Since our cars share the same driveline, I thought you STR boys might be interested to see how my XJR went down the quarter & on the dyno.

https://www.jaguarforums.com/forum/x...-my-xjr-96325/

I only want to post the link here, since not everyone looks in other model forums, so if mods want to lock this post up, feel free!

Cheers!

 

good info in there, thanks!

 

Can't speak for the mods but looks a worthwhile post to me!

 

Wonder how much you would gain if you modified the exhaust a bit... 108mph trap perhaps?

Consider water/meth injection kit to go with the 3lb pulley; I'm installing a meth injection kit now to go with the 3lb pulley I just installed over the weekend to compensate for the blower running so far outside its efficiency range...

Does the car launch much differently with the quaife?

Do you have a dyno read out of the torque curve (not the hp trace)?

Definitely a bit rich, but nothing outside the norm imo for a 'factory' tune, but indeed there could be power to be had by smoothing that .74 lambda up to .80 at least, maybe leave it richer around the torque peak,but by 5,000rpm i would be leaning it out .80-.82...

Consider playing with the idea of a MAPECU install, aussie tuning box, used it on several MAF equipped cars in the past to great success, I spoke with them a little while ago, confirmed working on at least another jag or two, 4.0L sc cars though, but can't see why it wouldn't work for us, could be worth it to help lean things out if you think it necessary,

 

I've posted the flywheel printout in the other thread which shows torque as well as HP.
Don't do lb.ft myself, the peak is ~550Nm at ~3700rpm, which sounds alright.

The cats/exhaust is a real unknown for me. Some of the claims out there are hard to believe, but my car does have an actual problem with one of the back boxes, so there must be something to gain. I will look into 100 cell cats & a new exhaust once the car is in Australia.

This was the first time I put the XJR down the strip, so I can't make a direct comparison with/without the Quaife. But there were two other XJR's there making similar mph, without LSD, and they were quite a way off on the 60ft times. But they were not doing burnouts to warm the tyres (not on purpose anyhow )

One other XJR with a Quaife there on the day, he wasn't doing a burnout either, but had super-soft Michelin Supersport tyres that hooked up without extra help, & only 0.1 slower than me for the 60ft.

I think the Quaife was making a difference, for the XJR's at least. The STR's always seem to launch better, i'm sure it's because they have coil springs, whereas we have the air suspension. An STR with standard diff did a 1.99 60ft on the day, without too much fuss.

Thanks for the lead on the MAPECU, i'll look into it.

 

Just bumping this one up, have a look at the thread in the X350 section, some interesting numbers on the dyno.

 

Thanks Cambo351