Rpm on jx

[JJJackson]

Hi, not sure if this is the right place for my question, please move if not.

My 1.6jx is reading 2800rpm at 62 mph( on sat nav as have kmph dash) is this about right? I'm running 16 inch wheels with 225 55 tyres.

What gearbox code would I have on a diesel Westy pop top can't see a code when I looked under the bus?

Many thanks James

[sciroccotune]

Would be difficult to guess with non standard wheels. Look on the sticker near the fuse box for gearbox code. 2800 is a good revs for the speed if you ask me

[JJJackson]

Hi according to the sticker the code is AAS don't know if that's good or bad?

[JJJackson]

Just had another look might be ASS, trying to look with a torch !

[sciroccotune]

I think that both those codes are 5 speeds and in the better range for longer gears /lower revs. Your larger wheels will be knocking off a few hundred rpm at a guess. Best look after it

[JJJackson]

Is there anywhere I can check what rpm I should be doing?

[clift_d]

JX engines are most comfortable around 3000 rpm, so your 62mph at 2800 rpm sounds normal.

You probably know this already, but your 225/55 R16 tyres are exactly the same diameter as the standard 185 R14 tyres anyway, so you wouldn't expect to see anything different to be honest.

[discipleofsketch]

yep according to this:-

http://www.etyres.co.uk/tyre-size-calculator" onclick="window.open(this.href);return false;

The diameter of your low profile 16's is nearly identical to the diameter of standard profile 185/80/14's, so the revs will be approximately the same.

This chart shows revs at 60mph for the different standard gearboxes - lowest revs on that chart at 60mph are 2951 for an AAP box:-

http://rjes.com/html/gearbox_types.html" onclick="window.open(this.href);return false;

[JJJackson]

My rev counter must be out then as it should be reading over 3k at 60, thanks for the links