Does anybody here know what the difference is? Lift? Duration? Power curve? I read about Bigdaddy's success with HPR3's. I have HPR4's and am having similar success. Just curious.

Ron

 

We could tell you but then we'd have to .......well you know.

 

[img]i/expressions/face-icon-small-happy.gif[/img]

I guess no one knows. Maybe 222 will chime in later. Betcha he knows.
[img]i/expressions/face-icon-small-wink.gif[/img]

 

I do today, but...
Cams are constantly evolving with each dyno session on each different motor build. There is no way a HR4 from 2 years ago is optimum in today's latest and greatest porting/carbs/exhaust, etc...It would still be good, but not optimum. I hope that 45 years from now, someone will find this post in an archive and quote me as saying the HR5 cams I ran at 2005 Planet Sand are NOT optimum cams in their liquid carbon dioxide cooled, nuclear powered hovercraft! They might work or even make some power, but if someone hasn't came up with something better.....It would be an insult to the HPR reputation for someone to bolt them in and say "so, this is all they had back then?"
Constant: The HR4 cams are more oriented for higher peak rpm motors or big bores. Adjustments are made to cams to compensate for a lot of factors, and in BigDaddy's case, for his weight. Your HR4 may be a little different from someone else's HR4 if his circumstances are different.
HR1,2,3,4,5 are starting places with a couple of constants on each grind, but there are alot of aspects that are variable on each grind. The HR5 cams in my 800 motor that Sandbomber is "borrowing" are already out of date. The HR5's MR HP ran at Dunefest are the latest and greatest, but only because of his latest and greatest porting and carbs wanted them. I am sure that Sandbomber's 850 will get a whole new grind #. Like a HR6, instead of a modified HR5.
Confused yet? I am..
222

 

Thanks Randall! Very informative. There is a lot going on in this business. I am glad there are people out there smart enough to figure this stuff out then willing to explain it to the rest of us![img]i/expressions/face-icon-small-wink.gif[/img]

 

So if I read that right, you are basically saying that depending on the beast you create it can and will change your cam needs? Is this true for pistons and other parts also? If that is the case, would it not be better to do the whole build at once as oppossed to doing it in pieces??? A little help for the still learning please [img]i/expressions/face-icon-small-smile.gif[/img]

 

I need the strongest and best cam I can get, It needs to be able to haul my (@#$E$*) around. What do you sugguest!!![img]i/expressions/face-icon-small-tongue.gif[/img]

 

DragonDJ11- yes! If you are not asked by your engine builder, make it a point of telling him where you are going in the future. Sometimes you have to take a smaller power gain right now to better suit your future mods. And, that is why it's so hard to get the absolute best camshaft in a head that was ported by someone else....then you mix and match carbs, pistons, exhausts, etc....it can still be good, but not optimum.

1BigDS: you need the all new HR300+ grind!! The lobes are shaped like a piece of pie.

222

 

Oops! forgot to write anything!

HR300..... Thats funny right there![img]i/expressions/face-icon-small-happy.gif[/img]

 

Ummm PIE!! Order me two!![img]i/expressions/face-icon-small-confused.gif[/img]