my question is back in highschool my shop teacher said that newer cars and cars ahead of there time had engine and transmission comp that whould record the first 25 times the car was driven and record how much power was applied from a stop to accelerate and then adjust the computer to only allow so much to be available from a dead stop regardless of how much the car has. so if you drove a fast car like a grandma then even though it has over so many horse power then it still will be dog off the line and then pick up further on. i dont know if this is true but if so can the computer be reset or can the program be erased. over 40mph i can take most cars i try but from a stop those cars i beat from a roll kill me. if anyone knowes please help me. i love my car but am embarassed when i have my friends in the car and i cant even get up to speed with the throttle wide open off the line but further down the road i can get from 50-120 like in the time it takes to get from 0-40mph.

 

So how did you figure out you have a 3.54:1 diff in an XJ8? You don't, but yuo'd be pretty happy if one existed so you could bolt it in.

 

being a jag tech you should know it all. is there something as stupid as the computer limiting power from a dead stop when accelarating. and are there any other gears out there for the xj8. everything else is fine has more than enough power but wont move untill over 40mph

 

I'd be an idiot if I thought I knew it all, not a Jag tech.

 

That sounds a little hard to believe to tell you the truth. You would think the first 25 times a car is driven the driver would be taking it easy anyway. You could always disconnect the battery overnight and then take it out for a blast on the highway, but if it's a euro spec you would need to reset the radio codes and the trip computer would get reset to zero. Strangely enough when I disconnect my battery to clean the terminals my radio presets were still there when I hooked the batt back up. Have you tried it in "sport mode" with the trac off ? The traction control will make it accelerate like a dog if it senses the slightest amount of wheel spin. I believe there is a speed limiter though, but that dooesn't kick in until 158 mph, and I haven't attempted that yet.

 

i didnt hold much faith in that either. i wouldnt kick the **** out of a car from day one unless i was trading it in on day 2 or 3. but i drive in sport mode all the time and traction controle off. i hat when it kicks on in the rain and stupid regular driving conditions. if im doing 35-40mph it picks up and hauls mainly because its in the top of first gear but as far as of the line it takes its sweet time. im just tryin to figure it out. it should run 15 flat and it runs high 15s. i did a full tuneup when i purchased it. spark plugs, coils, wires, air filter, fuel filter, fuel pump, coolant flush, transmission flush and filter. brand new pirellies get awsome traction, and it only has 57,000mi driven by an elderly gentlemen. i dont want it to be a racecar but would like it to move in the mid 14s.