Porsche 930 Transaxle Dimension

[Ron Earp]

Does anyone happen to have the dimension shown by "X" in the attached photo? I want to know the distance from the input shaft center line to the center line of the output shafts.

 

[Russ Noble]

Non hypoid pinion. Thats the gearshaft spacing Ron. 77mm.

 

[Ron Earp]

Thanks Russ. So if I flip the 930 my output shafts will drop by 154mm, or around 6". Hmmm. That might be too much of a good thing.

 

[Ron Earp]

Okay.

It looks like if I flip the tranny, all remaining the same on my setup, I can lower my half shaft angles from fifteen degrees to just over seven degrees. That would be a great thing.

But I'd have to make sure the chassis is setup the way I'd like it. I'm thinking we need to drop the rear ride height about an inch to 1.25", at least, and if I did that then my half shaft angles would drop to at a more manageable 9.XX degrees with no box flip.

However, If I flipped the box and then lowered the car 1.5" I'd be back up at 12.3 degrees.

Flipping the box seems favorable although a bit more study is involved. It could be I might be able to lower the car AND lower the engine/tranny in the car a bit. That might resolve everything favorably.

 

[Terry Oxandale]

The lower I went with the motor and the body, the better my angles got. Currently with the inverted 930, the angle is about 3º up at the gearbox. If I lowered the chassis down to a respectable race height (3 1/2" or so), it would be almost perfectly horizontal.

Are you considering not inverting it?

 

[Ron Earp]

Are you considering not inverting it?

Just trying to consider doing "the right thing".

Once I started measuring things the "right thing" was not perfectly clear. Regardless of what sort of chassis you have only two things really matter here - the size of tire dictates the center line hub position and the tranny height above pavement determines the half shaft height. Half shaft length plays a minor role, but unless the half shaft length is off to infinity or really short it isn't a major player.

 

[Terry Oxandale]

I don't think I'd been very happy with the inverted setup if not for the dry sump oiling. That is the one single thing that allowed the CV angles to be satisfactory in my own mind. A '40 configuration would have allowed the higher engine location (CG would have been compromised), but with my project, the lower rear body covering over the engine disallowed that as well. So I really had few alternatives.

 

[Roark_John]

Don't forget that at-speed your tires grow due to centrifugal force and friction causing the trapped air to expand...that might explain for the 25.5" measurement.

 

[Jack Dunn]

Terry,

How deep is your dry sump LS oil pan? And how much shallower is it compared to a Corvette LS wet sump pan?

I'm not as familiar with dimensions of LS engine oil pans as I am with SBC oil pans (obviously).

Jack

 

[Terry Oxandale]

A picture is worth a thousand words. The upper photo below is the standard pan, and the Corvette pan (shortest one available) is about 1 1/2" shorter than this one. In the upper photo the pan actually lifts the rear of the chassis up by 1/4" (the pan is sitting on the floor). Thus at a 5" ride height, the Corvette pan clearance is 1 1/4". In the lower photo, the red arrow shows the large increase in clearance gained with the dry sump pan (rods swing within about .060" of the pan's floor). The yellow arrow shows the KEP adapter used to attach the 930 transaxle and the protion of it that I will remove to increase the clearance under it. Thus the 930 bellhousing will be the lowest part of the car at about 4 1/4". Without inverting the 930 box, I'd need to raise the engine a huge amount just to keep the clearance around the bellhousing.

 

[Ron Earp]

I don't think I'd been very happy with the inverted setup if not for the dry sump oiling. That is the one single thing that allowed the CV angles to be satisfactory in my own mind.

Yes, and that is certainly a consideration as well. In the end I'm going to end up spending "X" dollars - tranny inversion and dry sumping the motor costs about the same amount of coin. Each have pros and cons.