This is pretty random, but I'm just interested to know if anyone knows.

All the FWD 1.8T Octavia 02J gearbox's share the same ratios, but the vRS has slightly different 4th, 5th and final drive ratios. Why? It's such a small difference.

I've made a spreadsheet showing what I mean:

The EVS (1.8T gearbox) and EHA (vRS gearbox) use the same gear oil, they both have the same modified syncro on 1st, same clutch, same output flange diameters etc. The only difference is the engine their attached to (150bhp vs. 180bhp). So why the hell are the ratios different by such a small amount?! What's the point?

The reason I ask is because I'm thinking of getting a spare gearbox, to fit an LSD to at my leisure, and if the 1.8T gearbox's have such similar ratios then that opens more options.

Cheers

Just a thought, I wonder if the diffs are different or something.....

Em, the data plates you've posted explicitly say that the 1.8T150 and 180 use different Final Drives mate (and the Seat box is totally different being a 6-speed).

cause they're special just like the special people who drive a vrs :p

Em, the data plates you've posted explicitly say that the 1.8T150 and 180 use different Final Drives mate (and the Seat box is totally different being a 6-speed).

Yeah I know, that's what I wrote!

I just wanted to know why they decided to use slightly different ratios for 4th, 5th and the final drive? Since it makes feck all difference to the calculated road speed. Unless you're saying that this indicates a different diff is fitted? I've only found one diff for the 02J on VAGCAT, so I'm assuming it's the same diff across the board.

I should have said to ignore the LCR gearbox bit, that's got nothing to do with this. I just threw it on because I had it!

I've updated the table below, to show the actual numbers of teeth. It indicates thats the 180bhp EHA box uses smaller gears than the 150bhp EVS box. Maybe this has something to do with it?

cause they're special just like the special people who drive a vrs :p

More than likely! :p

I can't quite see why you'd do it that way round (shock loads are higher in lower gears), but fewer teeth would mean that the individual lands could be wider.

I can't quite see why you'd do it that way round (shock loads are higher in lower gears), but fewer teeth would mean that the individual lands could be wider.

Yeah good point, hadn't thought of it like that. But like you say, if you're making gears stronger you'd expect the lower gears to be made stronger not the higher. Oh well!

I must admit I had to reach for my gear design book for a refresh when you mentioned land widths!

I'd like to find out the pitch diameters now.....

seems strange why they would go to the bother off the different ratios just for the vrs, i know it will physically fit, but as to why they are different :S