Thread: Camming this summer...gotta question...

Originally Posted by GTPpower

Somewhat recently. I'm not sure where the post is at, where zzp showed decent gains switching from 130# springs to 150# springs on an XPZ cam, due to valve float. The same thing applies to the XP though. LS6's or 105's are not heavy enough to keep the valves under control with the XP's lobe shape. Obviously, the LS6's and 105's work, but you are leaving some power on the table with those springs. I think that info is somewhat old on their page, but I'm guessing that if you email ZZP and ask them what springs to use, they will recommend something like a 130# spring.

My 01 has an XP cam, and I used to run Manley TI retainers with LS6 springs on it. I switched to Steel retainers and 130 comp springs about a year ago - I don't have actual dyno numbers, but the car picked up about 2-3mph in the 1/4, and about 30whp according to my scans.

When I did my XP cam like 6 months ago, ZZP said 105s were the way to go. I'd like to see this post you're talking about. Also those gains seem insanely high considering the gains from an XP in general are supposively 30-50WHP, and all you did was switch to inferior retainers and better springs? Granted you're not comparing the 105s to the 130s there but it seems like there had to be another issue there.

Originally Posted by GTPpower

Who did you talk to at ZZP?

I'll see if I can find the post.

Steve. As hes a good friend of mine. I'm not really trying to call you a liar or anything its just suprising/confusing and hard to believe information lol.

I sent him a message about this, I'll post what he says.

Response from Steve at ZZP:
"brand new 105's are fine with an XP. i have seen some cars pick up power going to 130's (i just did some on my car) they dont float BAD necessarily, but some cars will float some as the 105's wear out. usually it is a huge power drop, and boost climb at the top of the dyno chart.....the reason we dont put 130's in more cars, is because they are hard on a timing chain that already sucks to begin with."
So it seems like basically 105s are good for awhile and then could possibly lead to such situations as you observed.

Seems like you either pick replacing springs more often or replacing chains more often... Asuming he is refering to the double set as well on the 130s.