GT 40 replica tranaxles

Can somebody help on "total performance" tranny? Renault gives up under 300hp, Citroen you can forget immediately, Some people have good feelings w/Audi and seems that Porsche G-series is much wanted. Of course ZF-from Pantera or BMW is good, but difficult to find for a reasonable price. What audi box compares to Porsche? How much they can handle? Has anyone tried Hewland???

PS
Heard that ERA boys do original type Kar-Kraft castings for Mark II, where Ford 9`` was mated to toploader. Are they available and price??

Best regards


Jukka

 

Hi Again

I am flying to Germany on Tuesday to get a ZFDS25/2 for my car at £3200 it has 3.77 ratio.

But if I had the money I would go for the Quaife MK2 6 speed sequential Trans with synchromesh at £7950.00 this box is happy upto 700 BHP and has a push pull shifter no gate, and can be run inverted, for correct drive shaft angle.
If you purchase five boxes at the same time then you get a 20% discount.

Chris

 

[Guest]

Robert Logan

You seem to have as much experience with the Audi boxes as anyone. What do you consider
the max BHP (or torque if you prefer)?
And once you surpass that number, what
box would you recommend?

Bob Putnam

What is the status of the T-44?
Will it be available to anyone?
Projected price?

Thx

MikeD

 

[Steven N]

Jukka: The new CAV from south africa uses a remanufactured Audi Quadtro box from 1989. It seems to hold up over 300HP.I just visited my local rep,I was very impressed with their finnished product.Someone else might have more detailed info about the trans. Steve

 

Hi, The Renault Gearboxes are under estimated sometimes as most people are used to the renault 30 tx 5 speed. This only has 190 newton metres of input. The one GTD have been using for ten years is the r21 turbo, they hold 235 nm of input. The strongest is the v6 turbo 280 nm of input. i have made mods to this box, and it will take 295 nm. I have all types in stock and can offer spares of rebuild etc. We stock all adaptor plates, steel billet flywheels, AP Racing clutches, modified gear linkages etc. I will be answering some of the most asked questions on GT40 replica, now that i have logged on to this site.All the best. Mark Sibley

 

[Robert Logan]

Jukka and Mike,
The Audi / gatrag gearboxes are much better in design to the Renault boxes due to shaft seperation and casing design.
I understand and accept the experience of others on this forum who have used and raced with the Renault units. I am not saing that they are no good only that the Audi units are better designed.
There are many things that govern or indicate to the strength of the box but distructive tests in a controlled test is the only true test.
Gearboxes usually fail because of two reasons,
1. the shafts sheer, or
2. the gears unmesh and the teeth are broken off.

The first is best fixed with a bigger shaft diameter of a stronger material. This tends to make the cog diameters larger and therefore the seperation of the shafts increase (easy to measure, try it !!!!!)

The second is to do with shape of casings and bearing retension materials. If you can imagine that the two meshed gears are trying to ramp up eachother than the bearings holding the shafts will be forced to seperate. If the casing design is circular than the casings are distorted into an oliptical shape and the teeth clash and break. If the gearbox shape is rectangular and webbed than this distorsion is less likely. The second part of this is the bearing support and we are now fitting girdles to support the bearings of our gearboxes in FULL race specification (500HP)

The Audi is fundamentally sound in design and we are more than happy to fit them on the back of our 320HP engines. We have used them with well over 400HP and over 400 ftlbs of torque engines with little problems but I am not happy with them.

Finally the thing that kills boxes is usually BAD driving or TORQUE and the combination of both of these is a recipe for an expensive bang.

Best wishes, Robert

 

Robert and everyone, I agree with all Robert has said, with the exception that the quickest way to trash a box is no oil! dont laugh it has been done 3 times to my knowledge. If we are getting technical, ZF designed the Renault transaxle used in the 4 speed renault 30 v6. They then went on to redesign the gearox to be used in the Renault turbo 2, this was coupled to a twin turboed 1400 and a five speed version used in the v6. ZF did the adaptor plates. Frank Catt has changed some gearboxes in race cars recently as some customers prefer ZF, Quaife, though some are still running 500hp on a Renault 21 turbo gearbox and this is not the strongest version. Robert talks about the design flaws that can apply to any gearbox, not just Renault. The gearbox that takes the best input was used in Formula renault series racing. Its all down to preference at the end of the day. I know Renault boxes well, So i will prefer them. Ive been using them for 16 years. A customer of mine has a dyno 460 horsepower 351w running in his car with a Renault r21t since 1989, 87000 miles later. Not bad really, for a Renault! Though I will say, Renault Gearboxes are getting harder to come by. Hence the reasons for the Audi gearbox in the first place. This may clarify those who may be unsure what the hell set of cogs to use! Good luck, oil is important.
Regards
Mark

 

[Guest]

In South Africa, most of the GT40 replicas use the Audi 016 transaxle. However quite a few owners will tell you that they have trashed this box when using more than the standard Ford 302 (especially 351) and wide tyres. The middle cast iron section of the casing has a thin lip holding a bearing, and this breaks. There is a gearbox specialist in Pietermaritzburg that machines out this casting and fits a bell shaped bearing retainer to strengthen the box. If there are any builders interested I could try to find out more about this.
Cheers, Vic

 

Hi Victor, I never got down as far as Durban when I visited South Africa, though Ive been all around Jo'Burg and Pretoria, Kruger park
The Macullisburgs,I had a great time out there. However, to be fair, The roads seem to be very undesirable for a Forty! I nearly dropped 100 feet into a ravine whilst on my way back from Kruger. The Roads are hard going for any production car that isnt a bucky (pick up truck to others) 4 wheel drive and off road vehicles are a must. So I'm really not surpirzed that any gearboxes fail out there. Though you are right in saying that, with wider tyres and more than 350 hp, grip becomes torque and wind up for any gearbox. Audi maybe stronger be design, but in truth none of these gearboxes were designed to run a V8 with 350 hp and over 300 ft lb of torque! However, The box I use now is the strongest Renault variant, though the input is measured as newton metres at 295
This works well over 450 hp. Have a good one.
Mark Sibley
MDA

 

[Guest]

Hi Mas. Thanks for your input. You must have kept to the bush mostly. Our roads are fine and up to world standards. No, the problem I think could be due to using metallic cluth plates instead of organic. This with high HP and fat tyres could be the reason.
Regards, Vic