how much mph increase have you all got from changing valve springs?

[trbojo]

just wondering. i'm seriously(?) thinking that my old,stock ones are really holding me back. i am replacing them NEXT, regardless. i was thinking, front mount, 3" d.p., but why spend the big money when it's probably the obvious that i keep trying to stay away from, that will only cost about 60 bucks in parts. i guess i'm just thinking labor time, but then again, all 3 would probably take me the same amount of time. again, wondering how many mph you guys have picked up. thanks.

 

[KillrV6]

3 MPH and almost one full sec !!!


14.6 @ 94

to 13.7 @ 97

 

[Gn-ing]

I did it ,and saw no gain at all on a 73k motor...stayed at 103,until i did more mods....

 

[strikeeagle]

Valve spring changes are overrated. On the other hand, if the springs are too strong, goodbye cam.

 

[XLR8]

Made a big difference in my car. It could bearly rev over 4500rpm until I replaced the springs.

 

[KillrV6]

i should add that when i changed my valve springs the car had about 160k miles on it, so my old springs were quite warn.

the gain you experience depends on the current condition of your stock springs.

 

[6 beats 8]

I got a VERY consistant 3-4 MPH increase with new springs.

 

[trbojo]

ttt

 

[getchasum]

Here's some info on spring pressure I posted a while back. I would say do the springs if they have never been done. BUT! like advised above stay away from the high lb spring pressure, no need to stress the stock cam. Do the springs, 3" dp, good flowing stock location I/C, and turn that 60 up! You have a mid to low 11 sec combo!

These numbers are from a 1996 issuse of GSX-TRA. Test was done at recommended installed height of 1.71. Note GM recommends a minimum seat pressure of 78 psi.

Spring Type:

New stock GM...........................78-81 psi
New Comp Cam (979)...............86-88 psi
Stock w/30kmi. (raced often)....45-52 psi
Stock w/32k mi. (daily driver)....55-61 psi
Stock w/62k mi. (raced Often)...44-51 psi
Stock w/65k ( daily driver).........49-58 psi
stock w/98k mi. (daily driver).....45-56 psi
stock w/68k mi (overheated).....41-48 psi
Comp Cam w/34k mi (979's) .....74-80 psi

Test results were on all springs and these numbers were the range that was found. You can see that even a low mile car in 1996 sping pressure was down. I just recently changed the springs in mine, top end feels more peppy to me. These numbers anwsered the question for me.