205 Track Car Differential

[projectpug 0]

I have been thinking about going for a Lsd for a while now for my track day biased gti. I have seen the kaaz and tranx ones which one whould i go for and why ? I use the car for very rare occasions on the road and mainly track it at oulton park or anglesey. Also i have been advised to go with a mi16 final drive with the standard 1.9 gear ratios good choice?

[pug_ham 240 3 Cars]

TranX or Kaaz, the choice is yours, its mainly down to price difference. IMO there aren't any great reasons to choose between them as they are both good diffs.

 

What is the spec of your car?

 

The 1.9 ratio's with a 4.4fd is a common choice which should be fine for those circuits imo.

 

Graham.

[petert 550]

TranX, Quaife, AP, Kaaaz, ZF - there's lots of advantages/disdvantages. Do your homework. In regards to ratios, it's hard to go past the 1.9L gears with a 4.43:1 Mi16 cwp, whether 8V or 16V.

[projectpug 0]

Heres all the full spec

205 GTI 1.9 shell and engine gearbox

weber 45's in process of fitting there on just not setup

omp grp n

gaz adjustables all around 40mm lowering spring onfront cant remember the make

Poly top strut mounts

Upper and lower strut braces

Standard arms and TB and ARB witht the torsion bars lowered not sure by how much as i bought the car like this.

constella short shifter

Brakes - Standard 1.9 calipers master cylinder, Zero sixty front discs green pads all around standard rear discs.

Braided goodridge hoses all around

Ab/105p/126 omp 10 point bolt/weld in cage

Corbeau forza seat and harness

Standard 1.9 seat and harness

Perspex rear windows

Fully stripped out

Using speedlines i run 195/50/15s R888 and if wet Khumo V70s in a soft compound

 

Cant think of anything else at the moment does this help ?

[Batfink 201]

i take it "track biased" means its still used on the road?

If so I think a quaife type diff is easier to live with than a plate diff (tranx, gipper etc)

[projectpug 0]

Used on the road very very little about 4 times in the last year, I trailor it to track days. Does this sound like the next logical modification? Or would it be advisable to upgrade elsewhere first?

[James_R 3]

I've been running a TransX 40% plate for the last year, I've covered newarly 20,000miles with it and not had a problem, yeah you can boot it with full lock on, but when do you ever need to? on track it's very well manored, I comfortably can stay out at the ring for 3 laps stints and cover 15 laps in a day (some 200odd miles)

[Batfink 201]

James do you have power steering?

[Anthony 1,000]

James do you have power steering?

No he doesn't - he's running a PAS rack with the ram removed.

 

I've driven James's car a fair bit both on track and on the road, as well as a couple of other cars with Tran-X diffs, and I'm amazed at how docile they are even when pressing on. I'm sure that they'll be harder work with different ramp angles and in that case you might need PAS, but certainly with 30/60 plates (IIRC - James will confirm I'm sure) it's perfectly useable on the road and works very well on track.

 

If I didn't already have an AP Suretrak diff to put in my car this winter, I'd not quibble about getting a Tran-X. I'm not sure where the myth about plate diffs being unuseable without PAS and hopeless for the road came from, but certainly my experience suggests otherwise.

[Batfink 201]

i was only thinking the low maintenance issue for a road car is the advantage - as well as the price as I think a quaife is cheaper than a tranx byt a hundred quid..

[James_R 3]

Mines ramped at 45/45 from memory, so halfway house, it's only a 40% diff though, it's the 90% rally cross jobs which try to break your wrists

 

I've covered 20,000miles I'm going ot have it tested when the engine comes out in a few months, but I'm expecting it to be with in spec. I think the maintaince myth is just that really, the other thing which no one's mentioned yet is that a ATB is not as effective as a plate diff, they don't seem to be able to "hold on" to the corner/putting the power down as well as the plate set up does, clearly a reason the ATB's are cheaper.

 

Also ATB's are a weight disadvantage next to a TransX

 

the only downside I've found with it (bar the hole in your wallet) is on full lock the CV's make "I'm dieing/bluemurder" noises, but that's it. Only plus's

[VisaGTi16v 1]

I am not that impressed with my quaife. At normal speeds on the road, if you boot it on a roundabout its borderline lethal as it pulls you violently towards the inside. Then when on the track in sprints and track days, you never feel a thing. It has helped my times a bit but not as much as I was hoping. You also need to adjust your driving as previously just the inside wheel would spin up but if you give it to much with any type of diff the outside will as well leading to bad power understeer. I also had to grind a small bit of a rib off in the be3 diff housing to fit it which I had only heard of with plate ones before. A complete set of bearings cost me about £60 as well or something stupid, can probably source cheaper if you know where. I got a good deal from a friend else I would have gone for a plate one

[tom_m 0]

I am not that impressed with my quaife. At normal speeds on the road, if you boot it on a roundabout its borderline lethal as it pulls you violently towards the inside. Then when on the track in sprints and track days, you never feel a thing. It has helped my times a bit but not as much as I was hoping. You also need to adjust your driving as previously just the inside wheel would spin up but if you give it to much with any type of diff the outside will as well leading to bad power understeer. I also had to grind a small bit of a rib off in the be3 diff housing to fit it which I had only heard of with plate ones before. A complete set of bearings cost me about £60 as well or something stupid, can probably source cheaper if you know where. I got a good deal from a friend else I would have gone for a plate one

 

mmm me too, tho i don't find mine particularly violent on the road either. it will also still spin up the inside wheel if the is not enough reisdual grip. given the choice again i'd have gone for a plate diff, my only worry being the short service intervals. but for the price I paid and the fit and forget nature of the quaife i shouldn't be complaining really. i'm sure its doing something

Edited November 20, 2007 by tom_m

[brumster 135 1 Cars]

Tran-x gets my vote too; love mine for competition use. We've had this debate before and I know I was one of those who expressed concerns about fitting it to a road car, but let's put that into context. My car has sticky tyres on it when in road trim - typically A048's or Dunlop CR311s (between stages). Couple this with non-standard geometry with negative camber and the plate diff, and when part-throttling along her majesty's highways at normal road speeds, imperfections in the road pull you all over the shop. This is a feature of the suspension geometry, I'm sure. However, when applying load the plate diff only exacerbates the problem.

 

So I'll say this - if your car is set up properly then the diff option should only improve things (particularly on a nice smooth race track). But it can introduce new handling 'features' on a badly set-up car or on bad surfaces, so just be aware of that. Some increased feedback through the steering wheel is to be expected (but that's no bad thing).

 

Again, just to re-iterate, I am not putting the things down - they are bloody brilliant for competition use and, in your instance, I think you'll be making a sound investment. But people wanting to put a plate diff into a solely road-based car, to me, is on the whole unnecessary (200hp+ monsters excepted!).

[VisaGTi16v 1]

Im running slicks with 309 arms so have some -ve camber but still have excessive inner wheel spin. The quaife just seems a bit random. If I go into a corner and stamp on the throttle it will just light both up and power understeer, go in slower and gradual throttle, it just spins up the inside. I questioned a geeky friend who knows this stuff about whether this was how it worked and I needed to then give it more power to transfer the load to the outside wheel but he says no, the quaife has already torque biased way before that point and done as much as it can. The Visa is 800kg but only 170bhp so not mental power and the slicks are soft

[brumster 135 1 Cars]

I must admit I'm not up on the torque biasing diffs like the quaife. I've not driven one or been in a car fitted with one. For competition use, the benefit of a plate type diff fully locking (e.g. lose a driveshaft near the end of a stage, or drop a wheel into a ditch/loose gravel) put the ATB's out of the running. Sounds like they're heavier, not that much cheaper and questionable in performance - all for the benefit of no wearing parts? I wonder why anyone sells them

[projectpug 0]

Sounds to me like the TransX one is the one to go for , cheers for all the advice and input much appreciated! Who can supply a mi final drive ? I have the standard arms etc at the moment dont fancy the 300 plus adjustable arms atm but will see about that next year with some excentric(spelling?) top mounts.

 

Cheers

Phil

[brumster 135 1 Cars]

excentric(spelling?) top mounts.

 

eccentric top mounts? Funny things. They wear sandals, have leather patches on their jacket elbows, a monacle, drink drambuie and talk about art and history a lot. Bloody weirdos.

 

[James_R 3]

Also worth saying is the car becomes much more sensitive to suspesnion defects, hubs, bushes geometry, etc... I've put mine on Polyrace bushes now and that helped lots, new TRE's and I've been through a few hubs (mainly do to riding kerbs buggering them [cadwell in the tree's is bad for that]) so if something's a bit wrong a plate seems to make it lots more noticable.

 

As for ATB's and spinning the inside wheel, if there's not enough traction to hold even the reisdual torque I'd question the suspension set up before the diff, it's only trying to cure a symptom not the problem

[ifcho 0]

Has anybody found/seen OBX diffs for pugs?

They seem to be quite cheap alternative to quaife (probably because of the quality) but for a low cost, budget track car, may be worth

 

(couldn't use the search for OBX diffs )

[projectpug 0]

Any one have any info on these OBX diffs?

 

"eccentric top mounts? Funny things. They wear sandals, have leather patches on their jacket elbows, a monacle, drink drambuie and talk about art and history a lot. Bloody weirdos."

Probably class myself as eccentric then lol

[Rob Thomson 6]

Funny, the plate diff (Gripper) in my 106 gives power oversteer, not understeer. I would say that's because it's only got 100bhp, but I've driven a few much more powerful FWD rally cars with plate diffs that behave just the same.

 

I recently had a play in a 205 with a Quaife and really wasn't impressed, it didn't affect the handing in such a positive way as the plate diffs I'm used to.

 

Mine gets rebuilt every 1,000 miles or so. And it needs it too; there are usually a few bits and bobs that are shagged and need to be replaced.

[VisaGTi16v 1]

JamesR: Interesting point. My front is a bit soft and coupled with an attached ARB means as it leans in the corner it will be lifting weight off the inside wheel. I am planning to try it with the arb off but as I only do sprints its nothing something I can test easily. Pointless on the road as speeds are less, cant use my slicks etc. It will have to wait till next year and an early track or test day I think

[James_R 3]

I'm increasing the ARB size on the front of the 205 to try and help the tail "wag" on the car, when you turn in sharply the back wheel lifts then as the cornering accel reduces slightly you get a wagging of the back end, I'd prefer the back to stay on the ground or as near as possible, I'm happy with the spring rates so was goign to try add more ARB not less, but yeah I get you about it trying to pull the inside higher, esp with soft springs, I'm using 285lbs's on mine and road tyres.

[VisaGTi16v 1]

Doesnt that suggest the rear torsion bars need uprating though? I sometimes get mixed up with suspension but I dont think stiffening the front arb will keep the inside rear on the ground anymore? A thicker rear arb would just lift the inside rear sooner as it leans over on the outside wheel.