Woohoo, I think I built a pretty awesome little vehicle. I got to spend the last couple of hours of daylight test driving the jeep. night and day better than the NA benz XJ. The exhaust got finished up after lunch, but there were a few hickups that mostly got sorted out when I got there. Got a state inspection sticker; then started driving. Backed out the rack limit 1.5 turns, it made a big difference, I think I have some more to go there. I seem to be running very cool temps, I got the EGT up to about 1000, and the max boost I saw was about 14psi
A couple of notes on driving the AX15. the 1-2 gears are a bit too close, and the 3.53 rear end is pretty low. The jeep has no problem hitting 65mph as it sits. I still need to get it intercooled. Alternator is charging well, power steering works great, power brakes work great as well. accelerator foot pressure is very acceptable.
The only bad so far is it is pretty noisy. the SE Cherokee trim package has no underhood sound insulation. Now that the exhaust is closed up. The diesel clatter really comes thru. AND there is a maybe not normal sound/clatter that goes away when I depress the clutch... from low idle to about 1100 rpm you can hear this extra clatter that goes away when the clutch is depressed. With the clutch depressed The noise goes away and the engine seems to sound more normal. This is pretty concerning, and I really don't know what it could be. I will try and post youtube video sound link tomorrow.
I don't have a history on this transmission, I only got to drive this trans for maybe a mile or two before I pulled it from the donor. I will try an find the source of the noise tomorrow, it could be just some loose piece of hardware or wiring . I will keep driving and putting on the miles. So far 10 miles. It really is a pretty nice drive
I need to find the reverse light switch on the AX15 and get it hooked up to the correct harness wires

This thread seems to be close to finishing

 

My AX-15 clatters pretty loudly in neutral at idle. The sound is very similar to a Ducati dry clutch, and is especially evident when right next to a building, like waiting in a drive through.

 

Hey Red, Thanks. I just got in from some driving, I can't find anything wrong. I guess I am just going to run it and wait and see. I took another .5 turns off the rack , making even more boost now. The speedometer error is significant I thought I was really speeding, my gps speedometer shows a 7mph difference at just 30mph.
At what point does too much rack negatively impact fuel economy? Today I am out 2 full turns from how I got it.
Still no luck on figuring out a intercooler to fit up front . it would be really easy if I it weren't for the Aircon. I have lots of room to move the radiator aft, Not so easy to move the Aircon condenser. I checked into getting some custom Aircon hoses made, that may be the answer. I want to try and put a joggle in the OE aircon hoses, but that seems destined for failure. At least it is winter time and I won't need the aircon for a while. But it is a shame to wreck the working Aircon after I spent so much effort to keep the working system intact throughout the conversion.
Does anyone have any other resources to look for an Air to Air intercooler. From what I have seen CX racing has the best selection, and Mishimoto is ok , but not so easy to find the specs.
I got the vacuum hooked up to the climate controls, so I have heat. Still working on the reverse lights. Next is a big 12 mile round trip to the gas station.

 

The rack limit screw is just potential, it just allows you to use more fuel and put out more power. The same constant load will always use the same amount of fuel. The difference would be when doing more work than it could do at the previous limit, so accelerating harder, pulling hills at faster speed, etc.

Here's a good explanation of the gear lash neutral noise. The same thing happens with a gas engine fitted with a lightened flywheel.
UUC * TECH TIP: What causes gearbox rattle / rollover noise?

 

Thanks again Red, that was a good write up. FTE said you might be using the OE intake air temp???? I can use mine but only read it from the OBD reader. Did you manage a air temp gauge?
I had a minor fiasco. I was drilling my non permanent intake piping to put the jeep OE 3/8" pipe IAT sensor In the charge air pipe, and I guess it was too cold outside because the pipe cracked , to add insult to injury when I was making a new pipe set, I spilled my ABS glue all over my cylinder head, nice mess there.
still no luck finding a intercooler. I want to try and move my Aircon condenser coil a inch or too aft, I don't have a lot of space in front on the XJ.

 

I use a bluetooth OBD2 adapter and Torque Pro on a tablet to read IAT.




I'm not sure if ABS will work for a charge pipe, it melts around 212* and starts to get soft well before that. I used it for a few days as a temporary bandaid at one point and it was very warped when I took it off. Maybe someone else has had better luck with it though?

 

my first Air pipe only temporary was regular PVC, it held up pretty well for the first 10 miles. I switched to the ABS for the extra temp tolerance it should have. My water temps have barely hit 140 I think with the recent cold. I really wanted to wait until I got my intercooler installed before I build the permanent charge air pipe.
I got two IAT's hooked up today. one from the Glow shift 3 in 1 ( not so great as it is a liquid sensor), and the OE jeep IAT reading thru the OBDII reader.
It will be nice to not get filthy dirty today. but not for long. I discovered I still have a very small fuel leak somewhere near my filter housing. And I have not figured out how to clean up the ABS cement that spilled all over the cyl head. I was hoping the engine was greasy/dirty enough that it would harden and not stick, NO SUCH LUCK, That crap is everywhere and it is stuck, and it took the paint off the engine as well. I think the only thing I can do is let it burn off ( Doubtful) or take the top accessory section turbo, charge pipe, all the temp and pressure senders off, and then maybe either sand blast it or solvent wash. That crap got in all the little nooks and crannies around the injectors and head bolts, pretty big mess.
I want to go for a longer drive this afternoon to see some better hiway speeds .

I took a video today, but it is playing very jerky. the pic is what it looks like now. I still have not cut the excess wiring out. I am not sure I want to cut it just yet. I cut the MB XJ, and had no regrets there, but this is a much nicer jeep
I am still looking for some sort of 2.5" to 2.75" thick intercooler

 

little update the jeep is running well we did a 55 mile hiway road test. apparent MPG is 28 at 65mph and about 2250 rpm. I am not sure I was completely full fuel when I started. I was using a gps speedo on my phone which does not seem to be very accurate either. The installed speedometer is way off.
Still pretty loud, but no mechanical problems, I have some vibrations to sort out at several frequencies, it all smooths out pretty well at about 2400 rpm, but that will not yield very good MPG. I think I may know what FTE is talking about the wrong motor mounts. Or it very well could be that the XJ unibody is just different than body on frame. I need to have someone driving while I work around to try and find the stuff that is vibrating. I think something inside the glove box area is making a fair amount of noise, and my knee kick panel I think is noisy as well.
The air temps were in the mid 40's all day, and the coolant never got above about 155I am still not running a fan of any kind. The jeep OE IAT was showing higher than I thought they would be, almost 100 degree temp rise over ambient at hiway speed, and the Glow shift temp sender is showing 20 deg lower than the jeep IAT, and the sensors are about an inch apart. Solution I really need an intercooler
The specs were --
speed 65mph, rpm 2200-2250, boost 6-7#, EGT 780-850 ish, IAT about 140-145, coolant 145.
speed 70mph rpm 2420, boost 7.75#, egt 784, & IAT 155
max boost accelerating in 5th gear before I let up at 1150egt was about 20#'s. It is difficult to take the readings especially without cruise control. And the values I got in the real world are pretty far off from what the gear ratio/rpm calculators predict The accel pedal effort is ok , but it will be nice with cruise control
pretty fun to drive, maybe the fun screw ( rack limit ) is too far out and that Is why my mpg were not so great
tomorrow I will look to prep the 3.07 rear axle to go in. That should put the speedo back to correct reading,
I talked to a friend of mine that tried to assure me that moving the Aircon condenser and getting custom aircon hoses would not cause me long term grief. I am still not sure about that. I put in a lot of effort to keep that aircon hooked up working and unmolested. I would really need to move the radiator and the condenser to get a good intercooler install.

 

Just curious. Are you still running the carrier t-stat or a hotter 1. I know I could only get mine to warm up to about 150 and my heat sucked. If I turned it on high I could watch my temp guage drop. It will run and perform alot better when it at full operating temp I think I had a 190 degree in mine

 

Hi Rangmar, Yes I am still running the carrier t-stat. for several reasons. Don't forget I am in S. Texas. I had to turn the heater half way off this afternoon. Yes it does not get that hot, but down here we really don't need that much heat. I am much more concerned about losing my aircon when I move the radiator and condenser to fit a intercooler.
The other reasons are, These first runs I don't have any cooling fan installed at all; and I wanted to see how it would go. On my MB XJ when I first put it together it ran pretty hot 200F, and it kept blowing the radiator hose adapters apart. Next. without the intercooler I wanted the under hood temps to be as low as possible. When I really had my foot in it this afternoon the IAT was going up in the 170 range.
I am curious though. all literature and opinion shows that a not hot enough engine is not good. Funny, but down here, I have spent most of my life trying to keep engines from getting too hot, so it just goes against my experience to try and make one run hotter. The XJ's with the 4.0l are some of the worst hot runners down here. I was always having trouble keeping my 4wd XJ cool.
So with all that said and listening to others on this forums experience, I am willing to give a hotter T-stat a try. If the engine is not running hotter than the t-stat now, that means I finally have a vehicle with a big enough radiator. So I guess it makes sense that if it will hold 150 on a cold thermostat, I hope it will hold 190 with a hotter thermostat. FTE gave me a part # for a hotter t-stat I just need to go get one. I will probably have the cooling system opened up soon anyway

I am going to get one of those blue tooth OBDII readers like Red's got. I figured I can just get 2 more jeep IAT sensors, and wire them all up on a 3 way switch. Then I can have under hood pre turbo Intake temp, pre-intercooler temp and after intercooler temp. Plus I can hook up the OE MAP sensor and I will have 2 boost gauges.
I am sorry to report that the 3-1 glowshift gauge is not that great. I thought I had broken it trying to mount it and get the gauge to stay in its fairing cup, and the dimmer section does not seem to work. it changes a bunch of colors, but it won't dim, Yet?

OK tomorrow I really need to figure out the intercooler, I guess I will move the Aircon condenser and if it leaks out I will deal with it before summer