Looking for guidance in setting HP

[JLEONARD]

OK. I am starting to plan out a marine conversion of a 1989 first gen engine to eventually go into my single engine trawler.

This will be a moderate upgrade in power for this boat. I would like to set it up for about 190/200 horsepower at the engine at approx 2500 rpm. That will give the boat the kick in the aft it needs plus give reliability and longevity and fuel economy (I think ).

But I need a place to start assuming the engine will indeed have it's full rated 160 hp.

Now most of our dyno numbers are at the rear wheels so I need to backtrack to get engine hp numbers. I have heard and read that perhaps RWHP x 1. 25 (with a manual trans) would yield engine HP but am hoping someone here can confirm or deny that as a first point here.



Once that is settled I need to get there... to 190/200 hp. I'll "probably" intercool (with antifreeze) but might not so let's assume non intercooled.

I plan on upgrading to a modern head that will take 7mm injectors, so I am thinking the 190s might be the right injector.

The turbocharger will be have antifreeze cooled housing as all the marine ones are set up as they attach to the aft end of an antifreeze cooled exhaust manifold. My first choice would be to get an HX35M from a marine 210 thru 270 engine. That should be a good match.

Then comes time for pump adjustments to get to 200 hp, which needs to be done "smoklessly" (unless of course Tugger volunteers to be the continuous transom cleaner :-laf ).

Can this be accomplished by dialing in a certain boost pressure? I have heard numbers batered about like "10 hp per psi of boost" but that is for intercooled and RWHP.

Anybody have any ideas?

Another method would be (for me) to calculate propellor load (like a max payload in a truck going uphill) and do it by EGT (post turbo).

Maybe just the 190 injectors will do the trick?

Any ideas here? I know it's a different application that most of us are used to but I think we can finger it out.

Thanks in advance (maybe ).

Jay

 

[Greenleaf]

All of a sudden, I have a migraine.



I believe that 200 hp is a very obtainable goal, even w/zreo smoke. Do marine exhaust housings offer options? I hope so, because that is going to be a major player.



For the folks who don't know, Jay's engine will be operating under a heavy load, like all the time, unlike our engines in the truck. Boost/fuel/EGT/coolant temp/oil temp must be closely monitored unless the boat is going to be setting at the dock 90% of the time.

 

[Greenleaf]

I failed to mention that by installing said engine, your roof will likely rot out.





Tugger... ... ... ... . He means the "back of the boat"

 

[dpuckett]

I think the 190s plus some MILD tuning (AFC only) of the pump will be enough. Is there any disadvantage of going over your goal by 10-20hp? As for the load, I think it should do ok even nonIC'd.



It seems to me that the 10hp/ psi boost rule applies, but depends on what turbo/ housing combo you have, whether it is wheel or engine HP. I. E. if you run a 12cm housing, it is more likely engine HP; a 16-18 is more likely RWHP.



Good luck on the conversion. Is the transmission a manual or auto?



Daniel

 

[JLEONARD]

Is there any disadvantage of going over your goal by 10-20hp? As for the load, I think it should do ok even nonIC'd

No disadvantage Daniel, but no real advantage in the application. My goal is to not exceed 800 degrees post turbo thruout the operating range (750 would be better). The toughest part of that range will likely be around 2000/2100 rpm and at that point I'd like to be no more than 10/12 psi of boost if possible and max out at maybe 20 psi. I am hoping I can locate a marine turbo with a wastegate to help in that regard, but I think if I get this right I'll be right there anyway.



Thanks for all the comments so far . . keep them comming



The transmission is a keeper. Sorry.