I bought a TR 224/224 .568"/.568" on 112 lsa yesterday off of Tech. I'm now wondering which valve springs I should go with when I install this cam. Some people have told me go with the 918 springs, while others have said the LS6 springs will be sufficient. What would you guys recommend?

 

The original 918 springs had 318# of spring pressure at 1.200 and 130# at 1.800. The LS6 springs have 295# of spring pressure at 1.250 and 90# at 1.800. I have not seen the 918 measured at 1.250 but it likely wouldn't be much off of the 295# that the LS6 spring makes. There is quite a bit of difference in spring pressure at the lower lift, but with the mildly agressive ramps the problem is commonly in the bigger end of the valve lift. I've installed the LS6 springs in setups with cams all the way up to the XR281HR (228/230 .571/.573 112LSA). That car has almost 30K on that cam and valve spring setup without a problem. I've also put a GT2-3 cam in a truck with these springs and it now going on 100k with that setup in there. A local friend installed the same cam I have with LS6 springs in his truck and now has around 30k with that setup and no problems. I have many more examples, but that covers the idea. I feel that there is a place for the 918's and I've used many of those in the past also. I use those when the ramps are very agressive or lift higher than .580". If the lift is over .610" I then recomend Patriot Golds. I consider the ramps agressive when you run into something like the CheaTR cam, Old Man cam, TR Blower cam, etc. These all have duration under 220º and lift over .600". With that low of duration and that much lift it makes the ramp very agressive with an almost straight up/straight down. Something to think about, how many failures have you heard of from 918 springs and how many have you heard of from LS6 springs. They are quieter, run cooler, and have a lower failure rate. They also don't have problems with the knock sensor picking up noise from them causing faulse KR* like the 918's and other more agressive springs have. I've bought/sold around 100 sets of LS6 springs and have had no failures due to the springs. I have had 3 friends/customers that had their 918's create a window in their block.

 

Hmm... interesting information. Thanks Zippy, oh and thanks for your response to my PM.

 

yup I vote LS6 springs I have had no problem with mine.

 

Good to know. I was just wondering this myself since a few companies quote the LS6 springs as being capable of handling .550" lift and other companies quote .580" lift capabilities. Of course ramp rates have their place in this calculation, but it's good to see hard data.

The question at hand was if the LS6 springs could be matched with the Comp Cams XR265 high lift camshaft. That has a nice duration set of 212/218 but with mild lift characteristics of .558" intake and .563" exhaust. Looks like the LS6 springs will do fine.

 

Something else to add. GM's circle track crate engines use the LS6 spring with a 226/236 .525/.525 110 LSA cam. Now the lift isn't as big, but the valve control is just fine to the rated 6700rpm of the CT525 6.2L with the heavy 2.16 intake valves.

 

my ls6 work great up to 6600rpm .566 lift

 

so say I put in the LS6 springs, how high could I spin the engine to? over 6,500 rpm?

 

I've been to 6800 with mine, but I'd try to keep it below 6600 if possible. Your shift points would be below that anyway.

 

Great info, I was under the impression that the Thunder Racing cams required the stiffer springs due to their agressive ramp rates, but I guess that's not the case. Just out of curiosity, do the TR cams use XE or XER lobes?