Hello. New here. Is there any way or ECU sold to override the 155 mph governor?
Thanks.

 

It's an '05 XKR

 

Other than tuning, you can pull for fuse for the abs module and the car wont know how fast its going so no limter or trac control. Works on nissan and other makes, never tried on jag but the principle is the same, you dont know the speed you dont know to intervene

 

Slightly off topic, but would the same strategy apply to 121 mph limit on 04 and later normally aspirated North American xj8's?

 

Great response if accurate! The computer doesn't read the ABS system out? I was wondering what the computer is reading to determine your speed.

 

The ecu communicates with the abs module to get the vehicle speed from the wheel speed sensors courtesy of the abs module. Youll set fault and youll get xmas tree lights on the dash. I use a switch on my nissan with a relay wired in place of the fuse(FUSE IS INLINE NOW) so i can switch on/off from the dash. In my case the throttle still is inhibited even though traction control is turned off. with ABS dissabled I have no speedometer or throttle intervention...And im tuned so i dont have a speed limiter anymore other than hp and wind resistance. But you can only go so fast in a lifted 4x4 with a sail on the roof

 

I was thinking the answer also it a toggle switch and an inline fuse so if it ever happened I actually wanted to go over 155 I could. It is more knowing it could be done rather than ever would.

I'd rather be able to lower the rear axle ratio and live with 150mph top speed as relatively speaking that equates to free horsepower in terms of acceleration at the expense of gas mileage. If I cared about gas mileage I wouldn't have bought a Jag anyway and my other Jag is an old coupe with a 454 in it - 10 mpg.

I read that might be able to be done on an XKR using using the pumpkin off a different model Jag but that also messes up the computer.

Thanks for the comment.

 

Come to think of it, what is the rear end ratio? ('05 xkr)

 

Isn't 155 fast enough for you ? Most countries have speed limits, y'know.

 

The dealer computer can change the limiter settings although they may not do it due to liability. The limiter is set due to tire limitations. You would need som egood tires on there to get the limiter changed. I estimate the car could actually maintain closer to 165 with 3800 lbs, a Cx of 30 (and no ground effects) and 410 ft lbs of torque on a track, which is not a lot more. It would be a little scary to think people would consider driving 155 on public roads anywhere. The roads are not designed for it and most drivers cannot handle those speeds if anything happens. I am not sure about front end lift on the XKR, but it might be a good idea to check to see if another 10-20 mph might make the front too light for secure control. I know my 63 E type got so light in the front over 120 it was a handful to keep on the road. People used to ask how fast it would go and I would always say that anyone who owns an E type couldn't tell you this, they can't look at the speedometer then, too busy keeping the car under them.

 

not if you run the silver state race in nevada, the texas mile in,,,yeah texas, or bonneville in wendover utah

 

Curiously, in Texas old supercharged Porsche 928 5.0 32Vs do well in those runs. But people didn't run super exotics there last time I looked a few years ago.

 

That's probably because they want roll bars etc in cars they perceive as super fast and people with mega expensive exotics don't alter them. They also require they be entirely street legal keeping the race cars off it.

 

Can anyone tell the differential gear ratio for XKRs (mine is an 05)?

 

3.06 for 03-07 xkr's

 

Thank you for the gear ratio info!