refresh 500 hps
12-25-2005, 06:26 AM
#23
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Re: refresh 500 hps
you too... really
if you can't mud wrestle with your friends over dyno numbers , what good is having friends at all ?
interesting thing i found while researching my own stuff... i.e looking for about 100 hp the " easy way "
looked at the procharger web site and they have a pretty interesting section about one of their competetors and the claims made in their advertising. flat out accuse them of being willfully misleading....
i , for one , think it is a very interesting topic...
if you can't mud wrestle with your friends over dyno numbers , what good is having friends at all ?
interesting thing i found while researching my own stuff... i.e looking for about 100 hp the " easy way "
looked at the procharger web site and they have a pretty interesting section about one of their competetors and the claims made in their advertising. flat out accuse them of being willfully misleading....
i , for one , think it is a very interesting topic...
12-25-2005, 07:24 PM
#24
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Re: refresh 500 hps
700 reliable hp out of a 500hp...good luck!...that's just short of a SUPER CAT engine running 7600rpm...6200 rpm is about it on pump gas for a marine engine...then to run 700hp, your tq number is going to be out of hand...with a Bravo! 
12-25-2005, 09:05 PM
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Re: refresh 500 hps
The one absolute truth here is that you will definately have to rev the motor 6500 plus to get the horsepower. And yes it will take a healthy solid roller cam to do it. Which as we all know will take alot of valve spring pressure to control. To make big horsepower below 6000 rpm, you have to force the air in it, or have alot of cubes. You can build a bottom end that will spin 7000 all day long, but a $50 roller lifter going bad will ruin your summer in a hurry. 600 hp and reliable, very easy, 700 hp and truly reliable??? That depends on if you are willing to change lifters and springs every season, and dyno your motor to get the fuel right before you melt the valves out of it. 
12-26-2005, 05:40 AM
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Re: refresh 500 hps
ding ding ding.
and it really is that simple.... yes... you can ( for all intents and purposes make any hardware do anything for a VERY short time if you are so inclined... but to suggest 700 usable reliable, go to the gas dock and buy gas for it and run it around for a 250 hrs or so sort of hp out of a 500 inch, single 4bbl, 10.5 : 1 motor is quite a stretch for me...
thats 1.4 hp/ in and that is very very very good for a non pure racing, normally aspirated motor... something that you don't have to worry about having a spare in the truck every time you go out.
the power comes from the compression ratio ( and of course the total flow). either true mechanical or dynamic by virtue of forced induction. 10 : 1 is a very good number for pump gas and 10.5 is nudging the envelope and you need to have everything else correct... but what happens ( as smitty and other well know) is that when you pump the compression you risk melting the pistons ( detonation) so , naturally, the timing ends up retarded and the fuel ends up being too rich ( cooling rather than actually burning) to make the real numbers that you wanted in the first place.
can you actually make 700 hp from 500 in ? sure. it was never my contention otherwise ( altho im sure thats what it seemed) can you make 700 hp at 10.5/ single 4bbl normally aspirated on 87 octane pump gas in a manner that makes it a usable motor for real world application ? well...... all i am saying is that i have never seen any such thing. but i can be wrong and am well happy to be proved so. everything i learn today makes me better tommorow
and it really is that simple.... yes... you can ( for all intents and purposes make any hardware do anything for a VERY short time if you are so inclined... but to suggest 700 usable reliable, go to the gas dock and buy gas for it and run it around for a 250 hrs or so sort of hp out of a 500 inch, single 4bbl, 10.5 : 1 motor is quite a stretch for me...
thats 1.4 hp/ in and that is very very very good for a non pure racing, normally aspirated motor... something that you don't have to worry about having a spare in the truck every time you go out.
the power comes from the compression ratio ( and of course the total flow). either true mechanical or dynamic by virtue of forced induction. 10 : 1 is a very good number for pump gas and 10.5 is nudging the envelope and you need to have everything else correct... but what happens ( as smitty and other well know) is that when you pump the compression you risk melting the pistons ( detonation) so , naturally, the timing ends up retarded and the fuel ends up being too rich ( cooling rather than actually burning) to make the real numbers that you wanted in the first place.
can you actually make 700 hp from 500 in ? sure. it was never my contention otherwise ( altho im sure thats what it seemed) can you make 700 hp at 10.5/ single 4bbl normally aspirated on 87 octane pump gas in a manner that makes it a usable motor for real world application ? well...... all i am saying is that i have never seen any such thing. but i can be wrong and am well happy to be proved so. everything i learn today makes me better tommorow
12-26-2005, 01:03 PM
#27
Re: refresh 500 hps
Originally Posted by cstraub
Top End:
Have heads throughly gone through. Check and replace any gaulded valves. Retainers and locks are cheap and would just put new in. Have bowl work (porting) done on the intakes and exhaust. This is the best bang for the buck. Have shop do a nice 3 angle valve job. Keep intakes and carbs. I would check springs and replace if seat pressure is down more then 15%.
Middle:
Cam change with the bowl work will get you the power increase you want easily. New timing sets, double roller would be good, I would change the lifters out.. . .especially if the springs were real bad when changed at 200hrs.
Bottom:
Marine engines don't see much cylinder wear. If the P/W clearance is within factory specs I would hone and re ring. Polish crank and use new bearings.. Use stock Melling M77 and shim pressure spring .125".
Assemble with cometic head gaskets. Should give you a reliable 560HP
Have heads throughly gone through. Check and replace any gaulded valves. Retainers and locks are cheap and would just put new in. Have bowl work (porting) done on the intakes and exhaust. This is the best bang for the buck. Have shop do a nice 3 angle valve job. Keep intakes and carbs. I would check springs and replace if seat pressure is down more then 15%.
Middle:
Cam change with the bowl work will get you the power increase you want easily. New timing sets, double roller would be good, I would change the lifters out.. . .especially if the springs were real bad when changed at 200hrs.
Bottom:
Marine engines don't see much cylinder wear. If the P/W clearance is within factory specs I would hone and re ring. Polish crank and use new bearings.. Use stock Melling M77 and shim pressure spring .125".
Assemble with cometic head gaskets. Should give you a reliable 560HP
