L67 camshaft choice discussion

[vlad01]

Just updated my post a little.

I think if you have flow data on your actual heads then making a cam choice will be much easier.

[madmaxisback]

Just updated my post a little.

I think if you have flow data on your actual heads then making a cam choice will be much easier.

Am I right that the heads are stock L67?

[vHell83]

Just updated my post a little.

I think if you have flow data on your actual heads then making a cam choice will be much easier.

Am I right that the heads are stock L67?

No. There is lots of porting to the heads and intake manifold. The heads have larger valves and are fully reco. Unsure of actual flow data but I know that the exhaust ports are far larger than the stock ports and the intake ports were matched to the gaskets. Same as the inlet manifold, and also have clearance for .610 which is what it runs right now with Pac racing springs from an LS2

[madmaxisback]

What is the 3 main things you what to end up with mate?

For example: all out revs, good down low, rough idle, power in top end etc?

[vHell83]

What is the 3 main things you what to end up with mate?

For example: all out revs, good down low, rough idle, power in top end etc?

Good down low, with power throughout the rev range. I dont really rev past 6000 ever so something like the zzp xpz is going to be a waste. I want something that is going to make the blower scream and work very well with boost.

I used to want a lopey idle but I'm willing to sacrifice a lopey idle for performance.

The car is used for cruising predominantly with WOT runs and lots of mountain/hill driving.

[The1]

im not a cam expert others will chime in but lower LSA with not to wild duration would bring peak torque on at lower rpm and stronger as it's a narrower power band and peak power around stock or not to much higher?

Ive found this link handy
http://www.hotrod.com/articles/ccrp-981 ... aft-power/

i think clives street type cam for L67 is around 207 with 0.500 lift @0.50 but has a 112 LSA, So still good lift but setup to narrow the power band and bring the power on quicker, where as all the xp hot etc have 116 and more duration pushing the power up past 6k rpm and peak torque in mid 4k plus rpm.

With a lower LSA if your using enhanced mod you can tune the Injection timing so your not wasting fuel and power injecting at the wrong time. I created a spreadsheet it's in the enhanced mod thread, you can map your cam specs and then see where the events happen and find where you want injection to happen.

[madmaxisback]

Be done with it and build engine up around one of these maybe?

CAM-673 - INTENSE™ Stage 3 Blower Cam, duration @ .050": 222/228, lobe lifts: .338"/.344", valve lifts with 1.60:1 rocker arms: .541"/.554", lobe separation angle: 115, intake centerline: 111 (my pick)

CAM-674 - INTENSE™ Stage 4 Blower Cam, duration @ .050": 235/238, lobe lifts: .375"/.376", valve lifts with 1.60:1 rocker arms: .600"/.601", lobe separation angle: 116, intake centerline: 112

I like the rockers @ 1.65 or close to it for reasons mentioned before. But with these cams you might look at 1.8 maybe? I will leave that to L67 experts to comment.


http://intense-racing.com/Merchant2/mer ... e=3800_HCV

[vlad01]

I will add that the LSA needs to get bigger as the duration gets bigger to have the same or similar valve overlap. So the numbers need to be looked at together. The XP cam having 116 LSA would be similar overlap to say a 210 @ 50 at 112 LSA

anywho I found this as a good all rounder basis to modify from. It simulated really well.

http://www.compcams.com/Company/CC/cam- ... =1075&sb=0

Also a bunch of specs here, these guys are very very successful with the ecotec/L67 engines

http://abbottracingheads.com/gm3800.htm

[vHell83]

Thanks for the info.

I'm sorta leaning towards the xp hot cam from zzp and thinking to stick it with Yella Terra 1.7 rockers.

The quest to find a set now begins.

[vlad01]

Thanks for the info.

I'm sorta leaning towards the xp hot cam from zzp and thinking to stick it with Yella Terra 1.7 rockers.

The quest to find a set now begins.

Just buy them yella terra. 1.7 will be the pro street? Series. Or you can get the ultra lites as the cam isn't huge therefore won't flog the rockers and you have the bonus reduced weight which = better valve control.