Advice on valve springs needed
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,661
Likes: 1
Advice on valve springs needed
I'm looking at getting a cam for my '03 Z06 and wanted some advice on which valve springs to go with. The cam is on a 112 lsa and has less than .600 lift. The cam is ground to the similiar specs of a MTI X1 cam.
Should I go with the single or dual springs? The Comp 918's or the 921's?
Advantages and disadvantages of both?
I know that the 921's cost more and that's not a problem for me. I'm going to spend what I need to for reliability. I don't want to sacrifice performance though. I had heard that the newer 918's are stronger than the old ones and that they will produce more power. I had also heard that the hp falls off quicker with the stiffer springs.
BTW.. I do track the car (road course) and I plan on raising the redline a few hundred rpm just to let you know.
TIA,
X
PS.. I tried doing a forum search and couldn't pull up much specific information on the valve springs.
Should I go with the single or dual springs? The Comp 918's or the 921's?
Advantages and disadvantages of both?
I know that the 921's cost more and that's not a problem for me. I'm going to spend what I need to for reliability. I don't want to sacrifice performance though. I had heard that the newer 918's are stronger than the old ones and that they will produce more power. I had also heard that the hp falls off quicker with the stiffer springs.
BTW.. I do track the car (road course) and I plan on raising the redline a few hundred rpm just to let you know.
TIA,
X
PS.. I tried doing a forum search and couldn't pull up much specific information on the valve springs.
Premium Supporting Vendor
Joined: Jan 2001
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From: Central Jersey
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In what you have explained in a cam around 600 lift and road racing the car where you will spend most of the time in the higher rpm ranges I would go with the 921's. I use alot of them and they are a very nice spring.. 
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,661
Likes: 1
Thanks for the replies.
I'm not running a .600 lift though. The cam that I'm looking at is around 230 with a .571 lift on a 112 lsa.
I also track the car, but I don't race it. I attend about a half dozen DE's a year. Most of the time, the car is on the street though and that's why I wanted a 112 lsa cam. I like for the power to come on at a lower, more useable rpm for street driving.
I've heard that the 918's produce more hp and the hp falls off less quickly than the 921's. I don't know if this is true or not.
I want a good strong spring, but I don't want to go with too stiff of spring for my application either.
Are there any other drawbacks to the 921's besides cost?
Thanks again!
X
I'm not running a .600 lift though. The cam that I'm looking at is around 230 with a .571 lift on a 112 lsa.
I also track the car, but I don't race it. I attend about a half dozen DE's a year. Most of the time, the car is on the street though and that's why I wanted a 112 lsa cam. I like for the power to come on at a lower, more useable rpm for street driving.
I've heard that the 918's produce more hp and the hp falls off less quickly than the 921's. I don't know if this is true or not.
I want a good strong spring, but I don't want to go with too stiff of spring for my application either.
Are there any other drawbacks to the 921's besides cost?
Thanks again!
X
Racer
Joined: Jul 2003
Posts: 398
Likes: 0
From: Calera AL
I am using the manley single springs supplied in MTI's kit. They have been flawless for about 4-5K miles now and for many trips about 6 grand. They are single springs though. And I am running them with a both a .550 and now a .581 lift cam. I have never heard of a broken manley spring yet.
Melting Slicks
Joined: Jun 2001
Posts: 2,743
Likes: 3
From: Davie Florida
Originally Posted by X_03_Cobra_guy
I am using the manley single springs supplied in MTI's kit. They have been flawless for about 4-5K miles now and for many trips about 6 grand. They are single springs though. And I am running them with a both a .550 and now a .581 lift cam. I have never heard of a broken manley spring yet.
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Drifting
Joined: Jul 2003
Posts: 1,796
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From: Annandale VA
FWIW, the 112 LSA grind will not cause the power band to come on any earlier than a 114. In order to get the power lower, you need to get the intake valve opening earlier by advancing the cam. What the 112 will do is make your peak TQ a bit higher, at the expense of the power falling off a little quicker after peak HP is reached.
Most guys choose the 112 LSA because of the lope at idle --- sounds cooler.
Most guys choose the 112 LSA because of the lope at idle --- sounds cooler.
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,661
Likes: 1
FWIW, the 112 LSA grind will not cause the power band to come on any earlier than a 114. In order to get the power lower, you need to get the intake valve opening earlier by advancing the cam. What the 112 will do is make your peak TQ a bit higher, at the expense of the power falling off a little quicker after peak HP is reached.
I also thought that the 112 lsa cam brought on the power earlier, so I had more midrange than high end.
This is not true?
I'm still up in the air about which springs to go with. If there aren't any real drawbacks to the 921's other than cost, I might as well go with the stronger spring.
X
