What Petrol To Use?

[V28VX37]

All R34GTt should be running 98 fuel as a minimum due to the higher compression and boost, regardless if it's stock or not.

(I wouldn't know about older models)

This is interesting and in line with what I've heard being said about turbo cars in the past.

I just got an R34 GTT and it came with a 34-page Owner's Manual in English, copyright ADR Automotive Engineering Pty Ltd 2006 (Vs 2.10 02/06). Anyone else seen these things?

Anyway, on page 26 under Specifications it says the following:

Fuel

Petrol Engine: Unleaded fuel with Research Octane Number 91 or higher.

RB26 Engines

Petrol Engine: High octane unleaded fuel with Research Octane Number 95 or higher.

Fuel tank capacity:

65 litre, (14.3 Imp. Gal.)

There are mentions of RB25 and turbos elsewhere in the manual so it's quite clearly meant to cover all model variants.

I know that with the LS1s (different planet I know) the stock ECU can 'adapt' to different octane fuel but as soon as you get a tune it's done for a specific octane level - almost invariably 98 RON.

Can anyone confirm if the Nissan ECUs are adaptive, too?

[Marcus89]

The nissan ECU's would be adaptive. The ECU's retard timing to stop detonation so in theory should be able to put regular unleaded in and it'll just retard the timing enough to stop detonation (hopefully lol) but i wouldnt risk it.

[Galois]

it takes a while to retard the timing tho. when the ecu is reset it adapts quickly, but as time goes on the adaptation is effectively just fine tuning so it take longer to adapt to conditions

[V28VX37]

The nissan ECU's would be adaptive. The ECU's retard timing to stop detonation so in theory should be able to put regular unleaded in and it'll just retard the timing enough to stop detonation (hopefully lol) but i wouldnt risk it.

it takes a while to retard the timing tho. when the ecu is reset it adapts quickly, but as time goes on the adaptation is effectively just fine tuning so it take longer to adapt to conditions

Thanks guys, good to know.

I just ran the car until the fuel warning light lit up and then filled up with BP Ultimate.

I will do an ECU reset next just to make sure it learns the new octane as I'm pretty sure it was running 95 before.

[MrR33666]

98 OCTANE GOOD

E10 BAD

[tranman]

So if for example i do want to skimp on the dollars required for premium unleaded and in addition to that be comfortable with a small drop in performance (someone stated 10-15hp?).......i could reset the ECU and fill her up on say 91 and let the learning process begin?

[mad082]

there is a limit to how much the ecu will learn. and it isn't that much (and i think most of it applies to light load). the only way you could run on 91 octane would be to retard the timing, but then that can cause heat issues as well and you'll still end up with pinging. you can run the car on 95 octane provided you have the timing set to the standard 15 degrees and you aren't running too much boost. running 91 octane isn't going to be safe and the car would more than likely run like arse the moment you hit boost. the power loss would be more than 10 - 15hp. i'd say more like 30 - 40hp.

[N-DAWG]

A bit of a related question, probably a n00b question actually, but I didn't see the need to start a whole new thread...

is it ok to switch between fuel vendors on a car that has been remap tuned (eManage Blue) for a fuel type? Provided of course that the octane content is the equivalent..

My R34 has been tuned for BP Ultimate, but with my fuel economy over the last month or so being up shit creek with a turd for a paddle, I'd like to use something more cost effective like Shell V-Power with a good ol' fuel docket discount until I replace the oxygen sensor and finish troubleshooting my 16-21L/100km fuel economy

[linkems]

A bit of a related question, probably a n00b question actually, but I didn't see the need to start a whole new thread...

is it ok to switch between fuel vendors on a car that has been remap tuned (eManage Blue) for a fuel type? Provided of course that the octane content is the equivalent..

My R34 has been tuned for BP Ultimate, but with my fuel economy over the last month or so being up shit creek with a turd for a paddle, I'd like to use something more cost effective like Shell V-Power with a good ol' fuel docket discount until I replace the oxygen sensor and finish troubleshooting my 16-21L/100km fuel economy

If your testing for fuel economy your not going to be opening her up so jumping from one 98 to another 98 will be fine, as your car is always under light load. Even if you decide to thrash your car your tuner should have left a margin in the tune to stop car from pinging, for this exact situation. I don't know how much truth to this there is but I've even read that storing the fuel in your tank will slowly degrade the octane, so even if it were 98 if left for long enough it will be lower. So unless your tuner is an idiot or you specifically told him you want to run the car to the limits with aggressive timing, i don't see a problem.