Is optimax better than regular unleaded when used in the z? I have been told that it is better if you are running at higher boost levels (stops pinking) . I dont mind spending the extra if it will benefit the car.

Any ideas?

Ste.

Originally posted by Homebrew

Is optimax better than regular unleaded when used in the z? I have been told that it is better if you are running at higher boost levels (stops pinking) . I dont mind spending the extra if it will benefit the car.

Any ideas?

Ste.

been discussed mnay times on here and general conclusion is its better, have had official word frfom SHELL that its higher than 98 octane (guarenteed) if you have a jap spec car then its worth running, UK spec and the difference is not so great.

Originally posted by 300z

been discussed mnay times on here and general conclusion is its better, have had official word frfom SHELL that its higher than 98 octane (guarenteed) if you have a jap spec car then its worth running, UK spec and the difference is not so great.

 

 

I noticed a difference with my UK car. It ran better and I got slightly more to the gallon.

Never noticed any differance in my UK car,and there is a few UK cars on here that have not noticed a differance.

I have a jap spec (but non turbo) and it makes no noticable difference to mine - which is handy because the nearest Shell garage is bloody miles away

i dont really notice any difference in my UK car either. having said that I only use Optimax, as having a higher octane rating is never a bad thing. I also get the same amount of miles from Optimax as i do from reg unleaded, so may as well use it I say.

 

Its also meant to have additives that keep your engine clean too (no, not on the outside ;) )

But like me you have an SE chip and they are mapped for unleaded, unless you have something extreme.

 

I also use unleaded virtually all the time, only exception would be a dyno day or maybe long runs on very hot days when Optimax adds extra safety margin.

 

 

Originally posted by MAC 1

Never noticed any differance in my UK car,and there is a few UK cars on here that have not noticed a differance.

A noticable difference between unleaded and either super unleaded and Optimax. But not any difference between Opt and super...Jap TT

the first post also asks if it reduces detonation/pinking .....hopefully if its a tt you shouldnt get det/pinking at all or something is not right..:rolleyes:

I would hope that your timing map doesn't produce pinking on 95 Ron unleaded 99% of the time anyway. You may get detonation on a hot day when the intercoolers get maxed out and the intake charge is hot and while under full load WOT mid revs, this is where Super or Optimax gives you a slight safety cusion over standard premium unleaded. Optimax will not give you an increase in power unless your engine is tuned to use the extra anti-knock capabilities of the fuel (more advance or boost = more power). Depending on the specific gravity of the fuel (how dense it is) you may get more or less miles per gallon than other fuels, this is not unique to Optimax but varies with all fuels on a day to day basis.

 

No more techy nerdy stuff today I promise!!

 

Paul (SparkZ)

I bought my first Z 3 months ago and am still on a big learning curve as to what the engine is capable of. It has had the ecu reprogramed by superchips and it has 2 bleed valves to up the boost. The boost guage hits the +14 when I boot it, I dont know if that is a acurate reading. Anyway, I noticed it was pinking just a little when driven hard it very hot weather, so was wondering if optimax would help out, i'll give it a try. If this fails I've been told water injection helps prevent pinking, any suggestions on this?

I would strongly suggest that you get your boost checked. If it is pinking at all you need to find out why and sort it. Superchips are very muched frowned upon by the Z community as there chips are not prgrammed to do a lot in the way of enrichment and reduced timing lead. This means that when they fit the bleed valves the boost is OK 90% of the time for the stock map (sorry superchips enhanced map) but when you boot it on a hot day the timing map is too far advanced for the intake temp and boost combination and you get detonation. Get rid of the superchips chip and replace with a proper chip (you do not have t spend a fortune SE do one for less than 200 squid) and if you can stretch to it I would suggest an electronic boost controller. Sorry to be the bearer of bad news but that is exactly what Superchips are in a Z.

 

Paul (SparkZ)

I agree, change that chip as soon as you can. Superchip maybe OK for Corsas or Saxos and stuff, but is not really good enough for a car like a 300ZX. If you have a good chip and the timing is right, 14psi should be OK. However, the stock boost gauge is never any good. I run at over 14psi according to mine but my aftermarket gauge says I am running stock 9psi. Its worth getting an aftermarket one to find out exactly what the turbos are doing.

 

 

Stuart

Homebrew

 

Just so you know, Stuart is a nerd too!! LOL

 

Paul (SparkZ)

Thanks, will look into changing the chip. Do you have a web address for SE, don't know who they are.

SE Nissan don't have a website as far as I know. If you do a search for SE on the forum I am sure there are numerous times that the telephone number is on there. Dont know it off the top of my head, sorry.

Anyone else have it to hand?

When you do call them ask for Pete and say that you are from the forum.

 

Paul (SparkZ)

Nobody uses normal unleaded in their Z do they?

I use optimax all the time now (its only 77p litre here) , same performance but v.slightly more to the gallon and its better than super un. at same price.

Not if I can help it but my Z will run on 95 if required, just have to be a bit careful if its warm. The Z ECU has the ability to control timing based on Knock sensor triggering by a few degrees before going into the safety map.

 

Paul (SparkZ)

Yup !

 

I did a lot of testing and on the road, day to day, there is no noticable difference running/performance and only a tiny improvement in mpg. Certainly doesn't warrant the extra cost.

 

 

Originally posted by Trevz

Nobody uses normal unleaded in their Z do they?

The guy I got mine off used unleaded but I use optimax to be safe. No noticable difference in power that I'm aware of. It seems to varie from Z to Z.

How d'you spell varie?:confused:

Originally posted by Trevz

Nobody uses normal unleaded in their Z do they?

 

 

Yes me,it makes no differance!

Can't believe so many can't see a difference !!:eek: :eek: Mine runs much better on Optimax. I know the background to it, being a Shell guy - I promise you its good stuff. Gives extra BHP and cleaner engine.

 

And mine's a UK zed. Just thought the not seeing a sifference could be due to the engine taking a while to adjust settings to optimise the new fuel ?? (just a guess)

Nelson, any chance you can fond out what anti knock additive(s) are used in Optimax? Also do you know the Motor Octane Rating?

 

Paul (SparkZ)

I even noticed a difference when I filled my Rover 820 up with Optimax, it was noticably smoother and more willing to pick up speed in the midrange. Optimax or at the least Super U for me.

Even the wife can tell the difference, and she's a lady! (Ducks quickly for cover).

What about the higher calorific value of super unleaded + an octane booster...its said to be better than optimax.

In standard for, obviously the optimax witht the higher RON number gives better detonantion protection, but apparently has a lower CVL.

 

For the record, I run optimax, because its at a good price (compared to super), I cant be arsed with octance boost, and I dont require the higher CVL. Just was after info from the sheel man! :D

I'm no fuels expert as I work in engine lubricants, but Optimax uses a special base fuel made by a novel refining process - a special plant was constructed to make it. That is why it is principally so good - not just the additives and octane rating (highest in UK). Obviously more info (which I don't know) couldn't be given out as it's confidential to Shell.

 

Surely the proof is in he pudding ATEOTDay ?