Quote:
Originally Posted by RallyBob
In truth those are quite tame camshafts. They have very gentle valve openings judging by the relationship between the advertised duration and the @ .050 duration numbers. The advertised numbers don't tell the whole story.
An aggressive cam profile will tend to have faster valve openings and closings. Jack's cams by comparison have 244 @ .050 duration but with 268 advertised duration. VERY fast opening and closing ramps with very rapid valve acceleration.
|
Out of interest, why would one want the valves to open as quickly as possible - does it help with the NA applications? Would such an aggressive opening take long to damage the seats and or valves?
I've spoken again with the guys about my cams this morning, looks like they'll be able to do something along the lines of 220 @ 50 with around 8.1mm intake and 8.9 mm exhaust. It should be just enough of an increase to get the engine to where I want it performance wise which is to flow to 6500-7000 rpm and not drop off at 10-14 psi (although at 14 psi ti didn't drop off... it hit a brick wall!). Thanks to LAN for his assistance and guidance with these. Funnily enough on the Kelford site, this type of duration and lift cam is good enough for a 4 cylinder EJ to see 8000 rpm... good sign.
Already thinking of version 2 of my cam regrind... I've still got 2 spare sets of stock cams to play with and given how easy they are to remove, could swap and change to suit different tracks if I ever wanted to (assuming the regrinds all go to plan):
http://www.subaru-svx.net/forum/showthread.php?t=54965
Also my other mate has just installed his EG33 into his RS Liberty. He had some cams done as well - however it would seem these have been welded as the lobe heights have increased. One of my other mates in the mean time has scored an epic picked up a perfectly good eBay EZ30R on ebay for $1250 for his Impreza... fun times, H6 FTW!!!!
But anyway... cam stuff for the RS Liberty EG33:
Inlet: 255 deg advertised
Exh: 265 deg advertised
Duration @ 0.50 thou
Inlet: 199 deg
Exh: 215 deg
Lobe centre:
Inlet: 112 deg
Exh: 116 deg
Intake lobe height 39.97 (39.1 stock)
Base circle 31.61
Inlet: 8.4mm
Exhaust lobe height 40.25 (39.9 stock)
Base circle 31.71
Exh: 8.5mm
This car will run NA mode for a while until he gets around to putting a turbo on - so the results will be very interesting.