930 Transaxle

[Earl Balzen]

I am going to use a 930 transaxle in a Lola T70 III B. Should it be inverted or just flip the ring and pinion? Also, does anyone know the gear ratios and the ring&pinion ratio? Thanks in advance Earl

[Sandy]

Earl -

You should give a call to Roger at PowerhausII (www.powerhausii.net) . He did the 930 that is going in my RCRGT40. He is very helpfull and had done a bunch of them for v8's cars. He sometimes has cores in stock if you are lucky. He also has a bunch of different ratio gear sets in stock for the 930 boxes.

For my car the box is flipped. He has added and oiling system as well as changed the ratios to something more suitable for my intended use and engine package. I think he can flip the ring also, but might be first figuring out fitment into the car before making that choice, also note that the 930 box come in a couple of style, short and long bell housings (Also 2 types of long bells). The long housing can be converted to short if you are tight for space. Also he mentioned that the oil system is not manditory for flipped boxes, but a good idea.

For the 930 box as I recall the r&p was 4:22

I think the other gears fall out like this (Orig ratios, and rounded a bit)

1 - 2.25
2 - 1.30
3 - 0.89
4 - 0.63

Check around with the search feature on the list you should find all the info on the 930.


Good luck

Sandy

[John]

Does anyone know whether there's a parking brake rotor and caliper that will bolt onto the output shaft plate of the porsche 930 transaxle? This would allow for an inboard parking brake.

John

[Sandy]

I have never heard of one in the discussions on the list. (Parking brake for 930).

Sandy

[Mike Dozier]

John

What would be the benefit of an inboard parking brake if the main brakes
are outboard? Seems like added complexity to me.

MikeD

[John]

Mike,
The car lacks parking brakes - it has corvette rear suspension. I looking for a way to install a parking brake!

Got any ideas?

John

[John]

Mike,
The car lacks parking brakes - it has corvette rear suspension. I looking for a way to install a parking brake!

Got any ideas?

John

[Russ Noble]

John,

What are the legal requirements for a parking brake in your state. Can you use hydraulic? If so another master cylinder operated by the handbrake and plumbed in series into the rear brake line (or front, depends where you prefer) would be the easiest solution.

Cheers

[Phil]

John
I have seen a setup on a Porsche box with a solid rotor, looked like a home brew but nice bracket, and a Wilwood cable operated caliper..seemed pretty easy to setup. I dont think the hydraulic setup is legal in a lot of states, it also seems a little scary to me using static hydraulic pressure to hold a vehicle..even if its in gear and just parked. I have seen hydraulic parking systems on small construction vehicles, but then that is usually an off-road deal. Here is a photo of the caliper.
Cheers
Phil

[Sandy]

Phil -

I have those on the back of my 65' mustang (added willwod rear disks). The just need a different bracket for the caliper, the sit forward of the regular caliper and a simple pull cable to activate. Work pretty well and really simple.

Sandy

[CliffBeer]

Hydraulics are generally not used for a parking brake in the automotive industry because hydraulic pressure will, over enough time, diminish and potentially create a dangerous situation. Depending on the state of the seals and the oil this could be one day to several months. In either case, a cable brake is commonly accepted as the safest, and simplest, solution.

I have seen inboard rotors for a cable parking brake before - can't recall if I've seen one on a 930 transaxle or not. Best setup would be a simple machined/lathed rotor which bolts to the back side of the output flange (towards the transaxle) so that the suspension geometry (pivot points) doesn't change. A simple bracket can be fabricated which bolts onto the bolts for the output shaft cover to which a basic Wilwood cable parking brake caliper can be mounted. Shouldn't bee too difficult.

[Chris_K]

Just a random thought but doesn't the Corvette have an integrated drum brake in the rotor bell which serves as the e-brake? I am pretty certain the C3 and C4's have them. I'm not pretending to be a Vette expert but I thought that's how they resolved their issue. That should solve your problem too if that's the case...

Chris

[Bill Musarra]

Chris,
You are correct that there is already a built in option with the Corvette. It is simple and straight forward. There is a lever that the cable attaches to that expands the brake pad to hold the rotor. The small hump at the bottom of the drum section is where it hides.

Bill

[John]

Guys,

Thanks for all your input - the problem with the hydralic lock is that as the fluid cools, the brakes loose pressure and your car will likely drift away - not a happy prospect for a GT40 which has no bumpers.

I've looked at the Wilwood caliper but can't figure out how to mount it - I would like a bolt on solution. As to the built it parking brakes on the C4 - I've examined the caliper assembly and can't find the mounting for the shoe brakes. The prior owner changed the rotors to slotted rotors and I assume that eliminated the parking brakes.

John

[Russ Noble]

John,

That's a good point about losing pressure due to cooling of the fluid. I hadn't thought of that one. Hydraulic is probably not a good option if you want a reliable parking brake for a road car. The simple setup I outlined also has the disadvantage that if you inadvertently leave the handbrake slightly on you render that pair of brakes inoperable by the footbrake. Can be interesting!

I will be using this system to obtain registration for my car because it involves very little extra weight and I can make use of a special exemption clause that allows it, but I will likely remove it completely after I have achieved the goal of registration, since I don't really need a handbrake.

Cheers

[Jac Mac]

Someone posted a pic of a willwood 4 pot with integral mechanical h/brake not to long ago if thats any use. I think you had to look via the UK wilwood site due to USA site being updated.

Jac Mac

[Bill Musarra]

While looking at the Wilwood site, I see that they have a rotor for a drum type parking brake.

http://www.wilwood.com/Products/002-...DDPB/index.asp

If this is the rotor you have then I am sure any bone yard would have the parts you would need to complete them.
Here is the hat by itself and its technical drawing.

http://www.wilwood.com/Products/003-...fmih/index.asp

I would guess that getting what you need including the cables and pull handle has to be cheaper than the Wilwood stuff, unless you just want to complete the bling factor

Bill

[Mike Dozier]

The Vette drum setup is 1984-1987.
Many (including me) use the 1988-1992 caliper instead which uses a lever/cable instead of the internal drum/shoes.
This requires some different pieces, but all are readily available.

If you have C4 parts you must have either the drum or lever type.
Here is the newer lever type. Post a picture of yours if you can.

MikeD

[Mike Dozier]

try again?

[John]

I tried to post pictures of my C4 hub which is attached to the Porsche 930 - Unfortunately, only very small pictures can be posted on the GT40 site.

I removed the rotor just to be sure and it does not have shoe parking brakes

John