Hello chaps! I'm from the S-Type forum. We're investigating the means to have our TCM shift our ZF transmissions at redline. Ex.: 1st to 2nd is at 5900 rpm. One our former members loaded the TCM file from an XKR into his 05 S-Type R and claimed redline shifts. Question: Does the 03-06 XKR shift at redline? To give yas a heads-up, we purchased a differential and sent it to an outfit in Michigan (USA) to see if they can retrofit an "Affordable" limited slip differential (Quaiff LSD is over $2000). If yes, then the stock gears must be utilized as a means of not throwing the car into limp mode. Many of us wish to shift at redline and utilize lower gear ratios. Another S-Type member has a contact in Europe who can take the trans. TCM (must be removed from trans.) and reprogram it for redline shifts and accept lower gear ratios. Please visit our Lincoln LS LSD Swap thread to view our discussions and actions taken.

 

I stand to be corrected (I usually am) but I don't think so.
One problem is giving WOT on our French back roads makes one concentrate rather hard on the view through the windscreen but I don't think I've seen the rpm's get near redline.
I believe you have to hold gears manually with the J gate to do that.
One thing you will need to sort is that the ZF 6HP box only uses 1st gear when the 'S' sport button is pressed.
No doubt some of the crazy US XKR abusers will tell me I'm wrong !!

 

Thanks Steve. From a dig, in Sport Mode, does the XK hit redline or short shift (5900 rpm)?

 

I'd say it is comfortably under redline.
Again ISTBC (stand to be corrected) but I don't see much over 5000 before the shifts.
I wouldn't want to see my engine getting anywhere near redline - but then I'm an old fogey and an engineer.
.

 

LOL, thanks Steve. Ditto to lack of redline...likely the reason our original motors are still running.

 

I'm sorry to be the only responder to this thread, particularly as I'm not a fan of thrashing XKR's (let's leave other thrashings out of the Forum) BUT I have done a few demo WOTs - and it really is like an aircraft taking off - with nowhere near redline.

 

Ditto. The STR, XJR, and XKR's small V8's are blessed with hp and torque. With the mods performed on my STR, this has become more apparent, and further fuels the addiction for more hp and trq.

 

I've redlined my XK8 once or twice. It can be done under hard acceleration with the S button activated. J-Gate with S holds the best results, but first gear unless you step on it from the get go likes to shift early. Every gear other than that will shift about 100-200 rpm shy of redline. I'm guessing it depends on the transmissions memory of how you drive.

 

It depends on how you drive. I noticed that my XKR's shifting behavior is modified to how it is being driven.

 

I've noticed the same thing. After loafing around town for a while, the first time I get on it out in the open the car feels a little lazy, both in throttle response and the shift firmness. Do that a few times and she perks up and is much more responsive all around.

The ole Jag just seems to like when you run the sh*t out of it.

 

Thanks all. The same goes for the STR. In Sport mode with DSC off, she'll hit the rev limiter in the first three gears if the tires break loose from a dig. Would love if there were redline shifts when moderately getting on it.

 

I have not seen reference to the term within the Jaguar community, with my Mitsubishi this was called "fuzzy logic".

"Redline" is not necessarily the optimum shift point.

"Redline" means the highest rpm that the engine can safely be operated at, but in reality, engines almost always reach highest HP and especially torque well before "redline".

For maximum acceleration your shift point should actually be at a point at which your engine has an increasing amount of HP at the rpm that you will be in when you shift up to the next gear. In other words, you want to keep the engine operating at the highest HP and torque RPMs, not necessarily their maximum allowable RPM, where they have neither.

 

Yeah, definitely.

After driving it around perky style for a little bit, transmission shifts much less... it'll hang at 4k rpm if I abruptly let off the gas without shifting because it realizes I'm just as likely to stomp the throttle as I am to brake. If I'm driving casually, even with sport mode still on, it'll down or upshift at more reasonable rpms. It knows that if I'm playing race car I don't want those casual shifts unless I suggest where I want it to shift using the throttle. It actually adapts very well.

 

IMO, perhaps you've made the best point thus far. Hopefully the pre-set shift points remain valid with modifications?

 

I'm sorry to bore people once again with my constant complaining and sincere hatred of my 2003 XKR's 6HP26 ZF transmission, but here's my two cents:

I do tend to drive with a rather heavy foot, you know? Like I'm in a sports car, right? And unless I'm doing miles on the highway at speed, I want the engine to be at an optimum rpm for maximum acceleration most of the time. I drive nearly 100% of the time in sport mode and on the manual side of the J-gate. Because I want my car to shift WHEN I WANT IT TOO - not when some 'puter wants me too.

I must say that when my transmission is in automatic mode, it will shift pretty darn close to the 5900 redline when I'm hammering the throttle. That is the case from 2nd to 3rd to 4th and to 5th - I don't really know if she'll make redline before 6th, since getting caught at that kinda speed around my part of the country will often result in a night in the gray-bar hotel and a huge dent in my wallet!

The first to second shift is a sore subject with me. I would really like to find a way to force the tranny to stay in first gear until I WANT it shift into second. I HATE the 1st to 2nd short-shift bullsh*t ! That unnerves me to no end - particularly when I'm in a corner. I don't want the gear-change to happen until I've completed the turn - whether I'm driving spiritedly or not! GIVE me control Pleeeese! This stupid transmission will often shift into 2nd at as low as 2500 rpm (whether I like it or not) when I'm in traffic - thus putting me WAY below the torque center of my power-band - I HATE that. If I nail it from a dead stop (and I mean completely still) the transmission fairy MAY let the engine wind out to 5000 rpm before it shifts to 2nd - but that's not every time... And I have to be stomping it like a sixteen year old driving his dads 'Cuda to get it to up-shift to 2nd at that high of rpm.

Please don't get me wrong, I'm not trying to drag race my XKR (although I have, once - and it turned a respectable quarter mile in the high 13.90s by shallow staging and making the run in automatic mode) and I don't expect to "pop" the ring gear in my rear end with stoplight to stoplight antics. I'm just desiring CONTROL of my shifts.

Yes, the transmission does seem to "get used to" a certain driving style and start shifting differently when I'm being unusually mellow behind the wheel. Boy do I ever hate that - because if I decide to hammer it, it behaves like a slug again and I worry that something's wrong when it slides lazily into an upper gear prematurely.

I have even talked to several specialists at the ZF transmission parts depot here in Kansas City and they look at me like I'm nuts when I ask these kind of questions about ..... oh the horrors.... A JAAAAAG!

Crap, sorry... I'll wind down now...

I hope my rant answered at least part of your question.


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