Taller gears?

[Merlin]

Is it possible to convert a 'box to run a taller 4th gear?

I'm modifying my IRS 'box quite heavily, and want nice acceleration for me to play around with in first through to third, but would also like a slightly higher top speed...is this possible?

Cheers, N.

[fig]

Fourth gear on an ACVW is already an overdrive, so there's no point in making it longer. Split buses had a longer fourth gear than Beetles (IIRC, .82 vs .89), so a split bus box will give an improvement, and it's more or less a straight swap (axles and nose cone are different, and don't forget to flip the ring and pinion or you'll have four reverse and one forward gears).

What you need is to look for a longer final drive (ie, diff ratio). I believe 3.88:1 was the tallest diff ratio offered to fit a Beetle box. S, SP and other late model SA Beetles had this as standard. I believe 67 buses may also have had this ratio, and maybe some type3s as well.

Apart from final drive, another improvement would be to bring 2nd and 3rd closer together so you don't have the big "jump" from 2nd to 3rd, but I have no idea if there are alternate ratios available for 2nd and 3rd.

Your best bet would be to speak to a gearbox expert like Erlemann motors and ask them what options you have re gearing. They will know what you can chop and change.

[calooker]

Yes, its doable, 4th gear from a 75 fleetline is the trick

[Merlin]

Kewl; will do. Thanks for the info.

I'm ordering some nice kit for my new 'box, and it will go to a friend of my dad's who runs the biggest gearbox place in the country, so he knows what he's doing.

Cheers, N.

[IMPI]

If you have a SFAS gearbox swop in a fourth from a SFAB this will give you what is called a Freeway flyer in the states Sp2 Had this as std
Armand

[Merlin]

I'll have to check my IRS 'box the next time I 'visit' it IMPI.

Where do I find the code?

My ambulance has a Freeway flyer too.

Thanks, N.