ALFAGTV6.COM

[Dennis]

Has anybody out there experimented with removing/shortening the spacers between the DeDion crossmember and the chassis?

I don't know what everyone's experience with this has been, but I found that it reduced corner-exit oversteer.

-Al

That's interesting! However, I can't really think of an explanation of why it reduces corner-exit oversteer.

I also have to get into aligning engine and gearbox, because the front boxmounts need to be tightened every 500 km's! Even with locknuts......... Must be an alignment problem.

[Reale]

Someone once explained that the DeDion arrangement in the GTV6 produced some degree of "active steering." I have not sat down and attempted to figure out how this would work, but there is definitely a difference. I was able to get back on the throttle at a couple of spots at Road Atlanta much earlier than previously-one place in particular was at the bottom of the hill in turn 12. It was good for a couple of tenths, at least!!!
-Al

[milanoguy]

Hi

I once put a magnetic angle finder on the "arms" of a deDion tube and found them to be angled upwards at 10 degrees. I presume that if you remove the spacers that angle will increase, not sure what effect that would have.

BTW those spacers are not present on Alfetta's

Bye for now

[Maurizio]

Someone once explained that the DeDion arrangement in the GTV6 produced some degree of "active steering." l

The only thing I can imagine is when your bushing of the watt linkage is worn. The dion can turn around the front pivot point and actively steer under load. Angled arms won't have an influence on the working of the dion.

Leaving the dion cross member spacers out, will lower the center of gravity a few millimeters at the backside.

[Mats]

moving the front pivot point changes the squat/antisquat and will definetly change the way the car behaves.

[Reale]

I did not know the spacers were absent on the Alfetta. I can see how the roll center would change-it definitely helped the handling.

[patzo_3l]

quick question..by removing those front spacers wouldnt the front of the transaxle sit hirer up, thus disrupting the alignment of the drive-shaft vertically and in theory under load when the drive-shaft torques up and the front of the gearbox comes up with it becoming far more out of alignment. i say this bc i tried the same thing and it took alot of trial and error in judging the distance the shaft actual travels under heavy acceleration or load up ways. and adjusting the little rubber stopper at the top of the box that stops it hitting the bottom of the floor. it took me a fair while of getting back under the car and adjusting that little stopper before i finnally got it right though with no vibration at all afterwards. also bc my car is a 3.0l and i run the different style of centre donut (guibo) i found i had to play around with the position of the 2 nuts that mount it to the floor of the car. i found this also played a part in vibrations under acceleration..and something silly here but once i even forgot to put the little rubber that goes inbetween the end of the last donut and the bit that bolts onto the gearbox end. all trivial things i know but they solved my vibration problems. due to the fact that the more power i made the worse it got as the tailshaft flexed differently under load and then went into alignment again.

[Reale]

My transaxle doesn't move too much under load, because the rear support is pretty much solid, and the front mounts are cross-drilled with a bolt through them. I screw that bump stop down snug with the nose of the transaxle. I agree that under load the transaxle should pivot a little, but I note no differences in vibration no load vs on the dyno. I get a little shake at 1800, and less at 7100. Oddly, nothing in the 3000's. Now, when I get everything pointing exactly under STATIC conditions, I might discover some differences under load vs no-load, but who knows.
-Al

[CJ]

The 'pinion snubber' (bumpstop for the front of the transaxle) should NOT touch the clutch housing. There should be about 1/8 inch (or about 3mm) of clearance or it WILL transmit vibration into the chassis. I use a drill bit to check the clearance. Too tight, it vibrates, too loose and the dounut will hit the tunnel and you will get a feeling of too much slop.

Nice work on the CF driveshaft.

CJ

[Maurizio]

moving the front pivot point changes the squat/antisquat and will definetly change the way the car behaves.

I have thought a bit longer about this and must change my point of view: the COG will not change, ride height stays about the same.
The front rotational point of the dion will move a few millimeters up.
But looked from the side of the car the dion is a cantilever which rotates around the back wheels. So moving the front up a few millimeters will result in a movement of the propeller, of (rough guess) about 1/5 of the front movement, down. The angular change is very small for the (anti)squat, so this should theoretically hardly be noticeable....

[ingegnere]

Hi Guys!

Some weeks ago I was asking about syncros, how to fabricate them. Then Barry advised me to make them plasma sprayed instead of fabricating.

THANKS BARRY!

I' ve found a repair shop who was able to make the syncros plasma sprayed. The mystic material that was sprayed on the syncro was Mo (Molybdenum) Hope this is the right english word.

And this is how it looks like:

[ingegnere]

All the used parts were changed to better ones.
Here's a demonstration of a before/after gear.
Check out the teeth.

[ingegnere]

And also the 2nd and 3rd gear were lightened slightly.
Yes, only these two, and only that "much", because the gearbox should be able to carry an extra 100Nm of torque in a long reliable distance.

I think in this case the less is more.

[Mats]

Where did you get the new synchromesh-rings? Or did you salvage them from an old box?

I would LOVE to be able to buy them new...

[ingegnere]

Mats

They're from the old box.
I took them to the machine shop where the surface was cleaned from the worn material and re-plasmasprayed with molybden.

We didn't try the box yet, but we expect it will behave as new.