ALFAGTV6.COM

[MD]

Well, it seems to me that collectively we have pretty much customised, refined, improved, modified just about every part of these fine cars which are very good to begin with. Being the perpetual tinkerers that we are expecting just a bit better here and maybe a lot better over there, the quest to make it so goes on.

I cannot name you all but you know who you are. There are contributions for better engines, exhausts, suspensions, brakes (did I say brakes?) air con.and a host of other refinements. I myself fixed the gear selection design so with all these mods put together, you would think by now we would have the perfect GTV6 now wouldn't you?

We would if we didn't have to put up with that extremely expensive, most of the time out of balance, nightmare to service and replace, shredder of bits and pieces of rubber (if you really give it some racing style), poxy drive shaft.

I don't care how many supporters it's got out there nor do I wanna hear about how kind it is to the drive train. Ninety five percent of cars never had this type of driveshaft and got/get along just fine with a FRACTION of the problems these arrangements give. What we want is a robust unit that will take the power of our engines, be reliable and dependable to do the job it is supposed to do and stay together when it is asked to press on hard. Isn't that what sports cars are for?

So folks as far as I can see, you are as good as your weakest link and that abomination of a drive shaft is the weakest link in our transaxles. Collectively it's not Mars. It's the driveshaft that is our last frontier.

If you even smell anything that's close to good, common sense engineering,tough and a cost effective fix, stick it on this post.


MD

[John in Denver]

MD:
point me to your gear selection piece would you? I think I may have missed it. Re the driveshaft, suggestions never seem to progress beyond stronger poly "guibos" which seem to be prohibitively expensive to produce just for the GTV6. I do recall some discussion of some sort for a fixed metallic joint but the consensus was that consequent transmitted vibrations ruled out that possibility.

[Greg Gordon]

I can't see any reason you couldn't use a two piece alloy shaft with a center bearing and a conventional U-joint at each end. I am not buying this vibration argument. The problem is making it at a reasonable cost. It's very tough to get a shop to make 1 or even 10 of something like this.

[Dennis]

How about these guys? http://www.dennysdriveshaft.com/
Andrew mentioned the two piece shafts he uses on his racecars, but never showed some photo's. There are carbon shafts aswell.........

@John. here you go:http://alfagtv6.com/blueLightning/blueLightning.htm

[Mats]

Greg, would those U-joints give a constant angular velocity? I think the gearbox would not like to have a solid (torsion-wise) coupling to the engine if there is a non-constant rotation transfer....

P 944 has a torque tube, right? Very straight that is.

How are other cars (with similar layout) designed?

[joey]

well it depends what you're looking for.

the ultimate solution is a single carbon fibre shaft. And there are shops that make this, even in single orders. Hint : benincas.

i dont care who buys what argument, the word from the man himself is its do-able, but a race only solution, and IIRC a $2k job.

appartently its noisy as hell and not really a road going solution, i dont know what manufactures like ferrari and nissan etc do to their CF shafts to make them quiet and smooth.

Beninca himself rekons the stock jobbies handle the power ok and should last a while. I know thats not what you wanted to hear.

I totally agree with you tho, the stock jobbies, at least the ones sold here are very expensive and the rubber is awful in typical alfa fashion. Seriously, how hard would it be to reproduce the stock flex joints in P.U.? we could easily flog at least 20 sets around teh world here on alfagtv6.com - the unit price shoulndt be bad given the low price of other similar PU discs.. (eg. ford)

IMO, it just needs co-ordination and someone to be bothered to approach a company about this. Much easier than trying to fob a race going drive shaft and convincing someone there is a market for it.

[MD]

Hi John,

If you go to the original site : http://www.alfagtv6.com/

and select "Our Cars" -Featured, scroll down to the blue GTV6 that has an indulgent title of "Blue Lightning", you will find the article on the shifter modifications.

Be ready for a project and a half but it works great.

Pleased to see some of you lads applying the grey matter to the drive shaft problem. I somehow think this thing needs to go back to first priciples and see what we can devise.

There are things that improve the thing like metal shrouds over the rubber donuts to stop them from desegmenting under load but that's just another bloody thing to try and balance.

Most balancing shops in OZ haven't got a clue when it comes to Alfa tranaxle shafts because their machines are not set up for tailshafts spinning at engine RPM so they extrapolate(big word !) what they think it is going to be but most of the time it is wrong.

So after all the pain and sweat getting the shaft out, spending huge bucks to put in new parts, incompetency rains supreme 'cause there's no one that can balance it !!! Things only get better if you have to change the clutch as well 'cause now you have a whole new balancing problem as well as the rebuilt shaft.

I know as you read this you will be saying to yourself, I know where he is coming from and the old site is a huge testimony to it.

Anybody tried making a shaft from CV joints or perhaps the old Cardinal joint? Those donuts have gotta go for a start!

Welcome back Denis .

Hey Joey, is that $2k OZ bucks or funny money?

MD

[joey]

AUD.

www.beninca.com.au

for the record i would buy some poly flex discs..... then again, beninca is pretty good at balancing.

what exactly is ticking you off about the driveshaft MD? the wear rate of the guibos? the overcomplicated system?

i would imagine that once properly balanced by a good shop it wouldnt be a problem. long-lasting guibos would help tho.

[junglejustice]

I went round and round with Glenwood on this, as well as with Drivelines NW, Andy Garcia and Seattle Drivelines:
Level 1 Upgrade;
New center support, new center support bearing and 3 new guibos - send to a shop that will rebalance as a single unit at 3500 rpm (most shops only do 3200) with no more than a 10,000th of a variance - should be good up to 7200 rpm with no more than 280 horses.
Level 2 Upgrade;
Same as above, but with a small, flat, thin (2-3mm) triangular plate spaced between the forward donut and the shaft bolted on the flywheel bolts... (This is the route that Jes and I went) According to Dawie, this is good for the 350 horses we are putting in there - you just want to support the forward unit a bit (as it takes a LARGE percentage of the initial inertia when you first drop the clutch…)
Level 3 Upgrade;
As above, but find a balancer that will run 8,000 rpm...
Level 4 Upgrade;
Universal up front - has been done MANY times – it gets louder ad harsher – you really only need this if you have a turbo car with upwards of 380 horses
Level 5 Upgrade;
Universal at both ends - gets to be way too loud for the street - works well with track cars - insert aluminium/carbon shaft if you like – No one seems to know if the additional vibration has an effect on the TA box (as these would buckle under power at this stage before we could find out), or on the engine itself (as these would get rebuilt/changed/replaced) before any long-term vibration effects could be measured.
Level 6 Upgrade;
Cut away at the tunnel, 6-speed M5 box upfront, regular shaft setup at the rear going back to an Alfa 6 rear-end. (The way the turbo cars hold together with 550 horses.)
Level 7 Upgrade;
Somebody PLEASE start a 928/944 TA conversion on one of these.
Level 8 Upgrade;
Move to a chassis designed for this kind of power (such as the Ultima GTR) with a Porsche box good for the 620 horses it pumps to the wheels form the 24 Valve AR TT motor. (Not what we want to hear, but hey – at least the motor is still Alfa Romeo…)

Another thought would be poly discs, but at that thickness of material it's pretty rigid - are we now at the equivalent of a hard mounting at this point?

[joey]

that last point is exactly what i've been thinking JJ. However, we dont need to made them solid, the problem with the stock units is that the material is crap. If you dont rip them apart then age will.

i'm sure u guys running high hp motors have different requirements, but for most of us i think a remake of the original with a PU skin is the go, because its the most feasible with the most potential buyers.

Not even our original donuts are solid IIRC, all we need is a modern polymer skin that is impervious to the elements and resists shear better than the stock rubber items. All sorts of things can be looked into for extra tensile strength, ie kevlar and composite fibres. But in my superficial opinion, a simple, flexible and long lasting solution can be found by replacing the rubber with P.U.

This is not exactly an original thought, many other manufactures have aftermarket PU donuts, i dont see why it wont work here.

[MD]

JJ. Appreciate your scale of modifications and the time taken to write it up. There are some interesting starters there. You've got me thinking.

To answer your question Joey, I just honestly don't trust the system to stay together. A friend running in the Targa Tasmania nearly had a major accident because the driveshaft let go. It doesn't have to be when you are applying power either. In my case it was accidental. I was "racing"three other cars and was the lead vehicle at the time. Coming out of 4th @ 6500 RPM I selected 3rd due to a stupid and human error instead of 5th. This accidental selection caused a huge explosion in my driveshaft and blew out one segment from all three donuts.

If the tailshaft lets go, it could lead to an end-over-end rollover. Even though my car has a cage on it, it is not some thing I want to experience while the spinning tailshaft is trying to carve up my butt and legs with it.

You could say that speaking from personal experience and learning from others, they are the weak link both from a reliabilty and safety angle. But as I have also said, it's all the other crap that goes with them just to get them right in the first place so I don't want to repeat myself. Despite this problem, I have a passion for these cars and I am very keen to find my personal solution and I find this forum can and does generate a lot of good interaction and outcomes.

I am still keen to hear about Constant Velocity Joint applications if anyone has had any experience (good or bad)with them in this application.


MD

[Dennis]

Hey MD,

Do you mean something like this?
http://www.torqline.com/product_detail_19.php

Doing it with CV joints looks like the way to go...... How would a joint like that cope with the torque of the engines we have? I've had several failures with cv-joints on my trackcar, but that was due to old grease which got way too hot.

Anyways.......got my mail yet??

[Steve R]

Hi Denis, their stuff does look pretty good. I've made enquiries with that company & I'll feedback here with their replies.

[Sporttunergtv6]

Hey guys,
I just know that you have already seen these, but paul spruell makes those 3 ounce donut protectors (http://www.paulspruell.com/motorsport/r ... parts.html). They are expensive but for the piece of mind they provide i would almost buy them myself.
Vittorio

[Reale]

Hello-
any updates on the CV joints for the driveshaft?
Also, do we know if anybody makes the donut shields for the GTV6/Milano cars? I think Spruell's are for the older cars?
-Al