OK @gregma , here is an overly long post with everything I think about driving it!
After a week of driving the car, here is an update and some driving impressions. The short of it is that the manual transmission completely changed the personality of the car, more so than I expected. It continues to perform well with zero issues. If you like manual transmissions and you are NOT planning on converting your XJS, you maybe shouldn’t drive one that is a v12 manual 
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Overall:
The car feels lighter and nimbler. I think this is because you can “go quicker” thru the gears while working the engine less. It is effortless to run every shift up to 3000+ RPM and do a nice smooth shift. With the TH400 I always felt I was flogging it a bit to make it perform, now it feels like it’s not even working. As with any manual vs. the older autos, having the engine directly hooked to the driveline (no torque converter) means that you feel exactly what is going on. It is a very connected feeling that I never had before in the XJS. It is very easy to drive, I immediately felt very confident with it. There is no weirdness to the way it shifts or handles. The car has gone from being a power cruiser to something closer to a sports car. Dipping a bit into the psychology, the driving experience is more focused, because there is more to keep track of. I have almost always driven manual transmission cars; but this is the first time I have taken a car that I drove a lot as an auto and converted it to a manual. The change in personality of the car, for the better, really surprised me. My expectations were exceeded. We took it out tonight and Rene’ drove it for the first time, she absolutely loves it. I was a little worried about shifter effort and placement, she said they are perfect for her. She handled the manual like she’d been driving the car for weeks, not minutes. She’s a good driver and good with a manual, but this is also a testament to how naturally a 5-speed pairs with the V12 XJS.
One additional very nice benefit is that the coolant temps are consistently about 10d cooler in both city and highway driving. Since nothing related to the cooling system was changed, this must be due to the combination of a few things:
- The engine is operating at less load / more efficiently. Around town I can select the gear that keeps it in the most efficient powerband, it’s not wasting effort churning ATF in the torque converter
- Lower RPM at cruise, on the freeway, I am at about 2100 rpm at 80mph vs. 3000+ before with the TH400
- The radiator no longer must also cool the trans fluid (OK I guess this is technically a cooling system change…)
Ergonomics:
For reference, I am 6’3”, 215lbs, size 13 feet. I have always had to drive the car with the seat a bit reclined. I have on my someday-list to re-engineer things to allow the seat to slide back a couple more inches, but it really doesn’t bother me.
The short shifter stick (6”) means that the shift effort is a bit high. I think it will loosen up a little with time, but it will never be OEM-light. Shifts are rock solid, no squishiness at all. At this point I don’t even think about it, and Rene’ had zero complaints. A longer shifter stick would help, but…
…the shifter location is perfect for me (and Rene’, as it turns out. She’s 5’7”.) I rest my arm on the console and the shifter is right there. Couldn’t be better. I do need to get rid of the cell phone hole in the console lid. It’s annoying. I have a new console lid, with no cell phone hole, out to Paul’s Jag for a recover. For now, I have a piece of foam stuffed in the cavity.
The top of the shifter ball travels 2 7/8” fore to aft, which feels like a fairly short throw. I kind of shift it with my wrist.
Clutch pedal effort is in line with a modern performance car. It feels about like my 2016 Mustang. Clutch pedal height is even with the brake pedal. Release point is about ¼ to 1/3 of the way off the floor, so you can modulate with your heel against the floor. That’s how I like it. There is no change in pedal pressure or sensation at the release point, which initially was weird for me. I kept trying to “feel” when the clutch would engage. After some wheel time I know where the release point is. Just as I come off the floor, I feed it some throttle and it’s right there.
I have to splay my knees just a bit to clear the steering wheel and run the clutch and brake, but I don’t really think about it. Someday I may look at a smaller diameter steering wheel, which would make ingress and egress a bit easier. Both are more difficult than with the auto, gotta put my big feet under the pedals as I fold myself in.
Heel-toe downshifts are a little awkward, a larger, flatter throttle pedal would help. Also on the someday list is a dead pedal. There isn’t quite enough room for my shoe between the clutch and the left kick panel, so I cock my foot just a little to put it underneath when there is not any shifting to be done. Maybe I will look at a dead pedal when I have the kick panel out to run speaker wires. Rene’ did comment that the clutch pedal felt a bit to the left for her taste. I wouldn’t want it any further to the right. Agree to disagree.
Bottom line is the controls are easy and comfortable to operate. Zero concerns, and frankly better than I expected. Sitting in the driver’s seat everything feels right. My Mustang has Recaro seats and is stupid-comfortable, it’s the gold standard for me. For me to be this happy with the Jag is saying something.
Drivability:
The aluminum flywheel means that the engine gains and drops RPM very quickly. On shifts, the RPMs drop like a rock when you lift, so I like to keep the RPMs up with a little throttle pressure.
(Dad actually swapped his Fidanza flywheel for an OEM Jag unit that weighs a lot more because he did not care for this behavior in the carbureted eType. It also makes standing starts a bit easier.)
I am glad I got the ECU mods done; I can totally see how ECU cutting fuel injection on closed-throttle (standard on the auto trans) would cause stalling.
Warm up idle speed, courtesy of the AAV, is up from about 1000rpm before to about 1100 now. No torque converter drag, I guess.
On the very first drive I got some significant clutch chatter, which quickly went away. You can see in post #119 that the flywheel has some sort of green protective coating on it. I think once that wore off all was good.
Standing starts require just a bit of finesse to be really smooth. Nothing unreasonable, it’s just a matter of learning what the car wants, like you would with any manual. Managing the release point by pedal position vs. by feel makes things easier. I pride myself on being “above average” with a manual, so I am pretty self-deprecating when I don’t do it right. Being a passenger when the driver doesn’t really “get” how the manual trans works is no fun. Rene’ won’t put up with that crap, we’ll be switching seats so she can demonstrate the proper technique .
Performance:
Gears 1-4 feel close ratio, although numerically they are not. I think it’s mostly due to the v12 feeling effortless from 2500 RPM and 5500 RPM and beyond, it’s equally smooth and happy to work anywhere in that range. Leave the light, shift shift and you’re going 65 MPH… wait this is a 45 zone… It’s a constant, spirited acceleration. Passengers say “I can’t believe how smooth this is …”
Acceleration is quite good. I didn’t take any 0-60 times because frankly I am not going to beat the car that hard. More useful acceleration, say from 60-80 in 3rd gear, is very good and very satisfying. It’s interesting (and fun) how you think you are pulling hard and as the tach goes past about 4000 it pulls even harder. You are going fast with minimal drama before you know it.
Approximate speeds at 2500 rpm:
1st: 18mph
2nd: 28mph
3rd: 40mph
4th: 54mph
5th: 85mph
NVH (Noise, vibration, harshness)
The trans has some gear whine. Not excessive, and it’s what I expected, but it’s not silent. It will get a bit quieter as it breaks in. It sounds like every other T5 I’ve been around. In the lower gears it almost sounds like an electric motor spooling up.
You can feel a bit of road vibration thru the shifter, again, not excessive. The shifter does move a little over bumps and uneven roads, which is good. That tells me the trans mount is working. My exhaust is a bit louder than stock, and it of course sounds much better shifting at 3500 RPM every time than the lower shifts of the old setup.
So far, at least up to 100mph, I have not detected any high-frequency vibrations, and the pinon seems quiet, which is good. My seal change apparently didn’t muck anything up. Very smooth at higher speed.
This car has GAZ adjustable shocks, set at 3 out of 20 for stiffness, which puts them about 10% stiffer than stock per the butt-o-meter (20 is the max setting.) Any stiffer is just annoying and feels wrong with the stock springs. It also has poly bushes on the front sway bar links. This combo feels good with this trans, the “firmness and feel” of everything seems to match up well. I think the car wallows less in the corners. That should be the case with the reduced weight. Having said all that, I don’t beat the car. I try to drive in what I would call a “smooth and spirited” manner, not harsh or aggressive.
That was a lot, thank you for reading this far! If I haven’t made it clear already, this conversion was well worth it. It’s like I have a new car. I want to drive it all the time.
