How to swap a high amp Dodge Durango alternator into your Jeep Wrangler TJ
- Thread starter Chris
- Start date
The 65 Farad ones are often used for OEM starting purposes, especially in hybrid vehicles or vehicles with auto stop-start. Doesn't store much energy in total, but can spin a 3kW starter for a half-second without any noticeable voltage drop. You still need a battery to store energy, but the capacitor provides the pulses that would otherwise shorten the life of the battery.
The 500-farad ones are used for similar purposes in large commercial vehicles, like CNG/Propane or diesel vehicles.
I installed the remy alternator mentioned above, but kept the pulley that comes with it. Was i supposed to replace to pulley? Was it a must?
I do see that the belt seems to be little more stretched, so I am worried that maybe the Remy pulley is too large
Did the number of ribs on the pulley match?
If it were me I would pull the alt you just installed and switch the pulley, just to be sure. I don't know a lot about alternators, but if the pulley is larger it'll mean the alternator spins less, so you're going to have lower output. I imagine it creates more resistance and drag on the engine as well.
It was a bit of a hassle to swap the pulley that came on the Durango junkyard alt I installed, but it wasn't terrible.
I would check the diameter of the pulleys, then decide if it's worth changing. I switched over to a Durango alternator and didn't notice a difference. Worst case, it shouldn't be difficult to find a belt that is slightly larger.
Wasn't the pulley on yours the wrong number of ribs? I just did the Durango swap a few weeks ago and there was an extra rib.
I don't recall having an extra rib or changing the pulley.
Here's the link to what I've been running since 2021 (it was $125 then). The product photo matches the rib count on my current pulley and has the same finish (pretty sure my stock alternator's pulley was aged by comparison).
As long as the tensioner isn't bottoming out, it should be fine. However, I do recommend using the smaller stock TJ pulley so you can get the full power out of the alternator. The pulley is larger in the V8 as the redline in that engine is closer to 6,000 RPM. Since the TJ doesn't rev as high, it uses a smaller pulley to obtain the same maximum alternator RPM.
The 03-06 Liberty uses the same alternator and its typical range appears to be 1650-2300.
I don’t imagine the pulley is that much smaller considering I didn’t have to change belts and my voltage reading is fine.
Additionally, the same car charger that took days to charge my friends F-350 was fully charged on my rig in less than two hours, and I haven’t had an issue since the 2021 install.
I don’t see a practical problem, but maybe swapping pulleys gains you more amperage that I’ve yet to need.
Do you know what the amperage rating is on that one?
Not a bad price for a 160 amp if the alternator is decent quality. Just to get in the 200s you have to spend $300+.
You'll notice any diminished output at idle rather than when you're moving. If you aren't experiencing headlight dimming at idle (you can turn your AC on and off to test) then you'll likely be fine, as the other folks on here are saying it won't hurt your serpentine belt. I worry more about voltage and amperage usage at idle because I'm running a big stereo, but for those just running aftermarket lights and such it's less of a concern.
If you're running a winch it's good to have higher output at idle, and in that case it may be worth changing the pulley.
I'm interested in one of those clutch pulleys for mine.
160 amp (same alternator from the Amazon link)
That's how I felt and it's worked well for almost three years and counting.
FWIW, I've aired up my tires with an ARB compressor with the lights on and system blasting many times. No lights blinking under those conditions. Haven't tested the winch under heavy load but the few times I used it there were zero issues.
Sounds like you have the perfect amperage for your needs. I'll probably give that one a try, just couldn't pass up on 136 amps for $30 at the junkyard. Once I get this misfire figured out I'll be able to test and see if it holds up with what I'm rocking now.
They should both be 6-rib pulleys. The difference is the outer diameter. Since the crank pulley on the TJ is smaller than the Durango, the larger alternator pulley just means the alternator doesn't spin as fast as it would in the Durango at the same engine RPM. No real problems, just reduced idle and low RPM output. Might actually save a slight amount of fuel due to less bearing friction loss.
The only hazard would be if the belt tensioner is maxed out in its travel, which could result in a snapped belt.
The only hazard would be if the belt tensioner is maxed out in its travel, which could result in a snapped belt.
Right? Tested it at an auto parts shop and it came back as fully functional, so I was pretty stoked. It also fixed my O2 sensor problem, which was unexpected but appreciated.
Would you be willing to measure the outside diameter of the rib edges? I’ll measure mine and we can compare lol
