A-series on optimax?

[vrooom]

Would I see any difference in performace apart from wallet being lighter?

Jay

[miniandy]

yep, so long as you adjust the timing slightly. i found it to be good. this is a touchy subject though and no doubts you'll get a few differences of opinion!

[danwebster]

Ultimately its a higher octane rating than standard unleaded. This enables you to run more advance before you experience pinking. Unless you get your maximum advance set accurately to make use of it you won't notice a difference.

[Marquis_Rex]

I doub't you'll see any difference and this is an engineers view. Infact I'm quite sure even if you DID advance the ignition.

The A series and older engines in general were designed to run a lower Compression Ratio and had no knock sensing. As a consequence they were designed to never run into knock as this would cause damage.

Engines most likely to see any benefit from running higher octane are ones that have
-high volumetric efficiency or "good breathing"- the A series does not
- A High CR
-boosted engines-which effective have high a Volumetric efficiency
-It helps if engine has a sophisticated knock system that is capable of running into knock and out again continually making adjustments.
This means that just because a car has knock sensing- it doesn't neccessarily mean it will benefit from higher octane fuel.

>> Edited by Marquis_Rex on Sunday 23 January 18:42

[Plank]

I can only reccommend optimax.
My 1312 S which "breaths well" and on 10.75 compression runs very well on optimax, but lacks get up and go on std unleaded. For a car that is used only as a toy I thinks its worth the extra cost.

[danwebster]

I also only run my A series on optimax, but I have the benefit of 4 valves per cylinder and 8 ports, so it breathes rather better than most

[Extra 300 Driver]

with my 12.5:1 CR I always use optimax and a booster!

[Cooperman]

Both my rally cars seem to like Optimax, especially the '64 car with its 11.2:1 c.r. In addition, I add Castrol Valvemaster+ in the 64 car as well.
With lower c.r. engines, that is below 10:1 I can't see you would get much advantage,just pay more.

[love machine]

I've only got a 7.5:1 compression ratio.

I always use standard mucky petrol and lots of Tetraethyl Lead though. About 105 octane. Optimax doesn't respond as well to leading. It needs all the octane it can get

[WildfireS3]

I run on Optimax all the time. 11:1 CR though.