detonation. In this case, you´d see an improvement, more so in the top end. If your timing is stock, running premium won´t necessary be of any use to you, and might be a financial drain - usually only $.20 per gallon difference though so not much of a difference. What´s the state of your engine? They say as an engine ages it requires higher levels of octane to continue running the same.
 

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Discussion Starter · #3 ·
130 000 km - Syntetic oil
You can eat off the engine, clean as hell. No mods...

Thanks for the info


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[ Edited by FourDiceS04 On Date 08-09-2002 ]
 

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i´ve got a stock 93lx (still...
)
but i do notice a performance difference running premium compared to regular. fortunatly for me, i can get premium for the same price!
 

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my timing´s advanced, but ever since we bought the car it´s only seen premium. also, only synthetic oil for me also...its a lot better than regular.
 

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when gasoline engines were first produced and for many years thereafter the valves and valve seats were not hardend. any combustion that took place after the exhaust valve opened was a bad thing and could damage the valve and the seat. nowadays they are both hardend and internal damage to the engine is not a problem providing the spark is properly adjusted. keep in mind the higher octane is meant for higher compression engines because it burns slower. The escorts don´t have the compression to make use of the high octane especially at higher rpms. you may very well lose top end power. and no old engines would actually run better on lower octane assuming the compression has dropped due to leakdown. long story short use it if you want to but don´t expect miracles. If you want to make power you have to change the setup. plain and simple


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Birddog
´94 EGT
´02 ZX2

[ Edited by birddog On Date 08-13-2002 ]
 

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Here´s a info story about Octane. Octane is a measurment of gases RESISTANCE to detinate. That is why if you bump up you timing it won´t ping as bad as with regular gas. But since octane is a resistance to detination, the lower numbers actually burn faster, making the cylinder pressures rise faster, and there for produceing power faster. Think about what you are doing when you advance your timing. You are igniting the gas when the piston is farther down the cylinder, and since it is on it´s way up, the sooner you ignite the fuel the more resistance it will have as it´s trying to come up, eventually to the point where you hurt performance. THe idea timing setting occurs when you ignite the fuel in enough time for it to completely burn and produce it´s highest pressure right when the piston hits top dead center. Remember, it´s not the spark that makes the power stroke, it´s the cylinder pressure, the spark just gets the ball rolling. So you best bet is to find the best timing setting for the lowest octane gas you can use. The only reason super high performance cars use high octane is because the cylinder pressure is already too high before the moment of spark due to higher compression ratio, or forced induction, that the commpressed gas will light itself and cause pre-ignition. If there are anymore questions, feel free to ask, because i can ramble for pages about Octane.
 

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Zeemax said it all....but running premium with no mods is OK. 94 is some nice sh*t though...wish I could find that stuff.

Anyhow, if you´re motor is stock and you´re going to run premo...might as well advance your timing and feel the power for free too. I noticed the biggest difference with 2 degree advancement from 45-80mph.

Any gas is cool with the GT´s as long as its not leaded. If you want to run AvGas you´ll need to ditch your cat-converter and you´ll be replacing your O2 sensor often.
 

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Just wanted to add Pimp Scort gave some good info on understanding the process of creating power and understanding the basics of Forced Induction.

Remember if you´re going turbo...you´ll want to actually retard your timing.

Best thing...get a timing gun and play with your timing till you´re feeling the Scort run best.

My set up (no turbo yet) 2 degree´s advancement on 92 Octane... running the at 5500 feet above sea level.
 

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Blade: How many degrees BTDC does 2 degrees of advance amount to? 12?There used to be an article on this on the old site, I realize, but now I can´t find it.
- Rob
 

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thank you pimp_scort for saving me the details. I have spent hours arguing with people who claim that premium gas made a huge difference and all that. its good to know that we at least have one group of people who know the truth about octane!
 

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actually i had a timing light from the early ´70´s and tried to use it but the light was burnt out. I went to my local pep boys and a light that didn´t have any readouts was like $30. the nicest light that they had was $100, and it had a readout and everything. you have to find the ticks on the timing belt, i think the way it works is that the light should hit the belt at the tick that shows what your timing is set at. if it´s stock, it should read 0, if it´s advanced 2 degrees, then it should be 2 degrees up on the belt. tell me if i´m wrong i haven´t actually done it myself but i got the impression that that´s how it works.

the premium in my area is 93 octane minimum. i don´t think that my timing was wrong though, i think that my fuel filter might be clogged or my fuel pump could be screwy. that or my engine´s really beat up, or maybe it is just my timing and fuel.

my car seems to get more power at random points in acceleration than at other points. and i´m talking a really noticeable difference. it´s weird...and i know it´s not good. i just wish i knew what was wrong.
 
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