Anyone after a 3.73 diff?

[Ant.]

It's the Hyrdotrack......no association to me.


http://www.ebay.co.uk/itm/TVR-Hydrotrack-Different...

[RobertoBlanco]

I'd appreciate somee comments on LSD on the T-cars in general, the hydrotrack in particular and about the close gear ratio option.

When i heard about it, i was quite surprised, that TVR didn't ship their cars with LSD as a standard. Seems like a no brainer to me from the technical standpoint for (super-)sportscars. But what is your insight on this for road use or on track?

[Zippee]

I thought all 350s came with the Hydratrack? Mine has it from new anyway...

[K4TRV]

RobertoBlanco said:

I'd appreciate somee comments on LSD on the T-cars in general, the hydrotrack in particular and about the close gear ratio option.

When i heard about it, i was quite surprised, that TVR didn't ship their cars with LSD as a standard. Seems like a no brainer to me from the technical standpoint for (super-)sportscars. But what is your insight on this for road use or on track?

Can't comment on close-ratio gearboxes, but all T Cars came with a LSD, either Plated or Hydratrak.

The following may be of interest and is all IMVHO:

I am Not an expert, but some reading and researching, this summarises the differences.

The standard TVR/GKN (and non-Hydratrak BTR) lsd are a plate-type (act just like little sprung clutch plates) that locks up fairly rapidly and sharply if one wheel spins faster than the other. They can be taken out and torqued up tighter if you want less slip before it starts turning the other wheel as well. The downside is that they lock up just as sharply at low speed, which the viscous type don't, so the rear drifts out more easily if you provoke it in a corner at low speed - but fun as long as you're ready for it! The Plated Diff is very reliable/repeatable and favoured by Competion/Press-on merchants over the optional Hydratrak

A TVR Option was the Hydratrak limited-slip differential which uses a cartridge-type fluid coupling, which progressively and smoothly increases torque transfer to the wheel with traction. This is in direct response to the reactive speed difference between the wheel with traction and the opposing, faster rotating wheel -- the wheel that is slipping. Thus, the more one wheel slips, the more useful traction that is transferred to the opposing wheel. Commonly called a speed sensing Diff. One issue of this is the LACK OF repeatability and reliability of this slippage and its change with temperature and "other" variables 8-(( Hence, not good when Competing/Pressing on?

Hope that helps?

I expect "others" will have their views............that's what Pistonheads is all about 8-))

T

[RobertoBlanco]

K4TRV said:

Can't comment on close-ratio gearboxes, but all T Cars came with a LSD, either Plated or Hydratrak.

Thats news to me! Thanks! I've tried to find some tech info on the t-cars, but what you find is rather limited.

So i just googled a bit about the various LSD types and wondered, what kind of service these plate/clutch-type LSDs need. Somewehere on a Loutus forum i read something about diffoil-change every 5-6k miles and an additionally change of the plates/clutches if excessive wear occured (true?). Lifetime of these should then depend on how hard you pushed the car and/or amount of track use.

Do you have info on maintenance, too? A 12k service should only include diffoil-change, iirc.

[K4TRV]

RobertoBlanco said:

snippity..... A 12k service should only include diffoil-change, iirc......snip

I would agree with that. Unless you are Competing/trackdaying on a regular basis, whatever is in the Handbook for servicing would be sufficient.

It's "unlikely" that your average driver would feel the plated diff was "worn" or needing adjustment -but for competition use that's usually more likely, depending on how the driver feels how the diff is performing??

There are a number of UK specialists - Readmanracing (http://www.readmanracing.co.uk/granturaengineering.php) who specialise in various options with diffs. They also specialise in the BW T5 box and may answer your query re-close-ratio box??

T

[thatsprettyshady]

Went for almost £400, what's everyone else's view on the going rate for these diffs? If I was to pick one up I'd probably want it fully serviced (seals/bearings replaced) but would this add a massive amount to the cost?

[RobertoBlanco]

K4TRV said:

They also specialise in the BW T5 box and may answer your query re-close-ratio box??

Thanks again for your reply. I was more interested in opinions on the close gear ratio box regarding i.e. different rpms@speeds from standard 3.91 and how it effects drivability, acceleration and noise levels etc.
found something about it here btw: http://www.pistonheads.com/gassing/topic.asp?f=7&a...

new comments welcome though....

[Tom74TVR]

thatsprettyshady said:

Went for almost £400, what's everyone else's view on the going rate for these diffs? If I was to pick one up I'd probably want it fully serviced (seals/bearings replaced) but would this add a massive amount to the cost?

I was looking at this one as well but spoke to my local TVR dealer here in Belgium who told me that he sells completly revised diffs (same hydratraks) for about 860£ including two years warranty. He told me that if it goes for more than 350, I was paying too much....

Cheers,
Tom.

[ShiDevil]

£400 too much given you will want it refurbed anyway.

Grantura about £750 to refurb your existing one including conversion to 3.73 or 3.91.

Interestingly Dom's recommendation for a 4.3 engine is the 3.46 (it's not really a 3.43) and standard gearbox.

[ShiDevil]

thatsprettyshady said:

Went for almost £400, what's everyone else's view on the going rate for these diffs? If I was to pick one up I'd probably want it fully serviced (seals/bearings replaced) but would this add a massive amount to the cost?

Correct, better to take yours out and get it done

[Quentin1]

Regarding the Close Ratio:


• 1st gear - 2.43:1, 62 MPH
• 2nd gear - 1.56:1, 97 MPH
• 3rd gear - 1.24:1, 122 MPH
• 4th gear - 1.00:1, 151 MPH
• 5th gear - 0.80:1, MAX MPH

Standard T5:

• 1st gear - 2.95:1, 51 MPH
• 2nd gear - 1.95:1, 77 MPH
• 3rd gear - 1.34:1, 112 MPH
• 4th gear - 1.00:1, 151 MPH
• 5th gear - 0.80:1, MAX MPH

So only the first three gears differ. Acceleration in first three gears is distinctively different...very nice box.

Regards,
Björn.

[RobertoBlanco]

Thanks (again) Björn.

Thought that they'd differ through all the gears leading to a different top speed. Shouldn't there be some kind of a bigger gap between gears otherwise?
Is there any way to see which one was bolted under the car from just the outside outer shell of the gearbox (or is there any other indicator)?

[wadsapple]

I'm no expert, indeed pretty clueless when people speak about how there diff feels when driving hard on track or road. I think you would have to be an exceptional driver to tell exactly what is going on with the diff at any given time when driving hard on the road. I bought the said diff at what I thought was a good price , as I run these diffs in both my challenge cars and have no problems , I can't understand why people say a hydrotrack diff is no good for compertion. My Rover Engined car puts out about 400BHP and my Chevy puts out about 570BHP both run the hydrotrack diff with no problems infact we do rather well with them. I have had to beef up the top hanger though as this is a weak point.

For reference these are the cars running the Hydrotrack Diff 3.73