Camshaft questions

John*G · 04-28-2004, 11:52 AM

I have a EJ2.2. Looking into custom ground cams I would like a duration of about 265-275 and run about 11.2 CR. I Noticed Cobb, TWE, Webcam and others all keep their grinds about the same, mostly increasing lift and rate of valve opening. I heard reference to "problems" with too much duration/overlap but I don't know what that means. I imagine possible back pulsations at the MAF which is a little fragile.and overly rich mixtures at the O2 sensor at idle also thepossiblity of ruining the cat in time. Anyone know for sure? I don't really care about CEL's as long as it runs well and I have no emissions testing.
Thanks

obyone · 04-28-2004, 05:13 PM

They keep the duration the same to stay within the confines of the stubborn ECU. Anything else will throw a CEL.

John*G · 04-29-2004, 07:50 AM

After posting I also thought that when regrinding/welding it would be difficult to do anything but increase lift. Alot of metal would need to be welded to increase overlap.

04-28-2004, 11:52 AM	#1
JohnG Scooby Newbie Member#:* 19562 Join Date: Jun 2002 Chapter/Region: NESIC Location: VT Vehicle: 93 Impreza wagon L Mud	Camshaft questions I have a EJ2.2. Looking into custom ground cams I would like a duration of about 265-275 and run about 11.2 CR. I Noticed Cobb, TWE, Webcam and others all keep their grinds about the same, mostly increasing lift and rate of valve opening. I heard reference to "problems" with too much duration/overlap but I don't know what that means. I imagine possible back pulsations at the MAF which is a little fragile.and overly rich mixtures at the O2 sensor at idle also thepossiblity of ruining the cat in time. Anyone know for sure? I don't really care about CEL's as long as it runs well and I have no emissions testing. Thanks

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04-28-2004, 05:13 PM	#2
obyone Scooby Specialist Member#: 16523 Join Date: Mar 2002 Chapter/Region: MWSOC Location: Inbetween Hesco's and T-walls Vehicle: JDM Maxxpro	They keep the duration the same to stay within the confines of the stubborn ECU. Anything else will throw a CEL.

04-29-2004, 07:50 AM	#3
JohnG Scooby Newbie Member#:* 19562 Join Date: Jun 2002 Chapter/Region: NESIC Location: VT Vehicle: 93 Impreza wagon L Mud	After posting I also thought that when regrinding/welding it would be difficult to do anything but increase lift. Alot of metal would need to be welded to increase overlap.