Denso or Bosch from the efan oe redblock volvos works well on the mechanical fan 240 to run the a/c pusher fan and couple other bits.
Short of replacing the wiring & belt drive system, even if you leave the mech fan if you want A/C, no real way to increase the amps beyond that anyway.
I honestly think, even with perfect rubber accessory bushings/better washers or bracket and OE Volvo/Roulands belts that really grip that are near brand new, that it's not *really* possible to get more than ~68A idlin (max I could get out of the denso idling...the bosch 100A you can get ~50A on the Volvo pullies idling) outta *at best* ~66% efficient alt (even with a relatively efficient full bridge rectifier...yea, right
) at perfect belt tension that somehow magically adjusts tension for temp/humidity more than that ~1-2HP off those 2 V-belts wrapped such as they are without destroying the bearings in the engine/alt or waterpump or impacting fuel economy or belt life absurdly adversely, even if the clutch fan isn't fully locked & the water pump isn't spinning all that fast on the larger pulley or breaking the bracket with the heater valve open/normalish use.
I was spinning it on a socket on the 2hp drill press and measuring the draw on my kill-a-watt @ ~B21/B23 @ 900RPM idle and smaller pulley than the B230...even the denso drawing ~70A & torque required is drawing ~1.2-1.5KW on the drill press' motor! IDK how you plan to apply that with rubber-steel over ~30?% wrap on a lousy 2" v-belt pulley, even with 2 belts perfectly aligned on the hooptie volvo.
All you ME boys go ahead and impression the thing for surface area, temp and coefficient of friction and tell me I'm full of it...or test it with a belt rig I suppose?
See Dave Bartons debacle with his primary e-fan adventures & more powerful alt idling in TX?
The voltage reg lowers charging voltage and doesn’t have a cutoff for that for hot climate idling over hot pavement with the a/c on in the Deep South or scorching az desert, this might be a problem.
No issues here or ca. Maybe there’s an alternate voltage reg for the 240 that puts the temp sensor on the inner fender apron that reads a temp something close to battery temp like the old external regulators did (tho for early 240 they were often flickery and way risky to under and overcharge as were the sketchy aftermarket adjustable regulators no thanks) or a way to duct some air that isn't coming off 130? blacktop, the exhaust manifold and the 160? propeller wash of the engine fan?
With the Bosch I suspect even under the exhaust for sampling air for the temp sensor, there’s a max temp resistance in the regulator temp sensor circuit above which they probably figure there’s no point reducing charging voltage as presumably all the liquid has evaporated/boiled out of the battery!
The later FWD cars (& plenty of others with internal regulator & temp sensor) have a cute little plastic duct to the temp sensor to much the same position on the fender on the back of the alt and heat sink on the rectifier to source air from ~where the battery actually sits.
I don’t believe the denso to be sub standard part in hot weather in construction as such or will cease to charge and it puts out more amps idling on the alt load tester, even if the Volts are lower in hot climates due I suspect it it sampling hotter air without a charging voltage cutoff minimum that the Bosch seems to have. Fewer amps from the Bosch idling on the alt dyno and larger to use on the 240T..if that matters.
I might have one more denso 100A. IDK on the Bosch...those are effective too!
Battery life in extreme hi-desert with super cold nights/early morning use and extremely low humidity and hot afternoons is brutal, even if the alt charges exactly according to conditions & it's a 240 with the battery away from the exhaust and with tons of air around it shielded from the blacktop. Super low charging voltage when you drive the car home in the heat, super cold mornings/thick oil and deep battery draw down & brutal shock/overcharging on startup...runs low on water and a nice lovely paste to short them out between the plates.
Coastal/no salt air highway driven 55 degree ambient temp 60% humidity or damper? Battery lasts forever!