I just got a big upgrade to my charging system today… I’m pretty excited about the results. I replaced my original starter from 2001 with a remanufactured OEM starter from Toyota about 6 months ago, so I should be good in the starting/charging department for a long time.

My original 2001 80 Amp alternator finally started to crap out on me. It drained a new Interstate battery in two days, so I finally took the plunge for a serious upgrade. I always do a lot of research before I make big purchases for my 4Runner, so I like to share my results if I have a good outcome.

I decided on a DC Power 270-XP alternator. I opted for the rear billet aluminum for $75 extra so that the entire unit would have the same appearance and finish. I know that 270 Amps seems like overkill, but remember that 270 Amps occurs only at 8000 RPMs at optimum operating temperatures. At idle the true amperage is listed at 198. According to their chart amps can go as low as 127 in certain conditions, but that should be the absolute lowest output in any operating condition. I included a screenshot of the 270-XP performance test results (from the DC Power website) as photo #4 so you can review their data for yourself. My new alternator was delivered about 3 and a half weeks after my order was placed, so give yourself some time if you buy one of these. As you can probably see in the photos the 270-XP is almost a work of art when you look at it.

I already have an Odyssey battery holder installed, so I went with an Odyssey 34R AGM battery. This battery weighs 49.5 pounds and has 850 cold cranking amps.

To tie everything together I bought the thickest gauge wire set that JeepCables offered. The kit I purchased is specifically designed for 3rd Gen 4Runners. The Big 7 kit for 3rd Gens actually has 6 cables, not 7. I spoke to an experienced rep at the company to confirm that I had everything in the package. The cables are labeled on each and every end to make things easier for you or your mechanic. An exterior fuse attachment is included with four fuses with different amperage ratings. I mounted mine on the inside fender below the fuse box just a few inches back. You can see where I mounted this in photos #5 and #6. I installed the fuse holder by drilling 4 small holes and used the 300 amp fuse that was supplied.

My 4Runner drives great now. It is unreal how many issues can be tied to a weak link (or several weak links) in your charging system.

Although my electric fan is no longer installed, it is nice to have the extra amps at idle on hand. Allows one to run aftermarket lights, accessories, a booming stereo, etc. at night and not have your headlights go dim because the stock alternator is overwhelmed. 270 seems like a bit much but then again I don't know what you have installed.

What sort of warranty does the alternator and battery have? I'm about to replace my AGM battery, again, with something a bit more price efficient as the way I use my vehicle doesn't seem to suit AGM's very well.

Just a side note that the alternator pulley is much smaller than the crank pulley, which means that the alternator will be running at a speed much higher than the engine RPM. If it's say, 3 alternator rotations per crank rotation then you'd reach maximum output at 2666 engine RPM and minimum output at 410 engine RPM.

There is a 2-year warranty on the alternator and 3-year warranty on the battery.

I understand what you are saying about the smaller pulley size and RPMs. The DC Power 270-XP alternator uses the same size pulley for the 3rd Gen as the 80 amp alternator from the factory. I think that the DC Power performance data sheet that I posted refers to engine RPMs, not actual RPMs realized because of a smaller pulley.

DC Power also makes a 180 Amp alternator for the 3rd Gen.

With that big of an alternator I’m surprised you didn’t up the battery size too, like a group 27 or 31 battery?

I already had an Odyssey battery holder installed which was designed specifically for an Odyssey 34R AGM battery. I have had this battery before and was impressed. I’m not that familiar with Group 27 or Group 31 batteries. The Odyssey Group 34 battery holder is already a very tight fit. When I originally installed the battery holder I had to replace the plastic OEM coolant overflow tank with something narrower and longer.

One of the first things that I noticed with the new alternator was that it was impossible to brighten my headlights by pressing on the accelerator… my lights stay bright no matter what.

Yea, a 34 is shorter than a 24. A 27 is a longer 24 and our battery size is 24.


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I just always thought of electricity like water, so having a big alternator was like a huge faucet to fill up your water tank, and your battery was your tank that all your goodies drank from. So the bigger the tank the more stable the flow is.

The Odyssey 34 has a 62 ah rating, while the 31 has 92-98 ah. CBI has a tray & hold down bracket just for the 31 to fit in our rigs

How's this holding up? I'm going to be installing a winch, lights, the big 7 upgrade, and maybe some other electrical things here in the near future so i'm looking to upgrade my alternator. I'm leaning towards the DC Power 180 amp but could go up to the 270 amp if needed. What extra electrical stuff are you running with the 270amp?

When you upgrade your alternator make sure you size its pulley correctly. To low idle shaft speed and it won't charge your battery (as me how i know lol). It's a fine balance, at engine red line you can over spin your alternator so there is a bit of math. Also make sure your not creating 2 paths of power from the alternator, one to the oem fuse box and one to the battery. It needs to be one or the other but not both.

IIRC it's warned about in this thread:

Performing the "Big 3" Wiring Ugrade on a 3rd Gen T4R - A How To