2.1 DJ - unleaded 95 or 98?

[timski]

Hi Guys,

Would it be easy to tell if a 2.1 DJ (1991) has been timed to allow it to take unleaded 95 rather than 98? I've been using unleaded 95 since I bought it (2000 miles since maybe) as I wasn't aware it should be running on 98. The engine sounds smooth but to my untrained ear that's not much to go by. Are there any tell tale signs that it's unhappy?

Cheers,
Tim.

[Ian Hulley]

If it's been running fine on 95 then don't swap to 98 .... if it runs better you'll never want to go back and it'll cost you a fortune

Ian

[PetenAli]

Check out this thread started by Syncrosimon who knows a lot about 2.1DJs. https://club8090.co.uk/forum/viewtopic.php?f=4&t=85055" onclick="window.open(this.href);return false;

After reading this thread I changed to 98ron and altered the timing to 10 degrees BTDC and noticed a change for the better as well as better fuel consumption which made up for the extra cost of the higher octane fuel. As I understand it the 2.1DJs were designed to run on higher octane fuel being higher compression engines.

As for checking how the timing is set currently - find someone with a timing light who knows how to use it and get them to check. Remember that there are various vacuum lines that need to be plugged and electrical connections that need unplugging and plugging together - the Haynes explains clearly.

Good luck with it - I'll be interested to see how you get on!

[timski]

Cheers Guys,

Interesting thread. I will have to monitor my fuel consumption properly to see what I am getting and get my timing checked out.

In the meantime, could you cause damage to the engine by running on 95 if it is setup to run on 98?

Thanks,
Tim.

[kevtherev]

yes..
pre detonation will eat valves and pistons

[PetenAli]

Just what the man says ^^^^^^. Get a person with a timing light who knows what they are doing and its the work of minutes.

Cheers Guys,

Interesting thread. I will have to monitor my fuel consumption properly to see what I am getting and get my timing checked out.

In the meantime, could you cause damage to the engine by running on 95 if it is setup to run on 98?

Thanks,
Tim.

[timski]

Thanks guys.

I've just had mine converted to LPG by VW Elite (Gasure) so most of the time it will be running on LPG anyway now. They diagnosed piston slap in cylinder 1 when they did the conversion. Compression tests showed it wasn't effecting engine performance yet but not doubt it will do at some stage in the future. The slight knocking sound you can hear has been there since I bought her (I assumed it was the tappets as I'd heard they are noisy on these vans) but I suppose running the bus on 95 won't have helped if she hadn't been correctly timed to run on 95 especially in light of what Kev said re pre-detonation.

Now I'm wondering how they set the timing up if you have LPG? Presumably LPG requires a different timing to 98/95? They didn't ask me whether I use 95 or 98 when they converted it. Should I run in 95 or 98 when using petrol or should I give VW Elite a call to see what timing they set it with?

Cheers,
Tim.

[kevtherev]

I imagine elite would have thought you knew that the 2.1 runs on premium 98 ron as it's in the vans manual, haynes and various other places.

10 deg BTDC is the mark for 2.1's on LPG and 98 ron premium petrol (dual fuel)
some would suggest it being more with constant lpg use... as much as 17 deg BTDC even

if the timings been tatted with, then it was done to run on 95 ron normal unleaded and the timing set to 5 deg BTDC... so not by elite I'm sure

have you got a timing gun?

[timski]

I imagine elite would have thought you knew that the 2.1 runs on premium 98 ron as it's in the vans manual, haynes and various other places.

I guess so Kev. I presume VW Elite have set it up to run as it should on LPG which is presumably also compatible with 98? I'm guessing therefore it will be safer to use 98 from now on. There'll be some 95 left in the tank at the moment though. Is that an issue?

I haven't got a timing gun and don't know how to use one but I'm game to learn so I'll look into that.

Cheers,
Tim.

[1664]

There'll be some 95 left in the tank at the moment though. Is that an issue?

Dilute it with 'premium' petrol. Most garage 'premium' is 97RON but some are 99RON. Obviously 99's better for diluting than 97 if you can get it