Came across this video. Interesting match up. Both are modified but Jag appears to have more work done...

 

Jags making good power. The trans is the issue. Super sloppy shifts. What can be done to tighten up the shift points?

 

There’s a company the BMW 335i guys use called XHP. They cracked the TCU for the ZF6 in the BMWs and you can flash your trans like the ecu.

I had their stage 3 racing tune on my old 335i. Really pulls these ZF transmissions together.

I’ve often wondered if we could convince them to expand the platform to the Jags.

 

Sloppy shifts? Mine is very crisp whether at the redline or not .

Something is wrong if you experience "sloppy shifts".

 

Well, the Jag in that video had horrible shifts! nearly a full second to get that next gear! Sounded like a guy on a manual not knowing how to let the clutch out, and slipping it mercilessly.

(Although it had a nice exhaust note! I'm not sure I'd want that sound from that type of car, though. Rather gauche, intrudes on the elegance of the salon inside! )

 

My shifts are pretty damn quick. Tranny has about 50,000k on it but with new solenoids all of which I installed fairly recently.

With all my mods I probably have over 450 hp but thats a guess however I can put it down nicely with the LSD with limited wheel spin compared to no LSD.

 

Its definitely due for a trans flush and filter change. When I had my Xj8, I bought it with 99,000 miles and noticed the shifts weren't so crisp. Some were lazy, and some were hard. After the trans fluid change at like 105k miles, it felt brand new.

The Xjr is at 103K miles now. And makes a lot more power than the Xj8 did, especially on the nitrous pulls. I noticed recently its been a little rough shifting into reverse and down from 2nd to 1st. Ever since I got that larger thottlebody and ported intake a few months ago it feels like its slowly getting worse. I got this car with 56k miles and haven't done the flush. Trans just needs some TLC at this point.

It would be great if there was something out there that could tune the trans for these but seeing how complicated it is just to get an ECU tune, I doubt anyone offers anything for us.

On the first run, it might sound like the trans slipping but it was actually spinning the tires. 50 roll on a cool day with no LSD will cause that on the R888r's. We had been cruising for a while on the highway at that point and the IATs were nice and cool.

2nd run, I didn't know we were going again so soon. We had just finished the first pull and I hadn't let the car cool so I am sure it pulled timing and power. I wasn't in gear or anything, but chase is a race so I will take the L.

3rd run I called the guy and told him I had a bit of heat soak and I needed a minute of just cruising to get some air through the intercooler. After babying it for a bit, we did the 3rd pull. That was like a 70 roll (his choice, but worked for me so i wouldn't spin) and we were both ready for it. He honked and got the move. We both thought the runs went pretty much as expected.

No excuse for enough time to make a sandwich in between shifts. Hoping to address that here soon.

No nitrous on these pulls either. No need, really. Just a quick few pulls for fun on an empty highway.

 

I was referring to the video. Listen closely during upshifts.

 

thats my jag in the video.

 

I just figured that out. My fault and I replied to the wrong person.,

 

Jazzyjaggs whenever you get a chance could you post a video of a 50-110 pull from the drivers POV? I have a factory stock baseline video of me doing the same thing and am curious how much of a difference there is. As I start adding power I will take more video. Call it a poor mans dyno.

 

Yeah sure I will give it a shot. With or without spray?

 

No spray.

 

Here's one of the pulls that actually came out clearer on video. Might be able to get a little better than this when its cooler out, but its a good representation of a pull in normal weather (temp was low 70's). Seemed to be around 7.5 seconds to maybe a hair under 8 secs 50-110.

 

That’s awesome! Stock is 10 seconds or so. Your car really takes off after 90 mph. I’m still trying to figure out how to upload it from my iPhone.

 

did you need to tune for the nitrous? How big of a shot?

 

I do have a tune, but not for the nitrous. It would be best to have a tune but I get around it.

Its a 125 shot. The fuel nozzle I run is 2 nozzles higher than the recommended for the nitrous shot. I also blend the fuel, mixing just a bit of E85 in there and also a can of Boostane if I know I will be spraying within that fill up (if that makes sense).

I also had to do a few supporting mods, 2 step colder spark plugs with smaller gap. Lower temp T-stat. ... Make sure you have absolutely no vacuum leaks or misfires (plugs and coils need to be in good shape).

Normally on a nitrous tune, the tuner will take out some timing to avoid pre-detonation. Since I don't have that option, I just avoid spraying it when its cool out. When its colder, the ECU adds a bit more timing and power on its own. Usually the power it makes in cooler weather is enough to take care of business unless I am running against something way out of my league. Here in FL, though we don't get too many cool days, so I am able to spray it almost whenever I want as long as I added the Boostane.

I also have a nitrous purge, all the safety relays and also an air-to fuel gauge in the cabin that I watch like a hawk to make sure it wont run too lean.

Believe it or not, I rarely spray it though and I don't beat on the car as much as people would think. Its mainly a garage queen as my wife calls it. And If I take it out, most of the time it will be for a nice clean and cruise or maybe take it once a week to work if the weather is nice.