I'm guessing you'll be running slicks at the track?? If not, then drag radials must be your thing? I never could get the Nitto DR's to do very well.

Anyways, the reason I asked is because of the lower gear ratio you'll be running. Also, are you doing anything to strengthen the gears or do they hold up well in those diffs?

Lastly, simply related to your power output... Are you going to replace all the U-joints while it's all apart?

 

MT DRs. U-joints will be checked and changed if needed.

 

I'm sorry, it seems you are having to jump a lot of hurdles!

Just so you can prepare for the next one, how are you going about avoiding the "incorrect gear ratio" code with the 15hu and the gear ratio change?

Are you able to program yourself or are you running a standalone system or custom ecu-tcm so you don't have to worry about the normal speed sensor checks?

 

Hi Sami,
what was your original diff ratio?
I still have the original 99 XJR diff -
the amount of power mine is putting out - my diff wont last long either
The ECU I am putting in will program speed sensors (it is connected to ABS wheel sensors) - there is a LSD centre in a trashed car that I can get for about 300euro - so I might be smart and buy it, have it heat treated and replace it before mine blows.
Cheers
DC

 

TCU will be reprogrammed by the same guy who made it for your unit.
$$$$$

 

Same 3.06.

 

If someone wants to get his EGS51 to be reprogrammed to different gear ratio we can get discount for a group buy. It's still expensive but cheaper than ordered one by one. PM the details.

 

No programming was involved with my diff swap to 3.58 lsd.

Other folks in the past had been able to bypass the gear ratio check with the procedure mentioned here

https://www.jaguarforums.com/forum/x...change-108750/

but my car wouldn't let the gear check bypass happen. Because it was a very early model '98 XJR? I don't know. In your case of drag racing, or my case with autox, the bypass procedure is worthless unless you run the bypass procedure on the track before you do your actual passes because it has to be done every time you start the car. I had already installed a brand new Coventry West 3.58lsd and my car was stuck in 3rd gear no matter what I did, so this is my solution...

I don't run ABS or traction control via a non functioning abs control module. Therefore my front abs sensors are essentially paperweights connected by wires to the canbus system. I have never tried to run the car without them installed at all, i just leave them flaccid.

I had custom rear tone rings made to trick the rear abs sensors to thinking that i've got 3.06 gears. The downside is that I do have the stability/traction control fail message and my speedo is off by about 5mph. I don't tend to look at my speedo or the message center when the rear end is swinging around and the tires are breathing smoke, so all is good. The ABS light in my car never did illuminate from the day I bought it, so that is one light I have never had/have to look at. I would have deleted it somehow anyways.

Now I never have to press the traction control to burn BOTH tires. With all that being said, I wouldn't recommend no abs/tracs with an LSD rear for the many people who are not familiar with driving relatively high HP/tq "driver aid-less" cars unlike today's cars. If anyone is interested just reach out to me, i'm pretty sure i'm about the only person versed in this sort of ghetto trickery Enough hijacking the thread for today sorry

 

15HU 3.58:1 43/12 crown wheel. Diameter 8.5" .

 

It was due to some of that and also the incompetence of the two working on it. Lets raise a toast to Browett and Ball

 

There is an option for utilising the 15 HU (which it SHOULD have had from the factory)- with Dana 44 internals and a 3.08 ratio and either a Eaton Trutrack or Torsen T2R.


I'm still in the process of sorting this out. Check my other threads. The shafts and companion flanges have been fabricated and are being power coated now.


The Dana 44 parts are after market and designed to cater for monster torque from Big Block Chevys

 

Found this for a very low price, but shipping from another country doubled the cost. If the massive torque is too much for the crown wheel. I found NOS pinion/crown wheel set l. In this case shot peening for them.

 

The spare TCU came back from long trip around the world. Now coded for 3.58 ratio. Diff gets new LSD oil and RVS treatment. Great stuff. Diff change early next week.

 

Better to use tow truck than drive very slowly to the indy shop.

 

Glad to see that it's all getting taken care of. You'll be happy once it's on the road soon.
Now you have more problems to face... Traction.

 

No major traction problems with these:

 

Got a phone call from the shop owner. The diff and tuned TCU have been changed. Everthing is fine. He tested the car and said: "Even the AFR is still out of ideal this is most probably the sickest Jag I have ever driven during last 40 years and I have driven quite a many Jags." Well, lets see when I get the car tomorrow.

 

Good deal! Now go out and break something else!

(You know what they say, if you aren't breaking parts, your not going fast enough)

 

500rpm more than before when speedo shows 140km/h. The orginal diff in the trunk.

 

you need to buy a boat Sami, you have an anchor - love the tyres - what size