I'm wondering if anyone knows of mechanical alternatives to the viscous LSD that is in the V12 Vantage S (and as far as I know, in other Vantages too, though I imagine the transaxles are a bit different). I'm working on knowing a possible upgrade path there. By mechanical I mean a https://www.carthrottle.com/post/engineering-explained-the-best-kinds-of-differential-and-whats-most-suitable-for-you/]conventional mechanical limited slip differential that has clutch packs or similar. I'm talking about item 4 in the linked article.

For anyone interested in why I care, there's (skip to 10:20) https://youtu.be/8MYZpElW494?t=620]this old chestnut.

Thanks for your input.

 

Damn. Hardcore. I love some LSD discussion.

I have used Jim Blanton at http://performancegearing.com/

Jim built clutch type LSDs for my BMW race cars and street cars

Also have heard good things about Dan from https://diffsonline.com/

They may know someone who might build one for our V12VS.

 

May ask these guys in Texas.
https://hcfautoparts.com/aston-martin

 

Thanks for these leads. I'll definitely look into it with these businesses.

If anyone's ever done this directly, I'd love to hear what your experience was.

 

Why don't you go right to the source and ask Graziano if they ever build one...

 

I could try that, I suppose. I didn't figure a manufacturer would answer an email from little old me, but perhaps you've had better experience with that sort of thing?

 

You definitely have nothing to lose by asking, the worst is they won't answer. I took that approach with Aston Martin when asking how many 09 Vantage Coupe Manual with Sport Pack entered North America, and funny enough they answered me with 75 so my guess was they no more than 15-20 made it to Canada... Pretty happy with that.

 

Although I rate Chris Harris as one of the best journous out there, I believe he might be wrong.
I'm pretty sure I read that (at least) the V8's 6-speed box has a conventional clutch pack LSD inside.
I might be wrong though, but from my impressions the V8 also behaves more like a clutch type (in wet or snow that is).

 

[QUOTE=J doubleU;4896678]May ask these guys in Texas.
/QUOTE]
never knew about them. nice to know in case every need anything done on transaxle or clutch.

 

Nice, the drawing on that webside shows the clutch-plate LSD for the 6-speed manual...

 

Sorry to necro this thread, but I think there's some discussion still worth having here, and I think I was not notified of your reply when you made it.

So the 6 and 7 speed transes are different, not just in terms of the number of gears either. I think the diff being made less aggressive was intended to give the car a less spikey character. This is what I've heard journalists say, anyway.

I did find a link on HCF's webpage that is labeled as a V12VS exploded trans diagram here. I am not great with these things, but the section labelled differential doesn't look to my eyes like it has a clutch pack. In fact the big round thing on the LHS of the drawing looks like it could be some sort of blade apparatus for a viscous coupling.

I'm going to send them an email and see what they say. I'll get back with that update, for posterity if nothing else.

 

The "big round thing" is the outer diff cover/lid through which the diff&crownwheel gets assembled into the gearbox.
The diff itself can half be seen behind that on the RHS. The "blade apparatus" is commonly known as stiffening ribs.

 

I actually just emailed with Jeremy at HCF, and he confirmed that it was a viscous differential. He went on to say that he wasn't aware of any alternative differential for the 7-spd transaxles AM was making at that time.

I think you're right that those things are just part of the diff cover, but it seems that it is a viscous diff regardless.

 

So Chris Harris was right after all with the viscous diff...

If you are serious about replacing the viscous with a clutch-type, you would need to contact someone like Drexler in Germany or another LSD manufacturer (or AM's Q directly).
Replacing a diff can with a one-off LSD can be done - in the end its only about the shape of the casing and the matching splines for the driveshafts.
The "disadvantage" with the aston is that the diff sits inside the gearbox, which increases the overall effort.

 

I had some correspondence with AM Works. I don't know if that's the same as Q? I asked them a question about the diff amongst other questions, but they didn't reply to that question specifically. I've sent them a 'bump' email to see what they have to say about the diff specifically. I also sent Dana/Graziano an email, but the character of their contact form made it feel like I was howling into the void. There was a box to tick for 'end user' but it didn't feel like a user-facing portal. I doubt it'll get responded to. I've never heard of Drexler, but I know about other diff-makers from the lotus adjacent world (specifically wavetrac and Quaife). I suppose I could reach out to them.

I don't know if anyone knows this, but the GT12/V600 are said to have a slightly different transaxle in some of the press surrounding their release. I couldn't find anything about specifically how it was different, but someone (maybe Harris again?) noted that the diff in the GT12 seemed better than that of the regular car. However it's got like, 50mm more tire in the rear so if the journalist (whoever it was) determined that by feel it could have just been down to the additional traction.