Driveshaft for Alfa 75turbo 500ps+

[GiorgosCS07]

Hello,Im new to the forum and I will need your help.
We finished our project and the car produse more than 500ps with a GT35 Garrett.The problem is the driveshaft..(can't handle the power).
Now I am looking for a better one than the stock.Does anyone know where I can found one?

[ALFA TUNER]

Driveshafts,or the propshaft.When we run group S 75 turbos the props broke first.By the way how did you get 500 when Alfa corse could only manage 420/430 withj an engine life span of 200kms?

[Reg]

Have you tried alfagtv6.com? ALFAGTV6.COM • Index page

Theses guys are the cats **** when it comes to transaxles.

[alfaholic75]

Hello there,

Are you sure you mean drive shafts and not the prop shaft (between the engine and gearbox)? My 75 turbo has 550ps on its low power setting and with nos 707ps yet my drive shafts seem to be lasting ok at the moment the prop shaft has snapped a few times now with catastrophic consequences so I guess you mean this?

Gus he doesnt say what engine he is using so perhaps like me he is not using the 1.8 turbo engine.

[ALFA TUNER]

Fair do's Paul,but lets wait and see,i am always impressed by huge power claims,you know that,espesially on things that we had the best off,for years of competition.

[alfaholic75]

Totally agree, If that power is on the 1.8 and it lasts more than 10 minutes then I am well impressed!!!!!!

[GiorgosCS07]

Originally Posted by ALFA TUNER

Driveshafts,or the propshaft.When we run group S 75 turbos the props broke first.By the way how did you get 500 when Alfa corse could only manage 420/430 withj an engine life span of 200kms?

My car has SDS ecu.I hope that I ll see more than 550 at the dyno...The Alfa is the 1,8turbo model.
Now for my problem,I don t know the correct word..

I m looking something like this..

http://img24.imageshack.us/img24/148...onutaq1.th.jpg

Where I can buy one?

[alfaholic75]

You must be having to run serious amounts of boost pressure! 40psi?? If you are going to still use mounts like that one then It wont last. The design of the whole system is terrible. Im guessing that you are trying to replace the rubber propshaft doughnut? The alfa course cars used stronger mounts I believe that where incased in metal but they still broke. You have to change the design totally if you are going to run that sort of power. The next problem you will have is the nose of the gearbox just snaps off. I can tell you a way around the whole thing but it is not cheap and needs alot of work. Having that sort of power like mine causes very big problems. I had several totally custom made propshafts which included mounts that spread the loads differently onto the gearbox and they still broke. In total I have spent over £4000 gbp on the prop shaft and still have issues.

[GiorgosCS07]

Originally Posted by alfaholic75

You must be having to run serious amounts of boost pressure! 40psi?? If you are going to still use mounts like that one then It wont last. The design of the whole system is terrible. Im guessing that you are trying to replace the rubber propshaft doughnut? The alfa course cars used stronger mounts I believe that where incased in metal but they still broke. You have to change the design totally if you are going to run that sort of power. The next problem you will have is the nose of the gearbox just snaps off. I can tell you a way around the whole thing but it is not cheap and needs alot of work. Having that sort of power like mine causes very big problems. I had several totally custom made propshafts which included mounts that spread the loads differently onto the gearbox and they still broke. In total I have spent over £4000 gbp on the prop shaft and still have issues.

Please tell me what can I do?Can I buy somewhere this??I don t want all the propshaft..
Thank you for your reply and your time!

[ALFA TUNER]

Originally Posted by GiorgosCS07

Please tell me what can I do?Can I buy somewhere this??I don t want all the propshaft..
Thank you for your reply and your time!

You cannot run that kind of power through the standard propshaft,or with the standard rear flywheel and clutch assembly,it will fly through the floor,end of story.!!

[GiorgosCS07]

Originally Posted by ALFA TUNER

You cannot run that kind of power through the standard propshaft,or with the standard rear flywheel and clutch assembly,it will fly through the floor,end of story.!!

My clutch assably is not a stock one!The only problem I have is with the rubber propshaft (mount) it brakes all the time!Please let me know about any advice or solutions you may give me.

PS...Does anyone knows were can I get a really strong rubber propshaft doughnut

[ALFA TUNER]

You cannot run with rubber mounts,you have to change profshaft and go to solid with universal joints.

[alfaholic75]

As alfa tuner said that can't be done!!!! I had a plate shape mount made to bolt directly on to the front flywheel one end and then a similar thing on the gearbox end. I had to get rid of the 3 prong yoke on the front of the gearbox as they break to. I had a big plate made that the shaft that comes out of the gearbox went through. this bolted to another plate with 3 high tensile bolts. The prop shaft is tricky. I had the same size prop shaft that went on a 1000bhp lorry and still broke it. I had heavy duty uj joints that seemed to last a while but still not long enough. It depends on whether you are like me and insist on the gearbox still being in the back of the car or moving it to the front of the car!

But DO NOT use the rubber mounts, it was dangerous enough using solid steel!!

[GiorgosCS07]

Originally Posted by ALFA TUNER

You cannot run with rubber mounts,you have to change profshaft and go to solid with universal joints.

And where I can find the universal joints and the propshaft?


I found at the GTV6 forum this photo..
http://img24.imageshack.us/img24/148...onutaq1.th.jpg
or
http://img16.imageshack.us/img16/270...220tqh7.th.jpg

What do tou think about this?

[alfaholic75]

that link doesnt work to see the picture

[GiorgosCS07]

Originally Posted by alfaholic75

that link doesnt work to see the picture

Sorry,now is ok

[alfaholic75]

The fact that they are rubber incased within steel I wouldnt use them. How much torque are you running?

[alfaspence]

i still like your other idea Paul

(V6 twin turbo, in the back, no prop, or shell twist issues)

BTW, this is one of the other reasons iam giving my 75 up, i just can't afford the cost of putting that weak transmission right... permanently

[alfaholic75]

Spence I can't believe you have just given away my biggest secret lol The trouble im having is getting it all to fit!!!!! Still it looks awesome with all the cage and then an engine just sitting in it!!

As with the transmission chuck the alfa stuff in the bin and go front mounted, very cheap and easy to do and will last forever. can also make it 4wd if you plan on 800bhp but thats another secret ill tell you about another day!!

[GiorgosCS07]

The only problem of my car is the ubber propshaft doughnut .Maybe I will make 3 from aluminum.
Take a look of my car...

http://img294.imageshack.us/img294/6473/spa0095.jpg

http://img4.imageshack.us/img4/8417/spa0094.jpg

[alfaholic75]

It looks very nice If you are still going to use the same design then you will need something stronger than the doughnuts. The actual propshaft is not strong enough, not even close. When you use the power, at some point the metal will twist and snap. The shaft needs to be bigger in diameter and wall thickness, also you will need a bigger stronger center bearing. The shaft will need to be rubber lined on the inside to try and dull down the vibration the solid mounts cause. Then you are starting to get to where you need to be. I had 1 propshaft made that seemed to last but in the end the power snapped the nose off the gearbox its self. If you are running a genuine 500bhp with, i would guess around 450 ftlbs of torque it will literally pull the gearbox off the car. The gear box will have to be bolted solid the the rear di deon, not on the rubber mounts as these will break within seconds. Also you will need to beef the de dion up. Mine used to have to be replaced as it would twist. and then not fit. The centre bearing will have to be replaced with a spherical bearing and the tubing will need to be reinforced. The rear gearbox mount will need to be replaced with a total aluminium one as the rubber actually melts with the amount of work it will be doing. Should nothing twist bend or break, then the loads will be even bigger on the front of the gearbox so you will have to go back here and strengthen further still. There are a few ways you can do this, run the shaft in another bearing supporting it right at the point where it bolts to the gearbox. Secondly make a brace that bolts on to the same places as the clutch housing that then comes down to the shaft and again have the shaft running through the centre of the brace on a bearing. I promise you 100% the nose will still break off. it will just last longer. In between breaks the internals and diff will decimate them selves. The alfa box is not very good. My gearkit cost me several thousand pounds and came from colloti but it was the strongest box they had ever made. It still broke! the layshaft breaks. The biggest issue was 4th and 5th gear. It would strip them very quickly. So these had to be re made and then shot peened and also had another metal element put in them in the actual steal making process!! these where then perfect and no issue arose at all. The diff crown and pinion would also strip so I had quaife make me 2 that where designed for a dodge viper strength wise but then made to the alfa specification. Colloti also provided me with one. Diffs generally lasted longer but would move in the casing of the box which broke them. I really am only giving you info here that means you should last 500 miles with out breaking if driven hard. The second you start doing 1/4 mile runs you will kill the transmission. even after all that. What clutch are you running? is it a sintered clutch? if not it wont last to long. the pressure plate will idealy need uprating to. But all this is irrelevent as the prop shaft will still come through the floor when it snaps. Run the whole shaft inside an aluminium tube of at least 3mm thick which mounts to big plates welded to the floor of the car this way when it does snap damage limitation will be to the tube and not the floor of the car and you. phew, there is a lot more if you are really running that sort of power because the car is badly designed for it.

Oh lastly you will get to the point where because everything is solidly mounted the shell of the car starts to twist, then your doors will start to touch and the handling will become affected. The only thing you can do about this is to seam weld the chasis as best you can and then fit a very good multi point weld in cage!!

[fetta head]

Ive read your explanation and you know your alfas.tried and tested by the look of things.
How do porshe do it with the 928 they have a torque tube dont they
Whats a torque tube and cant there be a way of adapting a similar set up for the 116 chassis

[ALFA TUNER]

Originally Posted by fetta head

Ive read your explanation and you know your alfas.tried and tested by the look of things.
How do porshe do it with the 928 they have a torque tube dont they
Whats a torque tube and cant there be a way of adapting a similar set up for the 116 chassis

The 928 had a conventional mounted on the engine clutch,without the extra flywheel of the 75 on the rear,huge moving mass....and that is for starters,so not a very good comparison IMHO.

[alfaholic75]

Originally Posted by fetta head

Ive read your explanation and you know your alfas.tried and tested by the look of things.
How do porshe do it with the 928 they have a torque tube dont they
Whats a torque tube and cant there be a way of adapting a similar set up for the 116 chassis

Yes tried and very tested. Both me and the car have the scars to prove it

Well as gus said not a great comparrison However It was something I looked into and it can be done! But also as gus said they have a front mounted clutch which in my eyes is a life saver as as when the prop snaps you can stopo it from rotating. on the 75 it only stops when the engine does!!

The torque tube idea is a good way forward but to adapt the system and put on a front mounted clutch is not so easy to do. It would require a new bell housing to be made for starters and then all the work to design how the clutch will work etc. Once you have sorted this and say have it all mounted the boxes blow to pieces over 440bhp and they are already a very strong box hence why I opted out, Most of the work on my car was done along with a company called clubautosport who are a porsche specialist and they trial fitted a box and with a bit of work it can be done, There is then the issue though that the de dion flexes so much where as the torque tube idea needs it all to be perfectly straight and rigid. Its very tricky to sort out properly. In hind sight with the amount of money and effort that has gone into what I have I could have possibly made it work with the porsche box (if I could find one strong enough)

[fetta head]

I knew the porsche had the clutch at the front but it was the fact that it had a rear gearbox that got me thinkin there may be a way you could do the same but now you have explained it i understand.
I suppsose the porsche 924 944 and 928 never had 642 bhp to cope with.