I'm thinking if I should kick out the VTEC system for my soon to be started race engine project.
It would be new designed camshafts with just 2 lobes directly above the valve rockers.

Advantages: small dry sump pump, fewer moving parts, less friction, less oil in the head and easier tuning.

Disadvantages: bad idle and driveability below 2000rpm, I guess. But it's for a race car only.



Has someone here made expierences with VTEC Killer cams? I know Toda has made some.

 

Are you sure about those "advantages"? I wasn't aware that VTEC really increased the load on the oil system, even though I know that it is dependent on oil pressure. I've never understood why anyone would really want VTEC Killer cams.

 

When the vtec is activated a tremendous amount of oil gets dumped into the head as the oil path to the vtec pins/pistons leaks like a sieve.

I had to completely rework my dry sump pump pressure stage sizing as my first setup was unable to provide the volume required and the pressure would fall as soon as vtec was engaged. The volume available from the factory honda pump is around 90 litres/minute at 9000rpm.

Simpifying the rocker assembly with vtec killers also reduces reciprocating mass on the top end/valve train.

 

This is also why it's not recommended to drop VTEC to low; below 3k. At least it isn't on the H22.

 

check the cams thread if you havent already. should be some info there about em

 

I cannot find the cam Thread anymore. Is it gone?
It's not in the "official" list and I searched all pages here...

 

Thanks for the links.
Yes, I've seen the exhaust rockers from the thread. It seems a good idea to use only the high lobes on the exhaust valves when variable cam angles can be adjusted. So only with iVTEC.

 

Very true Chris, that is why I run 1.4", 1.4", 1.4" rotors and 120psi oil pressure.

The pump a I use is a Pace CD2000 and is available with rotor sizes of..
.85" (21.59mm) = 2.35 gal (10.57 litres) per 1000 pump rpm)
1.1" (27.94mm) = 3.00 gal (13.50 litres) per 1000 pump rpm)
1.4" (35.56mm) = 3.80 gal (15.30 litres) per 1000 pump rpm)

 

There must be so much oil in the valve area of the head at high speed, that a seperate scavenging pump should empty this.
BTW I have access to some diagrams with measures on the F20c engine. The Blow-By rate is between 20 and 30 l/min.
It could be that a bigger drysump pump is needed for this case also.

 

I've found that introducing a small amount of air into the rocker cover helps pull oil down to the sump. I have a 1/16" restrictor on a line that goes to my catch tank. This doubles up as an oil recycler as I get some oil spitting out of my main oil tank into the catch tank.

I've got a Razor gear style pump ( rather than the gyrotor Pace units) which has 1.875" stages.