might be a dumb question

[kbekl]

as title says

just reading the manual and it states i should use 98 ron fuel in my 1990 w124 230te i understand this is the octaine rating but does the engine require this ?

also as i live in cornwall petrol stations are dotted here and their down my end and most only have regular unleaded

also most of the fuel stations arround here have 97 ron not 98 ron so what is the difference in using 95,97 + 98 ron

and does the car truely need the higher rating ?

 

[Adam230K]

it will run fine on a slightly lower octane rating, it might have the tiniest affect on the performance and fuel consumption as a result but nothing is going to happen to your engine.

The only thing that i've read about engine longetivity is that if u use a higher octane rating all the time, on an engine with a life expectancy of 200k miles, it'll live maybe til 210-220k miles depending that its being looked after.

Its nothing to get worried about.

 

[kbekl]

cheers that has helped, mine has done 205,000 miles at the mo and still is pulling stronly

just woundered will just have to keep my eye on the fuel pumps markings now lol

 

[grober]

The car may benefit from retarding the ignition slightly 3-4 degrees if you want to run on 95 octane fuel on a regular basis. The only figures I have are for the 2 litre engine are 12-18 degrees BTDC at idle so there is a broad range of settings. Any garage with a strobe light should be able to check the timing for you on the front crankshaft pulley. You may find its already been adjusted. Your vintage of car doesn't have the adaptive timing of later ECU controlled ignition cars. There is also a ignition timing knob/wheel in the engine compartment for running the car on very poor quality fuel --its described in your owners manual but its really designed for very poor 3rd world situations of sub 92 octane fuels and would introduce too much retard possibly leading to overheating and very poor economy.see this thread http://mbclub.co.uk/forums/showthread.php?t=66673

 

[kbekl]

i think the total garage that is 3 miles away has the higher octane so if i am desperate will only put about £5 in and the go straight to the garage and fill up again

i wasnt too sure on what the difference would be if i ever needed to put in 95 weather it would cause damage or not and i have not had a car that has needed 98 befor

 

[kwakdonut]

And to answer your original question - the only dumb question is the one you don't ask!!!

Welcome to the forum

 

[grober]

The 98 rating is really design legacy issue because the engine was originally designed back in the 80s to run on the higher octane leaded fuels. When these were removed from the market 98 was the nearest equivalent. Personally I would run the 98 octane if you can afford it. You may even get slightly better MPG which would offset the price difference?

 

[kwakdonut]

If my (very dimming) memory serves me right....

5* - 102 RON
4* - 98 RON
3* - 95 RON
2* - 92 RON

wow, I can just remember 5* petrol!..... oof I'm getting old

 

[kbekl]

right so at a guess these ultimate fuels are 98 or over ?

is it better to go with bp's higher rated 102 or just stck to the 98

 

[kwakdonut]

Stick with the 98/99 - no benefit from 102 (when you can get it!)

 

[kbekl]

thanx for all your help

 

[hawk20]

And to answer your original question - the only dumb question is the one you don't ask!!!

Welcome to the forum

Old Chinese saying: -
He who asks, shows his ignorance. He who doesn't ask, stays ignorant forever.