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Sounds like it has power on crank but not run. Does it sound like it just sputters out?

Here is an output printout of a new 90a HO alternator. It would stand to reason that, at idle with all accessories running, a 90a alternator is not up to the task.

Yeah check them out. Also keep in mind that drilled and slotted rotors offer less pad contact area and typically reduced stopping power. Conversely, they are superior in high performance applications where over heating is common. They can also combat brake fade. But if this is a normal daily driver, a good set of centric pads rotors, calipers and some black magic pads is the way to go.

Only big brake setup for 15’s is the Vanco setup as far as I know. Blaine at black magic brakes sells them. He also sells the best stock brake components available for the 90+ knuckles.

Just a note in the HO FI system. Contrary to popular belief, it is completely tuneable. It can be socketed with a flashable eprom and setup for pretty much anything. There are several people who offer the service or you can diy. For Jeep specific tubing of the sbec2 controller (91-95 HO Jeeps) Reach out to Chris at christuned.

Not personally but if it’s prepped well it should hold up just fine. We used to use JB weld to seal up cooling ports on the 4.0 head when installing them on a 4.2 block

Yes it does

Agree with all the above. A cowl intake is noisy but does offer some noticeable gains. Also, look into stand alone efi. I’ve run Holley efi with great success.

That makes sense. I would think the fuel pump would be at least 5a also. Ac clutch has got to be a bit of a draw also. AC on idling in traffic and there is definitely a significant voltage drop on a 90a alternator. Those FF dynamics fans need a solid 14+ volts to keep temps in check. I have a singer 270a alternator I’m sending in for a rebuild but I seriously considering switching back to a mech fan setup. The ff system was a big investment to just dump though.

If that’s the case then no accessories would run at full alternator voltage (~14.25a). The alternator needs to be able to handle the full load of all accessories. That’s why it goes directly to the PDC I believe but perhaps I am mistaken

Replies posted in the quotes above. I’ll try to edit them to make them stand out better

99+ intake is the best flowing electric vacuum pump pulls a lot of amps. Think hydroboost or stay conservative with the cam specs for good vacuum

Any thoughts here guys?

Agreed. The info above is assuming that you have a good running truck that has been properly maintained all its life.

For parts, most xj cherokee front lifts will fit. There are few complete kits for the MJ available so you’ll have to likely source the lift for the rear. The rear uses a longer leaf springs than the Cherokee and the springs run under the axle. If you convert the springs to ride over the axle (known as soa) then you will gain approx 5.5” of lift in the rear. If your looking for 2-4.5” you could go with either an add a leaf setup (adding a new leaf your your rear spring pack to provide more lift) or you could go with an aftermarket leaf spring pack which replaces the whole spring and provides the needed lift. SD truck springs makes an HD 5 leaf sparing pack that will give about 2.5” of lift to a stock truck. Hells Creek off-road makes springs in the 4-4.5” variety iirc.

Welcome aboard. There are so many different ways to go with the build. If your looking to build an off-road or trail rig then a long bed is always a bit of a pain to work with. I always like the idea of a long bed 2wd towing rig. That was the real “work” truck model. But with time and money you could build anything you want. A mild 2” lift will let you run 31” tires. 4.5 would be decent for 33” tires.

Lots of people use beehive LS springs. If you have a decent machine shop that can machine the spring pockets and do the valve you might want to consider going with LS parts. LS valve are also 8mm and come in a huge variety of sizes and materials. I went with a complete Edelbrock head and have no regrets. The updated chamber design is quite nice and the springs are good for pretty much any cam you can throw at it. The issues I have with the comp cams setup is the vacuum at idle which will lead to inadequate brake booster respond. Also, they use a very narrow lobe which is more prone to wear. They are probably 35% narrower than the oem cam and have far less lifter contact. The Mopar 2229 cam is also a nice options for a mid rpm build. Most of these cams though will loose vacuum. On my last stroker build I went with a hydroboost brake setup to get the brake performance back.

I’d recommend reaching out to Russ Pottenger at Buehler racing. He can hook you up with the best cam and spring setup for your engine. He is the man when it comes to these builds. Here is his email: russbnbracing@yahoo.com

Going to tag @Minuit here since he’s one of our electrical gurus (I’m sure there are others as well). Wanted to discuss the actual current draw and charging system of the HO MJ’s/XJ’s. Not sure how much they have in common with the renix era stuff but the principles are the same. Alternator: when it comes to the current output, alternators are typically rated at a specific engine rpm (~2500) and a specific voltage. I’m no expert in this field and am mostly self taught from tinkering with electronics. But from what I have learned, as voltage decreases amp draw increases to maintain the same accessory output (eg electric fan). So let’s say a 90a alternator is only putting out somewhere around ~50a when idling. The HO charging system runs from the alternator to the pdc on an 8awg cable that has a splice to 2 8wag cables that enter the pdc. It then goes to 2 different 60a fuses and on to the fuse buss bar. The battery is connected to the opposite end of the pdc via the two stud posts. This is how the battery is charged on the stock system. And how it provides power to the pdc when the engine isn’t running. Now on to my issues (and I suspect many of you have had or will have similar issues). I run a FF dynamics triple 10 fan setup with shrouds. This is an overpriced crap system. Amp draw for each fan is 5a while running but startup is about 35-40a. Max cfm is 900 cfm but that’s at 14.4v and you will rarely see that kind of voltage at idle with that much current draw. So let’s tally this up (and this is where I need your expertise) Fuel Pump draw: ? Ecu draw: ? Lighting draw: ? Fan draw: ? TCU draw: ? AC clutch draw: ? HVAC blower draw: ? I'm sure there are many other items. My point being, I don’t think that 50a at idle is nearly enough to power everything. Thoughts?

Cuz electric fans suck

Looking for the stock mechanical fan and shroud in good condition. I can get the shroud new online if needed but if you have a good oem one it would probably fit better in the same box. Any xj or mj 4.0 fan should work thanks

So what’s the verdict on what model sender these are? I need one for my 91

84-96 XJ’s with some exceptions. Seats changed in 95 I believe. Also, xj seats will require the mj bucket seat brackets to mount. Some of the interior trim such as b pillar, drivers kick panel, and door sill trim are mj unique

Very good to know. I just may have to add one to my next order lol

Dirtbound has the cad drawings for Keusty’s right? Has anyone asked them what the plan is?