What octane gas for my 88 sc mk1?

[senordentaku]

I just bought my 1988 supercharged mk1. There is a switch that lets me designate between regular and premium gas. Since it is forced injection, I want to use the premium gas. What does toyota consider premium? 92? 93? 94? I am looking for two things. What toyota recommends, and what people have found works themselves best.

[senordentaku]

Anybody?

[Bryan H]

You did not mention if it is stock or not, even so
on my turbo cars I have run 93. I am sure 92 won't
hurt if thats what you got.

[palos]

In the Rockies, 91 is the highest you can find at most stations. My SC with a Cusco pulley has survived. That being said, if the stations offered a higher octane, I'd buy the highest available.

[88*mr2]

run 91 dont use a low grade thats the worst for ANY car because it burns badly and it just gums up and will leave resen faster than a high octane fuel like 91...i own a 88 2 and i run 91 fuel through it.

if u boost it up and are running i would say 12+ psi run 91 or if u can find it 92 it will help elimintate ticking in the motor and help it run smoother and cleaner because there is less crap in the fuel...run 91 it will be help your motor last longer and run smoother and its honestly worth the extra $ per gallon

and the fuel but 92 or 93 can be found at lets say rare type gas stations like BP gas stations if u have them in your area

[Raptor13x]

I'd run 91 octane at a minimum. Don't go below that.

[traintech86]

i been hearing from people not to run high octane all the time. true story?

[Raptor13x]

^ It's a waste of money to run unnecessarily high octane fuel. However, if you're running a turbo/supercharger, you're better off with some safety margin.

[328FTW]

Originally Posted by traintech86

i been hearing from people not to run high octane all the time. true story?

Sorta there is no point running a way higher than needed octane as it just clogs the cat and has a less complete burn and is in the harder to ignite in relative terms. Higher octane doesn't hurt just if you run 98 octane in your Morris minor it might be a bit overkill. I run 91 in my gze which has boosted n/a pistons and that thing can light the tyres at the flick of my foot, no pinging, no detonation, no preignition runs fine. And to be honest will keep running it until I hear pinging or sense its causing problems (or blows up I'm not that concerned really I have a swap in mind if that happens) otherwise I just hurt my wallet.

Normally not a big issue if you have your engine running right with a working O2 and and clean injectors.

[toyotaspeed90]

Originally Posted by 88*mr2

run 91 dont use a low grade thats the worst for ANY car because it burns badly and it just gums up and will leave resen faster than a high octane fuel like 91...i own a 88 2 and i run 91 fuel through it.

if u boost it up and are running i would say 12+ psi run 91 or if u can find it 92 it will help elimintate ticking in the motor and help it run smoother and cleaner because there is less crap in the fuel...run 91 it will be help your motor last longer and run smoother and its honestly worth the extra $ per gallon

and the fuel but 92 or 93 can be found at lets say rare type gas stations like BP gas stations if u have them in your area

This is actually somewhat incorrect information.

Gas ratings aren't by what's in them and/or what will gum up your engine -- the octane rating refers to the burn pattern of the flamefront and how easy it is to burn.

Higher octane gas is more difficult to ignite. The higher the heat in the engine (usually found in higher compression and forced induction applications) the higher octane you want so that you don't cause pinging, aka preignition.

You want to run the LOWEST octane gas possible without pinging under load. Reason for this is that if you're, say, running a bigport and using high octane gas -- then actually you won't burn all of the gas off (more difficult to ignite and there is less heat in the combustion chamber) causing carbon deposits on exhaust valves, 02 sensors, and in your cat.... with time the buildup will cause other problems.


So to the OP: the s/c's have a gas switch. I would play with gas ratings a bit and if you hear pinging with the gas that's in your tank, finish the tank with the switch set to regular gas, and move up in octane until you don't get pinging anymore.

[Kerry Phillips]

I have to agree about using the LOWEST octane that is satisfactory. I read that 87 Octane actually has higher BTU content then high octane.
On my old Ford, I could easily tell what grade of fuel it had, 87 pinged quite often, 89 only occasionally, 91+ NEVER pinged. I ran 89-got 200k miles out of it.

[8589]

I have jumped from 93 to 87 several times and frankly I see/hear no difference..probable..just probably a little more reaction on 93 but so minimal could be placebo. (SC)

[BennyTheW]

Here in the uk you can only get 95 ron and above.. i use 99 ron and i can tell the difference, throttle response, MPG and overall performance are all increased...

in the European Mr2 manuals it even says the engine was designed to run on 98 ron and above...

and as for it being a needless expense, higher octane fuels have less detergents in them, they are normally formulated for high performance engines and money for miles perform on a par with lower octanes as you get an increased MPG...

[Raptor13x]

^ I call BS on the increased MPG of high-octane fuel. Show me some proof.

[mr2tim]

Had a opportunity to run some of my friends 112 octane juice in my S/C racecar. I could actually feel a slight increase in power thru the seat of the pants type testing, even sounded different during WOT (better)

Although it is outrageously expensive and kinda stinks there was no adverse reaction to the engine or any of the components nor any overheating.

[Raptor13x]

I had no choice but to use 110 octane in my mki for a bit (I ran out of fuel at a dragstrip, and 110 octane was the *lowest* they had), and there was a noticeable decrease in power.

[ZIELINSKI]

98 octane..


Oh wait.. You only get dishwater over the states.. Umm 91? Wouldnt cars over there ping like hell? If i use anything lower then 95 in my MK1, it gets the death rattles..lol

[328FTW]

Originally Posted by ZIELINSKI

98 octane..


Oh wait.. You only get dishwater over the states.. Umm 91? Wouldnt cars over there ping like hell? If i use anything lower then 95 in my MK1, it gets the death rattles..lol

There is something not right there I run 91 in my SC mkI with higher comp pistons and its fine. I gave it a wind up today and I had almost forgotten how hard it hauls since it started getting death wobbles above 70kp/h, fixed that and did a big celebratory squirt

[ZIELINSKI]

Na my little MK1 has a few things done by the previous owner.. But even my MK2 or MX83 Cressida pings on 91.. so its 95,98 or 102 when i can find it..

[Justin Credible]

Europe and asia use a Research Octane Number (RON) to measure gas octane.
The US and Canada use Anti-Knock Index (AKI) which is generally 4-5 points lower.
So 98 RON in most of the world is pretty equal to 93 AKI in North America.