Supra minimum octane requirements

Hi Guys...

I am a potential Supra owner, I will be going to Japan for work & am looking to buy a TT Supra to import back to South Africa.

My main concern is the min octane rating that the 2JZGTE can accept. In SA we only have 95 unleaded on the pumps. Race fuel is 98 octane but very expensive & not freely available..

I was looking at getting a Supra with BPU at the minimum, so running around 1.2bar boost. Will it be safe to run such a Supra on 95 fuel? I understand that the Stock ECU can detect detonation via the knock sensors & compensate by dropping timing....

I saw one Supra for sale on the web with a Mines CPU, will this operate similar to the stock wrt detonation?

Following on from that is it safe to use octace boosters such as NF & NOS?

Sorry for many questions, i'm a bit inexperienced wrt boosted cars.

Thanks...

Sounds like you may find it easier to import a UK spec supra, as they are quite happy to run on 95 RON.

I don't know anyone running a JDM on 95 RON, but others might. Most run it on 97+

With the MINES ecu running a more aggressive fuel and ignition map I would have thought it would be even less likely to run on 95 without det but in either case I wouldn't want to run a JDM Supra at 1.2bar on 95 octane even on stock ecu.

All that hot air from those turbos running past their efficiency range plus the ambient air temp is SA probably being very warm already sounds like a recipe for det on stock ecu & BPU.

I suspect if you use 95 you'll be restricted to stock boost levels unless you have the car mapped specially for a lower grade of fuel though I'm still learning so someone more experienced I'm sure can confirm for you.

Is the 95 octane the same as our 95 octane or is it more like the US 93 octane?

I don't know enough about about the fuels to comment but I understand that the quoted octane figure is not the most important when it comes to det.

Do you know if the 95 octane unleaded in South Africa is in RON, MON etc?

I think UK 98 Octane is in RON which is ~90 MON therefore 95 MON I would have thought would be over 100 RON Octane in UK?

See if you can find out what system is used to measure the octane number in South Africa!

@Caseys - Importing cars into SA is basically not allowed, its only in cases such as mine were a returning resident can bring in a car, so I pretty much have to bring the JDM spec.

@ Scott M & leebuk - the 95 unleaded is 95 RON...

So is it safe using the octane boosters like NF & NOS continously on a 2JZGTE?

We have a locally produced octane booster called DF20, which has caused lots of damage on my mates 4AGE 20V engine, so I'm a bit sceptical...

you should be ok on the 95 as long as you dont over boost it, i sometimes if i have to run mine on 95 and it may knock on full boost in 5th a little bit so i turn the boost down 1 psi and its fine,

just my experience though

I'd knock the boost back to

I'd knock the boost back to

 

yes i didnt mention i only run 8 psi max anyway

I occasionally run on 95 when I'm very low and the 99 is sold out, but I don't drive it hard and only put in a few gallons at a time.

Couldn't really comment on any longer term effects or det but I haven't blown up yet

Thanks for all the responses guys...

I think maybe I will consider running on stock boost for normal use with 95 pump fuel & throw in an octane booster or race fuel (98 RON) on track days & crank the boost up!

I think that an Air/fuel Ratio gauge might be a good idea to keep an eye on the mixture to ensure its not running lean...

Japan are so fortunate to have 100RON at the pumps!!

Be careful with the octane boosters. I remember reading that a lot of them are fake and do absolutely nothing to the true RON of the fuel.

There are some that do do the trick though

Be careful with the octane boosters. I remember reading that a lot of them are fake and do absolutely nothing to the true RON of the fuel.

 

There are some that do do the trick though

So which are the ones to use & the ones to stay away from?

Down here NF seems to get good reviews. There are some local ones that I will definitely stay away from.

Should I just use toluene? Its fairly cheap down here & easy to purchase, no requirement as to what its being used for. Will it affect the engine in any way?

I had my supra in Ireland which has the same fuel issues ran 1.1bar for 6 months and the engine blew! New engine in and 0.9bar was all i could run on 95 even with octane boosters i was using millers oils cvl turbo octane booster which is pretty expensive 1 bottle only treats 20litres of fuel. I think it will be costly to try run bpu with 95. In the end i had to move back to the uk to save the car. If its only a jdm supra you can get in keep it stock mate.

There is also the option to fit either a stand alone or piggyback ECU and have it mapped for the lower octane fuel.

Sorry for the resurrection, but what is the best way to idetify your car is running safely at BPU ; AFR reading?

Sorry for the resurrection, but what is the best way to idetify your car is running safely at BPU ; AFR reading?

Yes. That and maybe a boost gauge to see if you're over-boosting.

Yes. That and maybe a boost gauge to see if you're over-boosting.

Thanks!

What about fitting water injection then run 50/50 meth, even the basic w/i systems will reduce the possibility of knock but direct port w/i is the daddy.

Just noticed this thread is from last year, he`s probably blown it by now:)

Toluene 10% mix seems to be the choice based on availability and price