02Reaper

iTrader: (2)

How about spring pressure. Yea, comp 918's seem to take a lot of lift, but they have lower spring pressures too. Is the SPRING PRESSURE of the 918's high enough to controll an XER lobe? What is the least amount of spring pressure (on the seat and open) an XER lobe needs to be able to controll the valvetrain and keep the lifters planted on the cam?

02Reaper

iTrader: (2)

well, here we go again. All of these smart people on the board, and no one has any kind of answer for me?

mikemodano9c

comp sells their xer cams with 918 springs, so yah they should work just fine

http://www.compcams.com/Technical/Cu...ML/200-203.asp

the "premium" or recommended choice for the vavletrain is 918's, titanium retainers, and hardened pushrods...

you will be fine...

PREDATOR-Z

224/220 .581 XE-R lobes here, running 918's and they run perfect. i'm a big fan of the lighter the valvetrain (while keeping within cam requirement parameters), the better.
My moving assembly per intake valve is 127 gr, too bad Tit. valves are so expensive otherwise i could achieve 98gr/int. valve

BrentB@TEA

I am not a fan of the 918 spring. I prefer the "gold" spring used by TEA,PRC and Patriot.

jrp

iTrader: (16)

less spring pressure as compared to what? 130 on the seat @ 1.800 is more then any single 1.250" spring that i know of.

1. Comp 918’s:

Outside Diameter (O.D.): 1.290"/1.060"
Inside Diameter (I.D.): .885"/.656"
Installed Pressure: 130 lbs @ 1.800"
Open Pressure: 318 lbs @ 1.200''
Coil Bind: 1.085"
Maximum Lift: 0.625"
Rate (lbs/in): 313 lbs/in

3. Crane Duals:

The installed seat pressure is 112 lbs @ 1.800'' with a maximum recommended lift of .650'' at the valve with an accompanying open pressure of 352 lbs. The 1.275'' O.D.

112lbs @ 1.800
352lbs @ 1.150
will handle .650 lift with .045 coil clearance

4. Comp 921’s:

O.D: 1.300
I.D: .870 (outer spring)
I.D: .655 (inner spring)
135 LBS @ 1.770
400 LBS @ 1.220
COIL BIND @ 1.040
MAX LIFT .650

5. Patriot Gold Duals:

O.D 1.29
135lbs @ 1.800
385lbs open
coil bind @ 1.08
.650 lift

My Personal Indepedently tested PP golds:

seat: 143 lbs @ 1.800
open: 363 @ 1.200
coil bind: 1.060
Clearance: .140
spring rate: 367


6. PRC Dual Spring Kit:

seat : 140lbs
open: 390lbs
install : 1.800
coil bind: 1.07
1.290 O.D.
max lift : .660
matl : super pure chrome silicone

nick3205

JRP, nice information

jrp

iTrader: (16)

you can see more in the cam guide, check the sig.

ssheets

iTrader: (1)

Manley sells them for about $1,400 a set...pocket change

bigdsz

iTrader: (1)

We really need to stick with our sponsors they pay the bills, this site wouldn't exist without them. I personally prefer the PRC kit, try Terry at Racetech.

PREDATOR-Z

Actually, I was thinking of a pair of 4.8/5.3, 2.02/1.57, 300 int/260 exh. (flow @ .600) with LS6 valves/tit retainers & of course 918's ,
It is for a "reverse" cam.
You guys would do that, wouldn't you ??

bigdsz

iTrader: (1)

I think the 918 is a great spring, however I'm more comfortable with a dual over say .550-.560 lift. This is not to say that the 918's can't take a much higher lift, psychologically I feel better with duals.

PREDATOR-Z

Hey Big, do you ever wonder how your car feels?

bigdsz

iTrader: (1)

dah????

02Reaper

iTrader: (2)

Jrp, I was comparing the 918's to the patriot dual springs. Thank all of you for the information, but I really dont want to hear (918's will be enough). I could have hit the search button and found that. If 918's didnt exist, and I bought a cam with xer lobes whether it would be comp, tr, futral, crane, etc. What are the minimum pressures that I would be able to run with a cam with aggressive lobes like that? Closed pressure on the seat? open pressure?

Cstraub

iTrader: (1)

JRP,
There is one. It was developed for Clay Smith a few years back for Circle track engines that have rules that limit spring OD to 1.250". So Pioneer developed a spring that is 145# to 150# on the seat at 1.800" install. This is a single with a damper. Several companies now market it.

Chris

jrp

iTrader: (16)

interesting, any more information on said spring. material, weight, rate, open pressure?

Cal

iTrader: (1)

Right on! I run Comp 918's and Ti retainers with a 600 lift cam, rev limt at 7000 rpm, but stock valves, not big heavy ones.

Cstraub

iTrader: (1)

Yeah,
Let me look it up here. . . .
.194" wire diameter
2.165" free length
1.260" OD
.876" ID (does not include damper)
6.2 RH Coils
137 to 151# at 1.800"
345 to 375# at 1.200"


Chris