At what rpm is there a problem with valve float with hydraulic roller cams? I'm trying to make a decision on wether to go solid or stay hydraulic. Need those 10's with an M6 tho.

 

Mostly it depends on your set up... a hydraulic roller. Set up with GOOD springs will take you deep in the 7k's RPM wise.

A Solid will make more power, but it is more expensive.
A Solid will make more power, but it requires more maintenance.
A Solid will make more power, but wont last as long in a daily driver.(IMO)
A Solid will make more power but will hurt your low end/mid range torque.(many times)
A Solid will make more power, but will require you to spend more money on "stuff". Such as valve covers, wires, coil relocation kit, completely new valve train (pretty much), etc.
A Solid will make more power, but the extra RPM's you will be turning if you are to REALLY use the solid roller cam will be VERY hard on your bottom end and a stock one wont live very long.(IMO)

There are trade off and choices to be made. You dont NEED a solid roller to run 10's. But it surely would not hurt your chances!

Good luck!

<small>[ March 25, 2002, 12:27 AM: Message edited by: Raughammer ]</small>

 

I pretty much agree with Raughhammer. I was running a solid roller setup about 6 months back on the stock bottom end. A big benefit of going to a solid roller setup is you don't loose as much driveabity going with a large cam.
We choose the cam wanting to shift the car at no more than 6700 or so (230/230 .612/.612 112lsa; before valvelash). It was more of an experiment than anything to see how it would do. The car ran VERY well (see sig). The car would have gone 10s if it would have hooked and the weather would have been better. I sold that setup because I didn't have a cage in the car and didn't feel like putting one in my daily driver.

However, there are guys making just as much RWHP with a hydraulic cam in the same RPM range. So, the $$$ is not really justified on a STOCK bottom end I don't think. If you want to spin the car to 7300+rpms, look into a solid roller and a built bottom end. If you have a nice set of pistons and rods, you will be all set.

I know 10.80s are possible with a hydraulic cam as long as you set the car up correctly. With a 6-speed car, you HAVE to set the car up for the first 60'. You are going to need a 12-bolt, steep gears, and some sticky tires.

I have 4.56s and 28x10x15 Hoosiers going on the car in the next few weeks. I am thinking of adding heads to my current setup this summer (along with a roll cage <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> , damnit..lol; should have just done that awhile back <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> ). That setup, in some good air and mid 1.5x setup, should be good for a 10.8x-10.9x I think. It all comes down to the first 60'....

 

Like Raugs said... it depends on your hydraulic setup just where valve float will occur.

Don't know if it's just marketing tactics, but Comp Cams offers a hydraulic lifter (CC 875) designed to prevent hydraulic lifter "pump-up" that they say may occur around 7K RPM's.

I seems like a good idea, but I don't know just how much higher than 7K RPM's that lifter pump-up becomes a definite problem.

7K RPM's seems to be the line in the sand for many of the stock engine components.