1988 Audi 90 Quattro re unleaded

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Mon 2 Apr 2001 22:31
1988 Audi 90 Quattro re unleaded - Tom Stoddart-Scott
My brother currently is running a 1988 Audi 90 Quattro 2.2 injection 10 valve. He is running it only on LRP and it does state that it will only run on 98 ron minimum on the fuel filler flap.

He is going to get rid but would keep it if he could run it on unleaded without a great cost of conversion. Does it need hardened valve seats or just its ignition timing changing?

It is a cracking car even at 141,000 miles and he is loathe to lose it as his girlfriend is hankering after a MK II Golf Driver as it is of similar price range and has more space but isn't 4WD and is a bit dull - no offence Golf drivers!

Please help as if he keeps it for another year I will be able to buy it off him!!!!
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Tue 3 Apr 2001 08:18
Re: 1988 Audi 90 Quattro re unleaded - Adam Going (Tune-Up Ltd)
Tom,
According to my data (Autodata Unleaded Manual, 3rd edition) the 2.2 Audi 90 Quattro (KV engine code) is OK for ordinary unleaded with only an ignition timing adjustment, resetting it to 8-10 degrees before TDC at idle (WITH THE VACUUM ADVANCE CONNECTED), and super-unleaded without any adjsutment at all. In other words the valve seats are OK. However, if it has a WR engine code (listed for the Quattro rather than the 90, but stranger things have happened !) it is not suitable for ordinary unleaded but OK for super-unleaded without adjustment. In other words the valve seats are again OK, but it needs 98 octane. In this case the other option is to use one of the octane-boosting / lead substitute additives (Millers VSP or Castrol Valemaster Plus recommended) with ordinary unleaded. Good Luck.
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Wed 4 Apr 2001 16:16
Re: 1988 Audi 90 Quattro re unleaded - Tom
Thanks Adam

will investigate further the engine code. It does say that it needs 98 ron minimum on the fuel filler flap is this either what was leaded now LRP or super unleaded ?

Cheers Tom
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Wed 4 Apr 2001 21:16
Re: 1988 Audi 90 Quattro re unleaded - Adam Going (Tune-Up Ltd)
Tom,
Leaded 4 star was originally 98 octane (ron), latterly only 97. Super-unleaded is supposed to be 98 octane (ron), but LRP is I think lower. I would take more notice of the engine code than a sticker on the filler flap, but to play safe use super-unleaded or an octane-boosting additive. The main point on this car is that the valve seats should be OK anyway - the higher octane rating is to combat pinking / detonation, and whilst high-speed pinking is not always audible you usually get the message at lower speeds when pulling hard. The ignition retard is purely to combat pinking.
Regards, Adam.
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