On the M6 the other day and HAD to put some Shell Optimax in my P1. Almost instantly there seemed to be a noticable drop in top end engine performance after 5,000rpm and has remained so until filling up with Esso Super Unleaded yesterday. I know optimax is supposed to explode in the cylinder sooner during the cycle but why the drop off in top end grunt?

 

i haven't noticed this effect in an my96 m8

 

dog wait for your ECU to get use to optimax, ie after a couple of tanks then it should be noticeably better.

 

I use it in the P1, 2nd tank and much better stick with it its worth it
Ian

 

ive put £100 worth in my p1 since sunday, felt very good above 5k yesterday on the way home from powerstation, i was previously running shell super unleaded and millers octane booster
mark

 

Think I'm the same as you P1DOG. Normally use super unleaded, put in a few tanks of Optimax and I can't see what all the fuss is about.

I'll stick with it though cause it's about £8 a tank cheaper

 

engine much smoother since using optimax on my 99spec uk model but didn't notice fully till second tank full .

 

Although I have posted this before, its worth repeating. Ralliart UK ran back to back tests using 2 cars and Optimax gave 4 and 5 bhp extra on the 2 cars. I run it and always notice if I have to put some normal SUL in the tank.

 

There is talk of Optimax causing headgaskets to fail..... Not convinced either way yet tho.

 

There will ALWAYS be scare stories, generally issued from competing companies - worries a few simple minds!!

Optimax is used in all my cars - the least performance orientated ones are the ones that seem to benefit most, Oddly??

I have noticed that Optimax is creeping up faster in price however, they will push until there is a drop-off - so, it may be good for those who believe everything they read to stop buying for a while - will pull the price down!!

Pete