Track-day Diff

[Hellmun]

Guys looking for some clear opinions on what's the best, no compromise track diff(Discounting spools!). I basically never drive the car except to, from and during track-days lately so I'm none too worried about comfort and noise. Especially having the hollow muffler I have right now (those at the interstate challenge may remember a very raspy red NB8B:P).

I got my Tax back and ordered my jap spec mono-flex with EDFC plus some nice new r888's are likely to happen as soon as I finish correcting some gutter rash on 15' rims I bought. So Diff is next on the agenda for performance per dollar.

From some reading I am starting to focus on the Tomei Traxx 2-way. I've been told it tends to wear significantly better than a standard clutch pack LSD . I'm just a bit concerned at how frisky the oversteer will be if I back off the throttle as the 2-ways seem more drift orientated. If this however is the fastest when mastered...sign me up.

On the same note, how much would I be looking at for a higher ratio ring gear and Bevel and how far would people go on a 6spd?

[CT]

I used to run a 4.1 with a 6sp - did over 100,000klms that way. Not sure I'd waste more money than a decent mazda torsen centre will cost you 2nd hand - until you have really big power, fancy diffs won't give you any advantage. I killed a guru with an NA race car so just use a stock torsen lsd until you kill it - at least they are relatively cheap. All the QLD 2F cars use the mazda torsen so it can't be too bad.

[Hellmun]

Well I'm not planning on having a heap of power for a while. Would like to go the eventual SP turbo replica path however for the moment I've got about 92kw atw.

I've still only seen second hand torsen centres for about $600 and up. I can get a clutch-pack for about$900 on import. I guess I just thought i'd be wise to simply future proof the car now. Doubt a turbo upgrade would be on the cards for atleast a year though. Still need Front sway, brakes and a cage by that stage before that.

[Babalouie]

Import LSDs can often be worn out, whereas torsens never wear out.

But I hear ye about the future-proofing tho. IMHO torsens aren't so crash hot once you have lots of power.

[Blue94t]

I have the factory 4.1:1 torsen in my 94 Clubman. My car is turbo'd, making about 160 rwkw.
The torsen is great on the street but I am not happy with it on the track. I am running Bridgestone RE55s tyres and find that the inside rear gets light enough on the corner exit that I get wheelspin meaning I can't get on the power as early as I would like. I also find it inconsistent which irritates me.
I only ever experienced the same issue on the street rarely. This was with my street tyres, Dunlop somethings. The tyres where nothing special though.
I think my car needs a stiffer front sway bar which may help combat this issue but I will still be fitting a clutch pack LSD as soon as funds allow, probably going to a 3.6:1 or 3.9:1 ratio.
HTH

Jake

[Alex]

best thing about torsens is they don't wear out as stated, but if you brake really hard while cornering and one wheel lifts then it will act like an open diff

[Hellmun]

I found an advantage for having a clutch-pack diff outside of racing....

I've installed my Tein Monoflex and now the springs/shocks are too rigid and too low...meaning I can no longer get up my drive-way going forwards. As soon as both front wheels are partly up the driveway the rear left wheel is lifted off the ground by about 3 inches...then I just get a single wheel spinning with the open diff. A torsen isn't going to help this problem

So clutch-pack diff it is.

On a related note, if I wanted to change to a 4.4:1 ring gear do I need to source a different bevel gear or will it all mesh fine? I think flyin miata had a 5.1:1 and from the american forums it looked like it went right in...not sure if our cars are the same though.

[CT]

Anytime you want to change ratios you must use both crown wheel and pinion. A 4.4 comes from an Econovan. Are you trying to pull stumps or something? A 4.1 will give you a decent change (14%) without making 1st and 2nd useless. With a turbo, I doubt you'd get an advantage going greater than 4.1 unlike an NA engine - my old one reved to 8500 every shift so it could make a 4.4 work. With turbos, you use the lower down torque - revs make them unreliable.

[Hellmun]

My mistake was I thought I had a 3.9:1 standard and not a 3.707:1. So the 4.1:1 is about the increase I was looking for where I previously had the 4.4:1 in mind. Main goal was actually to stop needing to go back to 2nd for just a little while on the fishhook and main straight entry plus the whole general acceleration increase overall. Have sent Mania a few emails now trying to see if they had an NB8A ring and pinion but they're not the greatest at email responses...I think I'll give up and call them tomorrow.

[CT]

If you have a 6sp NB, you have a 3.6 final drive ratio.

[zoomzoom]

I found an advantage for having a clutch-pack diff outside of racing....

I've installed my Tein Monoflex and now the springs/shocks are too rigid and too low...meaning I can no longer get up my drive-way going forwards. As soon as both front wheels are partly up the driveway the rear left wheel is lifted off the ground by about 3 inches...then I just get a single wheel spinning with the open diff. A torsen isn't going to help this problem

So clutch-pack diff it is.

On a related note, if I wanted to change to a 4.4:1 ring gear do I need to source a different bevel gear or will it all mesh fine? I think flyin miata had a 5.1:1 and from the american forums it looked like it went right in...not sure if our cars are the same though.

Torsens multiply the torque being applied to the wheel with less grip by the torque bias ratio, and sent that to the wheel which has grip. ie for this situation, getting up the driveway, if you apply the brakes somewhat, the diff will multiply the force being applied by that brake and send the multiplied torque to the other wheel.

[Hellmun]

Yeah I have a 2001 NB8B with the 6 speed. Daniel actually gave me his mobile so if I have too much issue I'll try him and hope he's not bothered by it. He's always been extremely helpful. Maybe mania's just getting swamped atm.

[Hellmun]

Just an update.

Thanks Babalouie for the 4.1:1 Ring/Pinion. Came in $200 cheaper than elsewhere....and arrived 2 days after payment.

Got the Tomei Traxx 2-way direct from Tomei through Race-supplies..again $200 cheaper than everywhere else.

Kon at Drive-line Gears in Wollongong was really helpful, showed me all the bits he replaced (had all bearing/Seals done) then gave me the old ones. Neatly packed up the old diff and ring/pinion. Took the time to make sure I didn't put any wrong oil in especially seeing as he wasnt' familiar with Tomei diffs.

Overall things I learned, Stubs axels were surprisingly easy to take out of the NB diff carrier, pulled right out once I got the crowbar in the middle. Next time I'm going to unbolt where the hand-brake holds on so I can pull out the wheel hub further and I shouldn't need 2 people.

Breaking in a Kaaz/Tomei diff is a right pain...finding a flat wide surface to do figure 8's for 30-45 mintues is surprisingly hard to find these days.... every single place is locked or has cars in it 24/7. I spent two hours on Tuesday night coasting around trying to find somewhere from Port Kembla to Albion Park.....

Tomei/Kaaz do NOT want you using anything but their gear oil if you google it... I didn't get the tomei hypoid gear-oil with my centre. So seeing multiple websites say \"don't put synthetic oil in your clutch-pack diff it will destroy it\" caused a stressful afternoon. Especially when nowhere in the world seems to sell either bottles of oil separate. On Irwins advice I called the guys at Hi-Octane Racing and Ian Baker was kind enough to tell me that some 75-90 Royal purple would perfectly fine ...but that he was out. Few phonecalls later I have 2 quarts of it from Autobahn where a helpful sales man waited an extra 10 minutes(5:40 and they close at 5:30) for me to arrive in Albion Park(I got trapped behind an accident in Wollongong).

After breaking it in I dumped the oil tonight...which was full of small particles($30 of oil for 300k's distance travelled ) and refilled it. Will taxi it for the rest of the week and should have some fun Monday. Got my confirmation.

I got up my driveways front end first...totally worth $1800

[Babalouie]

hi guys, sorry to interrupt but i thought since we are on the diff topic, im planning on getting a 94 model clubman. I am assuming it comes with the facotry torsen diff. i know its not gona grip or bite as well or hard as the aftermarket 2way or 1.5 way kazz type, but can anyone with track experience tellm e if its still good tho? the cars got about 200 000 plus kms on it. does the torsen diff wear out at all? (not sure how the diff works) will i be able to rebuild it to make it work better since its high kms? thank you appreciate it

The oem torsen seems to work quite great, right up until the point where you have tons of turbocharged power, at which point the torsen gets a bit confused and spins up the inside rear wheel a bit.

But for stock or light tuned power levels, it's fine for track use. I upgraded to a Mazdaspeed 2 way LSD and to be honest there is no performance gain on track at all, save for a slightly greater consistency.

In terms of wear, they are non rebuildable AFAIK and you basically use them until they go bang.

[Babalouie]

ah ok, so the question is, when will they go bang? assuming normal driving on road and its got 200 000plus kms, torsen meaning they are gears therefore cannot be rebuilt yea?

Well I haven't seen a Mazda one go bang, but I have seen Toyota ones self destruct in Supra turbos.

This is what mine looked like after 110,000km, which included a few seasons of trackdays and drift events, and it was in still in good condition.


What seems to happen is that the edges of the helical gears (those spiral-looking ones) chip away, and then the diff starts to behave like an open diff before going bang.

You could probably shine a light into the diff drain hole to see the condition of the gears....but if it's still doing its job then it's probably still ok...