Honda Prelude. Unleaded fuel?

[CHPD]

Hello everyone,

I've just bought an E reg Honda Prelude, it's in fantastic condition inside and out, but there's a little question that needs answering.

It has 2 litre engine and is a UK model, not an import. I need to know whether it is suitable for unleaded fuel or not. PC doesn't have the 'u' next to the MPG figure for this model and the label inside the fuel cap has 4 stars and '97' on it. But the previous owner says, and I quote "All Japanese cars sold in the UK since 1975 have been suitable to run on unleaded fuel" The handbook that comes with the car, (which is not specific to my fitted engine) says that if unleaded fuel use is required, an adjustment by the Honda dealer is required. To further confuse the matter, I used to use a fuel additive to my 1977 Toyota Celica when I had it as the previous owner had done the same.

I really need a definitive answer on this, I may just be being really thick and should use an additive as it has the 4 star label inside the filler cap, but I don't want to do that if it doesn't need it. It currently has unleaded in the tank, without an additive and it runs fine, but obviously I don't want any valve damage to occur. Does anyone here own one of these, or can anyone help please?

Many thanks one and all!!

[JPB]

It doesn't need the lead, but is set up from the factory for 97 octane fuel so just fill up with 97 (or 99 if you use Shell V-power or Tesco's own brand of Super unleaded) and away you go. No additives are required.
Your information about Japanese cars being suitable for unleaded from 1975 (in all markets, not just the UK) is correct, that is to say; they're metallurgically suitable but some need the high octane rather than Premium (95 octane) stuff.

To run on 95 (say, for example, if there's no super in your location), there's a simple reversal of one ignition connection required, but as these don't have a knock sensor, you'll blunt the performance to a small extent and will use very slightly more fuel than you'd do by simply filling with super.

Either way, the valve seats will cope fine.

Information taken from the 1991 edition of Autodata, ISBN 0-85666-601-7, Page HON19.

[CHPD]

Thank you very much for that! That's put my mind at rest! I'll be sure to full up with premium, but might also keep a bottle of Octane booster handy, in case I need it, there's nothing like having a happy engine!

Ian

[OneCarefulOwner]

it is a confusing situation, and has been for years. Dad bought a brand new Space Cruiser in 1987, so it was around the advent of Unleaded at the pumps. However, despite me (at age 14) pointing out exactly where in the manual it said it was okay to use (it was even pretuned for it!) the main dealer swore up & down that he'd *have* to have a cat fitted, as that was the only way to use Unleaded! Took me months to persuade him otherwise...