Taller Gears

[GuerrillaGarage]

I’ve got a 71 GTV with 2liter out of a later car in it. I was planning on swapping out the rear end for one with an LSD. It would be nice to have a taller ratio to drop the RPMs a bit on the highway. (with gas at $4.50 a gallon a little more economy wouldn’t hurt either) Stock gearing is of course 4:56, I know the later spiders were 4:10 or there about. I’ve heard that the automatic spiders had a 3:70 or something like that, but I’ve never actually seen one.

My recollection is that there were Milanos with a 3:54 but I assume if that ring and pinion fit in a 115 rear end I’d have already heard about it. Somebody must know for sure on that one?

Has anybody swapped in another kind of rear end to get a better availability of ratios? It might be good opportunity to go to a panhard rod at the same time.

Is there some alien make of 6 speed transmission with a taller gear that makes sense with the stock axle?

Or any other options I should consider? thanks, Steve

[crashmctavish]

The berlina has a taller ratio and very difficult to find an LSD unit. What profile tyres are you using? Alfaholics now do 15" rims.

[crashmctavish]

Forgot to say my GTJTS has a 2l LSD and its still pulling at 120mph.

[genericwood]

The 4.10 r&p makes a good ratio for a GTV. I sourced one from a later spider, but just haven't gotten around to putting it in yet. It's about 11% longer than the 4.56. The 3.70 from an automatic would be 23% taller. That's a LOT.

Erik

[msiert]

Quote:

Originally Posted by genericwood The 4.10 r&p makes a good ratio for a GTV. I sourced one from a later spider, but just haven't gotten around to putting it in yet. It's about 11% longer than the 4.56. The 3.70 from an automatic would be 23% taller. That's a LOT. Erik

[Alfar7]

The nice and less expensive than aftermarket gearsets solution for street and track is the Junior gearing (.86 fifth) with the 4.10 R&P. Lower gears are more usable and fifth has more pull. (3,53/.86 vs, 3.24/.79)

I just happen to have a fresly rebuilt .86 gearbox with all new syncros & sleeves, input & output bearings, seals.
And a 4.10 rearend with properly set up 4 disk LSD. The R&P is lightened as all of my set up assemblies were. This has never been used. Can be finished with light brake caliper brackets or full backing plates for (or with) parking brake assemblies when axles are installed which have new bearings to be installed on them.
If interested just Email me.

Also have a LSD for the smaller 101-105 diff. set up with 4 disk. It is in a 4.56 center but can be removed.

[1166]

I know someone who installed a 2.80:1 R&P set from a 3 series BMW in their spider in search of better milage...they like it!

[Alfar7]

What series BMW??

[1166]

I think a 2002 or 3 series. The ring gear was a bolt in (no surprise - ZF) but I think the pinion needed a different bearing.

[180OUT]

[

Quote:

QUOTE=1166;595765]I think a 2002 or 3 series. The ring gear was a bolt in (no surprise - ZF) but I think the pinion needed a different bearing.[/QU

[Subtle]

Richard did up the 4.10 lsd for my 101 Spider.

There were a couple of carbon-fiber coated clitch discs that were left over and Rj put 'em in.

The gear box needed a rebuild and a friend had a set of cr gears left over from racing--a couple of decades ago.

Put in taller first, second and third. Kept the .85 fifth.

This is a very drivable set up.

I think that 3.9 would be better, but not available. 3.7 might be too tall.