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Super unleaded -- "alternative" ?


MikeyM

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Ok.. now living on the Isle Of Skye the only garage with super unleaded is a 30 min drive each way.

 

So..

 

just how high a risk is running it on unleaded ?

 

Could I use an octane booster ?

 

Could I get the zed remapped for leaded fuel ? Can that be done ?

 

Thanks in advance for the help 😎

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What 350 do you have? If it's a HR then you're fine, no issues at all. If it's a DE car then you'll need to limit yourself to the lower RPM (like 2500revs tops), which isn't much fun.

 

Octane booster will work a treat, however for long term use you'll want some good stuff that does it properly, not just a small bottle you chuck in with every tankful (although they're fine in an emergency). Leaded fuel is a no-go, you'll kill various bits in the engine.

 

I see no reason why you couldn't get it mapped for 95 though, just means you'll lose a slug of power.

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I believe it's fine to run on normal unleaded IF you don't drive it hard. It's not recommended, but it won't do any real damage unless you push it - though that kinda defeats the point in having the Z, so it's not really a solution...

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What 350 do you have? If it's a HR then you're fine, no issues at all. If it's a DE car then you'll need to limit yourself to the lower RPM (like 2500revs tops), which isn't much fun.

 

Octane booster will work a treat, however for long term use you'll want some good stuff that does it properly, not just a small bottle you chuck in with every tankful (although they're fine in an emergency). Leaded fuel is a no-go, you'll kill various bits in the engine.

 

I see no reason why you couldn't get it mapped for 95 though, just means you'll lose a slug of power.

 

Yep.. it's a DE .. but 2500rpm 😣 I may as well cycle around !

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LOL

 

How many miles do you do ?

Simple answer - just suck it up and drive to get to that garage, get some jerry cans and fill them for when you CBA.

 

You don't need to buy another car, or remap it :lol:

10 min drive I might live with, but an hour on the round trip just to refuel? That's an awful lot of time essentially wasted. I think you're underestimating just how irritating that would be, or how much planning is required to make life as easy as possible. Imagine having to drive to Loughton every single time you needed some fuel: That would quickly suck the life out of ownership.

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I would just enjoy the run out and admire the Skye scenery.

That's what I do, don't find it a problem!

My nearest garage which happens to be Shell, is 20 minutes away here in west wales.

 

Different story though if its a built up area

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My nearest tesco for Momentum is 12 miles and my nearest shell for V power is 20 miles.

Just factor in a fill up when your out and about. The trade off for living in a rural location..... just don`t mention the broadband :teeth:

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By using 95 Ron you'll be losing somewhere in the region of 10-15 BHP. A remap to 95 RON would probably get you those horses back.

 

Pete

 

100% positive it will not lose this amount of power, Performance bikes magazine once tested a GSXR 1000 on standard fuel 95ron, BP Ultimate 97ron and Shell V Power 99ron, they emptied the tank completely between between testing on the dyno on the same day so conditions were no different the bike overall gained 1.7bhp using Shell V Power from standard fuel.

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By using 95 Ron you'll be losing somewhere in the region of 10-15 BHP. A remap to 95 RON would probably get you those horses back.

 

Pete

 

100% positive it will not lose this amount of power, Performance bikes magazine once tested a GSXR 1000 on standard fuel 95ron, BP Ultimate 97ron and Shell V Power 99ron, they emptied the tank completely between between testing on the dyno on the same day so conditions were no different the bike overall gained 1.7bhp using Shell V Power from standard fuel.

 

Might be different on bikes but i've seen 350's/370's mapped for 95 and they typically make less than stock, as said 10-15hp or so

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By using 95 Ron you'll be losing somewhere in the region of 10-15 BHP. A remap to 95 RON would probably get you those horses back.

 

Pete

 

100% positive it will not lose this amount of power, Performance bikes magazine once tested a GSXR 1000 on standard fuel 95ron, BP Ultimate 97ron and Shell V Power 99ron, they emptied the tank completely between between testing on the dyno on the same day so conditions were no different the bike overall gained 1.7bhp using Shell V Power from standard fuel.

 

I am certainly no expert on Bikes, but if this bike is set up to take normal unleaded then putting in super will result in no increase in power (or marginal) whereas I am not sure the opposite is true.

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It's more that higher octane fuels require a spark at a different stage of compression compared to lower ones. Having lower octane fuel means that the ignition needs to be retarded to avoid detonation at the wrong part of the cycle or as others have said "Knock". When super unleaded fuels started coming out most manufacturers put knock sensors in the cars so that the ECU would fix the timing itself, unfortunately Nissan were a bit late to the party, so in the early Z's you have to be careful.

 

In theory, changing the spark plugs to a colder set could help with preventing knock, the higher the octane of fuel the harder it is to ignite, so a hotter plug is required. If you're using lower octane fuel a colder plug would fractionally slow down the ignition of the fuel, in practice, I don't know if this would work or how to work out the "correct" plug to do that with.

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I stand corrected then, I understand it's a different motor & ECU etc but never thought it would make that much of a difference, I would love to see back to back dynos on a stock 350z running 95ron then 99ron to actually see what gain/loss is made.

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The thing about knock or pre ignition is that although there are a lot of factors that can contribute, but on a std setup the ECU combined with the knock sensor will detect knock and pull some ignition timing and add a little fuel to combat most do a very god job, but the DE ECU does not monitor knock after 5,000 RPM so its a risk if you want to use high RPM/WOT when using lower obtain fuel.

 

The rest of the time it should be OK, the only problems occur when the std ECU is not capable of retarding the timing enough, or add fuel, a plug change could help but it wont stop det if its due to pre ignition IE when the mixture ignites due to hot spot with in the cylinder, and or the flame front ignites ahead of the ignition point because of low obtain/high compression, this is the main cause of damage from detonation.

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