Optimax in an '02 CTR ?

[Noodles]

Hi Folks,

Apologies for bringing up the subject of Optimax again. I know it's been covered a lot in other forums and threads but...

I have been doing some research trying to work out if I should consider using Shell Optimax in a CTR. There is a lot of chat about it other forums, and the general concession seems to be that it is a better petrol and it helps keep the engine clean. However, it was also suggested that you only get a real benefit if the ECU in your car can adjust to the higher RON grade of Optimax.

I know the CTR is set to use 95 RON petrol by default. The only threads I have been able to find about ECU changes have been in the TVR ones, so I thought I'd try and find out specifically what other CTR users are doing regards using Optimax.

I also read on one thread that using the wrong grade fuel can damage the cat of your car. This is not something I have found stated anywhere else (quite the reverse), and indeed Shell’s own web site suggests any unleaded or super unleaded car can benefit from Optimax. However, I’m naturally nervous about doing anything that could break the CTR so again would appreciate the views of any other CTR users out there.

[stu_allen]

Run mine on it fine. NO benefit from the extra octane, only benefit comes from the detergent properties.
However, may play with the ignition timing in a couple of 1000miles to use the extra 3.6 RON.

[VTECDave]

I ain't going make any claims about performance enhancements but I can assure you that the CTR will be fine on the stuff.

On my old 96 Civic the fuel filler flap says 95 RON (MIN) - 98 RON, ie: the ECU is meant to sense to the difference and adapt. My car is fine on Optimax so the new CTR will be fine.

Nip over to the Honda-R club and ask:

www.r-forum.net/

[CJN]

There was a piece in Evo last month or the month before about Optimax. They tested it in the M3 Breadvan, the CTR & another car. The CTR showed best of all cars on Optimax, with better acceleration throughout the rev range after 1500 miles of Optimax, with most improvement in high gears & low revs. The engine was also cleaned up internally (pics in magazine), but there was no change in economy. The ECU does adjust itself - apparently.

[dougal]

I read that and I can feel a difference, not that it feels faster when Optimax is being used, it just feels slower when I have to fill up with the ordinary stuff!?! If you see what I mean.
The CTR has a Knock sensor and the ECU adjusts to the fuels octane rating, takes a tank full at least to really notice the difference. Engine also feels smoother when using it.
Makes a hell of a difference in the Griff, goes much better.

[CJN]

I'm on my second consecutive tank of Optimax so will post my findings soon. The fuel guage doesn't seem to have moved as much as normal (after 155 miles) but that might be something to do with the missus having her first quick spin in it yesterday (or not). She loved the gearbox(after saying that it was in a strange position), the strong brakes & also managed to overtake a few cars.
ms 'Can I overtake then?'
me 'we're doing 60, drop it into third & press the loud pedal hard'
me 'watch for the redline!'
bouncing of rev limiter
ms 'ok'
bouncing of limiter in 4th
ms 'it's quite fast, isn't it?'

Compared to her Ka it is.

That should keep her quiet for a while

[douglasr]

My S2000 apparently has an adaptive ECU, and I've noticed the car runs more smoothly at low revs (say when crawling in traffic). Outright performance is unchanged from standard SUL.

[Mark Benson]

The S2000 ECU takes a few tanks to adjust to the new fuel, if you want it to learn a new fuel (or a new driving pattern, for instance if your daily drive has changed from motorway blast to city crawl) you can pull out the ECU fuse for a few seconds, this performs a quick reset.
This may also apply to the CTR.

[stu_allen]

No difference as the CTR is designed to run on base 95 octane, as opposed to the jap built cars.

[SJobson]

Stu, that only means the mapping's been done down to 95RON so it can run on lower octane fuel. But it alters the timing to allow it. The ECU will detect higher RON fuels and adjust the timing to suit. So there is a genuine benefit, however small.

[CJN]

Second consecutive tank of Optimax returned 31.5MPG with normal driving (fairly quick then) which is a new record for me!!
The next tank doesn't look promising though.