Mechman alternator

Before turbo bricks was down I posted a thread about aftermarket alternator mounting on a B230 and someone replied with a 240 amp mechman alternator on their car. Since my post wasn't saved I can't go back to see that thread. Anyone have an aftermarket alternator on their B230?

Mechman 170A in my 740, stock location.

Did you have to do any modifications to make it fit? Which alternator model was it? And do you have any pictures?

No pictures off-hand. Given it was spec'd for the vehicle, don't recall that they are doing them anymore it, the only thing I had to grind a little on was the adjuster, simply due to case size. That was supposed to have been fixed on future versions I believe, not sure if that is the case now or not. It was built around a DR44 alternator, with a different housing.

I have this GM/denso 150 amp hairpin alternator in my volvo 240. https://www.rockauto.com/en/moreinfo.php?pk=8767592&cc=3441540&pt=2412
In hindsight, it is quite a bodge job install as it needed more than a little work to fit:

• The pulley needs to be swapped to a v-belt pulley.
• The mount holes in the ears are M10 so they needed bushings pressed in to be able to use 240 M8 alternator mount hardware.
• The long swivel bolt on the lower alt mount needed a bit of washers to space the alt correctly in line with the belts.
• The upper/adjuster bolt needed to be replaced with a longer one to go all the way through the mount and tensioner hardware at the top ear of the alt.
• The output terminal is further from the stock position, so a non-stock charge cable will be needed. Should upgrade that anyway with twice the output from stock.

It needs a rev to ~1300 rpm to excite, but I think that is due to my underdrive setup, it may not be necessary stock. Rock solid power from idle to redline. Also the voltage output is adjustable with a 128hz pwm signal to one of the pins, 12.5v-15.5v. 13.8v stock.



I am also pretty confident this 220 amp hairpin would fit with the same amount of work. Though the case is slightly bigger than the 150a. https://www.rockauto.com/en/moreinfo.php?pk=8767580&cc=3441540&pt=2412&jsn=915

I'm wondering if there are diode packs with higher output that fit into the 100amp denso case? I don't need a whole lot more but about 120 to 130 amps would be just right.

Dave has some great info on his site: https://www.240turbo.com/alternators.html

dl242gt said:

I'm wondering if there are diode packs with higher output that fit into the 100amp denso case? I don't need a whole lot more but about 120 to 130 amps would be just right.

Click to expand...

^ Yes, but the versions of the higher output rectifier are often setup for ECU control &/or external temp sensor (not a bad thing in the 240 location, really ).
Start opening hoods & taking apart alts on the mopars & toyotas in the junkyard & taking them home to your test bench to figure out how they work/what's compatible?...

That said, I'm not convinced that even in perfect shape there's more than the ~70A @ idle available from the stock Denso 100A (best of the OE alts used in the Volvo) @ idle from the Denso in belt traction even with the OEM 9.5mm wide Volvo/Roulands Denmark dual belts with good traction.

Conti makes quality stuff, but I don't get as good grip out of the conti 10mm width sold as direct fit drop-in for the same belt tension? IDK? Slightly different taper/grips the pulley a little better on the Volvo/Roulands metric?? (instead of 10mm/3/8" nominal sold in the american market???) belts???

Maybe with a more efficient 3-phase brushless setup with a controller &/or serp belt that really wraps the pulley almost all the way around there's sufficient belt traction, but more complicated/involved conversion & time/ $$$/1-off thing without drop-in replaceable/recombinable pre-chinesium junkyard parts held to stringent OEM high volume & implied quality control warranty/class action lawsuit/critical application standards of manufacture?...

The hi-amp conventional-design alt is less efficient under partial load with more drag & less precise battery charging (more minimal slow gentle trickle charging for longer battery life, potentially?), anyway (may be no big deal/good battery live anyways? in a mild climate like OR coast/sea level, CA or NV?)? Low atmospheric pressure/super dry & extreme day/night hot/cold like high-desert AZ with tons of UV sure does a number on batteries? BRUTAL! In 60 degree/60% humidty mild San Francisco coast batteries can last basically forever if you don't take all short trips...
There's always a compromise & unintended consequences to account for...

Denso has been the most reliable easy to repair alternators I've had for the 240. They have a slightly smaller pulley so it's good to use the 918 long belts instead of 925mm. So far when they have failed on me. It has always been the regulator failing. Sometimes the brushes are worn out. The bearings have lasted and lasted. Good stuff.

I have a 6 phase hairpin stator 240 amp mechman on my wagon on a b230f+t .It?s the red one I think I posted on your thread. I have it mounted on the lower driver side mount I had minor modifications to be perfect. Never slipped once in 7 months. Knock on wood. It?s in my build thread I believe

There's the guy! I cant find it on your profile though.