Which Fuel

Which Fuel

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Discussion

Euphoria

Original Poster:

45 posts

277 months

Saturday 12th January 2002
quotequote all
What's the best fuel for my '89 350i? I've noticed my car 'pinks' when I floor the loud pedal. I tried some shell optimax today which made some difference. It could be the timing but I suspect it must be the fuel I'm using. Any ideas?

jmorgan

36,010 posts

293 months

Saturday 12th January 2002
quotequote all
I was told that 95 ron was for my old 350 (1983) dunno if the same applies to an 89. It also needed an additive as the heads were not suited to unleaded, again 1983 not newer.

Edited by jmorgan on Saturday 12th January 22:21

shpub

8,507 posts

281 months

Sunday 13th January 2002
quotequote all
It should be running Super unleaded and not plain unleaded. It also takes several tanks to clear out the old fuel so you may find things will get even better with a couple more tanks.

As for a 1983 350i needing additive... where did that come from?

According to TVR and nearly everyone else I have spoken to, all TVR Rover v8 engines are unleaded friendly. The TVR statement is actually in the bible. The main problem with these engines is pinking (timing adjustement usually on the 350i engine, can be a lot more on the more esoteric engines).

There's an unleaded FAQ on my website and in the bible.

Steve
www.tvrbooks.co.uk

jmorgan

36,010 posts

293 months

Sunday 13th January 2002
quotequote all
quote:

It should be running Super unleaded and not plain unleaded. It also takes several tanks to clear out the old fuel so you may find things will get even better with a couple more tanks.

As for a 1983 350i needing additive... where did that come from?

According to TVR and nearly everyone else I have spoken to, all TVR Rover v8 engines are unleaded friendly. The TVR statement is actually in the bible. The main problem with these engines is pinking (timing adjustement usually on the 350i engine, can be a lot more on the more esoteric engines).

There's an unleaded FAQ on my website and in the bible.

Steve
www.tvrbooks.co.uk



I took it to Colin Blower when 4 star replacement came out and they contacted the factory with the details and the factory said so. CB also sourced a good additive for me and it run sweet as a nut. 4 star replacement was a bit rough. I seem to remember that it was actually set up for super.

Edited by jmorgan on Sunday 13th January 11:37

shpub

8,507 posts

281 months

Sunday 13th January 2002
quotequote all
quote:

I took it to Colin Blower when 4 star replacement came out and they contacted the factory with the details and the factory said so. CB also sourced a good additive for me and it run sweet as a nut. 4 star replacement was a bit rough. I seem to remember that it was actually set up for super.



Hmm... I suspect that this is more to do with the Octane rating rather than whether the heads are unleaded friendly. These are seperate issues but many have assumed that they are one and the same. There was some confusion at the time where people were saying that the engine needed an additive to restore the octane and this was then interpreted as meaning that the engines could not run unleaded at all and needed conversion. I know several Wedge owners who then forked out for new heads when there was no need to. It wasn't helped by several of the Classic Car magazines wrongly classifying engines in this way.

Part of the problem is that the official line from Land Rover who made the engine is any post 1970 engine is unleaded friendly and has the right valve seats. However, the line from Austin-Rover is that they do not approve of the use of any unleaded fuel in any of their engines yet the MBG V8 was set up for 94 octane unleaded. This may be due to the fact that they did not use unleaded tolerant hoses. I don't know. However I seriously doubt that they got the engines and changed the valve seats and then fitted the engine so I think there may have been other reasons such as the octane reduction with U/L. Except that the MBG V8 was set up for 94 octane so that argument goes out the window.

If using an additive improves the running then it does confirm that your car has been set up for super 98 or better octane and that it runs better on that. I use an Octane boost on the 520 when I can't get super (Millers).

Steve
www.tvrbooks.co.uk

jmorgan

36,010 posts

293 months

Sunday 13th January 2002
quotequote all
Super Blend 2000 seems to ring a bell. A firm near Liecester?

Euphoria

Original Poster:

45 posts

277 months

Sunday 13th January 2002
quotequote all
Thanks for the info guys. I was using LRP and an additive. But what about Shell Optimax are we agreed that it would be good to use, does it have the right octane for unleaded or superunleaded?

As for the wedge bible - steve expect my order any day now!

jmorgan

36,010 posts

293 months

Sunday 13th January 2002
quotequote all
Did I read that LRP has agressive degrading actions (?) on certain fuel pipe materials?

shpub

8,507 posts

281 months

Sunday 13th January 2002
quotequote all
quote:

Thanks for the info guys. I was using LRP and an additive. But what about Shell Optimax are we agreed that it would be good to use, does it have the right octane for unleaded or superunleaded?



All V8 wedges are set up for 98 octane fuel either 4 star (very limited availability and over 100p a litre) or Superunleaded which was originally 98 octane but was reduced to 97. Optimax is supposed to be 98. Either superunleaded or optimax is the fuel to use or ordinary unleaded with a fuel octane booster (not the same as LRP additive). LRP fuel is not made to any standard and the best recommendation I can give is not to trust it, especially as it is not needed. Use it in an emergency but stick to unleaded fuel I reckon.

Alternatively you can get the engine adjusted (usually just the timing but a rechip may be needed with the more esoteric engines) to run on plain unleaded.

My Griff 500 has been chipped to do so and runs fine on plain U/L. The 520 doesn't like it and gets treated to super/optimax/plain +millers boost as availability dictates.

Steve
www.tvrbooks.co.uk

MIKE390SE

18 posts

286 months

Monday 14th January 2002
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i agree, optimax works a treat, it stopped my 390 pinking and saved me a few quid on additives too

Euphoria

Original Poster:

45 posts

277 months

Monday 14th January 2002
quotequote all
Guys - after I've run down the tank I'll be switching to Optimax. I noticed a big difference even though the car pinked a bit which is probably due to the residue of strange fuel mixtures still left in the tank. I ran out of fuel on Saturday even though my gauge was showing a 1/4 tank. Is there anyway I can adjust it to make it more accurate or will I have to engage my brain in some mental maths each time I go for a spin?

gavinr

629 posts

276 months

Monday 14th January 2002
quotequote all
I've been using Optimax since I bought my 350i in september and it seems to have improved it a bit. It now cruises at 70 at 2700rpm instead off 3000rpm. It might just be me but it seems smoother. I could be going mad though.

HarryW

15,328 posts

278 months

Monday 14th January 2002
quotequote all
quote:

I've been using Optimax since I bought my 350i in september and it seems to have improved it a bit. It now cruises at 70 at 2700rpm instead off 3000rpm. It might just be me but it seems smoother. I could be going mad though.



Bloody 'ell they change your ratio's as well for you, must be good stuff