petrol

[DRUE1]

what petrol goes in a maestro turbo cheers people

[Beaker]

Unleaded

[H48HPE]

Book says 97 RON which is leaded.

[Beaker]

The Maestro Turbo has the O series engine in and they were designed to run Unleaded from the start. It has never been formally classified as able to run unleaded, but there has been no known problems as long as you retard the ignition timing.

I am sure Gareth will be in here in a moment to back my story up. If not I will feel very silly :)

[E_T_V]

As a minor aside 97 RON isn't leaded I don't think, just the octane rating of the fuel that it is designed to use. Super unleaded is 97 RON, unleaded is 95 RON.

[H48HPE]

different petrols have different octane ratings, like you say 95 and 97 octane unleadeds are currently available. The leaded petrols were available in different octane ratings known by number of stars, they were 2, 3, 4, and 5 star, with respective minimum octane values of 92, 94, 97 and 100 (according to an old book I have).

the rover repair book says 97 octane leaded, which it appears may not be the truth. But like you say you would need to alter the timing a few degrees to stop the engine knocking if you wanted to use 95 octane.

Seems typically silly that they didnt state unleaded was ok, but I supose at that time superunleaded wasnt about so the only fuel at 97 would be leaded.

Andy

[talkingcars]

most super petrol is 97 ron, optimax is 98. I run both my EFi and my V^ espace on this and get both more power and better mpg.

I beleive that in un touched form the turbo is similar but if you start tweeking it you will need aditives.

James

[MGTurbo]

For a standard car, normal unleaded is fine for everyday use. It requires 97 RON because thats what the ECU is mapped for, but it can make minor changes to the ignition to compensate. You will get a slight loss of power though.

A O series heads have hardened valve seat inserts so are 100% ok for unleaded fuel use.

When you start increasing the boost (IF) and other things that improve the performance, 97 octane or higher is needed (I.e BP Ultimate, normal Super Unleaded, Shell Optimax etc) to take full advantage of the extra performance, otherwise pinking may occur, and if really bad, you may get detonation that can melt pistons.

Gareth

[DRUE1]

cheers 4 that guys so super,optimax,and the new bp stuff is cool

[Sam]

Where cvan you get Optimax from?

What Ron is standard LRP?

[H48HPE]

Where cvan you get Optimax from?

Its from any shell garage.

What Ron is standard LRP?

It is a replacement for 4 star so that should mean its 97 octane but I bet it isn't, at a guess i'd say its 95 octane unleaded with whatever amount of aditive they felt like adding (which may include an octane booster).

using 97 octane petrol in a car designed to use 95 is a waste of money unless you are prepared to play with the timing. in an old engine designed for 97 octane, using 97 instead of 95 would be beneficial (with a lead substitute if required).

the octane number is the petrols antiknock value, so in an older engine that was knocking with 95, 97 octane petrol would cause an improvement.

Andy

[DRUE1]

the maestro im getting has had the head worked on 2 run unleaded so i have no worries about that

[Sam]

Ive just bought some of that Castrol Valvemaster Plus with octane boost as I am told it is better than LRP for leaded engines. Does anyone know how much the octane is boosted if you are using standard 95 Ron unleaded?

Previously I was using just a lead additive without ocatne boost but the engine was pinking a lot...Hopefully this will improve the performance a substantial amount.:confused: :confused:

[MGTurbo]

LRP is dead, many garages around here have phased it out.


Originally posted by DRUE1
the maestro im getting has had the head worked on 2 run unleaded so i have no worries about that

Well whoever told you its had the head worked on to run unleaded is telling porkies, they can already run Unleaded straight from the factory.

Gareth

[e692wtt]

My Monty's a 1.6, pre-1989 model year and can use 'leaded petrol only' but it has the knock sensor on the engine as per the Turbo models so this is relevant.

I used Shell Optimax since approx June 2002 with Millers 'Superblend 2000' lead substitute and found the car ran much better (much smoother, will run smoothly to 5500rpm, more economical, faster accelerating) than on premium Unleaded (whatever brand) plus the same additive. The car was the same on other Super Unleaded + additive fillups, but Shell Optimax was the only convenient one for me.

Then I filled up with BP Ultimate (December 2003), which mixed with the same additive is, frankly, a world apart again. Monty is so much smoother again, even compared to Shell Optimax. And the price is the same but, for me, it's not quite so convenient but I go out of my way to fill up with it.

I'd say shop around for the 'high octane' petrol that serves you best. For me, it's the BP Ultimate (and don't be put off by the 'sky blue' nozzles - doesn't 'blue' = Diesel?! 'sky blue' doesn't...) but for other cars it may well not be.

I'm not sure if this still applies, or if 'proper' Four Star (Leaded) is still available (it was, at a few garages), but "Four Star" available in the last few years had an Octane rating of 99RON, apparently (ie much the same as Five Star in the good old days). Might be worth trying, but it costs a LOT more than SuperPlus/Optimax/BP Ultimate...

Articles on various sites state that Unleaded can be used in all the 2.0 litre Maestros and Montegos without an Additive, which bears out what Gareth and others have said above. It's just the Octane rating needs watching.
:)

[DRUE1]

Well whoever told you its had the head worked on to run unleaded is telling porkies, they can already run Unleaded straight from the factory.

Gareth [/B][/QUOTE]

he is a very close mate there has been alot ov work done 2 the engine its had a full rebuild new roof lining cos the other one was sagging full respray performance exhaust big turbo so i know the car is mint and i dont have 2 worrie about the engine will find out what build number the car is when i get it is this car cheaper 2 insure on classic insurance

[DRUE1]

and i found this on my travels

Unfortunately, the MG Maestro Turbo was never approved to run on unleaded fuel. Even if you own a 1991 registered car four-star fuel is recommended. This is because, although the MG Montego Turbo was capable of taking unleaded fuel by this point, all MG Maestro Turbos were built in 1989 with 1989 engines. In effect there is no such thing as a 1990 or 1991 MG Maestro Turbo because the last one left Tickford in November 1989.

so i know my mate would not lie about the head

[G51 NAV]

Not suggesting your mate has lied about doing the head; suggesting instead that he completely wasted his time!

ALL O-series engines (from about 1980ish, maybe earlier) were unleaded compatible, because they were designed to go into the 'new' MGB which was to have a 2-litre O-series engine, unleaded-compatible so that it could be sold in the USA.

As has already been stated, the reason Maestro Turbos (and some EFi's) were said by BL/AR/Rover to be incompatible with unleaded fuel was because the onboard mixture-computer was programmed to expect a fuel supply with an octane-rating of at least 97 RON, which at the time meant only 4* leaded (don't forget back then there was no such thing as "super unleaded" and the new high-octane fuels), NOT because unleaded fuel itself would damage the engine. Subtle difference.

[e692wtt]

Try http://www.mgcars.org.uk/cgi-bin/gen5?runprog=mgoc&p=emg/mgoc-unl.htm for starters... unless I've messed this up in which case I'll do something that you can cut'n'paste!!!

O-series engines were Unleaded-compatible from the start in 1979 apparently... it's quite possible to change the valve seat inserts (ie have an 'Unleaded conversion') but it ain't strictly necessary unless your exsiting valve seats are shot (as happened, I believe, on some of the early 16-valve head on the Rover 820, which was also 'Unleaded compatible' but the block was based on, if not the same as, that of the O-series engine). I've not heard of such problems on any O-series in a Maestro or Montego, though.

Sorry to muddy the waters but I hope this actually makes it clearer in the end.

[MGTurbo]

Originally posted by DRUE1
and i found this on my travels

Unfortunately, the MG Maestro Turbo was never approved to run on unleaded fuel. Even if you own a 1991 registered car four-star fuel is recommended. This is because, although the MG Montego Turbo was capable of taking unleaded fuel by this point, all MG Maestro Turbos were built in 1989 with 1989 engines. In effect there is no such thing as a 1990 or 1991 MG Maestro Turbo because the last one left Tickford in November 1989.

so i know my mate would not lie about the head

Well let me tell you this, i speak from personal expereince, i've run two O series cars one nasp and one Turbo with a combined mileage of 80k. Both were never officially approved by Rover to run on unleaded, but isnt it weird how the valve seats inserts and exhaust valves are to exactly the same spec on approved and non-approved models?

Mechanically the unleaded and leaded engines are virtually identical APART from slightly lower compression and different spec inlet valves to go with upgraded valve seals (so nothing to do with unleaded anyway) and also steel cam buckets instead of cast iron. All O series blocks were identical to the earlier Turbo only blocks aswell from approx 1990.

You don't have to take my word for it. I also have inside information that the O series was designed for the outset to run unleaded fuel because it was intended to be fitted in the MGB for the american market back in the late 70's.

Gareth

[e692wtt]

What's "nasp"?

Some of us more-experienced, nay jaded, Forum Members can guess, but everyone else is gonna struggle to guess what "nasp" might stand for.


Thanks.

[MGTurbo]

Originally posted by e692wtt
What's "nasp"?

Some of us more-experienced, nay jaded, Forum Members can guess, but everyone else is gonna struggle to guess what "nasp" might stand for.


Thanks.

NASP = Normally aspirated. Which to less experienced people means no turbocharger.

Gareth

[threelitre]

Originally posted by H48HPE
LRP:

It is a replacement for 4 star so that should mean its 97 octane but I bet it isn't, at a guess i'd say its 95 octane unleaded with whatever amount of aditive they felt like adding (which may include an octane booster).
Andy

That's what my feeling about the LRP stuff is! I did use it when going to the UK in the old cars designed to run on 4* or 5*. But the last times I noticed that the car would run bad with lots of pinking on some of these fuels. So they really seem to be of a very low quality (and it was not only supermarket stuff) sometimes. I switched to use 97-Octane unleaded (as I do here in Germany).

To the O-series: Our MG 2.0 EFi (1986) has received an official status from Rover Germany back in 1989 (or so) that it can be run on on unleaded and 95 Octane fuel. And since then about 160,000 miles have passed... Due to the wide range the knock-sensor operates the timing there appeared no problems with the occasual use of 92 Octane (cheapest fuel over here) or burning old fuel relesed from older cars before going to scrap.

Regards,

Alexander

[G51 NAV]

Originally posted by e692wtt
What's "nasp"?
Then there's the other version as found in original 850cc Minis, Austin A35s, Morris Minors and Citroen 2CVs: "nexp": Normally Exasperated!

:laugh: :laugh: