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95ron vs higher octane fuel, standards and tunes RS's

12K views 48 replies 27 participants last post by  paulthemilk 
#1 ·
where I live super unleaded is about 30mins drive away, I wondered how many of you run standard unleaded (91ron,mainly non UK fuel), premium unleaded (95ron), or higher octane fuel 98+Ron. Do you use it on a standard RS or tuned? I'm also curious to see if any one does or would / recommend using some methanol or other Octane booster mixed in to increase the octane each tankful?
 
#2 · (Edited by Moderator)
Hello Thomas. Standard is now 95 RON in the UK. BP ultimate is about 97, and Shell Nitro + is just over 98 RON. I don't travel 15 miles to get Tesco Momentum anymore (supposed to be 99 RON), as I find my car responds better to the Shell Nitro+

All RS's, standard or tuned will benefit a little from the better fuel, but some tuned cars should really run 97/98 if your tuner tells you it is set for it.
Mine is tuned for Shell. i had to drop a bit of 95 in once as I was nearly running out of fuel and they had run out of nitro+ at the pump. I just didn't push it until I could get Nitro+ in the next day.

Forget the octane boosters. They are a waste of money for the gain you get. Just stick with decent fuel in the RS!


Saying all this, 95 RON won't hurt a standard RS. If you run a few tanks of say Shell Nitro+ through and then go back to 95, you will notice a slight drop in performance I reckon. I did at stage 1 tune anyway.
 
#4 ·
I never run mine on anything other than SUL (unfortunately nothing better than that available in N Ireland neither 99Tesco or V-Power)...I spoke to Simon at Sitech about this very issue when he was setting up my Revo maps, as the car was on V-Power whilst I was in Scotland...I had the chance to refill prior to mapping with BP Ultimate (same as I use regularly) but was informed that the RS sensors and management compensated almost instantly for a change in fuel octane and not to worry.......

I would imagine that there are minimal performance gains with the higher octane and a larger safety margin, but it could also be the placebo effect of filling with decent fuel
 
#8 ·
Remembered seeing this back in my RS dreaming days, had a quick flick through my old PF and FF magazines (I have them all since I could afford them lol).

Anyways, PF issue March 2012:

Tire Wheel Car Motor vehicle Automotive design


Standard car with K&N expecting to make 300bhp

Made 263bhp

Operators comments: That's cheap fuel! V-Power Needed!

Most likely some others on here were there that day too, give me a shout if you want yours put up


I always use Nitro+ 10p more a litre isn't that expensive..

Cheers,

Bill
 

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#12 · (Edited by Moderator)
Remembered seeing this back in my RS dreaming days, had a quick flick through my old PF and FF magazines (I have them all since I could afford them lol).

Anyways, PF issue March 2012:

View attachment 116018

Standard car with K&N expecting to make 300bhp

Made 263bhp

Operators comments: That's cheap fuel! V-Power Needed!

Most likely some others on here were there that day too, give me a shout if you want yours put up


I always use Nitro+ 10p more a litre isn't that expensive..

Cheers,

Bill
Haha, that is me! I'd had the car a couple of weeks and at the time I wasn't as clued up on the advantage of higher RON fuel, didn't really think it made a difference. I had about a 50/50 mix of Shell 95 and BP Ultimate in the tank at the time.

But this was at Dynodaze near Hinkley, there's been a lot of debate about them and their dyno on various forums and clubs. It was at the RST forum dyno day at the time, everyone who rolled was complaining on the day of being about 30 - 40 BHP down on expected, most of the guys there rolled a lot at various places so they can't all be wrong right? Many a Focus RS and ST has been run their since, always with similar drops in expected power. My car was standard at the time, but the operators also blame it on Ford tuners bigging up their maps and lying about power gains, but in fact their dyno is just no good for high torque cars as per the manufacturers info/spec sheet, but they won't be told. Seems if you don't have a Jap car you don't do well on their dyno


Incidentally I ran my car at a different dyno shortly after and it made slightly over stock power, although that was on V-Power, then made 360 with Revo stage 1 and more hardware.

The dyno operator argued that if I had V-Power in on their dyno I would have made an extra 40 BHP, just from 99 RON fuel...... wouldn't that be great if it were true!

Anyway for the record, even in standard form I noticed a huge difference in performance and MPG between 95 and 99 RON fuel, after mapping I have never put 95 in, only Momentum 99 or V-Power/Nitro +.
 
#11 · (Edited by Moderator)
i remember a mk1 frs rolling road day i was at years ago, one car turned up with normal 95 ron fuel and AFR's where all over the place and the car was detting!!! (run aborted)
that was a standard car that should have been running super unleaded 97 ron

to add: the guy was told to take it easy and use the 95 ron fuel up, then fill up with shell nitro
then go back for another dyno run,

AFR's were back in line to what they should have been
No Detting
 
#20 ·
I'm keeping quiet on this...

From now on I'm using shell nitro...

Brother always used vpower and stated there was a massive difference. To cut costs I've used the cheaper one. But by doing some extra research and reading everyone's comments I'll be using nitro from now on.
Also the dynos he went to when he had the car the figures were 383 and 389bhp!
Guy at dyno said the best fuel will give you the best results. It's more money for a reason he kept on stating.
 
#24 · (Edited by Moderator)
It's not all about performance, if your car needs to run 98/99 Ron and your using 95 or even 97 I promise you your car will be detting!!!
I've owned a lot of performance turbo powered cars in my 24 years of driving, so I've been there and got the t shirt,
You can't really hear det out on the road unless your wearing det cans of course, I've had a lot of cars on hub dynos and I've heard cars det while wearing det cans, my mk1 detted on one dyno run with tesco 99 Ron I went back to the same dyno at a later date with shell nitro and not one bit of det,

Please use the correct fuel people as det is bad and a engine killer!!
 
#28 ·
Detonation (generally caused by fuel with a low octane rating) is the tendency for the fuel to pre-ignite or auto-ignite in an engine's combustion chamber. This early (before the spark plug fires) ignition of fuel creates a shock wave throughout the cylinder as the burning and expanding fuel air mixture collides with the piston that is still traveling towards top-dead-center. The resulting knock/ping is the sound of the pistons slamming against the cylinder walls. Severe detonation can break pistons and destroy engines.
 
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