ZF RBT vs. ZFQ

[Ron R.]

Alan,

I agree, Quaife has said that they have parts, definitely a plus for owners.

Technically, they are not making them. Though Quaife is offering to do so if the demand presents itself. Not exactly a guarantee, but it does offer hope.

I think that the reality of the situation is that with RBT cranking them out in a reasonable volume, the added cost and probable extended delay of having additional ZFQs manufactured makes that an unlikely proposition.

True enough about parts. I myself never heard that Quaife "wouldn't" supply parts, but nearly everybody that I had spoken to was concerned about owning an "orphaned" unit, and the possibility of not being able to find parts.

Nothing against the ZFQ, it was originally my first choice. But, apparently like others, I was spooked away and went with the RBT.

 

[Seymour Snerd]

Part of what confuses me about the demand picture is that nobody mentions their use in cars other than GT40s, but perhaps that wasn't a significant fraction of the original 80. Anyone know?

Also, this discussion so far has treated the two transaxles (RBT and ZFQ) as being equivalent, whereas (IIRC) the ZFQ set out to be functionally superior to the RBT product. I'd have to plow through Chris's original long thread to distill out the claims, but I recall Dennis Olthoff saying the ZFQ shifted more smoothly than the RBT. And I don't recall the ZFQ having any propensity to engage two gears at once. Also the ZFQ's ATB differential is different; is it better?

Are there any other interesting differences?

One thing Quaife could do if they wanted to attract more orders is put out a more aggressive message on the ZFQ's superiority (if any) over the RBT.

 

[Grant S]

You may want to call Fran Hall at RCR, I am in the understanding, that He is in the developing stage of his own Transaxle. They are made from off the shelf components.
Will come in 5,6,and 7 speeds and will handle 1000 hp depending on which one you choose. And best of all he is trying to make them affordable

 

[Ron R.]

Alan,

I do know that Quaife had made an extended input shaft version that was/is used in Porsche 917 replicas. The shaft was extended to allow putting the motor further forward in the chassis, such that the motor (usually from a 911) would line up better with the 917's horizontal fan.

I understand that Dennis uses an RBT in his race GT40...with a single disc street clutch no less.

 

[Seymour Snerd]

You may want to call Fran Hall at RCR, I am in the understanding, that He is in the developing stage of his own Transaxle.

Yes, Griffin Gearboxes at: Home Page.

 

[Jim Rosenthal]

It would not take long to saturate this market, if you think about it, in these days of instant communication of everything. Plus the poor economic conditions; there aren't a lot of customers for GT40s in great economic times, and the contraction of everything makes the demand even less. Quaife have a finite production capacity, and it makes very little sense for them to tool up again and make 15 transaxles which then take years to sell out, when they can concentrate on building things that turn over a lot faster.

AOTBE, I think most of us would want a ZF, either original or made by Lloyd. What demand that does continue is more than likely going to be met by him. I didn't realize that production of SPF cars had slowed that much; I'm sorry to see it, but not surprised.

 

[Jac Mac]

Because the ZFQ uses a Hypoid R&P as opposed to the Spiral Bevel in the ZF it cannot have the R&P flipped for Pantera or similar applications, hence the apparent use in only engine crank c/l below axle shafts applications to date. There was mention at one stage of making R&P sets with the reverse tooth pattern to enable the Pantera type setup, but I am not aware of any ( or to be more correct , have not read anything to this effect ). If such a R&P set does exist ( its tooth design might involve compromises that are unacceptable from a strength & noise point of view ) the ATB? 'gears' would also have to be swapped side for side [ if thats possible ] or replaced with a set having a reverse helix from standard in order to function in the correct fashion.

In the end it all comes down to how many you can sell, but the one over-riding impression that I get is if the transaxle fails in any of these cars there seems to be a lynch mob out after the supplier, yet if you have an engine failure it does not seem to get the same amount of derision on a pro rata basis, in most cases the engine might have cost two or three times as much, while the transaxle will be expected to live thru perhaps two or three engine lives...

Must be a tough life trying to be a transaxle supplier to a market where you have no real control over the power output the car builder is going to choose, or how he is going to apply that power to your transaxle, not sure I would want to be one..must be easier ways of making a buck..

 

[Kevin L]

Jac,

Interesting perspective and I am not sure I looked at it that way but now that you bring it to light, I believe you are right. I wonder if the fact that the ZFQ is made by Quaife, a company, and therefore individuals have different expectations than if a major component is built by a person (such as a custom engine).

Most of these engines are built piecemeal, engine block sourced different from all other parts and assembled by one builder. Therefore when there is a failure it is easier to blame the piston company, the builder, the cam shaft, etc.

Maybe folks create more of a relationship with the engine builder and shower them with less criticism during a failure than if a component comes from a company. Who knows...

In any event, interesting perspective

Kevin

 

[Jim Rosenthal]

I would think that the transaxle would have at least as rough a life as the engine, seems to me.

I've had a few engines give trouble when new, in particular the one in my Cobra. Without exception, it was never a parts failure; it was always assembly error. In other words, the fault of the builder. Parts can break right out of the box, but most of these engines are dyno'ed before they go in a car, and if they survive the break-in and dyno runs they should be good to go. Transaxles are not dyno'ed from what I can gather- maybe that can cause failures later on?

 

[Jac Mac]

Part of the problem is there is no 'aftermarket' as such for these , if you break either type you dont have much choice other than go back to the original supplier for parts or repair, a bit like if there were no Scat cranks, Dart blocks, AFR heads, Isky cams etc etc, imagine if you were still stuck with only using 1960's tech stuff in the motors & only being able to purchase from Ford, what essentially changed that was racing & competitive events. Im not suggesting that we go back to those days, although in some respects it would be a good thing, but that real competition improves tends to improve the products... 10 lap sprints at vintage meets held once a year dont really count in that respect, if there were half a dozen broken parts outside the front door every second monday morning things would either improve or disappear...quickly.

 

[Rich E.]

Birds: "Quaife...won't be making the ZFQ anymore nor will they support the existing ones with spare parts....."

vs.

Quaife: We wil make them if there is demand and we hold stock of all spares.

​

I doubt RBT would make transaxles if there were no demand either.

Alan,

Promises made and promises kept, especially by a company, can be two different things when there is no real future profit margin. Time will tell....

BTW,

I actually wish Quafie would've stuck it out. The ZFQ had the potential to be a better unit than the ZF BUT, as re-iterated here, I don't see enough demand for the aftermarket to supply. RBT continues to make because, over time, there have been enough demand to justify the supply.

.02
Rich.

 

[Jay Adams]

In the end it all comes down to how many you can sell, but the one over-riding impression that I get is if the transaxle fails in any of these cars there seems to be a lynch mob out after the supplier, yet if you have an engine failure it does not seem to get the same amount of derision on a pro rata basis, in most cases the engine might have cost two or three times as much, while the transaxle will be expected to live thru perhaps two or three engine lives...

Must be a tough life trying to be a transaxle supplier to a market where you have no real control over the power output the car builder is going to choose, or how he is going to apply that power to your transaxle, not sure I would want to be one..must be easier ways of making a buck..

I couldn't agree with you more.
Good call :thumbsup:

 

[Seymour Snerd]

Alan,

Promises made and promises kept, especially by a company, can be two different things when there is no real future profit margin. Time will tell....

BTW,

I actually wish Quafie would've stuck it out. The ZFQ had the potential to be a better unit than the ZF BUT, as re-iterated here, I don't see enough demand for the aftermarket to supply. RBT continues to make because, over time, there have been enough demand to justify the supply.

.02
Rich.

Sure, you're right. It will be interesting to see how/if all this changes as we climb out of the current doldrums. The guys at the high end of the market are having no problem buying stuff (cf Monterey auctions this year). I wonder what it takes to get the GT40-types to perk up again. I suppose most of us work for a living so 9% unemployment just isn't going to suffice and for the retired ones a Dow of 11K won't either.....

 

[Jac Mac]

I actually wish Quafie would've stuck it out. The ZFQ had the potential to be a better unit than the ZF BUT, as re-iterated here, I don't see enough demand for the aftermarket to supply. RBT continues to make because, over time, there have been enough demand to justify the supply.

.02
Rich.

Maybe, but I am not really convinced of that, Yes perhaps as a direct competitor to the original ZF, but not as a real big HP/wide rubber/lots of grip solution [ And I am not suggesting that it was ever intended for those applications, but it very quickly became obvious from questions asked here on this site that was what many wanted ]. The apparent non-availibility in a Pantera version probably does not help either & after having a look around other sites it appears that was the case.

Then there is 'that' one unit that had the rear case literally 'blown' off the rear end, it highlighted to me that the RBT/ZF with many more bolts/studs attaching the rear housing where the pinion load is distributed was a more robust setup, at least in that regard.

 

[Rich E.]

Maybe, but I am not really convinced of that, Yes perhaps as a direct competitor to the original ZF, but not as a real big HP/wide rubber/lots of grip solution [ And I am not suggesting that it was ever intended for those applications, but it very quickly became obvious from questions asked here on this site that was what many wanted ]. The apparent non-availibility in a Pantera version probably does not help either & after having a look around other sites it appears that was the case.

Then there is 'that' one unit that had the rear case literally 'blown' off the rear end, it highlighted to me that the RBT/ZF with many more bolts/studs attaching the rear housing where the pinion load is distributed was a more robust setup, at least in that regard.

I'd like to think that Quafie, after reviewing some of the failures, would've adapted, revised, and returned with a better box. They had the "Potential" to be better. It seems though that reducing demand and the initial failures forced them to stay off the horse after the first fall.

.02
Rich.

 

[Seymour Snerd]

It seems though that reducing demand and the initial failures forced them to stay off the horse after the first fall..

I follow the "reducing demand" argument but I don't see the "initial failures" argument. For one thing I know of only one failure, and they turned around immediately with two different fixes for it (billet rear housing, and/or shifting pinion thrust away from the rear housing).

It's also not clear to me that with one or the other of those two fixes it is less robust than an RBT as Jac Mac claims. There have been multiple RBT failures under similar circumtances, according to Chris Melia.

 

[Jac Mac]

Alan has a delightful way of slightly twisting others posts to fit his perception...so I will try to clarify my thought at the end of post # 34... If the ZFQ rear cover/housing in question had been fitted with the 12/13 bolts instead of the eight it has it 'might' not have failed in that area, and yes if they have now changed the pinion thrust bearing back to the R&P end that would be a much better solution & placement as it reduces the case heat expansion factor & how that affects the R&P setup.

But then if we were to compare the tooth angles, Ring gear dia & factor in the hypoid dimension we might find that one of them actually generates more end force at a given torque figure, in which case we are not comparing apples to apples anyway... Time for a T44... with decent shaft heat treatments..

 

[Seymour Snerd]

Alan has a delightful way of slightly twisting others posts to fit his perception...

"...the RBT/ZF with many more bolts/studs attaching the rear housing where the pinion load is distributed was a more robust setup"

vs.

"It's also not clear to me that with one or the other of those two fixes it [ZFQ] is less robust than an RBT"
​

I'm sorry that you didn't write what you meant, but how is that a reason to slam me personally?

 

[Jac Mac]

Obviously a continental divide in what constitutes a 'Slam' around here

getting back to the brand X vs brand Y discussion, I compared the Pinion tooth profiles of both ZFQ/ZF last night, to put it in simple terms: If you were to lock the Ring Gear in position & apply torque to the Pinion, the pinion with a hypoid gear profile should tend to put more pressure on the pinion along its shaft centerline eg: drive it out of mesh along that centerline...

So taking this simple explanation a step further & suggest that if the ZF was already having problems in that area [ damage or wear to the parts that constitute the pinion location ] and part of the cure was to change to a hypoid from a spiral bevel, then it would seem prudent to upgrade any possible strength issues around the pinion location... I am having some difficulty in visualising how reducing the number of bolts would help..

 

[Jac Mac]

I was just looking at these two drawings from ZFQ, anyone spot the difference between drawing & reality??