@koss2j

how is your trick holding up since the original writeup?

 

Hey plums good to hear from you. The beast is just so beautiful and responsive to drive I fell in love with her all over again. She doesnt see many miles as I am very busy with work but she hosed an AMG mercedes last week that was half her age so that always feels good.
I am thinking I may take the 22 inch rims off and go for a 19 or 20 which should make her feel even more alive.So in answer to your question yes the trick is so simple and works every time 100%.
I will upload a vid when I close my workshop mid December and have some holidays.
cheers for now.

 

That's really good news. BTW, you're running a 3.54, but from what car?

There's a method to the madness ... checkout my adventure in long distance parts
acquisition, in particular an entire rear subframe with a 3.58:

https://www.jaguarforums.com/forum/x...-131715/page2/

Regarding tires, with a 3.54, 255/45-45 would put redline right at 275 km/h indicated and
accounting for calibration error, 288. 245/50-18 would be about the same.

 

Has anyone else tried this? I would imagine speedo is off with this method and millage is being recorded faster? Do you have to repeat the sequence every time you start the car?

 

With my 3.58s my speedo is off by about 4-6mph depending on what speed and gear you are in. Also a word from the wise, this trick does not work on all all XJRs, especially early USA 98 models (or just my car) and yes, this has to be repeated every time the car is started

 

If you like your 3.58 ratio diff you would love the car with a 3.77. I was amazed at the difference. Did you also install the blue top solenoids in the transmission as well? I see you are in Mount Vernon NH. Do you do all your own work? The person who helped me build my car now has his own shop in Hollis. He did all of my major upgrades including the Twin Screw.

 

If you have the TCM reprogrammed the speedo will read correctally. I think Phil @ Eurotek Designs is still the only one that can do it.

 

All work by me, always but Hollis is just a skip away. 3.77 would be fun for sure, I always advice clients, "don't fear the gear".....they are just not usually for the Jaguar folk!
You and I have spoke before, years back when I still lived in Boston, just checked my phone and still have your email and phone# actually. I think it was about twinscrewing, but I decided ultimately that when i'm done building a few other cars over the next couple of years that I am going to go TT with standalone and a manual box. So, only 3,4, or 5 car builds away

 

Great read and glad its still holding up!

 

So glad i found your post as i want to change the ratio for the sole purpose to increase acceleration
BTW what times are you getting from 0-100km now?

 

Slower 0-100km/h but faster 100-200km/h