Optimax or 97 in 4.2

Optimax or 97 in 4.2

Author
Discussion

jimbob2

Original Poster:

142 posts

250 months

Tuesday 30th September 2003
quotequote all
What's the verdict here guys - bizarrely, the manual says 97 for 4.2 and 92 (?) for 4.5. Odd.

gazzab

21,135 posts

284 months

Tuesday 30th September 2003
quotequote all
think there are some old posts on this ? Try a search for some definitive statements?

oliverkelly

116 posts

272 months

Tuesday 30th September 2003
quotequote all
I have always found optimax is the best in my 4.2.

GCerbera

5,161 posts

253 months

Tuesday 30th September 2003
quotequote all
oliverkelly said:
I have always found optimax is the best in my 4.2.
Same here.

Go create some weather...
Graham
TCR The Cerbera Register

www.TVR-Cerbera.com

arcbeer

485 posts

265 months

Tuesday 30th September 2003
quotequote all
me too

kojak69

4,535 posts

255 months

Tuesday 30th September 2003
quotequote all
Optimax.

olly

2,174 posts

286 months

Tuesday 30th September 2003
quotequote all
Optimax is slightly better (I think), BUT, I get a lot more pops & bangs on 97 (Super)

seasider

12,728 posts

251 months

Tuesday 30th September 2003
quotequote all
olly said:
Optimax is slightly better (I think), BUT, I get a lot more pops & bangs on 97 (Super)


Interesting any idea why?

weekender

33 posts

249 months

Tuesday 30th September 2003
quotequote all
mine says to run on 95 which I did whilst on holiday in Portugal. Began to sound like a bag of nails and I thought it needed a good service. Got back to the UK and filled up with Optimax, unbelievable, immediate difference and most of the pinking disappeared. Will only use this in future.

ro_butler

795 posts

273 months

Tuesday 30th September 2003
quotequote all
It is 97 for early 4.2's (or possibly even 98) but 95 from then on i.e. most 4.5's and later 4.2's.

Confusingly mine had a sticker saying don't use less than 98 ron (it was a '98 4.2) but I think that was because they were trying to use up the old stickers

Preferable to use 97+ ron.

Not sure if optimax is really that much better. It certainly has plenty of cleaning agents in and has a higher octane rating than other fuels but not necessarily the highest calorific value.

Sorry, this is getting really boring, if you want to know more check some of the jap forums, there are some good threads there (because octane rating can become critical when you start tuning cars).

Rob.

jamesk

2,124 posts

281 months

Wednesday 1st October 2003
quotequote all
Use Optimax for ALL TVR's. Its a simple as that. I know of Griffs (Rover V8), Tuscans (Speed 6) and Cerbs (AJP) that all suffered pinking and general rude behaviour - all of which went away running Shells good stuff.

Trust me

olly

2,174 posts

286 months

Wednesday 1st October 2003
quotequote all
seasider said:

olly said:
Optimax is slightly better (I think), BUT, I get a lot more pops & bangs on 97 (Super)



Interesting any idea why?


No idea at all ! But it means I run on 97 (Super) more often than I do on Optimax !

Anyone have a scientific reason why ?

mark h

32 posts

272 months

Wednesday 1st October 2003
quotequote all
Definite difference between Super unleaded and optimax.Mine flys on optimax.Is there any chance of that VPower juice coming to this country, i understand its rated at 100ron ?.

carl_w

9,250 posts

260 months

Wednesday 1st October 2003
quotequote all
It's rumoured that VPower will be coming to the UK next Tuesday.

Joe Cozy

64 posts

262 months

Thursday 2nd October 2003
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My 4.2 seems to prefer Super. runs like a dog after filling up with Optimax for a few miles... then settles. If it was due to grit in the tank, it would do same with Super, which it doesn't.

crazycats

700 posts

251 months

Thursday 2nd October 2003
quotequote all
Much better on optimax, and the girl that does the till is stunning

yiw1393

23,018 posts

263 months

Thursday 2nd October 2003
quotequote all
carl_w said:
It's rumoured that VPower will be coming to the UK next Tuesday.


What is this Vpower? Which brand? Anyone used it?

j_s_g

6,177 posts

252 months

Thursday 2nd October 2003
quotequote all
yiw1393 said:

carl_w said:
It's rumoured that VPower will be coming to the UK next Tuesday.



What is this Vpower? Which brand? Anyone used it?

It's Shell. You can currently get it on the continent (and other places like Asia). Seem to remember it being 100RON in Germany, but could well be wrong. Would be interested to know of any TVR owners that've tried it, too.

Singapore version (lower octane, possibly?)...

www.shell.com/home/Framework?siteId=sg-en&FC1=&FC2=&FC4=&FC5=&FC3=/sg-en/html/iwgen/shell_for_motorists/fuels/vpower/faqvpower_01211900.html

carl_w

9,250 posts

260 months

Thursday 2nd October 2003
quotequote all
Sorry, I was referring to the BP 100 RON fuel that's apparently coming next week (though I bet it ends up being 98 octane like Optimax).

matt101

299 posts

261 months

Friday 3rd October 2003
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OK, so now Im realy confused......

Ran my 4.0 chim on Optimax always and found it to be far better. Had the Cerb for 5 months now and until today have used the very same Optimax in this.
I recently noticed that I had a slight pink at 2.5K revs when accelerating so I got the throttle pots checked out and all was fine (along with a major service)

I put super (97) in it today and agree with the extra pops and bangs but strangely, the pinking has completley gone.

The car is apparently mapped for 98 so one would think that Optimax would be the best choice, so far is seems not. However, is the ECU not capable of adaptive mapping and would this "learning" apply to adapting to different fuels as well? and if this is true, why do the lightweigt cars have a 95 and 98 octane switch to select each different fuel type?

There is a post in general gassing for a 106 octane rated racing fuel. What happens if I feed the Cerb this stuff?????? more pinking?

And another thing, I know I have lambda sensors, but is there a knock sensor???? and if not, how would the ECU adjust to different fuels anyway?

And........ and....

Oh I dont care anyway. It would still fly with a tank full of Tequila!

(dont we all eh)