ZFQ new proposed GT40 transaxle

[Chris Melia]

Hi Miles

John Wisher one of the team working on the project has original bellhousing already made, These will fit the ZFQ and also the ZF DS25/2. They do require the smaller flywheel though, see Frank Catts thread on this subject for the SPF's.
Kennedy Engineering make the bellhousing without the bottom GT40 mounting for the 157 tooth flywheel.

regards

Chris.

[wanni]

Hi Chris,
I am the designer of the CIMA transaxle. In order I think that we should have a collaboration in state of a competition, please take note of my suggestions.
1) Perfect choice for the differential but without preload. Between 2.5 and 3 of torque biasing is the best in traction, and an honourable 5 to 6 in coast mode. ( feasable if Mike jumps in the case )
2) Lovely choice about driving the oil pump through the secondary set. It avoids hard cold shiftings.
Let me know which synchronisation system you are using ( diameter and number of cones )
3) I would do it in 6 speed by keeping the same spread in order to help the synchros. The revs jumps are lower.
4) The biggest point which I do not agree at all, is the choice of isostatics shafts. I believe that the center distance is the historic 79 mm. With this value you definetly need a third bearing to transfer the torque you are claiming. Considere that the actual tyres are reaching 1.4 as grip coefficient. This means that the box is 30-40% more loaded then in the passed. I suppose that the gears fitted in the middle of the shafts are not helped by the tyre spinning. Try to fit a pulled support in the middle ( an eight with 2 bearings ). This will not avoid the torsion of the shafts but it will be very helpfull against the deflection.
5) Cut the input shaft in 2 parts.
A) Extremely helpfull in flexibility for meeting customer requirements.
B) If the first bit is made in 34NiCrMo16 fully tremped ( extremely tortional material ), this will cut the peaks of torque considerably, allowing a lighter gear design and.......allowing non damped clutches ( it is already a torsional damper if setted at 1° of torsion every 80 Nm ).
A non damped clutch has an inertia to be synchronised of about half of a damped clutch. The synchros will be so quick in responding to the shifting demands for the pleasure of the final customer.
If you do not mind, pls contact me for a private chat.
My details on default

[Chris Melia]

Hi Wanni

Thanks for your positive expert comments about the ZFQ transaxle. Your assumption that we have 79mm shaft centres is incorrect our shaft centres are 85 mm.
We did not go for a six speed because we are building specifically to replace the ZF/GT40 configuration and a six speed arrangement would have increased the case length by approximately 100mm (4") and would have clearance problems with the GT40 frame and body work.
Our input shaft is actually a two pieces unit as you suggested and is specked for the same material you mention and is dimensionally the same as the /2 ZF box, so customer purchasing our transaxle don't have any issues with clutch, spigot bearings and bellhousing.

Our aim is to supply the GT40 market with a specifically designed modern transaxle that is rated higher than the ZF at an affordable price with off the shelf availability.

Regards

Chris Melia. ZF Q Gearbox a GT40 Transmission Solution

[wanni]

Hi Chris,
what is te torque capability? Constant use and peak.
What is the max torque transferable to the ground?
I have some clients who can not afford my transaxle because it is made for VIP cars who would be interested in a smaller transaxle. By using a spacer is it possible to fit a sixth gear? Is the reverse on the 1/2 synchro or is it a propper gear?
Which synchros are you using?
Let us be in touch wanni@gearfox.net

[Chris Melia]

Hi Guys

the ZFQ CAD drawings are now finalised, and Quaife's Pattern maker will commence work on the casing pattern next week.

Regards

Chris.

[Big-Foot]

THAT is just bloody gorgeous!!!!

[wanni]

Tell me which synchronisation system you are using, Chris.
Are you ready to move the pump onto the secondary shaft?
The box is warming up in speed. Why are you killing the synchronisers, especialy in down shifting? Believe Cool it in speed ( power ) and not in torque.
But you will see alone.
Ciao
Wanni
On top of it, it is not possible anymore to turn it upside-down due to the pinion off set to the crown wwheel.

[John Lowe]

Chris

That looks a wonderful and compact piece of engineering, congratulations to you and Quaiffe. See you at Detling - do you have the RCR yet?

John

Grow old disgracefully and mostly sideways.

[Chris Melia]

Hi Wanni

The Quaife design team recommended, the oil pump to be located on the primary shaft to maintain continuous oil supply whilst the trans is being driven. They pointed out that if the pump was driven by the secondary (pinion) shaft, that in neutral the pump would not be driven and heat build up could then occur in the oil.
The oil pump is an optional extra as it was on the original ZF, for extreme or competition use.

The output shaft positions are in the same X Y plain as the ZF you are correct that the pinion shaft is 16mm higher than the centre line of the differential but this is within the case and the gain in strength from this bevel gear arrangement is a specific design element. The ZFQ can and will be used in the inverted Pantera position.

The ZFQ has 85mm shaft centres compared to the ZF's 79 mm this allows the gears to be larger in diameter for the ZFQ, reducing the loadings on the gear teeth by comparison.

Martin Gough, John Wisher and I are all GT40 guys and have worked together with Quaife to develop this transaxle specifically to handle the high horsepower demands of this mid engine market.
I know that in the coming months people requiring the ZFQ will be substantial and working with Quaife will give us the advantage, technology and scale to be able to meet that demand.

Regards

Chris Melia.

[wanni]

Originally Posted by Chris Melia

Hi Wanni

The Quaife design team recommended, the oil pump to be located on the primary shaft to maintain continuous oil supply whilst the trans is being driven. They pointed out that if the pump was driven by the secondary (pinion) shaft, that in neutral the pump would not be driven and heat build up could then occur in the oil. REMEMBER THAT THE PRIMARY SHAFT IS TURNING IN THE OIL AND THAT'S ENOUGH TO GARANTY THE LUBRICATION IN IDLE.
The oil pump is an optional extra as it was on the original ZF, for extreme or competition use. THAT'S WHY YOU SHALL USE IT CORRECTLY. THINK THE SYNCHRONISERS WORK FOR ACCELERATE THE PUMP IN DOWN SHIFTING. REMEMBER THAT THE USERS HAVE THE SHIFT LEVER IN THEYR HANDS AND NOT A TEMPERATURE SENSOR.............SHIFTING CONFORT IS A MUST.

The output shaft positions are in the same X Y plain as the ZF you are correct that the pinion shaft is 16mm higher than the centre line of the differential but this is within the case and the gain in strength from this bevel gear arrangement is a specific design element. The ZFQ can and will be used in the inverted Pantera position. THAN THE PINION WILL BE A PULLED TYPE AND YOU SHALL INVERT ALL THE GEARS ANGLES IN ORDER TO DO NOT KILL THE TRUST BEARING.

The ZFQ has 85mm shaft centres compared to the ZF's 79 mm this allows the gears to be larger in diameter for the ZFQ, reducing the loadings on the gear teeth by comparison. AND TO HAVE A BIGGER SIZE OF THE SHAFTS FOR DEFLECTION REDUCEMENT, CORRECT.

Martin Gough, John Wisher and I are all GT40 guys and have worked together with Quaife to develop this transaxle specifically to handle the high horsepower demands of this mid engine market.
I know that in the coming months people requiring the ZFQ will be substantial and working with Quaife will give us the advantage, technology and scale to be able to meet that demand.

Regards

Chris Melia.

REGARDS

WANNI

[Chris Melia]

Hi Wanni

after further discussion we are indeed going back to our first decision and driving the oil pump from the pinion shaft. In addition to the points you have rased we feel that driven from the input shaft may lead to overspeed, creating cavitation in the pump. Mounting the pump in the higher position aids clearance also.

You are correct that the 85mm shaft centre's allows us to have a larger shaft and bearings.

regards
Chris.

[wanni]

Hi Chris,
I am sure you will enjoy the decision.
I am at your total disposal for any matter.
Remember that it is already 20 years that i am fiting with road applications and believe that they have nothing to do with motor racing, which is only the start position, in comparison.
Ciao my friend and feel confortable to ask me anything you may need.
I love to make transaxles working at the highest potential they have.
You shall try also GearFox oils which are made for those matters. No foam at all. Let me know if you need some samples for testing purposes.
wanni

[Chris Melia]

Hi Wanni

Thanks for the offer, I may just come to see you to collect the samples and try out your restaurant. I love Italian food above all others.
I appreciate your positive advice and I am one that is always prepared to listen to good advice.

regards

Chris.

[wanni]

The restaurant is open to all the positive friends.
Waiting for visits.
Who is comming saying GT 40 is winning one dinner. ( One por group of persons, of course. I can not offer a dinner to a bus of 52 people getting there )
Ciao a tutti.
Wanni

[Kenny J]

Chris, Do you have out side measurments on the trans? And how do they compair to the ZF? I am mostly interested in the length of the box as it compairs to the ZF. Also how does one place an order and what is the delivery time?
Thanks in advance, Ken

[Chris Melia]

Hi Kenny

The case length on the ZFQ is 569 mm or 22.4" the stock ZFDS25/2 is about the same.
we can add your name to our order list by sending an email to me, melchrismelia@aol.com or to Martin Gough, Jonathan.gough@ntlworld.com.
We will be taking deposits after we have fully tested the prototype ZFQ around the June time frame.

Regards

Chris Melia.

[wanni]

If you need a professional transmission developper as a consultant, never mind to disturb me. I think that I am one of the best trouble shooter and vehicle applicator of mid rear transaxles.
Especially if the budjet is not out of Rockfeller's pockets.
Ciao my friend and good luck.
Albert Wannstein