https://www.exxon.com/en/octane-rating

In all honesty you only benefit from higher octane when running high compression engines, 11-12:1 or over to prevent engine knock.

The only way to improve an engine performance is more cooler air plus more fuel and sometimes higher comp; ratio together with gas/air flowing = more mixture. The rest is either snake oil or plain BS. Been there, done that, 285 BHP (dyno results) on a 2.0 litre engine. The higher the tune the shorter the engine lifespan and reliability, talk to the top fuel V8 guys and they'll tell you exactly the same. RPM is king after tuning an engine. The Rover V8 engine is a 'tractor' engine as standard but don't bother tuning it as it'll last a short time without problems or grenade on you.

 

I stand corrected! I swear 'be been told 11:1 or 12:1. Thanks for the correction

 

All true.
Which is why I asked why the high octane reccomendation for these engines a while back.
Simple answer was no EGR valve.
Cleaner engine internals, less build up.

 

I was thinking 9.35 was high compression. I see that it was just relative.

Anyway I stand by my findings from years of personal experience. Better mileage, performance, and overall smoothness on top tier premium 92 octane. Keeps the FI happy as an added bonus too.

Nothing good comes from cheap fuel. That would be like expecting to live a long healthy life eating nothing but Subway Sandwiches, Top Ramen, and Safeway brand diet cola.

 

Engines perform better at sea level in winter where the air is cold and dense but conversely they perform badly 3000' up a mountain in summer.

If possible, legally, dump all emissions control crap, EGR's, O2 sensors, sump recirc: systems and even mufflers they choke engines and are fitted to appease governments so they can claim 'green' credentials.

Read this article in full, it's long and boring but very true:

How toxic is your car exhaust? - BBC News

This article highlights the complete rubbish the media and governments are 'feeding' everyone and the reason, MORE TAX, be it on the general populace or the motorist. It is fashionable in certain circles to believe in the Nirvana of emissions and buy electric Noddy cars.



All ECU's are metering devices for fuelling and ignition and are optimised for all drivers under all conditions to maximise fuel efficiency for idiot drivers, old women, crazy drivers etc. Re-mapping the ECU only deals with a small item of tuning the engine as engines run on more fuel plus more air to improve performance everything else just improves on this scenario. Old tech pushrod engines are inefficient due to frictional losses. Multi-valve overhead cam are the way to go but these still require mods to improve intake efficiency.

On comp: ratios, 9.35:1 is a fairly medium to low ratio. Low being around 8.0:1 and high being 11:1 or 12:1, some engines even run in certain conditions at 13:1 or more but require specially manufactured fuels. For efficient high revving engines take a look at Japanese motor cycle engines which although 'fuel' inefficient they are very mechanically efficient.

 

Yep, fell asleep twice while reading...but that may have been because I worked a 12 hour shift and I'm to old for that crap anymore. Anyhow, I found the testing/results interesting.

But, the biggest revelation was...finally figured out what the symbol on the cruise control switch was on the dash (of our Discovery's)...the road sign (pictured in article) for London explained it all. It's basically a symbol for an expressway, two lanes with an overpass.

Brian.

 

finally, someone else who will openly oppose the BS emissions scam.

One point, high revs are efficient for HP, not necessarily for fuel efficiency or work achieved. Diesels achieve huge torque levels with low rpm and still remain fuel efficient. It's a trade off for HP but you compensate with gearing. The same can be done with a "tractor" rover v8.

 

Brian, I too had a serious problem concentrating whilst reading the whole protracted script, far too long IMO.

 

I have always believed the green emissions thing to be a scam to extract tax and divert attention from the real issues in government King Koopa, the only reason I never voice my opinion in public is that it's always treated as being controversial.

 

Exactly! I'm honestly very surprised to see so much backlash on this forum for this viewpoint. It's been my experience that most auto enthusiasts are well aware of the hypocrisy and bull**** associated with the green movement, and openly chastise it.