Which ZF transaxle to use?

I see on RBT's website they have three models listed.

5DS-25-0

5DS-25-1

5DS-25-2

The ERA website refers to the last two. Anyone have suggestions? Comments?

Bill D
 

Lynn Larsen

Lynn Larsen
Bill,

I am not a ZF expert, so uncharacteristically, I won't say much. But, in general, I think it is safe to say that the transaxles improved with each model. There is one exception out there, the transaxle built for the BMW M1. While they have some advanced features, like synchros, they do have smaller input shafts and are not rated for as much torque. While they have been successfully used, one should be aware of this.

Bob Putnam, at ERA, knows a LOT about these tranaxles. Also, see ZF thread for more information on ZF people.


Regards,
Lynn
 
Again, IIRC, all ZFs come with standard bellhousing config,
and are flipped later. The exception to the rule I believe
is the BMW M1 -1 box, which came from the factory flipped.
Again, that might be wrong, but I am almost 100% that a
flipped bellhousing would be a custom add. ERA sells them,
as do PI Motorsports and the place Lynn mentions.

Ian
 

Ross Nicol

GT40s Supporter
Bill I have a ZF in my car sourced from a BMW M1.It is a -2 as all the later ZF's are.The -0 is the box in the original cars and parts are rare, -1 is from the early 70's and were fitted to early Panteras until -2's replaced them.The -1 has short ratios and only 4 bolts to the bellhousing, so unless your racing -2 is the one to go for.Most -2's are sourced from Panteras and are fitted upside down (well that's what I reckon)so you have to do mods to allow it to be flipped for GT40 use.These mods are very well explained in the ERA Manual.ERA also have a 7 bolt bell housing to suit the -2.I have not read or heard of the input shaft in the M1 -2 being smaller and more delicate as Lynn describes and I would probably argue about this as I have had a Pantera -2 box and an M1-2 box side by side.The M1-2 is known to have a stronger case.Mine has been no trouble through 2 years of racing and the close ratios are just wonderful.Once you get used to the gearshift changes are as fast as a straight in stick.Check out my video" A race with Ross at Sandown" for proof.You wouldn't say changing ratios is easy though cause if you change the C&P or any of the gears it's a total strip down with the delicate setup with shims etc on reassembly.I have had a good fight too trying to reassemble the gearbox to the diff assembly as 3 selector shafts have to line up at once for this to happen and they're hidden from view. How come you only remember the bad things!
Ross
 
Are any of you running coolers? Where do you attach supply and return. I would guess a modified drain plug could act as the output. Return at the R&P? I am going to run my dual coolers as shown on this page (black FE car):
 
Thanks for the detailed explanation Ross. My concern right now is did I buy the wrong bellhousing from Kennedy Engineered Products. It's the 7-hole mount but in the standard (non flipped) position. I would hate it if I have to purchase another at $380!!

I'm getting my ZF from RBT. I talked with Lloyd at RBT and he said when I'm ready to buy one, they can put any gear ratio and final drive ratio in that is best suited to my needs and engine.

Bill D
 

Ross Nicol

GT40s Supporter
Bill here are a couple of pics.When you look at the opening where the ZF bolts on,and bellhousing rotated to fit the motor, you should have a hole at 6 oclock at the bottom and the top 2 holes at 11 and 1 oclock.If that single hole is at 12 oclock start swearing.Notice how the bottom of the bellhousing is cut away, makes for a neat installation when this is flush with bottom of chassis.I would go for the stock Pantera ratios and 4.22 final.I have spent hours pouring over ratios.I have purchased parts from Lloyd at RBT and had no problems.
 

Attachments

[ QUOTE ]
Are any of you running coolers? Where do you attach supply and return. I would guess a modified drain plug could act as the output. Return at the R&P? I am going to run my dual coolers as shown on this page (black FE car):

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Gary, do you have any more pics of this car ?
If so I'd love to see them (probably best in another thread though, or mail them to me)

Ross, doesnt the BMW box have different drive flanges & inboard disc mounts ?
Do the pantera drive flanges just swap over with them, or does this require the diff to be rebuilt to swap them ?
 

Ross Nicol

GT40s Supporter
John Yes the drive flanges on my M1 transaxle are for C/V joints whereas the Pantera transaxle has universal or hook drive flanges.This is actually a good way to establish the transaxle source.The drive flanges can be swapped but are attatched to the cast Iron side covers with an internal circlip.So to change drive flanges you would have to remove these side covers and in doing so resetting of shims for crownwheel/pinion backlash would be necessary.I'm not sure about inboard discs on the M1 but there are a few mounting points on either side of the transaxle that could have been used.I'm not sure if all M1 ZFs had an internal clutch slave cylinder but mine did although i have replaced it with a new unit.
Ross
 
I used a BMW M1 NOS transaxle. It still had BMW parts tags on it. The M1 has the driver on the left side so it needed to be modifed to put the shifter on the right-hand side of the unit. (1149 is RHD although also RH shift) Also the ring-gear bolts safety-wired and a few other mods. Mine was done by Bob Byars at Pantera Performance in CA but RBT is fine as well. We are using a standard size Ford-type 10.5" clutch- we hope all this will fit into the tub of 1149, as there is less room in an original-style tub than there is in later replica cars. All of the Safir cars had BMW M1 transaxles which worked fine, and some of the earlier Safir cars had very robust engines indeed- aluminum big-blocks,etc. I think the M1 ZF is pretty tough. MAP in Tampa, FL may still have some M1 units left.
 

Ron McCall

Supporter
[ QUOTE ]
I used a BMW M1 NOS transaxle. It still had BMW parts tags on it. The M1 has the driver on the left side so it needed to be modifed to put the shifter on the right-hand side of the unit. (1149 is RHD although also RH shift) Also the ring-gear bolts safety-wired and a few other mods. Mine was done by Bob Byars at Pantera Performance in CA but RBT is fine as well. We are using a standard size Ford-type 10.5" clutch- we hope all this will fit into the tub of 1149, as there is less room in an original-style tub than there is in later replica cars. All of the Safir cars had BMW M1 transaxles which worked fine, and some of the earlier Safir cars had very robust engines indeed- aluminum big-blocks,etc. I think the M1 ZF is pretty tough. MAP in Tampa, FL may still have some M1 units left.

[/ QUOTE ]


Bob and Don Byars own Precision Proformance in Cali. Dennis Quella owns Pantera Performance in Denver.
Marino at Pantera East(MAP) has,as of Tuesday, two M1 transaxles for sale @ $7500.


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Lynn Larsen

Lynn Larsen
Guys,

I never said the M1 ZF wouldn't work, indeed, I said that had been successfully used. But facts is facts, and I am sorry Ross, argue all you want, the two boxes ARE different and the input shaft diameter is one of the differences. Just because the part of it that you could see looked the same, IT IS NOT.

I think that someone who is researching transaxles (or any part or component) should be told everything, good, bad or indifferent about the parts he is researching. (What I have pointed out about the M1 ZF probably falls in the latter category in most cases; the Audi transaxles also work, as do Renaults, but I'd use an M1 before either of those.) Better that, than down the road somewhere having him say, "I wonder why those guys on GT40s.com didn't tell me about that?"

Regards,
Lynn
 
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