High Altitude CPS vs. Regular CPS?

[onlyinajeep726]

Sorry if I'm beating a dead horse, but besides advancing the timing by 2 degrees, is there any major difference between the two?

 

I know to get a MOPAR one and I plan to follow Cruiser's tip to enlarge one of the bolt holes.

Is there any negative affect to using the HA CPS?
 

[daking]

do you have the part number for it? 

[Strokermjcomanche]

Mopar #53005421 for the renix years .

[daking]

I'll pick one up. I have the transmission out right now. best time to install a CPS..

 

I can't find one on line. guess its a dealer item

[onlyinajeep726]

I have a part number for both, but that doesn't answer my question lol. :P

 

The regular Mopar CPS is P/N: 33004761

 

High Altitude Mopar CPS is P/N: 53005421

[mik666]

i actually compared the two in a non- quantitative way just last week-  both were new. Since i have a 4.0 2wd auto it takes minutes to swap them out and after drilling out the  mounting holes as recommended in the renix tips swapped the two and compared the general idle quality and acceleration about the hood sort of method - I found  the HA to give a slightly better  idle , acceleration was hard to say but certainly was no worse with the HA CPS so i went with it -  i would of liked to compare them on some hills to see if there was a discernible difference, but i'm happy i  went with the HA one

[64 Cheyenne]

I have the transmission out right now. best time to install a CPS..

 

 

Maybe so, but I recommend waiting to install the CPS until after the tranny is bolted up, prevents the CPS from being damaged while you wrestle the tranny into place.

Guess how I know...

[Blue88Comanche]

:popcorn:

[Eagle]

I've been running one in my '88 Cherokee for fifteen years. I'm basically at sea level -- you will NOT see any difference in performance, but if you drive gently you will see an improvement in gas mileage.

 

All the high altitude CPS does is allow the timing to advance a bit farther. But when you drive peddle to the metal, the engine is always at the point of detonation and the knock sensor is controlling how far the timing can advance -- so under heavy load or heavy acceleration, the knock sensor overrides the CPS and doesn't allow that extra 2 degrees of ignition advance to kick in. Where it does become operative is at cruise throttle.

[onlyinajeep726]

Thanks for the kind responses, especially yours Eagle.  That's what I was looking for.