Thread: VS cam pulley size?

stock rockers + VS = more power than a xp/s1x with 1.7/1.8 rockers.

Less float.

Originally Posted by matt5112

Less float.

Yes.

Originally Posted by darkhorizon

stock rockers + VS = more power than a xp/s1x with 1.7/1.8 rockers.

thats interesting looks like i need to go rethink my build i was planning on using a xp cam with 1.61 yella terras

like, 4200 is where it starts with a float happy setup... Boost is going to float you before RPM does.. and RPM related floating is usually found in places other than the valvespring pressure to rocker design "ratio" (valvespring harmonics, lifter harmonics, valve spin).

The lift is really the killer part... the 1.8 even struggle to keep up with stock rockers power wise (at least on my crude "tuner dyno" that looks at boost pressure/maf flow)... and the camshafts out there have been mainly designed to produce their gains around the variable ratio stock rockers, so its likely you go backwards a bit with the extremely square looking lobes found on our performance camshafts.

I would like to have some dyno testing of this... but i really doubt its worth the effort as nobody with normal heads / normal boost levels needs to ever worry about NEEDING a big dog rocker to make power.... The small handful of us guys with heads and boost pressure that requires these big dog rockers (for reasons of adjust-ability and 150#+ springs) will be concerned about float, but we will then be able to overkill the springs/lifters/pushrods to compensate.

Overall, anyone with a roller rocker that has a nearly stock mounting system (not shaft mounted / stock bolts) has a completely useless and most likely power reducing part on their car.

Originally Posted by DoubleBlown

thats interesting looks like i need to go rethink my build i was planning on using a xp cam with 1.61 yella terras

xp with stock rockers makes for a great setup... Just toss the stockers on and set the head up for ~570 lift.

Originally Posted by Swiggles

I have stage 3 heads so you posting about all this was pretty pointless here. My float is compensated by my springs, lifters and pushrods. And since you have no dyno or anything to back up your theory I don't understand why you keep telling people no to use rockers.

Uh, no its not... Just because you have PORTED heads means you would make MORE gains from more lift.. so its even MORE relevant in your case. The fact your heads were touched by intense do not mean you have a rhodes lifters, custom pushrods, and adjustable shaft mount 1/2inch stud mounted rockers and 150# springs running 600 lift.... in fact you are running a tiny cam with lift similar to a stock cam/rockers!

The reasons people HAVE to run roller type rockers are completely irrelevant to you, so there is no reason you should have them... but obviously the above reply was just done to troll me, as you obviously didn't even read my post.

Personally I'd rather you roller rockers knowing that they are 1.6/1.7/1.8 over stock that range from 1.6 to whatever. That might just be me though.

My question about what pulley size to use was answered on page 1, can we close this thread and start a new one if we all want to argue about valve float since it had absolutely nothing to do with OP.

uh, as I said before, pulley size vs peak power is very reliant on what rockers you should run..... as you will make best power not floating over floating a small pulley.

No, nobody else makes power going to 1.7s... I can find more than a few that lost 20+whp though.

I said I can not produce some numbers due to the lack of precision in my test rig... It does not mean that the rest of them are incorrect.

curious to see some logs.

Also curious if you left the 1.7's on.