ArvidW
New member
- Location
- Netherlands
Hi,
Recently i've installed a "MFACTORY VOLKSWAGEN GOLF GTI MK4 19972004 02J 5MT HELICAL LSD DIFFERENTIAL" in my 2006 Golf mk5 GT 1.4 Twincharger. While I was searching for a helical TBD I couldn't find all the info I needed. Therefore i'm writing this review so others don't have this issue.
The Golf GT has a 02S manual gearbox, a 6speed version of the 02J which is sometimes also referred to as a 02J-B. The 02S gearbox features a 113mm ringgear (114mm for 02J) with slightly thicker rivits to solve final drive faillures (common) in the 02J transmission. This unfortunately means that there are only a couple of diffs available for the 02S.
Wavetrack and Peloquin both offer a 02S compatible LSD, but are quite expensive when imported to Europa. I’ve therefore decided to order a Mfactory 02J differential and modify it to fit the 02S gearbox.
As I was voiding the waranty anyway, I decided to take it appart to take some pictures:
The fit-and-finish is fantastic. All visible surfaces are beautifully machined and protected against oxidation with a preservative oil.
Preload of the diff is approximately 1.65mm
Diff is helt together with 9bolts (M8, 12.9 quality) and one dowel pin. All bots are loctited and required aproximately 25Nm to loosen.
The planet gears have very little play in the housing (23.17mm gear, 23.23mm cavity). The shim stack is held in a (probably) billet spider, with (probably) billet keepers. The tolerance of the spline in the spider and keepers is good.
Bellville washer stack is: )(()) with 28.04mm OD, 14.25mm ID, 1.47mm thick and 2.28mm total thickness washers. They appear to be high quality washers.
Quality of the sun gear and planet gears is excellent, grinding quality is OK for a this low speed application. The planet gear do show some facetting on the flanges which would result in gear whine if it was a drive gear. But for a differential it is perfect as these planet gears rarely turn at a high enough speed to make noise.
Engagement length is excellent, even for the chamfered plannet gears.
Housing is beautifully machined. All edges are chamfered / cleaned up before assembly. Oiling groove for the driveshafts is also nicely finished. The case seems to be nitride hardened (black coating) and afterwards ground for all critical dimensions (Bearings, mating surfaces). Workmanship is perfect. Way better than OEM diff.
Dimensions of bearing surfaces is spot on. Bearings fit perfectly after they've been heated to approx 100C. Distance between bearing is identical to OEM (within 0.02mm) so re-shimming was not required in my case. Concentricity of the bearing to ringwheel diameters is spot-on, couldn't measure anything significant with a 0.01mm dial gauge.
The diff is perfect except for 2 details:
- No torque spec available in the box, or the Mfactory website, or via the helpdesk (no reply)
- The dimples of 2 planet gears contained debris from beat blasting (see picture above)
The beat blasting debris is unlikely to loosen by itself, and even when loose can't go anywhere quick. Still it's not ok that it was left in the diff. An increase in centering dimple size could easily have solve this risk for debris entrapment.
Bolts are a bit weird, they are left hand tread M10x1 if I remember correctly. They seem to be forged as a clear forging line can be spotted on the cylindrical part. Tread is rolled which is nice. Quality is OK.
The installation in my 02S gearbox:
I've used an installation manual for the 02J gearbox. Getting 5th and 6th gear of the primary and secondary shaft was annoying as the synchro hub is pressed on tightly. Not a fun job, and should only be done with good quality 3 arm pullers in my opinion to prevent damage to the synchro ring and hub.
As previously mentioned the 02J differential doesn't fit the 02S ringear as the diameter of the diff is too large. I've machined it down on a 1958's worshop lathe using an independent 4yaw chuck. The case hardness of the differential is high enough to melt off the coating from carbide tips if insufficient cooling is applied ! It is properly hard. In the end I managed to reduce the diameter by 1mm by taking cuts of 0.1mm at a time. Not very enjoyable with a 800euro new part ;-)
To take up the slop caused by the slightly larger holes in the ringgear i've manufactured some bushes.
The diff operates flawlessly. You don't notice it when commuting to work: no noise, no torque steer, no weird behaviour.
Only if you stomp on the gas the car really comes alive. Nice even black lines while accelerating from a standstill. But the grip in a corner is the most amazing feature. Instead of modulating the throttle you can you throttle up during the corner. It actually pulls the car in the corner, increasing the car yaw rate with the same steering angle. The only scary thing is that the steering wheel doesn't self center if you let it go. This only occurs if you go WOT in a corner, and can easily be compensated by just centering the steering wheel yourself.
In the wet the grip while accelerating out of a corner is also impressive. But if you overstep the line both wheels spin and the car will only go straight like any fwd LSD vehicle in the wet. Still a lot of fun and way way quicker than an open diff.
The mk5 ESC likes the LSD as well, way less interventions.
Conclusion: perfect diff for a competitive price
Recently i've installed a "MFACTORY VOLKSWAGEN GOLF GTI MK4 19972004 02J 5MT HELICAL LSD DIFFERENTIAL" in my 2006 Golf mk5 GT 1.4 Twincharger. While I was searching for a helical TBD I couldn't find all the info I needed. Therefore i'm writing this review so others don't have this issue.
The Golf GT has a 02S manual gearbox, a 6speed version of the 02J which is sometimes also referred to as a 02J-B. The 02S gearbox features a 113mm ringgear (114mm for 02J) with slightly thicker rivits to solve final drive faillures (common) in the 02J transmission. This unfortunately means that there are only a couple of diffs available for the 02S.
Wavetrack and Peloquin both offer a 02S compatible LSD, but are quite expensive when imported to Europa. I’ve therefore decided to order a Mfactory 02J differential and modify it to fit the 02S gearbox.
As I was voiding the waranty anyway, I decided to take it appart to take some pictures:
The fit-and-finish is fantastic. All visible surfaces are beautifully machined and protected against oxidation with a preservative oil.
Preload of the diff is approximately 1.65mm
Diff is helt together with 9bolts (M8, 12.9 quality) and one dowel pin. All bots are loctited and required aproximately 25Nm to loosen.
The planet gears have very little play in the housing (23.17mm gear, 23.23mm cavity). The shim stack is held in a (probably) billet spider, with (probably) billet keepers. The tolerance of the spline in the spider and keepers is good.
Bellville washer stack is: )(()) with 28.04mm OD, 14.25mm ID, 1.47mm thick and 2.28mm total thickness washers. They appear to be high quality washers.
Quality of the sun gear and planet gears is excellent, grinding quality is OK for a this low speed application. The planet gear do show some facetting on the flanges which would result in gear whine if it was a drive gear. But for a differential it is perfect as these planet gears rarely turn at a high enough speed to make noise.
Engagement length is excellent, even for the chamfered plannet gears.
Housing is beautifully machined. All edges are chamfered / cleaned up before assembly. Oiling groove for the driveshafts is also nicely finished. The case seems to be nitride hardened (black coating) and afterwards ground for all critical dimensions (Bearings, mating surfaces). Workmanship is perfect. Way better than OEM diff.
Dimensions of bearing surfaces is spot on. Bearings fit perfectly after they've been heated to approx 100C. Distance between bearing is identical to OEM (within 0.02mm) so re-shimming was not required in my case. Concentricity of the bearing to ringwheel diameters is spot-on, couldn't measure anything significant with a 0.01mm dial gauge.
The diff is perfect except for 2 details:
- No torque spec available in the box, or the Mfactory website, or via the helpdesk (no reply)
- The dimples of 2 planet gears contained debris from beat blasting (see picture above)
The beat blasting debris is unlikely to loosen by itself, and even when loose can't go anywhere quick. Still it's not ok that it was left in the diff. An increase in centering dimple size could easily have solve this risk for debris entrapment.
Bolts are a bit weird, they are left hand tread M10x1 if I remember correctly. They seem to be forged as a clear forging line can be spotted on the cylindrical part. Tread is rolled which is nice. Quality is OK.
The installation in my 02S gearbox:
I've used an installation manual for the 02J gearbox. Getting 5th and 6th gear of the primary and secondary shaft was annoying as the synchro hub is pressed on tightly. Not a fun job, and should only be done with good quality 3 arm pullers in my opinion to prevent damage to the synchro ring and hub.
As previously mentioned the 02J differential doesn't fit the 02S ringear as the diameter of the diff is too large. I've machined it down on a 1958's worshop lathe using an independent 4yaw chuck. The case hardness of the differential is high enough to melt off the coating from carbide tips if insufficient cooling is applied ! It is properly hard. In the end I managed to reduce the diameter by 1mm by taking cuts of 0.1mm at a time. Not very enjoyable with a 800euro new part ;-)
To take up the slop caused by the slightly larger holes in the ringgear i've manufactured some bushes.
The diff operates flawlessly. You don't notice it when commuting to work: no noise, no torque steer, no weird behaviour.
Only if you stomp on the gas the car really comes alive. Nice even black lines while accelerating from a standstill. But the grip in a corner is the most amazing feature. Instead of modulating the throttle you can you throttle up during the corner. It actually pulls the car in the corner, increasing the car yaw rate with the same steering angle. The only scary thing is that the steering wheel doesn't self center if you let it go. This only occurs if you go WOT in a corner, and can easily be compensated by just centering the steering wheel yourself.
In the wet the grip while accelerating out of a corner is also impressive. But if you overstep the line both wheels spin and the car will only go straight like any fwd LSD vehicle in the wet. Still a lot of fun and way way quicker than an open diff.
The mk5 ESC likes the LSD as well, way less interventions.
Conclusion: perfect diff for a competitive price