cosmick

So a few years ago I read in here that it has been made to work with a Comp XE268H10, that's 224/230-110, so 6* more overlap than the 224/234-114 I'm on the verge of ordering. I'm wanting this thing to pass emissions, and since my choice has only 1* of overlap at 0.050", it should pass if I can get the carb figured out.
What needs done to make this work?

Damon

I think you're going to have a hard time getting that to run right and pass emissions. I've done 224* cams on 110* LSAs before with a CC-QJet and it was.... marginal. And I didn't even care about emissions in that situation. With a 114* LSA it will probably be quite a bit more docile but I've never tried a cam like that personally on a CC-QJet setup.

There's not much you can do in the way of "tuning" inside the ECM with these setups- I don't know if anybody has bothered to figure out the programming in the CC-QJet chips. Plus there isn't even a fuel map, per se. Just a target A/F ratio (14.7) for closed loop operation. The rest happens mechanically inside the carb. You're pretty much limited to what you can mechanically change inside the carb, which for emissions purposes mostly means the idle circuits.

86LG4Bird

iTrader: (1)

cosmick,
The factor to be concerned about is manifold vacuum, and that's more dependent on advertised (.006") duration than on .050" duration. In this case, the Comp 268/280/110 cam has 54 degrees of overlap, whereas the 290/300/114 cam you're considering has 67 degrees of overlap. Not even close. When you look at the overlap area represented by that 13 degrees difference in opening angle, it will translate into a lot more than a 25% area difference! That's what will influence your (lack of) vacuum and (lack of) driveability with the CCC Q-jet and (lack of) emissions compliance.


No dice

Chuck84TA

Here is a post I did on your same cam profile.. Can't help you with emissions issues, but I managed around 15psi vacuum and decent driveability...https://www.thirdgen.org/forums/carb...4-cam-ccc.html

cosmick

Ok, for the sake of understanding, not argument, IF I had Comp grind a 268/278-114, that'd be 9* less overlap, but still a 224/234, and it'd be 477/498 lift. I can give lobe numbers from Comp's Master Lobe Catalog if necessary.
So IF I order this, what would it take?
You're right if you guess I'm gonna try any advice received on the cheap generic cam, but I disagree based on my own past experience about the value of advertised duration of generic cams. I've had a generic 280/280-111 208/208 420/420 pull more vacuum than a Comp 252/260-112 425/440, 206/212 cam.
Using advertised duration to compare overlap of 2 different Comp HF cams is valid.
So that's where I'm at. If my results prove you right and me wrong, then I'll have noone to blame but myself.

cosmick

Interesting, thanks!

cosmick

Ok, so I got a used CCC QJ off an '84 LG4, that's progress. I got a gallon of Chem-Dip. More progress. Now I'm trying to find a cheap rebuild kit that's compatible with gas that's 15% Ethanol, and comes with good instructions for adjusting the computer-related stuff. Any recommendations?

Fast355

iTrader: (2)

On the two ECMs I have looked at for the CCC system, BOTH had Duty Cycle maps for the solenoid that referenced engine vacuum and coolant temperature. The code looks like it only referenced the base maps for Open Loop operation however and above X throttle position turned the solenoid off all together.