Jaguar 4HU power lock diffs
Discussion
I am looking into changing my stock Jag 3.31 Power Lock diff in my modified Vixen S1 for a 3.54 diff.
Would a diff out of a TVR 350i have been modified in regards to ramp angles etc? or would it be stock Jag?
Who in the uk would be able to alter a stock 4HU Power lock diff to suit a 980kg car? The stock settings are way to strong for such a medium light weight car.
Anyone got a 3.54 power lock diff going spare?
Would a diff out of a TVR 350i have been modified in regards to ramp angles etc? or would it be stock Jag?
Who in the uk would be able to alter a stock 4HU Power lock diff to suit a 980kg car? The stock settings are way to strong for such a medium light weight car.
Anyone got a 3.54 power lock diff going spare?
Adrian@ said:
Yes. My turbo has a ramp rate changed 3.54 in ...most likely this is going to come out at some point to get a gripper unit put in...recently I looked for someone to ramp rate change an LSD, with no luck, it was cheaper to fit a gripper unit.
Adrian@
I'm in no hurry so let me know when you're changing diffs and I might take that diff off your hands Adrian@
A gripper to my mind is a plate type diff very similar to a 4HU. The benefit of the gripper which I believe is a ZF copy is that it can be made to any spec and has adjustable pre-load so can be set up to suit various applications and is available with all parts... A 4HU is very similar but a lot more complex to have re-built with the Ramp angles made to suit an application. Adjusting the ramp angles on a 4HU involves mechanical fettling and shaping. in addition Bearings and clutch packs etc are getting harder and more expensive to get with limited specialists offering a re-build service.. I have a couple of 3.54 4HU's one bought as scrap since I fancy having a close look to see how they all go together and also to look at ramp angle setting..
Whilst a gripper is an option I would state that if you are building a road based car you will be much better off with a Quaiff ATB unit built into your sourced 3.54 4HU.
A gripper is quite clunky, noisy in operation and suits a racing or rally application. I have an ATB in my race car running a 3.31 ratio which is going to be re-built into a 3.54 very shortly since it is just a little too tall for the application and a little slow out of the blocks on a short circuit. I find the ATB perfectly fine for a race car but I am not blinded that a Plate type diff correctly set up in my car would undoubtedly be faster if a little more skittish on the limit.
For a road car though an ATB every time. its a fit and forget and a job for all seasons, being gentler and offering a little more driver safety if you are pushing on…In extreme cases on lifting wheels you do spin some power away and I have only really found this on very tight hairpins where I am pushing on..
If you just want a nice fit and forget LSD which runs on std EP and doesn't have any clutches or plates etc etc to wear out it would be ATB every time if I were you.
Plates can be made to go faster but also made to give really poor results if you are not very sure it is being set up correctly.
You could also save a lot of weight in the rear and switch to a Cosworth diff for not much money second hand…Again ATB's and Grippers are available for retro fitting in these but chances are you could get away with a std original second hand which as std is for a similar weight car!!
This is quite a good little article to help see the relative merits of all options open to you..
http://www.taylor-race.com/pdf/understanding_diffe...
N.
Whilst a gripper is an option I would state that if you are building a road based car you will be much better off with a Quaiff ATB unit built into your sourced 3.54 4HU.
A gripper is quite clunky, noisy in operation and suits a racing or rally application. I have an ATB in my race car running a 3.31 ratio which is going to be re-built into a 3.54 very shortly since it is just a little too tall for the application and a little slow out of the blocks on a short circuit. I find the ATB perfectly fine for a race car but I am not blinded that a Plate type diff correctly set up in my car would undoubtedly be faster if a little more skittish on the limit.
For a road car though an ATB every time. its a fit and forget and a job for all seasons, being gentler and offering a little more driver safety if you are pushing on…In extreme cases on lifting wheels you do spin some power away and I have only really found this on very tight hairpins where I am pushing on..
If you just want a nice fit and forget LSD which runs on std EP and doesn't have any clutches or plates etc etc to wear out it would be ATB every time if I were you.
Plates can be made to go faster but also made to give really poor results if you are not very sure it is being set up correctly.
You could also save a lot of weight in the rear and switch to a Cosworth diff for not much money second hand…Again ATB's and Grippers are available for retro fitting in these but chances are you could get away with a std original second hand which as std is for a similar weight car!!
This is quite a good little article to help see the relative merits of all options open to you..
http://www.taylor-race.com/pdf/understanding_diffe...
N.
Edited by Dollyman1850 on Monday 2nd February 17:20
Edited by Dollyman1850 on Monday 2nd February 18:38
Bit of a thread revival here but is the picture of the Quaife LSD in a Salisbury 4HU from a Jag?
I notice that the Quaife docs say 4HA. Having stripped my Jag 4HU unit down, the carrier internals have 4HA on it. Is it safe to assume they are the same internally and the 4HA is a live axle whereas the 4HU is an IRS?
Looking to get an ATB but its a "once ordered, cant return" item and for a £1k thats a big price for the wrong part.
Thanks
I notice that the Quaife docs say 4HA. Having stripped my Jag 4HU unit down, the carrier internals have 4HA on it. Is it safe to assume they are the same internally and the 4HA is a live axle whereas the 4HU is an IRS?
Looking to get an ATB but its a "once ordered, cant return" item and for a £1k thats a big price for the wrong part.
Thanks
justinb01 said:
Bit of a thread revival here but is the picture of the Quaife LSD in a Salisbury 4HU from a Jag?
I notice that the Quaife docs say 4HA. Having stripped my Jag 4HU unit down, the carrier internals have 4HA on it. Is it safe to assume they are the same internally and the 4HA is a live axle whereas the 4HU is an IRS?
Looking to get an ATB but its a "once ordered, cant return" item and for a £1k thats a big price for the wrong part.
Thanks
Yes. same diff. HA Live axle, HU Independant axle but they are all the same unit. I notice that the Quaife docs say 4HA. Having stripped my Jag 4HU unit down, the carrier internals have 4HA on it. Is it safe to assume they are the same internally and the 4HA is a live axle whereas the 4HU is an IRS?
Looking to get an ATB but its a "once ordered, cant return" item and for a £1k thats a big price for the wrong part.
Thanks
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