I just purchased a cam with the specs of 232/230 580/575 with a lsa of 110. I know that everyone likes the patriot gold springs and the crane duals. My question is, what is the cut off for useing comp 918 springs? Any thoughts would be great.

 

price of 918's + tit. retainers = 325
price of PP gold kit = 300
price of Crane kit w/ tit. retainers = 378

seems like a no brainer to me. with the PP golds you get the most seat and open pressure over the 918's and cranes.

 

first off, you dont have to use titanium retainers on the 918s. So that means that they only 150.

 

A lighter valve train is a valtrain that doesnt float valves so it would be in you and your engines best intrest to invest in TI retainers

 

yes you dont have to but with the cam still making power up top (6500+) you'll benefit with the lighter valvetrain.

 

I know what you are saying. But your not talking about a nascar engine that turns 9000 rpm. There is alot more to worry about before retainers. Like a balanced rotating assembly. Is it not true that titanium retainers are not good for street use?

 

your car, your money, do what you want *shrug*

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

for an extra 150 bucks you get PP golds.

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

 

Look, Im not trying to get into a pissing match. I simply wanted to know what the real life max lift was on the 918s. I will be going with the patriot golds. I just wanted to know what everyone else had delt with. Oh and I earn my living by working on cars.

 

max what; spring life, duration, lift, ramp rate. will that cam work with 918's, yes, thats your answer. just install them at the correct install height and properly heat cycle them. but somone who works on cars for a living should already know this, right.

 

I can get you the PRC dual spring kit.The kit will handle up to .660 valve lift.It comes complete with titanium retainers,seat bases and seals.This kit is $289.95.

 

Your not hearing what Im saying. Just because comp says it will handle 600. Doesnt mean that it will. I am asking in the real world, what is the max lift that people are seeing with the 918s. Before they break. And yes I do know that.

 

I talked to a comp cams cam tech today and he said that there are people running those springs at .620 lift with no problems. He said that they underate their springs. Hope this helps

 

Terry since these haven't been out lot, they don't have much feedback(if any). How do you think these stack up compared to the patriots? Obviously as more people run them we shall see for ourselves, just curious to hear your inpurt beforehand.

Also, fastblack, you're kicking a dead dog. If this is a purely academic question, then repost in the forum and call for everyone's experiences. In this thread you asked for advice concerning which spring you should run. Thats exactly what you received....advice towards that end. Now concerning the 918's....people are running tsp's 231/237 in their daily drivers on them. but when their springs fail, they will FAIL. period. no second spring, no saving grace, its just a crap shoot. they'll kiss a piston or they'll get lucky. i don't like the odds, nor does jrp. i wouldn't run a cam that large on single springs if someone paid me to. anything over .575 or so on a somewhat harsher ramp rate and i want the extra peace of mind. i'm seriously considering both the fm13 and the 231/237 right now, either way its a double spring set for me. JMHO.

 

Here's an interesting article from Engine Builders Mag. about the design benefits of the 918s.

http://www.krcperformance.net/newcontent/beehive.html

 

Thanks cyphur. Thats what I was looking for. I have allready had the chance of using a set of 918s on a customers car. And yes they did cause problems. All I wanted to know was what people outside of the manufacturers had used them on. I do not plan on running the 918s. I was simply wondering.

 

You guys that are running the double spring set-ups...You really think that if the main spring breaks at 6000 rpms that the back-up spring will somehow keep the valve from floating and/or contacting a piston??? I look at the double spring set-ups like a snake oil elixer...Sure, they offer great seat pressures and allow you guys to run the big cams with very aggresive ramp rates...But...If the main spring lets go at high rpm, that back-up spring will not save you...

This is one of those mods that everyone jumps on the band wagon and thinks they are the greatest things since sliced bread...

Bottom line, if you drop a spring, be it a single or dual style...You will either be lucky and have minor damage or not so lucky and have some major damage...

I personally like the single springs...

Peace...Gman