Petrol Grade for NSX

[NZNick]

There have been many threads about petrol for the NSX over the years, but I can't find anything definitive on this subject:

My NSX says that it requires 98 (it's JDM).
Here in the South Island of NZ 98 isn't widely available outside the main population centres.
So far I have always been able to find 98, but heading over to the West Coast there seems to be only one place that sells 98, which may be too far away to reach without compromising the purpose of the trip.
Would a tank of 95 be ok before I get back to civilisation?
Would the NSX run on 91 (some places only sell 91 - especially in very rural areas) - would this cause any harm / issues further down the track?

I appreciate that this isn't a situation that applies to (m)any of you, but I would be keen to hear views on whether 95 is good enough, or should I stick to 98 except for emergencies, and in that case will 91 be ok not to do harm.

Should I put an octane boost product such as http://www.supercheapauto.co.nz/Product/Wynn-s-Race-Formula-Octane-Boost-500ML/155539 in if I have to fill up with 95/91, or will this do more harm than good?

Thanks,

Nick

[hkz286]

There have been many threads about petrol for the NSX over the years, but I can't find anything definitive on this subject:

My NSX says that it requires 98 (it's JDM).
Here in the South Island of NZ 98 isn't widely available outside the main population centres.
So far I have always been able to find 98, but heading over to the West Coast there seems to be only one place that sells 98, which may be too far away to reach without compromising the purpose of the trip.
Would a tank of 95 be ok before I get back to civilisation?
Would the NSX run on 91 (some places only sell 91 - especially in very rural areas) - would this cause any harm / issues further down the track?

I appreciate that this isn't a situation that applies to (m)any of you, but I would be keen to hear views on whether 95 is good enough, or should I stick to 98 except for emergencies, and in that case will 91 be ok not to do harm.

Should I put an octane boost product such as http://www.supercheapauto.co.nz/Product/Wynn-s-Race-Formula-Octane-Boost-500ML/155539 in if I have to fill up with 95/91, or will this do more harm than good?

Thanks,

Nick


the purpose of high octane fuel is to limit the chance of pre-ignition :) this USUALLY occurs when your producing large amount of power within the rev range. So using a lower octane fuel and taking it easy will USUALLY be okay.

I have no specific experiences in using low octane fuel in the NSX however.

Also be careful in terms of octane numbers. For example, in the UK we use RON. So when we talk about 99 octane over here, in the USA its the equivalent to 93 ish, as they use MON to rate the octane (there is no direct comparison, but its usually 6-7 points lower).

I think in Japan they use the same RON rating as the UK but NZ might be different.
Also the octane booster is a good idea, as the high quality ones do work. However I would do your research about which one is best etc

[Kaz-kzukNA1]

If you are referring to RON, you are fine as long as you don’t have other engine control related issues.
Car manufactures are testing the car considering the variety of fuel grade around the world.

No need to use aftermarket chemicals such as octane boost especially, if you have never analysed the pump fuel in different countries by burning and checking its spectrum. I have ;).
You never know what base fuel they are using and all sorts of blended additives that may react with the aftermarket chemicals.....
Same brand fuel in one country doesn't mean exactly the same in another.

In Japan, the fuel spec is stated in JIS and randomly tested by the authority.
Since the octane figure is achieved by blending several additives, there is always some deviation so to be on the safe side, the petrol companies are blending it at higher RON than the JIS requirement in Japan.

JIS states 'Regular' grade requirement to be at least 89 RON but all manufactures are producing it at 90 RON minimum.
JIS 'High octane' requires minimum of 96 RON but the manufactures are producing it at about 100 RON as many imported vehicles specifies 98 RON as their choice of fuel grade.

For IP reason, I won’t go too much in detail but all Honda models are tested against different level of RON and for NSX, you can run about 89 RON without causing any damages.
ECU will deal with it.

I know several owners in Japan using 90 RON for years without any issues.
Here in UK, there are several owners running on 95 RON and not 98 without any issues.
In US, they use AKI/CLC/etc index instead of RON and although there are several differences in the ECU, imported Acura NSX in Japan with JIS high octane fuel showed the same dyno result as the JDM NSX so this shows that the ECU is handling the fuel difference very well.


You won't be running with the empty tank so if you are worried, just fill up the tank to the top with 98 or 95 RON before entering the 91 RON area and when you hit about half the tank, fill it up with 91 RON to keep it much higher than 91 although full of 91 RON tank won't be an issue.

I would worry more about the quality and ethanol level of the fuel than the RON…..


Kaz

[havoc]

I would worry more about the quality and ethanol level of the fuel than the RON…..
Kaz
I'll bow to Kaz's greater knowledge about the detail, but I would emphasise this statement heavily - high-ethanol fraction IS a problem for older cars, and if it's not been shipped/stored properly, then water contamination is properly :(

[NZNick]

Thanks for the comprehensive answers as always - I won't stress too much about not being able to find 98 whilst out of town.
AFAIK NZ uses the same system as the UK (RON), not the US system (RON+MON/2).

Cheers!