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Tuning the 350Z to use unleaded fuel


Mark@Abbey m/s

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Hi Guys,

 

been thinking about a few things with regards the price of the fuel in the UK.

 

I am thinking of returning my UK car back to totally stock and working on a UPREV remap using

95 octane fuel.

 

Prehaps once we have some dyno results we can see if it is a worth while way to go with these

cars to try to make them a little more "less" expensive to run.

 

Do you think this will be worth while boys n girls?

 

 

Mark

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I think there would be a lot of interest at the moment! V-Power has hit over 1.40p/lt where I am.

 

Can I ask, as I'm a bit uneducated about fuel, what is the main thing that makes high octane fuel, high octane? I'm under the impression that it is essentially the same base fuel as regular unleaded, but with cleaners etc added?

 

If you were to use normal unleaded fuel - would putting a decent additive in the tank every so often provide a similar benefit?

 

Cheers,

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Can I ask, as I'm a bit uneducated about fuel, what is the main thing that makes high octane fuel, high octane? I'm under the impression that it is essentially the same base fuel as regular unleaded, but with cleaners etc added?

 

No stock unleaded is only 95 octane where as Super is 98 octane rating. The higher th octane rating the more aignition timing you can add into the ignition map so making more BHP/torque.

 

With a lower octane rating fuel we need to adjust the igntion/fuelling within the stock ECU to make the car run safely without any engine damaging detonation.

 

The car do have knock control at part/full throttle which can control detonation but this will cause the car to run at a lot lower BHP level as the defualt high knock ignition map removes around 10 degree igntion so trying to stop the engine destroying itself.

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If you were to use normal unleaded fuel - would putting a decent additive in the tank every so often provide a similar benefit?

Surely that would cost more than just using Super Unleaded in the first place! First thing I would be doing is swapping from BP/Shell to supermarket Super Unleaded like Tesco 99RON (Momentum)

 

Would certainly be interested to see how this goes and see if a decent saving can be made, especially if you can have multiple maps, one for daily driving and one for a bit of fun when you put super in :thumbs:

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I am thinking just tune for Unleaded with out any additives. If we tune with the additive what happens when you fill up with out the additive?

 

I am always worried about tuning cars with seperate maps for unleaded/super as the onus is on the driver to load the correct map. The cars will kind of look after thereselves with regards detonation but I am not happy with tuning cars for multi fuels.

 

Early Uk DE (276bhp) cars cant have multi maps.

 

 

Mark

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No stock unleaded is only 95 octane where as Super is 98 octane rating. The higher th octane rating the more aignition timing you can add into the ignition map so making more BHP/torque.

 

With a lower octane rating fuel we need to adjust the igntion/fuelling within the stock ECU to make the car run safely without any engine damaging detonation.

 

The car do have knock control at part/full throttle which can control detonation but this will cause the car to run at a lot lower BHP level as the defualt high knock ignition map removes around 10 degree igntion so trying to stop the engine destroying itself.

 

Learning has taken place!

 

Thanks for taking the time to explain it to me :thumbs:

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Interesting .. but one question I had was regarding the additional detergents in some super unleaded fuels.

 

In addition to its higher octane rating, Shell V Power, for example, claims to have additional additives/detergents for better engine conditioning for want of a better phrase. I wonder what importance you would attach to those?

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Odd, I thought the tescos standard for instance actually has more additivies in...I'm sure there was an article somewhere on it, I'll try and dig it out. I think it mentioned running with standard every now and then to clean it out a bit.

 

Anyway, I run my 313GT on standard petrol from tescos and she runs fine. I've only owned her 2 months tho but my previous BMW 330 I ran on super unleaded and whenever I changed to standard I didn't see a difference so with the GT I started with standard. Perhaps I should run her on super for a while. I ran my old JDM 2005 zed on super and whenever I switched to standard didn't see a difference.

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I think this is a great idea, although having two dyno charts for the same car with the same mods (one with a SUL map, one with UL map) to show people how much they're losing by switching to UL would probably be needed to put people's minds at rest. I would expect a properly mapped car on UL might make the same as an unmapped stock car on SUL. Or is that wishful thinking?! :lol:

 

The car do have knock control at part/full throttle which can control detonation but this will cause the car to run at a lot lower BHP level as the defualt high knock ignition map removes around 10 degree igntion so trying to stop the engine destroying itself.

 

Wow that's a lot of timing to lose! :surrender: How long does this ignition trim last for? Is it just until you switch off the engine or until you reset the ECU? I'd hate to think that one crap tank of fuel on a hot day could put a huge hole in my map that requires a reset.

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I'll be interested :thumbs: , how much power do you lose by running normal unleaded? whenever I've used it I've never noticed a difference

 

I don't notice a difference in power, but on the occasion when I was stuck for Super and had to fill up with a small amount of unleaded I noticed it impacted on MPG quite significantly.

 

I can get 28-29mpg on my average week's commute on super, but the regular unleaded got me down around 22-23mpg...I wasn't driving any differently.

 

25% more mpg for what is often only 10% more cost?? The figures speak for themselves, hence why I always fill up with super! :thumbs:

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I don't notice a difference in power, but on the occasion when I was stuck for Super and had to fill up with a small amount of unleaded I noticed it impacted on MPG quite significantly.

 

I can get 28-29mpg on my average week's commute on super, but the regular unleaded got me down around 22-23mpg...I wasn't driving any differently.

 

25% more mpg for what is often only 10% more cost?? The figures speak for themselves, hence why I always fill up with super! :thumbs:

 

Which model do you drive?

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I'll be interested :thumbs: , how much power do you lose by running normal unleaded? whenever I've used it I've never noticed a difference

 

I don't notice a difference in power, but on the occasion when I was stuck for Super and had to fill up with a small amount of unleaded I noticed it impacted on MPG quite significantly.

 

I can get 28-29mpg on my average week's commute on super, but the regular unleaded got me down around 22-23mpg...I wasn't driving any differently.

 

25% more mpg for what is often only 10% more cost?? The figures speak for themselves, hence why I always fill up with super! :thumbs:

This is what I noticed on my old MY03 350z too. I think to really see it, you need to run the car on SUL for a while then swapping back to even one tank of UL see's a nose dive in MPG. However, for those that run on UL, it will take a good few tanks for the car to adapt fully to see the gains as it will only advance the timing a small amount each time compared to if it detects knock where it will wind it back really quickly.

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I'll be interested :thumbs: , how much power do you lose by running normal unleaded? whenever I've used it I've never noticed a difference

 

I don't notice a difference in power, but on the occasion when I was stuck for Super and had to fill up with a small amount of unleaded I noticed it impacted on MPG quite significantly.

 

I can get 28-29mpg on my average week's commute on super, but the regular unleaded got me down around 22-23mpg...I wasn't driving any differently.

 

25% more mpg for what is often only 10% more cost?? The figures speak for themselves, hence why I always fill up with super! :thumbs:

 

Interesting, I'm getting 22mpg out of my 313, I'll go back to super on the next refill and will advise of the difference. My driving for the zed is nearly always just to work and back, I don't take her anywhere else so I should be able to easily see a difference if there is one. I think the next fill up is Monday.

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I'll be interested :thumbs: , how much power do you lose by running normal unleaded? whenever I've used it I've never noticed a difference

 

I don't notice a difference in power, but on the occasion when I was stuck for Super and had to fill up with a small amount of unleaded I noticed it impacted on MPG quite significantly.

 

I can get 28-29mpg on my average week's commute on super, but the regular unleaded got me down around 22-23mpg...I wasn't driving any differently.

 

25% more mpg for what is often only 10% more cost?? The figures speak for themselves, hence why I always fill up with super! :thumbs:

 

:thumbdown: Myth busted, on my car anyway. Filled her up with teco super (99) and she might be a bit livelier but its not helping the mpg, still getting 22 at best. I've reset and I've tried to keep my driving style the same. Shame. I'll give it another couple of days if the petrol lasts that long!

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:thumbdown: Myth busted, on my car anyway. Filled her up with teco super (99) and she might be a bit livelier but its not helping the mpg, still getting 22 at best. I've reset and I've tried to keep my driving style the same. Shame. I'll give it another couple of days if the petrol lasts that long!

 

I've always used V-Power and never had more than 23mpg, with 22mpg being the average. I tried Tesco 99 and that was the same too. :( I've seen people saying they're getting close to 30mpg which amazes me, I can only assume they're being towed to work! :lol:

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If you use unleaded on the stock map the car will always be pulling timing so your not burning the air fuel mixture properly, so he car will be more unecomoical.

 

We tuned a rev up car this week , which was running unleaded on a stock map the car was only giving around 230 hub bhp. After re tuning the fuel ignition cams maps we go the car back to 260 hub bhp which is pretty good for a car running on 95 octane fuel.

 

I am in the process in putting my DE 276bhp car back to stock to allow us to build a 95 octane map.

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I was doing a lot of miles under controlled conditions last year (100 mile motorway round trip, outside of rush hour, over many weeks).

 

Regular Unleaded = 30mpg

Super Unleaded = 29mpg

 

Under light loads there's not enough fuel going in to cause detonation. Under hard acceleration though you can feel (and hear) it's holding back the fuel. Hence overall, it was slightly more economical.

 

The compression ratio isn't that high so would expect you could get it back up to 75 bhp/litre ~260bhp. As standard it's adjusting to a conservative ~65 bhp/litre.

 

I suspect the later engines suffer more because they're higher compression and pushing 85/90 bhp/litre.

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:thumbdown: Myth busted, on my car anyway. Filled her up with teco super (99) and she might be a bit livelier but its not helping the mpg, still getting 22 at best. I've reset and I've tried to keep my driving style the same. Shame. I'll give it another couple of days if the petrol lasts that long!

 

I've always used V-Power and never had more than 23mpg, with 22mpg being the average. I tried Tesco 99 and that was the same too. :( I've seen people saying they're getting close to 30mpg which amazes me, I can only assume they're being towed to work! :lol:

You need to learn to carry speed/keep momentum and throttle control. Its constant stop-start and prodding the throttle that kills MPG ;)

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:thumbdown: Myth busted, on my car anyway. Filled her up with teco super (99) and she might be a bit livelier but its not helping the mpg, still getting 22 at best. I've reset and I've tried to keep my driving style the same. Shame. I'll give it another couple of days if the petrol lasts that long!

 

I've always used V-Power and never had more than 23mpg, with 22mpg being the average. I tried Tesco 99 and that was the same too. :( I've seen people saying they're getting close to 30mpg which amazes me, I can only assume they're being towed to work! :lol:

You need to learn to carry speed/keep momentum and throttle control. Its constant stop-start and prodding the throttle that kills MPG ;)

 

I thought it was because I was beasting it everywhere?! :lol:

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