Driveline/CV Supplier..GKN a joke?

[nofearmxer]

I am trying to find some better CV replacements for my Drakart. Plan was to find some CVs that would hold up under the 30* of angle, absorb the 1/2" of plunge i have and go with a solid axle.

So I called up GKN and he told me no, they are not set up to be able to deal with the public and cant help me at all with a CV in any way.

Has anybody dealt with GKN and how did you?

Where can I find some C Vs or a supplier that can help me out?

I've been fighting this axle and CVs on this car for 2 years now with no luck.

I have a choice of buying a Citroen replacement for $185 but am afraid that just going to land me back in the garage throwing hammers. Idont believe its the actual Citroen CVs that are my problem, maybe more the slip half shaft binding up. So that what I want to get away from and the rear suspension geometry has been changed to where I dont think I need a slip axle.


I have been told these axles will hold up fine, and im sure they do, and would, but not with me driving. Im not one of these guys that just cruises around the dunes with a beer or does a bunch of bowl turns in the dunes and thinks thats cool. Wide open accross desert style train and huge whoops is whats fun to me and would like to find a way to have my Drakart drive train hold up longer then 5min.

If I had the money and the legs Id put an RPM and an R-1 engine in my Triple E im selling. That thing would fly in the dunes.

Thanks.

[yoshi]

A lot of manufacturers won't deal with the public, they give their distributors discounts and part of the cost of that is the dealers deal with the questions and individual sales. Just find a supplier of their product and if they don't know the answer, they will contact the manufacturer and get the info. Seems like a lot of work but the distributors are usually familiar enough with their products to answer any questions, or have a book to reference......

[LiveWire]

Take the slip joints apart clean then debur them. Make sure that they slide cleanly dry. I put lapping compound in mine and cycle them. Clean again and smear just enough grease on them to to put a thin coating. Too much and they will hydro lock.

That being said, I blew two of the original joints that came on the 2000 Formula Cross before switching to the modified Audi ones: Flanged Inner CV Joint [Drakart Formula Cross / Extreme] : Aftershock Motorsports

To be able to switch to the Audi one would require changing the splines on the inside end of the slip joint. After an incident where I did not properly seat the C-clip, I needed to replace the splines on one of mine. I turned the slip joint in the lathe and cut the weld holding the original stub on. The splines that I had, I cut off one of the newer one piece axles so the shoulder to weld to the tube was not there. I made a bushing for the stub to go in and fit to the slip tube. I cut the stub to such a length that I could weld inside the end of the bushing and not interfere with the plunge. I also welded the stub on the outside on the other end. It has been 3 years since I did that with 10' high dune jumps and various other abuse. I also like to hammer the brakes, twitch the wheel to spin it around then nail the throttle while still sliding backward.

High angle and the ability to plunge are mutually exclusive in a CV joint. The joints on a Drakart are Rzus joints or better known as fixed. A plunging joint like a Porshe 930 is known as a cross groove.

The 2000 has the gear box mounted with the bottom level with the top of the frame. The later models have the box dropped down. There is a small tube welded through the frame for the bottom bolt. Lowering the gear box will reduce CV angle and reduce plunge by getting a better alignment between the suspension linkages and the axles. You could take it a step further and shove the gear box to the right centering the drive flanges. The original setup is centered based on a spacer then the brake disk on the right. If 6 additional holes were drilled and tapped between the original and the spacer modified to span over the CV flange mounting ears, the brake disk could then be outside the CV. You would gain about 1/2" axle length per side. I have laid it out in CAD. It will reduce CV angle and plunge. I have not done any of this to my own machine though. I just rebuild the inner CVs when they get sloppy and replace the outers.

You could raise the inner suspension link mounts to reduce plunge. That will make the car wallow in the corners. If doing any frame mods for the purpose of CV life, I suggest moving the gear box and retaining the fabulous handling that car has.

[MC@ Performance Fab]

I buy the GNK stuff thru their wholesale dealers. Thats what their there for. The small non plunging cvs your running are more then capable of handling anything you throw at them with the weight and power you have. I bought the splined shaft and drive flanges from Alain and have zero issues with any of my drivetrain. I am running a R1 engine and around 35 degrees at max droop on the outer cvs, the outers on my car run more due to camber increase at droop. If you are having issues fix the issues... the cvs are not the real problem. By the way I am running the early 81mm Audi Fox cvs.

[nofearmxer]

If you are having issues fix the issues... the cvs are not the real problem. By the way I am running the early 81mm Audi Fox cvs.

If the CVs are not my real problem what is? Why did you have to buy the Audi stuff from Alain?

[minibajaman]

If none of those options work out, then you could contact the guys at http://www.rcvperformance.com/ as they can probably help you out.

[LiveWire]

nofearmxer and I talked on the phone. I thought I would add the info back here for search purposes. What I learned from him is that the early axles were an off the shelf item in entirety. I assumed they were made from pieces like the later ones. The inner joint is a fixed joint with a flange mount. It assembles from the back side then a thin cover goes over it. It would not surprise me if the wheel hubs are off the same car.

The new axles were built as a beefier replacement. Both ends of the newer axles are an outer CV (fixed) from an Audi. The inner has the stub cut off and a flange welded on to match up to the bolt pattern of the early axles. The hubs were changed to fit the same wheel bearing, but the larger CV and are custom made. The shaft itself is a female slip joint from a 4x4 front drive shaft. I know there is some issue with that most of them have a U-joint yoke on them and are not weldable. I think Alain had them made out of different material. There are two different spline counts for Audi CV based axles. I think the change was when he moved from Quebec to California and probably a different supplier.

[MC@ Performance Fab]

Yeah blaming the cvs is like blaming the chain for running hot on the FNR boxes that run 17 tooth sprockets front and back with a 6 to 1 reduction. Not the chains fault just plain poor enginering. All I bought from Alain was the splined shaft and mating drive flanges, they were old stuff he no longer used with the Busa and his FNR box. He did show me his splined slip shaft witch I thought was rather stupid and the cvs with the flange welded. His new setup did not use the splined shaft and I think his old setup would have been much happier without. I belive if you look EMPIS catalog you can check out the app section for cvs and see witch cars and years use the 81mm cvs. By the way the 90mm cvs have the same spline inner and outter. The starr is a little wider but same spline. I modified my inner cvs for the drive flange and had a pair of axles made fron 3oom. Expensive but no problems. New axles are the first thing I would do. Hope this helps.

Monte

[LiveWire]

To go to the single piece axle requires modifying the suspension geometry to minimal plunge. The problem is that it hurts the handling of the car.

[nofearmxer]

Well as of now i cant even drive it, so i would sacrifice some handling just to have the car drivable. I have a solid 0.5" of plunge on each side, Im told outboard CVs, ones from a 4x4 truck would work to soak that 0.5" up. But then Im worried with such short axles and high angle that the Cvs wouldnt hold up running at such high degrees. im at 30*, needs limited to 27* to keep the rear link bar from hitting the frame. The shocks dont limit the down travel, the bar hitting the frame is. At 27* it clears. Isnt this the same max angle for a 930? There has to be an easier strong answer that shouldnt take custom made splines slip shafts, I just dont know what, i dont know enough about buggys and geometry.

I was under the impression that since the Citroen axles were bought off the shelf that so would the Audi axles.

So if I am understanding correctly, everything about the Audi Axles is custom, except for buying a flanged Audi inner Cv and wheel hub from Aftershock Motorsports. That the axle itself is not an Audi but a custom made slip shaft, or one out of a 4x4 truck and then modified to accept the Audi CVs? This all sounds like one big headache.

So if this is all custom should I stick with Audi or any outboard FWD car CV? is the Audi special? And find a 4x4 front driveshaft thats a slip shaft? I really just dont know.



What would you do if it was your Drakart, and didnt have tons of money to throw at it?

Livewire, you have the CVs and other parts, what would the $$ be for everything i need to make a switch over to the bigger Audi cvs and stronger slip axles and wheel hubs?

Should I be looking for a front driveshaft out of 4x4 truck?


Monte- did you swap out for solid axles?, which part of the axle did you have custom made out of 300M?, the male or female part?