Technical LSD options

[mazzata]

Hi, back here again to bother you
I'm not very good to explore this form (Is there any way to direct the search just in the x1/9 section?).

On my Mazda MX5 I got a torsen (thanks to a scrapyard). It is probably the best money I've spent on her. Some 300GBP asnd it is perfect to have fun and to enjoy the small traffic circles .
When I went through the subject for X1/9 I found
bacci http://www.bacciromano.com/

colotti http://www.colotti.com/

o.m.i.r. http://www.omiringranaggi.it/

All of them are offering very famous (at least in Italy) racing LSD, usually for uphill race.
But we are talking of 1000 to 1300 euro!

So I saw here the quaife (interesting Group buys also )
And I asked for info on
http://www.quaife.co.uk/catalogue/products/qdh2k-50


It seems to be a Torque sensing (gear not clutch based) as the Torsen.

Tech Spec:
http://pdfcast.org/pdf/quaife-diff
Models (but the X1/9 is not in )
http://www.text-upload.com/read.php?id=43458&c=4626258

Have you got insights/info/suggestions?

 

[jimbro1000]

I've only used geared LSDs in the past - in my Integra Type-R where it worked like a dream and in my Seicento, where it was of questionable results. Both are obviously front wheel drive but the Integra proved to me how good a LSD system can be although that also had a lot to do with the suspension geometry and layout too. The Seicento completely swamped the same basic setup and it made very little difference.

My racer uses a viscous coupling (from a Fiat Coupe) with a bacciromano gearbox to damp the wheelspin rather than use either a mechanical or clutch LSD. My Abarth uses Fiat's torque transfer system to achieve the same by dragging the brakes on the inside wheel.

In general if you must use a LSD in your car the advice is to stick with a mechanical (torsen) diff for road and track use. For off road or gravel use (ie rally) the clutch plate diff is far superior since a mechanical diff only works while both driven wheels are on the ground. If either lifts free the diff goes open and you effectively lose all drive. The reverse of this is that the clutch plate diff is pretty easily tunable while the torsen style LSD is not so for proper racing on track the clutch plate diff is also popular.

 

[mazzata]

Thank you.

Actually I'm so happy of my T2 torsen on the mx5 that I'll happily follow your advice.

Have we got some direct experience of an LSD on the X1/9?

Or at least some cross reference table about the gearboxes?
Just to know is this model would apply (http://www.text-upload.com/read.php?id=43458&c=4626258).
In the ita forum they are saying that mk1 Uno T gearbox is really similar but they are not mentioning the diff.
Would a diff for mk1 Uno T fit in the X?

 

[jimbro1000]

No it won't fit - you need the 5-speed ritmo/strada style gearbox option, not the tipo style option. I know it lists the Mk1 Uno Turbo but only the very late Mk1's came with the Tipo box, the earlier ones used the aforementioned ritmo/strada box.

I suggest talking to the autocross guys in the states (mirafiori.com or xweb) for experience with LSDs in X1/9s, either that or the various sprint test/hillclimb racers in Italy if your Italian is up to the job.

 

[mazzata]

Yeah, I'm italian but the italian guys are used to the cluthc type...
I like torsen/torsen like..
But you are right, I can ask for fitment purpose!
Have you seen in the link the text "ONLY with modified crown wheel (fiat 128 style gearbox)" for the quaife QDH2K?
The ritmo/strada is also listed...