|
I was just wondering if using 87 octane in my 88 Turbo II was ok? Would i be better off using a higher octane to prevent plug fouling? Also what type of plugs should i use for it since i want to change them this week. Thanks!
|
You want to use 93!!! Not for the plugs but to keep your engine from detonating. All it takes is a ping to blow a seal. The NGK designed for rotaries will do fine. The don't have the hook for the spark the bottom is flat. They are pretty expensive though.
|
87 isnt great for it. I recommend using a good premium fuel.
And for plugs, stick with NGKs. BUR7EQ and BUR9EQ. I forget which are leading and trailing, but they are marked with an L or a T. |
this question is kind of related to his question. anyway, i have an 88 NA and there is really nothing done to it except e-fan, intake, POS pacesetter header. Was wondering what would be the difference in using an 87 versus a 93 octane besides 87 burning cleaner than 93.
|
Originally Posted by joe2dmax' date='Apr 28 2003, 05:26 PM
this question is kind of related to his question. anyway, i have an 88 NA and there is really nothing done to it except e-fan, intake, POS pacesetter header. Was wondering what would be the difference in using an 87 versus a 93 octane besides 87 burning cleaner than 93.
|
fro n/a 87 is the best gas to use, it burns cleaner and performs better
|
Yes, Non turbo.. 87 runs best.. (i've seen dyno numbers, i acctually lost 4-6 HP with 93 octane in my car...
If running turbo, you have to run 93, only cause its a turbo, and you dont want to detonate. |
too many different opinions!
there has to be a decision maker here |
89 for me
|
Just run mid grade. Not too high, not too low. Actually I'm J/K. That is what I run in my N/A, though. It's what gives me the best performance. Also, I think it depends on what you've done to the engine...
|
i've been running 89 ever since i got my TII over the summer. i've heard a variety of opinions on this. isn't the purpose of the intercooler to cool the air before it enters the engine? if so, high octane gas shouldn't be necessary, leave that for cars with like 11:1 compression ratios. if high quality gas is so necessary for the TII, why isn't there a warning by the fuel gage?
|
Question.
What do you guys mean my "detonate"? |
Originally Posted by RX-7Aggie' date='Apr 28 2003, 09:41 PM
i've been running 89 ever since i got my TII over the summer. i've heard a variety of opinions on this. isn't the purpose of the intercooler to cool the air before it enters the engine? if so, high octane gas shouldn't be necessary, leave that for cars with like 11:1 compression ratios. if high quality gas is so necessary for the TII, why isn't there a warning by the fuel gage?
mike |
i dont have an owners manual, i have haynes and FSM, i saw it nowhere in teh FSM
|
if the compressed air due to the intercooler is cooled back down to ambient temperature, T_o, before entering the combustion chamber, then the change in pressure within the engine delta P due to compression will increase the temperautre of the AF mixture just like a NA engine. only if the compressed air from the turbo is too high will it auto detinate or knock.
i belive it's the compression ratio of the pistons/rotors that determines the gas type, not necessarily the use of a turbo. i understand on blown cars w/o a intercooler that premium gas would be needed, but i dont see about other cars. PV=nRT --> if T is the same for both a TII and a NA due to intercooling, and compresion or change in pressure is the same, and we know displacement is the same, then the change in temperature has to be the same, resulting in a final gas temperature that is the same between a TII and a NA, assuming the intercooler is sufficient and the initial temperature entering the engine is the same. |
Originally Posted by RX-7Aggie' date='Apr 29 2003, 11:34 AM
if the compressed air due to the intercooler is cooled back down to ambient temperature, T_o, before entering the combustion chamber, then the change in pressure within the engine delta P due to compression will increase the temperautre of the AF mixture just like a NA engine. only if the compressed air from the turbo is too high will it auto detinate or knock.
i belive it's the compression ratio of the pistons/rotors that determines the gas type, not necessarily the use of a turbo. i understand on blown cars w/o a intercooler that premium gas would be needed, but i dont see about other cars. PV=nRT --> if T is the same for both a TII and a NA due to intercooling, and compresion or change in pressure is the same, and we know displacement is the same, then the change in temperature has to be the same, resulting in a final gas temperature that is the same between a TII and a NA, assuming the intercooler is sufficient and the initial temperature entering the engine is the same. mike |
Originally Posted by RX-7Aggie' date='Apr 29 2003, 12:34 PM
i belive it's the compression ratio of the pistons/rotors that determines the gas type, not necessarily the use of a turbo. i understand on blown cars w/o a intercooler that premium gas would be needed, but i dont see about other cars.
|
its not though, the turbo heats air up to like 250f and the ic cools it down to like 175f, it not as cool as an na. also the t2 intercooler doesnt work very well mike So with a FMIC, you could run lower octane gasoline? |
yup
mike |
Originally Posted by ILUVMY88CABRIO' date='Apr 29 2003, 02:07 PM
On a turbo the compression ratio is infinitely variable. The more boost you're running the higher the compression ratio. https://www.nopistons.com/forums/pub...1047683561.gif
|
Originally Posted by j9fd3s' date='Apr 29 2003, 01:43 PM
[quote name='RX-7Aggie' date='Apr 29 2003, 11:34 AM'] if the compressed air due to the intercooler is cooled back down to ambient temperature, T_o, before entering the combustion chamber, then the change in pressure within the engine delta P due to compression will increase the temperautre of the AF mixture just like a NA engine. only if the compressed air from the turbo is too high will it auto detinate or knock.
i belive it's the compression ratio of the pistons/rotors that determines the gas type, not necessarily the use of a turbo. i understand on blown cars w/o a intercooler that premium gas would be needed, but i dont see about other cars. PV=nRT --> if T is the same for both a TII and a NA due to intercooling, and compresion or change in pressure is the same, and we know displacement is the same, then the change in temperature has to be the same, resulting in a final gas temperature that is the same between a TII and a NA, assuming the intercooler is sufficient and the initial temperature entering the engine is the same. mike [/quote] yes, but the TII has a lower compression ratio, 8.5:1 compared to an NA compression ration of 9.4:1 (FSM Engine section). this should compensate for the increase in temperature due to turbocharging combined with a undersized TMIC, should it not? |
no its doesnt, the turbo "adds" compression. just the ratio of largest chamber volume to smalest chamber volume does not tell you what octane you can run, nor what cylinder pressures are gonna be like. i think a stock t2 will run on 87 cause they cant have the think blow up if you put the wrong gas in the tank, but they recommend 92+ octane in the book.
mike |
simple, N/A=87 best
Turbo=93 best |
wow nice responses everyone, i was wondering for my dad and i. we've always run 87 on it and its run fine, its been breaking up a little around 2000-3000 rpm under light pedal pressure (Just enough to keep it rolling when in traffic speeds or like cruise control). So i was thinking that maybe it was because of the gas, we'll start running 93 which sucks $$$ wise but oh well, got to keep her running well. Thanks for the plugs also.
|
you didnt get it then, if you have an N/A it is better to use 87! better for the engine it runs better, and better gas mileage
for turbo its the other way around 93 |
like i said previously, the turbo adds compression BEFORE the engine intake, and it is cooled BEFORE the intake. The cause of detonation is high AF mixture temperature, not pressure within the chamber. If a car is intercooled and the ENGINE compression ratio is decrease, there is no reason why a turbo car cant run on low grade gas.
when you say the turbo adds to the overall compression of the air, you are correct. however, you could compress the intake air with a ratio of 20:1, properly cool it down to ambient temps, and compress it again in the engine 8.5:1, resulting in an overall ratio of 28:5:1 and NOT have detonation until spark. you have to look at air cooling and AF mixture temperatures, NOT just pressures |
It is a turbo, its an 88 turbo II anniversary. So yes I did get it, thanks https://www.nopistons.com/forums/pub...IR#>/smile.png
|
Originally Posted by ChainSawOnSteroids' date='Apr 29 2003, 06:45 PM
you didnt get it then, if you have an N/A it is better to use 87! better for the engine it runs better, and better gas mileage
for turbo its the other way around 93 i have heard somehting about adding 2 cycle oil to the mix, or something like that. what's that all about? |
Originally Posted by j9fd3s' date='Apr 29 2003, 04:40 PM
no its doesnt, the turbo "adds" compression. just the ratio of largest chamber volume to smalest chamber volume does not tell you what octane you can run, nor what cylinder pressures are gonna be like. i think a stock t2 will run on 87 cause they cant have the think blow up if you put the wrong gas in the tank, but they recommend 92+ octane in the book.
mike |
Its not that you cant run low octane on a boosted car (especially stock)... its just safer to run higher octane which is why most manufacturers recommend it. I remember boosting to 15psi on 93 was the best I could do before mild detonation and the ecu cutting fuel to avoid a blow up (DSM)... At the track, I put in 104 octane and ran 17psi no problem.
|
Originally Posted by RX-7Aggie' date='Apr 29 2003, 07:33 PM
[quote name='j9fd3s' date='Apr 29 2003, 04:40 PM'] no its doesnt, the turbo "adds" compression. just the ratio of largest chamber volume to smalest chamber volume does not tell you what octane you can run, nor what cylinder pressures are gonna be like. i think a stock t2 will run on 87 cause they cant have the think blow up if you put the wrong gas in the tank, but they recommend 92+ octane in the book.
mike well yes, but the t2 one is slow and it cant pull enough timing to help much. newer cars are a lot more flexible about gas, the t2 isnt mike |
| All times are GMT -5. The time now is 12:33 AM. |
© 2024 MH Sub I, LLC dba Internet Brands