I made the shifter hole bigger by 1 inch in two places with a dremmal, in order to make the TKO 600 5sp fit. I can't say how much tunnel work is invoked with any 6sp by I know it more.
As they say " the chain is only as strong as its weakest link", sorry the stock 10 bolt rearend is the weakest part of the XJ-S driveline no matter how you put it. Followed by those 4 rubber v mounts & radius arms.
Those Cobra want a be's with any IRS are all about show & car cruises. Put that 427 Ford torque & HP to that chrome Jag IRS & see how long it last. Why do you think Shelby put the 9 incher in the Cobra.
Lawrence

 

Huh?

The particular vehicle I was reading about belongs to a serious
drag racer. 600+ horsepower, forget whether that was at the
crank or rear wheels. Still serious horsepower.

As most readers in this forum would probably know anyways,
the Jag IRS is a close twin to a Dana 44, and in fact was sometimes
a Dana 44 in certain years. The Salisbury version is reputed to
have better gears than those in the Dana version.

 

So, could you tell me more about the speedo pickup? How does it work? Can it be retrofitted to a 3.31 set, or are you simply out of luck?

 

Let me state up front, that I love Cobras...for what they are.

Sure, the Ford 9 inch is legendary for its strength, and that's part of the reason Shelby used it. The other reason is because he was only allowed to use and modify items scrounged from Ford's parts bin. At the time, Ford didn't have anything nearly as sophisticated as the Jag IRS, and, Shelby had neither the time, nor, the budget to develop a proper suspension. The 9 inch, even in its slickest guise, is still just a live axle, and, because of that, the Cobras didn't handle well by sports car standards. They didn't win races because they outhandled everything on the track. They won races because they had the best power/torque-to-weight ratio, allowing them to outrun the hell out of everything else on the straightaways. For decades, Cobras held the record for the 0-100-0 dash, but, not a single record for the slalom, thanks to that archaic Ford 9 inch out back. A 9 inch underpinning an XJS would be both a huge leap backwards, and, a ride/handling nightmare.

The Cobra, and, the XJS are apples, and, oranges. Neither car can hope to compete with the other within the criteria for which each car was designed. Few XJSs will ever beat an original 427SC in a drag race. The ones that can have been heavily modified. By the same token, a Cobra makes a ****-poor GT car, for the very same reasons that made it such a legendary street and track terror.

 

of interest; late model GM Camaro has a 10 inch diameter ring gear,with IRS, so the old antique ford 9" live axle is really dated,(introduced in 1957 Fords).
all this talk about how strong Dana 44 are,yes they may not be the strongest, but with the Jag flexible rear cage you will rip out all the mounts holding the thing under the car 1st. believe me i know,LOL.

and it really has to do with how much grip the tires will hold, most times even the 10 bolt Dana 44 with an 8.5 " gear will take serious abuse, for 95% of Jag guys!

manual shift with a good clutch may shock the diff. and drive line, but an automatic is far less abusive on the complete drivetrain!

lets not forget GOOD automatics are nowadays faster than manual trans(maybe not so much fun).

and everybody knows,on a side by side race, each time you shift you fall back around 1/2 car length, compared to an automatic, that keeps pulling at full throttle,no lift! especially when you miss a gear trying to catch up with manual!! HMM, how do i know that?

few fast street cars use manual much any more.

 

Edelweiss, i did an LS conversion on a Buick Grand national, trans had no provision for speedometer, not on rear end either>

so i used a modern GPS speedometer ,both analog and digital, accurate within 1/2 MPH, worked out fine,it had speed zone warning bells, and miles travelled etc.

it was a complete set up just ignition power when swiched on, nothing connected to the car.

 

How would you keep the odometer working without a mechanical speedo pickup?

 

Re:


Earlier comments on the strength of the Jag diff, and the Ford 9", etc.: I leave this to the guy who must run it to decide how much they need in the diff. It has seemed to me based on my own experience that there are other bits that will fail before the diff (mounts, half shafts known to twist off, that sort of thing), and, keeping those diffs sealed at the output shafts is always fun. But for most of us, they work.


On the pickup and the question of the odometer turning without a mechanical pickup: on my 1990, the speedo input comes from a reluctor ring sensor in the diff. It is electronically processed by the instrument cluster and that in turn, spins the odometer as well as indicating speed. There is NO mechanical connection whatsoever. Had the instrument package complete apart, a couple of times. And, I have the speedo pickup port on my Tremec trans plugged.


If you go with a an older style diff in a newer car (one that requires the electronic pickup located at the diff), you have a couple of choices: you can use the pickup port in the transmission and get an aftermarket box that converts this pulse rate to the one needed to give a correct speedo readout. This setup will intimately depend on the diff ratio, as the trans pickup only knows how fast the drive shaft will be turning, not how many wheel revs per drive shaft rotation revs.


The other way is to somehow pick it back up at the diff. You can do this by taking your current 2.88 diff and pulling the carrier assembly and removing the reluctor wheel, then taking this to a local machine shop, along with the carrier for your 3.31, and have them machine the 3.31 carrier to use the reluctor. This will enable you to run 3.31, and plug the pickup back into the rear diff cover and no one will be the wiser: it will look OEM all the way. I know a guy who did exactly this.


The other way is to find a reluctor ring with the same tooth count as the one in the OEM diff, but a ring that can be somehow mounted in the half shaft chain. There are aftermarket kits like this, most going between the drive shaft and the pinion flange of the diff (and hence, still need to have an aftermarket box to adjust pulse count). But it turns out Jag themselves already solved this- on the XJ40 sedans, they used a reluctor ring with the same tooth count, and this is specifically designed to slide onto the output shaft studs before the halfshafts are mounted. Usually, on the XJS anyway, there are camber shims at this location. What you do, is, measure the thickness of the reluctor stamping, and then the thickness of those shims, and figure out what must be added or removed to maintain the same camber with that reluctor bolted in line. Then, you have to figure a mount for the pickup, so that it points at this reluctor and then off you go. I have one of these reluctors, and have test fitted it to the 3.31 I had planned on running, so I have more than cursory experience with this. I have also counted the teeth on the 2.88 reluctor and so speak with the authority of experience on that point, as well.


-M

 

.

amc; a GPS,(Ground position satellite) speedo. picks up from satellite in the sky,is used by most all civilized countries in the world, for traveling.

after using one for a year, i'm convinced it isa great way to add a good speedo. to a modified car. it has other apps to go with it, like speed trap info, miles to go and miles to destination.
it is very accurate, new ones down to a tenth of MPH. they come in different face types, analog(i like), or digital which is nice also!

in fact you can get an app on your I-phone, and get some experience using app... google it and check out companies selling them.

its a new world out there in technology

 

just lookin around GPS speedo. Amazon and E bay many to pick from!

also you get what you pay for!!

 

.

found some info about Dana 44 rears.
what shocked me 1st dana 44 came out in WW2 for military trucks(whoda thought). Salisbury was/is a division of Dana corp.

most jags starting with the E-type, had Dana 44 IRS, ratios from 2.37 all to 5.50s, some with LSD. along with Corvette, Viper, some Ford GT40,etc

what is interesting the ring or crown gear in std. 44s is 8.5 inch diameter, but they make a 9 inch gear also like the size of famous ford 9".

now with some slight mods the big gear will fit into a 44 housing(big gear is refered to as DANA 45 at 8.9" dia.,never knew that).

and matter of course, 2012 up Camaro has 10 inch gear, IRS.

" and the beat goes on" sonny and Cher

anyway more useless trivia

 

I got my V12 converted to manaul 3 weeks after I bought it
I have it around 5 years
The difference in the car is unbeleivable and so much more driveable
I used a 3.6 manual XJS with 3.54 diff as donor car that I paid £200 for so I did save quite a bit there
A crowd in the UK did the conversion for me at a cost of £2500 for the clutch/flywheel/adapter plate and labour costs.

Here is a link to it on you tube,

 

Sounds great. I did mine about 6yrs ago. Did you have to rework your ECU ? My car stalled between shifts, I understand this is common in some cars.
I don't know weather it was because of the aluminum flywheel or the ECU. Anyway I sent it over to Roger Bywater @ AJ6. He reworked it to solve that problem plus "enhanced" it , so it was a two fold advantage .
I love the aluminum flywheel but it does have its pro's & con's.
Lawrence

 

I had no issues with my ecu Lawrence
However,
I'm eventually going to go with a mega squirt ecu as I'm planning plenty of other mods for the car
At moment the car is parked up and is at the beginning of a 3 and half year planned restoration
Here in Ireland I would have to pay €1850 in road tax a year because of engine size but in July 2019 my car will be 30 yrs old and then it's classic road tax at €58 euros per year

 

darn Jag wont hook the tires, must be the automatic trans faulty.

 

My 1985 has had a manual conversion done (with a Toyota Supra 'box), and while I can't speak to the cost, as I bought it already converted, I can speak to it's driveability!

The manual really does transform these engines. End of story. My ECU is stock and unmodified, and although the fuel cut-off is odd (compared with other cars) you do get used to it, and mine has never stalled - you just get more rapid deceleration when in-gear and off-throttle than most cars. I would like to get it reprogrammed, but won't, as I have half a mind to go for an aftermarket fuel injection (distributorless) in future... my wife would say I have half a mind full stop.

Mine has had a 3.31 diff fitted (or 3.something... can't quite remember but have it written down somewhere), and the performance is amazing. Having just bought an XJ40 V12 (6.0L V12 with the GM 4-speed auto - which I think is the same driveline as the late XJS cars) I can attest that the 4-speed auto is a world of change compared to the 3-speed (I actually have never driven a 3-speed XJS, but have driven a number of 3-speed XJ V12s). That said, the manual is far better than both. Unless a driver has a strong aversion to manual gearboxes, I would not recommend changing an XJS 3-speed auto for a 4-speed auto - if you want more gears go manual and you'll never look back!

I should state that I don't mind autos at all. The XJ40 I have is completely suited to the auto 'box, and I'd never dream of having anything else in it. The XJS can really lift its skirts and hustle with a manual gearbox though, and despite it's significant mass, it can take the XJS from being a long-distance Grand Tourer, to something approaching more of a sports car (albeit a heavy one!). The XJ40 (Daimler Double Six) will never be anything but a tourer!

Dave

 

Dave I really can't speak for any trans combination used with the stock 5.3 other than the TH400 or TK0 600 5sp.& aluminum flywheel used with a 3.54 diff. I did have the 3.54 for a short time with the automatic before I changed it to the 5sp. I think I mentioned my goal was getting the gearing as close to my old BB Corvette M22 close ratio & 4.11 as possible, only this time I have the 5th gear OD. Best of both worlds.
I did consider Gear Vendors @ one time for use with the TH400 but it involved tunnel work plus comparable 5sp cost reasons, needless to say the 5sp won, even though the 5sp wound up costing $3K more. As mentioned the only questionable parts (IMOP) are the stock rear trans mount & the IRS/10 bolt diff. Normally driven will get many miles.
Lawrence

 

My solution:

 

That IS a nice solution...until you've been terrorized by a well set up manual box XJS!


That V12 is quite something when it is allowed to run.

 

it would be nice to my automatic trans.XJS V12 up against one of your manual XJS V12 s.

i tried to give it an agressive stance, for looks etc. i think it worked out OK!

calibrated weight 3365lbs,, dynod 355hp at the wheels, simple and effective.