thanks for the reply like i said still learning abit and 1 more question what rpm is the duty cycle that you are talking about
Not to speak for Ilmordude or Ilmor but marine apps see sustained rpm and loads greatly exceeding auto apps and must still be warranty-able.
A boat never coasts at a part throttle opening like a car or even a truck in downhill conditions- its always under a load - pretty much like towing up hill 100% of the time. This sustained carrying of the load while simultaneously spinning comparatively waaay faster than an automotive counterpart creates an environment that chews up bearings, valves, and reciprocating parts like a puppy does the sunday morning paper.
Controlling oil, heat, thermal expansion, under loads like this over hundreds of hours of operation- is tricky.
Not sure bout the newer gen4's , but my gen3 710 redlines at 6300rpm. This is an 8.3L engine.
I cant imagine a scenario where an auto app would sustain 4-6K RPM for more than a few minutes and can really only do so at racetracks or place like the nurburgring whereby a boat engine routinely does this for
hours on end every time you go for a weekend cruise.
Net net ilmor marine powerplants have a reputation for lasting for many hundreds of hours- some claim 600+ now with only fluid changes at this sustained output level.
The trick isnt to pick up another 1-2-3 hundred ponies or even more- they can do that. It's to do it without changes the maintenance schedule or impact the longevity of the mill.
Check out the maintenance intervals of the various mills making more than 700 ponies. You get into absolutely ridiculous money dumps at 25-50 and 100 hour intervals. Were talking about 30-50K + for a REBUILD at very low hours. Check it out- its really pretty amazing.
Despite all the mouth music from many guys on these sites, very very few can really afford to buy , and even fewer really maintain these packages at the recommended intervals - boats with these packages are a lot like airplanes in that you can watch the value of the whole cycle in direct relation to its approach toward overhaul time.
Uncle Dave