Ok I have my motor/tranny out of my car and am going to rebuild it. I just want to know why HRC upgraded the vavle springs but nothing else? I was under the impression that the springs only needed to be upgraded for higher lift cams or significantly higher rpm. I was originally going to go with crower stage 2's, oversized valves and crower springs but i'm starting to lean toward leaving it stock since HRC ran a 10.7@136 or w/e on the stock head. However, should I upgrade to crane springs? what gives?

im not sure really, maybe their old ones were finally crappin out on them, or they wanted to reassurance that the valves were going to close properly, or maybe they are turning significantly higher rpm, the stock valve springs is basically what controlls that to a point.

Think about it.

The valve spring pulls the valve closed. Boost is trying to push the valve open. Our stock valve springs only give about 40lbs of "pull" on the valve to close it. When you're running almost 30psi, 10lbs of force isn't much to close a valve.

Originally posted by CarbonFiberRST
I just want to know why HRC upgraded the vavle springs but nothing else?

Bll was running it this way to prove the power of the kit on a somewhat stock set up, with the basic build ups.

"Was" is the key word... I'm looking forward to this race season...

Exile Racing Technologies
http://www.exileracing.com
Go that way, really fast, if something gets in your way... turn.

Ah ha, I forgot about the boost pushing them open... Ok thanks for the fast replies...

I always feel like the biggest dumbass after I start a thread... thanks for that feeling guys :)

Originally posted by CarbonFiberRST
Ah ha, I forgot about the boost pushing them open... Ok thanks for the fast replies... I always feel like the biggest dumbass after I start a thread... thanks for that feeling guys :)

haha i know that feeling too... the upgraded springs are to prevent valve float right? anyways, if you have the motor apart and plan to leave the head stock, why not put in some SS valves so you can run a nice shot of nitrous with the turbo?? :evilgrin

yea, that is the plan
to save money i'll keep stock cams but run ss valves, now i am debating on wether or not the machine work will be worth it to put in 1mm oversized valves... I am doing the machine work myself. My dad is going to show me how and then let me do it... so my car may never run again :( (he has access to a machine shop a friend owns)

Ummmmm....valve springs wear out...even low lift stockers. Under aggressive use with higher lift cams and turbo boost, they're gonna wear out even faster. They probably started seeing some erratic valve timing and knew it was time to upgrade.
As Dark One said, boost is working against the spring trying to open the intake lessening the spring's ability to "pull" and hold the valve closed...this is not a normal situation.