i have a trs engine/drive combo.the oil coolers have 8 plates both for the engine and trans.how much h/p will the cooler handle?

Contact the guys at CP Performance. They have replacement 13 plate coolers and cover plates you should use for this system as the 8 plate old coolers are marginal at best for your use.

Best Regards,
Ray @ Raylar

The 8 plate is good for about 550-600 hp. Any more than that and I would go to a 13 plate. As mentioned, CP sells a 13 and 15 plate cooler upgrade with covers.
Eddie

Eddie,

How much horsepower do you think a single 13-plate cooler is good for? On my builds, we were debating whether to double-up and use both a 13 and the other side 8 plate, but in the end ended up using the stbd side 8-plate for a fuel cooler.

Motors are 1000 hp, no thermostat, but thermostatic oil control valve. No circ pump either, just a crossover.

I'm pretty much always going to be in water 70 degrees and below.

I have done over 1200 with a single 13 plate. That was only because that was the biggest at the time, but it worked fine. They have since come out with a 15 plate. I use that on anything over about `1200-1250 now.
You will be just fine with 1000 hp on a 13 plate.
Eddie

Eddie,

Thanks. Your advice is appreciated as always.

thanks guys for all the info.i think i will one day soon r/r the plate coolers and go with round coolers.the starboard side motor was blown up when i bought it,the coolers,covers,bellhousing were so stoped up/ate up with salt that i did not even bother with buying.i just removed the coolers and re-routed the cooling system and used round coolers for the trans,and motor.it looks like the port side was already done with new covers,bellhousing,and covers.so i will keep them untill i get enough $$ to replace.thanks again.

I been reading that the factory merc bellhousing coolers had issues possibly due to water flow thru the casting? Is the water passage restrictive? I see where some have modified them and ran a #12 line from one side to the other? I'd like to use these bellhousing style setups with the 8 plate coolers, but, seems the 8 plate wont be enough for me? I know I can use both 8 plate coolers for oil, and run a separate tube style tranny cooler, but was trying to get away from all that rigging and like the clean look of the bellhousing ones. A 13 plate cooler and cover is pricey!

yes they are,i just orderd 2 from cp performance,over a grand.

I remember also those were part of a purchase that hurt a lot. At least once you have the covers, the replacement cooler elements are only half or a little more.

It's been a while since I've looked at them, but I didn't remember a 13-plate being available for the stbd side. Now you can go 15 plate on port and 13 on stbd.