Not if a twin screw is in the picture. Or, rather, one that fits on a twin screw rather than an Eaton to be more accurate. Paramount UK claims they would build a set up for me in 2 months, but Avos might be a better prospect to reach the aspect. Paramount has the resources, but Avos likely more communicative if there are installation sag ups.
If Avos could put together something repeatable he probably could market it through Mina, Paramount, Driven Man and the couple other outfits that deal with Jaguars. It seems like a very clean setup he's building but has a little ways to go on details. The challenge, it would seem, would be down in the pulleys and tensioner?

Other than simple wrench work, I'll have to farm out most the work. I tend to just mess it up, break it, and install it shoddy. Worse, I stall and then lose interest because I'm slow at it. "Time is money" to me to in some real terms.
It would make sense to ECU tune on a Eaton, to then just change to a Whipple. Alternatively, doing major exhaust mods etc without an ECU re-map could lead to damage such as cylinder wall wetting etc. Other than little stuff like air filter, thermostat and maybe temporarily making it a bit louder, I'd like to get it done all in one motion - so to speak. That means getting the components in hand first.

The only one that seems the snag up in the rear gear issue - and this something of fairly rare interest focus to me. But the quickest way someone could snap up the performance of their XK8, XKR, XJ etc is a 3.50 or 3.73 gear - like putting in an extra 60 to 90 horsepower and the aesthetics of more rapidly winding out the gears.

 

Ok, that actually seems like it would make life easier as far as the instrument cluster being unaffected. (Assuming the correct wheels were selected). I think he's running on 20's right now.

Do you have a definitive answer as far as which transmission is in a 2005 XKR?

Thanks,

George

 

I am lucky to have friends in the Mustang performance business who have a dyno.
I added a K&N open air filter in my air box and removed the top cover.
We saw a 35hp jump at the wheels with this one addition.
Based on airflow ratings on the 4.0l motor, I believe Jaguar restricted the air intakes and exhaust on the XJR when new, but they could brag that at 370hp it was the most powerful car available at the time.
I would love 3:55 gears but the blower side is the fastest way to more power.
Just open up the air flow and use a less restrictive exhaust system.
Look at the Ford cobra motors as a base, 4 valve 4.6L 390hp standard, with just blower mods they are looking at 650hp.
As my XJR ages (175,000 miles now) I will probably rebuilt a new motor with a much larger blower, and swap engines when the original gives up the ghost.

 

Wait you you're saying putting a k+n cone on the car, and taking the top of the airbox off brought 35hp on the dyno? What happens on the street though, with the hood closed, the motor hot, and the cone sucking in non insulated air?

I do believe the limit on the S/C cars is the fact that Jag choked them on purpose, but I believe moreso on the software side of things. Even if you look at what the naturally aspirated cars make v/s what the s/c ones do, it become fairly obvious that they didn't want to go crazy with the S/C, just enough to get them in a bit of a different league.

The other thing you have to consider is the rest of the driveline and the long term reliability factors. If these cars made an extra 50-100ft / lbs of torque, how would that hold up?

George

 

“Do you have a definitive answer as far as which transmission is in a 2005 XKR?”
You have a ZF 6HP26, where the TCM is located in the box itself. It is also tightly linked to the valve body, and just the slightest issue, would require both new…

“If these cars made an extra 50-100ft / lbs of torque, how would that hold up?”

So far she is holding ;-)

All depends on how you use the power, and how often. Always make sure the engine is at operating temp (not the coolant, but oil!), also important for the transmission. Use good oil, and change it when needed (also your transmission oil!). You can wreck a stock car if raced all the time/bad maintenance.

I use my car only on the street, no races, but do use the power regularly, can still enjoy the acceleration each time ;-).

 

So I don't know if I should consider it reassuring for me or scary for you that Jag decided to put the same transmission behind my S-type's modest 3.0 as they did behind the s/c 4.2.

So for the purposes of this discussion, is the output shaft speed sensor wiring external, or internal to the transmission casing?

George

 

Consider it reassuring for the 3.0. The box is capable to withstand a sustained 600nm, and of course occasionally more.

The Output shaft speed sensor is internal in the box.

 

Yes, that is a very critical question for your explanation.
Anyone yet have any idea where to find an 05 shop manual?
Not just for repairs, but hopefully to see what internals look like. What does the bottom end of the motor look like (main caps for example). Where is the TCM in relation to the transmission? Where is the sensor on the transmission - what is it reading? Is the sensor internally or externally mounted?
I truly hope you find a solution in the electronic aspect.

Who should MOST be interested in lower gears (and an LSD) are the KX8 folks who wish they had XKR power, but don't. 3.73 on the rear with good tires would get them nearly on par. A decent exhaust, decent tires and 4.10s and I suspect an equal year XK8 would out-accelerate a stock XKR. And they'd still have a top speed approaching 150mph - a speed they/we never go anyway.

(note: I have 20 inch wheels on my 05 but might drop down to 19s or 18s. The choice of tires is MUST larger if drop down, particularly if going as low as 18s. Because I have very +2 tires, I could reduce the diameter or leave it about the same with 18 inch rims and even more if going 19.

 

Yes that's pretty critical. If we can't get between the output shaft sensor and the tcm, we can't modify the value the tcm sees.

I found this which gives a pretty good look at the internals.

Take a look.

George

 

Checkout www.jaguartechinfo.com, not cheap, but lots of info (not for this type of TCM reprogramming).
There is lots to find on the internet about the 6HP26 transmissions, but as ZF links the TCM to the valve body, if there is only 1 sensor failure, you need to replace the whole set, so you will not find specific details I guess.
IMHO Forget playing around with the output sensor, you can't adjust that, as when you adjust it for the new rear end, it will fail as the input speed sensor compared to the output is wrong. Best chance is to find a good tuner, they might be able to adjust the TCM program, as these units are also used by BWM and Audi (and more) there is where you might find something. The TCM files are available on the IDS DVDs (from the Jaguar VCM diagnostics computer), as there are different variants that are uploadable with the VCM (for different cars/rearend ratios...). Next you need to understand where the specific data fields are, or even more difficult, adjusting the TCM program itself. A good tuner (by that I only mean the best in the field), is also a good IT/Data specialist, and sometimes also have connections to people who know (i.e. from the supplier) might then be able to do something.
Good luck.

 

Following this intently, don't wish to draw it off topic, but have you guys considered brake upgrades along with performance of the engine and diff?
I'm in the middle of developing a brake system using Alcon monobloc 6 pot calipers at front and 4 pots at rear. The mounting brakets are cnc customs in EN31 steel, with a nitrile coating.
I decided the Brembo system, whist adequate on my XJR100 are no match for current brake systems. They rotted at the backs, and were marginally better than standard. The Alcons, well, on a dry day, with good rubber are defiant, will not fade and are seriously aggressive stoppers - they're fitted to the 2010 XKRS, at the front anyway. I've out broken some serious cars, I questioned the driver of an R8 and he said he ran out of road, and didn't bottle it, not bad for a 2 ton saloon against an aluminium sports car. The rotors are 355mmx32mm, with aluminium bells and bobbin kits, the standard brembo discs should do.
Pagid RS9 pads.

I too seriously wish for a powerloc 3.77 on my car, it would make so much difference.
Having spoken to Gerrald at Paramount, the diff they supply is Quiafe, and supply and fit only, or exchange. The Quaife is 3.54 ratio giving only stability, no lower gearing. This to negate any electronic adjustments. Cost is ?1560+vat ($2,379.53, you guys dont pay vat, just shipping)
Can anyone shed a light on the IDS tool - a) can we alter shift points from 5900 to 6100?
b) can we adjust ratios' via BCM to TCM?
That would be magical. I guess drive train>rear axle ratio, this could be then selected from a list of ratios fitted - or do I dream, over to Brutal, or any of the Jag techs with this system????
________
BMW K1

 

Useful on the trans. Particularly where to fill/drain/replace the fluid. I couldn't see any indication of any sensor location.

I'm puzzled...

The traction control will not allow wheel spin (burn-outs). But I've read if you turn it off (sport mode) and ABS (I'm not up on the controls yet), then the computer won't block tire spin nor put it into the limp mode.

How can the computer distinguish between tire spin (burn-out) versus an undersized tire verse a taller gear - if all it is doing it reading the transmission imput shaft? Wouldn't an undersized tire or tall gear do exactly the same thing as far as a sensor is concerned that a burn-out would?

It can't be as simple as turning off the ABS and turning on the sport mode (permanently) could it?

Second, if it is ONLY metering the imput shaft on the transmission, then it would seem the computer would have to be calculating that shaft speed to actual ground speed - ie whatever is reading the speed you're going. It would seem that would also be what would communicate to the speedometer.

I read here that the setting for the speedmeter can be changed to match changes in tire-wheel size. IF that is also the information source that is used for the calculations that put the computer into "limp mode" if you alter gear ratios, could it be as simple as re-programming-mapping the speedometer setting - calculating out the gear ratio change would equal to a tire circumference change? If so, then it would just be a matter of living with an inaccurate speedometer.

Possibly not even that because there are Kits out there to electronically alter the speedo showing. So the computer could be "lied to" about the tire circumference in terms of lower gearing, and then an electronic unit correcting this between the computer and the speedometer.

The electronics of it is beyond me, but that's just because I know nothing of this. For a person in the know, there seems to not only be ways around this but even kits/boxes for other cars/vehicles addressing the same issues. Potentially it is just a question of what to buy to plug in where?

But, again, I don't see how the computer can be shut down enough to allow burn-outs/tire spin, while not allowing different gears. Both would be "way-off" and in the same way - the tire seeming to travel farther than the car is going.

 

Isn't the rear ratio 3.03 on an KXR? Are you referring to an XJS or different model? (my 76 XJS has 3.54 gears if I remember correctly. Later models dropped down to 3.0ish - and turned them into acceleration pigs by comparison. )
So I gather the Quaife includes the gears themselves? (or am I just totally off-base with that question??)

 

Isn't the rear ratio 3.03 on an KXR? Are you referring to an XJS or different model? (my 76 XJS has 3.54 gears if I remember correctly. Later models dropped down to 3.0ish - and turned them into acceleration pigs by comparison - having 1 of each the difference was very dramatic. ) A 3.54 ratio would work just fine and basically my question is how to get a lower gear Quiafe setup to work in my XKR?
So I gather the Quaife includes the gears themselves? (or am I just totally off-base with that question??)
I previously emailed Paramount on the question by emails. They answered all emailed questions about exhaust components, but no response in relation to a lower gear and a Quaife for my XKR. I took that for a "no."

 

Do you know where and what the sensor is measuring?

 

First of all, it would be great news if you would be able to find a way.

"if all it is doing it reading the transmission imput shaft?"
Can't recall anyone saying this, these are very complex and advanced software programs, and as the proper operation of the unit and safety depends on that, I’ll bet many millions have gone into developing this, leaving little room for what might seem the obvious. There are 4 wheels sensors, which of course also used to determine whatever it wants. Turning of traction control only means that you allow the computers on the car not to intervene when wheel slippage occurs.

“I read here that the setting for the speedmeter”
Good thinking, might be an option but this depends on the signals the ABS unit is providing on the CAN bus. I have no knowledge on this, if it is wheel revelations, then this will not work again. If it sends out a speed value per wheel, then it would mean the ABS unit also works with a tire diameter, and it could workout. I have no idea how the different computers share signals on the CAN bus, and how they use it, but each could use the info in its own way. Maybe someone in the know could answer, I might know someone, will check.

 

@Sean B

If it is for your XJR 100 (from 2001?) , than you are in luck my friend.

That one uses the Mercedes 722.6 gearbox, and there (some) Mercedes tuners have the ability to adjust some of the data fields, and to name just one, the rear end ratio ;-). Still not an easy job it seems, so reprogramming might not be cheap, bit at least it is possible. The TCM can be shipped to them as it is outside of the box (contrary to the 6HP26).
For A) and B) You will not be able to do this with the IDS software from Jaguar (at least not with the offered menu options).

 

Avos, thanks for the update - yes its for the merc 'box. This changes everything, I wrote a long message about the trac feature, but now I know the box can be programmed to accept a ratio I'd like to fit potentially, I'll be going down this road! Happy days, Cheers to You ;-)
I'm also In the middle of sending you an email with regard to the s/c upgrade. Paramount and TLJaguar have clouded the waters long enough!

DFWX
The 3:54 I have is standard on the XJ/R - your correct when you say the XJS was fitted with this 3:54 ratio and it was a power loc, this could be an option, but a pwrloc 3:77 would be far better, I now need to find a Jag that had one fitted - XJ40? XJS? XJ6 Series 3?
________
Radian

 

Ok we're confusing things here. Here's a quick breakdown of the systems and their primary functions First ABS.

Anti Lock braking. Has a wheel speed sensor at each wheel, and can tell how fast each wheel is turning. IF and only IF you're on the brakes and a wheel locks up (stops moving) the anti lock brakes pulse the brakes for you to avoid a skid...

Traction control / dynamic stability control

Uses the same wheel sensors, but in a different way. If it realizes the rear (drive) wheels are turning faster than the fronts, it assumes wheelspin (Or the potential onset of wheelspin based on steering angle, throttle position, yaw (body roll) etc... ) And tells the pcm to take your foot off the throttle for you, and if necessary uses the brakes to stop a spinning wheel (before god forbid you oversteer).

You can turn the traction / dsc off (and hence do a burnout) But you cannot turn ABS off (at least not with a switch). It's federal law. Just like the airbags.

Sport mode is just a program for the transmission (which holds each gear longer, and in the ZF 6 speed, locks out the 2nd overdrive - 6th gear) Basically designed to keep the engine in the powerband longer, so it feels "sportier" accelerates quicker (and only takes one downshift to get into a multiplicative ratio). The sacrifice of this is fuel economy.

Now. The input shaft v/s the output shaft. And the code that is thrown when you change the rear.

Now you hit the nail on the head as far as lying to the computer about what's going on, but you don't need to do it as just far as vehicle speed.

The easiest way to understand this is to consider the rear end as an extension of the transmission. Almost how there are primary and secondary drives in 18 wheeler transmissions. (3 ranges, and then the 6 fwd gears). The overall gearing is the combination of the particular gear ratio the trans is in at the time, multiplied by the effect of the rear end. Taller gears in the rear simply mean less turns of the wheels for each turn of the driveshaft. Hence the car revs higher to keep the same speed, but the effect is that it accerates faster (by transfering more torque).

What I think is going on here is a comparison of some sort. The car knows how fast it's going, (how many revolutions of the wheel). The car knows the engine rpm.

Now internally the transmission knows that the for every revolution of the input shaft, the output shaft (and hence the driveshaft) should rotate X times at any given vehicle speed. (Because the rear end ratio is fixed). If you go drop a set of gears in it, the transmission is is sitting there going um... somethings wrong here, my numbers arent matching up. limp home mode because something might have let go inside the trans. (driveshaft spinning faster could be an indication of a car not having shifted into the gear the computer THINKS its in). So it shuts the party down till a mechanic can look at it, theoretically preventing a more severe failure.

The output shaft sensor, AND the tcm, are built into the valve body of this particular ZF transmission. They are NOT external. On any GM / Ford trans they are, and you can get to the wiring. (and hence modify the output shaft sensor's output).

As far as the moment you're doing a burnout. The computer is smart enough to recognize this condition. Front wheels turning slower than rear wheels. It lets you have your fun, or tries to stop you from killing yourself depending on where you're keeping the traction control switch.

Now. The solution isn't simply disabling All of the above mentioned systems. Or any of them individually.

The IDEAL solution would be to reprogram the trans so it just expects the new gears. Problem solved. Each of the following is a a non ideal solution, because it may affect the way the trans behaves and or performs.

Next in line solution. Modify the reading between the output shaft sensor and the TCM, so the trans thinks the output shaft is turning the number of times it expects, and hence thinks the stock rear is back there, and all is wonderful in Jaguarland. That was what I was trying to do, or proposed. Although this may lead to some other odd behavior. Potenitally delayed shifts etc. The problem is this is INTERNAL to the trans in this particular transmission. You cant go splicing into wires, and or plugging boxes in.

Now the final and this is a complete hack solution would be to proportionately adjust all 4 wheel speed sensors, so the trans thinks the car is actually going faster than it is. This may lead to early upshifts though.

All in all its basically a big mess.

George

 

Unless of course, like me you have a 98 XK8 and don't have to worry about any of that trash


From this thread, it would appear that putting in a limited slip wont be THAT much trouble.
https://www.jaguarforums.com/forum/s...t=31450&page=6
the Aston Martin Db7 had a LSD in it, and granted I'm making an assumption here but that rearend should bolt up. Though it solves the LSD problem it's still a 3.07.