Springs 'n' things, or who's on first?
Springs 'n' things, or who's on first? Sometimes this crap drives me crazy. I called Comp about springs for my custom 232* cam and was told that the 918s wouldn't work and my heads weren't cut for big springs, so Comp had nothing. We (the tech and I) fooled around a while trying to put a 920 in there, but I got tired of waiting and when I saw the highly recommended EX-616 from Combination Motorsport on here, I talked to them and bought a set. The car has never run the way I thought it should and is now not pulling past 6500, so I decided to change springs. I call Comp to see what they have, and the LS1 guy there says to use 918s, they will work fine. Sigh, nothing like conflicting info from the manufacturer, eh? So I order some 918s and retainers and build a spring changing tool. I got started today and of the six springs I've changed so far, none of the removed CMS springs are the same free height. There is ~0.120 difference from tallest to shortest. These springs have a dozen passes and maybe 2000 street miles and I carefully temperature cycled them thrice before I got on it. I don't have a spring tester, but I will bet that these EX-616 springs are not to spec anymore. Any of you others who have these springs might be advised to take a look at them. Any of you who want to run 918s on a 232* XE-R lobe are OK, per Comp. I'm shimming them to 0.050 short of coil bind - we'll see how they work.
On The Tree
Joined: Aug 2004
Posts: 150
Likes: 0
The 918 is a great spring but some people, including some at comp, need to realize that just because a spring can handle .600 lift doesnt mean that it can handle the rpm of all cams that happen to have .600 or less lift. The more you push a spring lift wise, the less rpm it can handle. There is a general rule of thumb that to make a spring as strong as the most agressive cam that that particular spring will be matched to. But with the advent of a particular cam with the matching spring may not be matching anymore for optimum results with a higher ratio rocker to apply more lift, hence pushing the spring harder and limiting the rpm capabilities of that particular combination. This may not be the case her but food for thought.
There is no way I would put a 918 on a 232 XE-R lobe. With any XE-R lobe, I would reccomend a good double spring just because of the aggressive lobes. The patriot golds or the new springs from Terry at Racetech would have been my first pic. They'll fit stock locations too.
Originally Posted by Beast96Z
There is no way I would put a 918 on a 232 XE-R lobe. With any XE-R lobe, I would reccomend a good double spring just because of the aggressive lobes.
Update: At least one of the CMS springs has lost 20% of its force.
I ran the 918s on three different XE-R cams, around 230ish duration. That is to say, the same set of 918s on each cam. Ran them hard as hell, with over 200 passes also. Not one breakage. Of course, there's no guarantee on that.
