What Happens If....?

[Phil Megroin]

Not that i've done this before.. ...honest..

i wanted to know what would happen if i used 92 or 93 Octane (whatever regular is) in a turbo car which is tuned for at least 95 octane...

Are the consequences really that bad?

Edited August 23, 2005 by Phil Megroin

[Driver]

ping ping

[Abo Bob]

ping and hurt engine. I did it once. I put 2 bottles of octane boost in and drove around with no boost until it ran out.

[ossie_21]

If I had no other ways of getting home, and that was all thats available, I would use it, preferably with octane booster. I only use 98 from day 1.

[LBR33]

ping ping.........BANG

[grigor]

Don't panic.

I use regular unleaded in the jigger always. Rb20det, might not be making full power but it's certainly not pinging, that's what your right foot and the CAS are for.

I have found the regular starts much more easily than the PULP, just one touch and she's away. Same car on BP Ultimate has to crank away for quite a bit.

My only garage is a Matilda and their premium ain't too flash. Closest BP is 30mins away on the highway.

[WazR32GTSt]

ping ping!

in response to grigor... hmmmmmmm let's see:

extra $5per tank of petrol vs. $600-800 second-hand engine + labour + inconvenience + possibility of new problems with that engine

hmmmmmmmmm i might just go any put in what is was designed for myself

of course, its your car so best of luck with it

[Cubes]

I considered getting the car tuned for std. regular unleaded.

Then figured, $5 extra per tank.. bugger it. who cares.

I've considered throwing regular unleaded in it and watching the knock monitor to see how much of a difference it really makes. I would then pull ign. timing out until there is no longer knock.. It would be interestering.

[Cain]

common, dooo ittttttt

[grigor]

Come on guys!!! There is a difference between ping and knock.

How do you think your car was tuned in the first place? You advance up the spark until in pings then back it off a few degrees.

I don't have access to top quality fuel here in the sticks so I sacrifice a bit of power by winding back the spark.

What I said was don't panic. One tank of fuel won't kill it IF you use your right foot sensibly until it's been diluted with premium.

[WazR32GTSt]

agreed - one tank won't kill you

i was referring the situation of someone using it every time, even if they had access to 98 RON premium...

[Cubes]

One tank will kill an rb25det.

Do a search, it wasn't driven hard either.

[CEF11E]

my car pings going up hills with regular unleaded so i dont boost it at all on the rear occasions i have to use it.

if there is no other alternative to povo fuel i will just put in what i need to get to a servo that has PULP

[nmcmahon83]

It sounds like i'm the only one who plans my fuel stops so that I only ever fill up at a 98ron servo...

[PHATGTR]

It sounds like i'm the only one who plans my fuel stops so that I only ever fill up at a 98ron servo...

<{POST_SNAPBACK}>

Not the only one

[ferni]

Try it and let me know how much the engine rebuild cost you.

[AMS]

So really not worth using even 95?

[scathing]

You should be OK if you drive the car conservatively, and your tuner has given you a street tune that allows for margin of error. I wouldn't go do a track day or the drags with it, though.

If you're using a piggyback or light tuning the factory ECU, the knock sensor and the learning functions should compensate.

If you're using a full aftermarket ECU (like a PowerFC), most of them don't have the learning function. It won't retard timing etc if the engine pings.

Occasional pinging isn't that bad (cars are engineered to sustain that kind of load occasionally) but if your car is constantly pinging (audible or not) then you're just causing undue stress on your pistons.

I'd use 91 to limp home if I was stranded in the middle of nowhere and couldn't get octane booster, but I'd put in as little as possible and be keeping an eye on my revs and throttle load.

[Tommyk]

i did this in my stocky 33 and 32 gts-t's (only when i couldnt get premium).

I didnt have any problems. I didnt drive it hard.

If you need to tank up on 91 or 95 octane, please stay out of your boost range, otherwise your engine will knock if it is tuned for a specific fuel

[Nozila]

i know of someone who didnt know much about how to maintain his import and drove on unleaded fuel for a good 6months to a 1yr and the car is still running fine. so is this perception that, a perception.