The "right" Transaxle

[ken1939]

Ok being that new guy thing, I have been reading alot of the builds at are posted, looking at engine choices etc.

Now I realize there are alot of you working toward the tribute car build. I can understand that. My quesitons are how do we get to here or here, cursed as an analytical. Now comes the variation.

What are the preferred transaxles for the GT40 kits? I have seen the Porche name bandied about, which one, which year? Audi etc?

The new production GT40, any thoughts on that transaxle, or even the engine? I know, in that case go buy a new one right? Saw a drop out on ebay for 29K.

I ask only because since I am hands on, if there is the right one to get today, I can snag it and start the rebuild, same with the engine. Other cars I have built have been based on an overall theme, big pic to the details. The GT40 I want to build will start at the rear end, or transaxle if you will, then move forward 3 inches to the power plant. I will build the rest of the car in my mind off of that combination.

I am kind not a purist on the GT40, do like my hand in on some of the ideas, but I am partial to a 302 of some sort. 400 hp deisred.

 

[Jim Rosenthal]

Right? You want a ZF.

 

[ken1939]

Ok ZF seems to have taken many forms. I guess thats where my personal head scratching comes from. I know Panteras had ZFs as well as the original GT40. I see that there is mention of the C5 Corvette using a ZF variant?

 

[Ian Clark]

As Jim says, ZF plus I'd include the ZFQ as a dimensionally correct alternative. Both great boxes, neither cheap but still way below what you'll pay for a Hewland. The Ricardo 6sp from the new Ford GT is too big for our cars, Xtrac out of the question, Porsche, Audi and Renault boxes excellent choices if your in a pinch. Best not to start a GT40 project if you're in a pinch My 2c worth... Cheers

 

[Ron Earp]

:wrongforum: Needs to be in the Transaxle forum.

 

[ken1939]

:wrongforum: Needs to be in the Transaxle forum.

OK my last post then, sorry to have upset the forum gods.

 

[Dalton Veitch]

Ken, nobody's upset. Ron just runs a well organised forum, with topics in the respective categories so we can all find them easily. You've simply been moved to "Transaxles".

Good luck with your decision making,

Dalton

 

[Jac Mac]

Hi Ken, hope you havent been scared away completely by the 'Good Sheperd'.
Your question will open a Pandoras Box of advice.

The REAL GT40's came with only one of 4 trans types- Colloti 4speeds in the very first cars, Then ZF 5 speeds, Then with the FE 427 came the T44 in some MKI & most MKII's & MKIV along with a 2 speed auto version that utilised some parts of the T44. Of these the only one you will find for reasonable $$ is the ZF, the rest you will need to have a sizable amount of discretionary spending capital to even think about.

Now Kit Cars & Replicas... you will find Audi's, Porsche, Renault, VW, in fact if its a transaxle from a rear engine or in some cases even front it has probably been fitted to a GT40 replica somewhere in the world.

The Ford GT ( Ricardo ) trans you mention HAS been fitted to some replicas as you will find as you further explore the site, it requires that the rear tray be clearanced & may not fit all the various replicas due to different chassis designs.

I would suggest that you take a few days to really check out this part of the site & go back thru some of the older posts & links & use the 'search' button a bit, Ive been here a few years now & still do!

 

[Mike Drew]

Ok ZF seems to have taken many forms. I guess thats where my personal head scratching comes from. I know Panteras had ZFs as well as the original GT40. I see that there is mention of the C5 Corvette using a ZF variant?

When we speak of "ZF", we are speaking about a very specific gearbox built by ZF in Germany, called the 5DS-25. ZF is a very old company and they have made hundreds, if not thousands of different transmissions and steering boxes and steering racks over the years, including the one in the Corvette. Your six-speed automatic in your 2009 pickup truck, for instance, is probably made by ZF. But 'our' ZF was used in only a very few cars.

Originally, Ford contracted with ZF to come up with a five-speed transaxle for the GT40 program, because the Italian-sourced Colotti four-speed transaxles were woefully inadequate. ZF came up with a clean-sheet design for Ford.

That was the original, 5DS-25 gearbox. They were made in relatively small quantities, and although they were primarily used for the GT40, other period mid-engined racers used them as well.

An improved version was produced for street cars, the 5DS-25/1. As far as I know, the first car it was used in was the De Tomaso Mangusta, circa 1968.

Ford identified areas of the design they wanted improved when they launched the Pantera program, but they were unwilling to wait, so the first few hundred Panteras were built with /1 gearboxes (curiously now called a "Dash-1" instead of a "Slash-1", but there you are....). De Tomaso actually had a whole pile of ZF Mangusta gearboxes sitting on the shelf (he bought a bunch in the hopes of building far more cars than the 401 that were made), so those were sent back to ZF in Germany and modified extensively for use in the Pantera.

To raise the engine height to provide additional ground clearance over the crazily low GT40 and Mangusta, the ZF gearbox was inverted for use in the Pantera, with the input shaft on the top. This required changes to a bunch of internal oiling passages etc. (This also means that people who buy a Pantera gearbox for use in a GT40 have to have it modified to run in its original configuration, a non-trivial job that itself costs at least a couple of thousand dollars, since it requires complete disassembly of the gearbox, and while you're at it, you're going to have it rebuilt, new seals, new bearings, new synchros, plus whatever else it might need).

After quite a few Panteras were built (close to 1000), the new Dash-2 gearbox was brought into production. Many early Panteras were retrofitted with these newer gearboxes as part of a dealer servicing scam (Ford unwittingly gave the dealerships license to steal, by creating a false impression that there was something inherently wrong with the Dash-1 gearbox; this lead to dealers abusing the system and replacing every Dash-1 under warranty that came through the door of their service bay, even if it was perfectly fine and the car was just in for an oil change!)

Hundreds and hundreds of perfectly good Dash-1 gearboxes were literally scrapped because of this scheme. :<(

The Pantera Dash-2 was made in far higher numbers than any other variant. The design subsequently underwent subtle changes when the gearbox was used in the BMW M-1; these changes are basically undocumented (at least in the sense that there is no "Dash-3" varient, even though many parts don't interchange). The principal philosophical design difference between the Pantera and M-1 gearbox (other than the fact that the M-1 was set up to use CV-joint driveshafts instead of conventional U-joint driveshafts) has to do with the manufacture of the synchro rings. On the Pantera setup, the inside of the synchro is smooth, and it rides on a grooved surface machined in the gear. On the M-1 box, the gear is smooth and the synchro is grooved. I don't understand why this would be considered an improvement, but it does complicate logistics quite a bit.

The current-generation ZF gearboxes built by RBT are of the M-1 variety, but fortunately all the parts for the Pantera-style gearbox are still in production for RBT as well, so they aren't obsolete. Instead, the two seemingly-identical-but-really-rather-different gearboxes exist side-by-side.

 

[Ron Earp]

OK my last post then, sorry to have upset the forum gods.

Hi Ken please don't take any offense. The forum is well-organized and it is only that way because the members take time to place their posts into the proper categories. As a new person this might not have been apparent. I nor any of the other moderators have anything personal against you as the others have mentioned.

 

Hi

The ZFQ thrashes the rest at Road America by a country mile, it's the logical upgrade to the 45 year old design of the ZF for today's high output power plants, with better ratios, shifting, and putting the power down through the ATB differential.
(costs less than an RBT ZF too) A direct bolt in option.

Fitted to the New Superformance GT40R.

Read about it here
http://www.gt40s.com/forum/vendor-m...20751-zfq-new-proposed-gt40-transaxle-17.html

Regards

Chris

 

[Erik]

Well I guess I should add my 02 cents in to this one.

I would recommend a couple of options. First is the ZFQ, as this has shown itself to be a very well shaken out new option for the GT40 builds. I like this gearbox as it offers a couple of things, first it is new. There is no worry about inheriting anyone's bad driving habits, by going with a used gearbox. Second, it has pretty good gearing selections available for the GT40, and third, it has been specifically designed for the GT40 builders, by GT40 Builders.

While this is a slightly more expensive option then say the Porsche G50 option, I like the idea of using new parts for a new car.

That being said, I feel that it would be a bad idea for you to not at least consider the Porsche G50/01 option. Here is why I feel that for a build here in the US, it is still a very viable option for the GT40.

First it is a Porsche gearbox. I understand that there are many who even hearing that name immediately look for something else, but I would caution against taking this point of view. The G50 has been a proven gearbox platform for nearly 22 years now. It was very well designed and features things that I really like.

Second, there is no problem with finding replacement parts here in the US as you can go to any Porsche dealership, of Porsche service shop and readily find someone to help you, like me for instance, should you need them.

Third, there is no issue with someone able to service a G50 in the states. They are not especially difficult to work on even for the home builder, and have shown to be very durable so long as you keep HP and Torque ratings around the 600 mark or less.

Lastly you just got to love the price on the G50. Figure it this way. The ZFQ is going to come in somewhere just North of $12K for everything you are going to need to bolt it onto your engine platform. The G50 will be a bit less, in my opinion, and could be significantly less if you search one out yourself as a used unit and rebuild it yourself.

You might want to consider getting one that has been already built and modified by someone who is really experienced with these gearboxes. Someone like me for instance, but be careful with your choice too. While I would be happy to help in any way I can, with either the ZFQ, or the G50 option, I am not the only company here in the US that can. In my opinion, and probably a few others here on the board, I am one of best you can work with, but there are others that will promise the moon and not really come through with the goods.

There are a ton of options for the G50 with regard to gearing ratio's, ring and pinion options, as well as LSD options. A benefit of the Porsche racing heritage and the general Porsche mentality in my opinion. Porsche owners love to go fast. As such they have inspired several companies to manufacture gears and other products to help facilitate that desire. This ends up being great for the home builder, as you can really customize the gearbox to perfectly suit your idea of the ideal gearbox.

I would be happy to talk with you more about this if you have any additional questions that you would like to see answered. I always here to help anyone I can. (It does not matter if you are a customer of mine or not.)

Hope that this helps a little.

Warmest Regards,


Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell

 

[ken1939]

Thank you for the meat and potato answers I have gotten. This is why I am on this site.

I think I am leaning toward the G50 transaxle, mainly due to availability and price. I know, this car is not to be cheaped out. My intentions are to make it perform like it should. I have noticed the ZFQs are pricey. Heck, that would be a first to have less in the engine and twice in the driveline! But will still do the research. Not ordering any kit this year, mabey by the fall of 2010, but I can at least start to assemble some key components.

Do you run special half shafts or do you run the stock, in the case of the Porsche?

Semi familiar with Jag and Vette Rear Independent halfshafts and outer bearings, similar deal with the transaxles then?

No harm no foul on which heading. My fault, I have been on pleanty of sites and didnt realize the detailed orientation.

 

[Mark]

When I begin my build I will be looking for something that is dependable and will not require the $$$$ to maintain such as my previous Ferrari. The budget to build is not my main concern, but the budget to maintain after the build could be a concern. Coming from the Ferrari world names like Porsche and Audi scare me when it comes to repair. Should this be a concern? and would the ZF be the best choice?

 

[Erik]

Mark with regard to the Porsche gearbox option, I would say No. You really do not need to be too concerned with the expense aspect of rebuilding a gearbox. You will find that most rebuilds on a G50 rarely exceed $3500.00 the exception would be if you damaged the ring and pinion on one. Then they could get a bit more expensive. I would recommend if you are going to be approaching the redline for application, ie 600 HP with your build that you consider a couple of strengthening options, such as Cryogenic treatment of the internals, and a billet side plate to ensure no ring and pinion deviation, but outside of that, you should be really good shape.

I hope that this helps a bit.

Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell

 

Hi Mark

You think that RBT gives good service for the ZF's, look up past posts on this forum, regarding RBT's failure to communicate and deliver.

The ZF costs more than the ZFQ and is half the trans. you get a life ownership warranty on the ATB differential and 12 months parts and labour on the rest of the components. Superfinishing also greatly increases life expectancy.

The transaxle is the key component to a successful mid engined car.

regards

Chris.

 

[Scott]

Very good post! I would add that you need to specify your budget, as you've got everything from used dirt cheap to new/reman gearboxes in the teens and up.

If you opt to go the used route, there's the Audi 016 5 speed which is marginal at the power levels you are discussing (although some people swear they can handle 450hp with ease). Cost on these vary but are typically under 500 bucks.

Here you have the various flavors of used Audi gearboxes, the 01E, 0A2, 01X etc.
The only gearboxes I'd recommend for 400hp and up are the 0A2 or 01E.

There's the upgraded and re-manufactured 5/6 speed Audi 01E's, which start at the mid 2G's and up.

3K and up is your used Porsche gearboxes in various configurations.

Here's a decent explanation of the various flavors of Porsche gearboxes.
http://www.gt40s.com/forum/gt40-tech-powertrain-transaxles/22599-porsche-g50-g96.html

North of 5K is the kingdom of reman/upgraded Porsche gearboxes.

And now your in the range of new/uber rare gearboxes 10K and beyond.

I guess the whole thing is what maybe a "Right" trans for me might not be right for you, it's just a matter of how much you got in your wallet, and what you want/need.

 

[Jac Mac]

Q for Erik@GBox, having noted your preference for clutch type LSD's over ATB's such as the Quaife unit, with your 'new' alliance or agency for ZFQ in North America will you be pushing for this setup as an option in the ZFQ?

 

[ken1939]

LOL well I want to build a Cammer for another project. I never pick the simply priced things do I?

Well a budget on this being what it is, I think the ZF is out of my leauge. With the RCR GT40 Deluxe Package at 35K, plus a few add ons to that, I think if I am in the range of 5K for the transaxle I will be satisfied with that. Beating and banging aside, reliable and functional. Most of the cars I have built have that feature.

As mentioned in reference to the Ferrarri, you want to spend more time driving it than fixing it. Reminds me of the old days when my brothers freind got a E type roadster. Lots of fun to drive, when it was running right.

Although with the ideas of the Audi hardware, I will give it some looks too.

 

[Howard Jones]

My advice would be to do exactly what you have said but sorta tongue in cheek. Spend twice the money on the remaining power train than what you spend on the motor itself.

$10K on power train and $5K on the motor is a good starting point. No matter what you decide install or choose a box with a limited slip. I believe that a proper LSD is the most important performance option you can put in a GT40. They are right up there with very good brakes in my opinion.

I know this sounds a little extreme but I assure you that if you do the gearbox right the first time you won't be re-engineering the car later to change the gearbox type. Mid engine cars ARE THE GEARBOX! No fun with a bad one and better than sex with a good one. I like a G50, Quaife TBD, taller 1st and 2nd gear and stronger side-plate. But this is not to say it is BETTER than a ZFQ or some of the others. It's more the availability and service ease for me that anything else. Lots of people in the US to help you with parts and a few good re-builders spread out across the US.

Put it behind a 350HP 302 and sort it all out. Adding more power on the other hand is really pretty easy. Later you can put in another 100HP when you feel the need and the rest of the car will be ready for it.