Hey guys, building a turbo lq4, The cam I have is a TFS 228/230 .588/.588 112
, using stock rockers and comp pushrods. The springs I have are:

Spring Specs:

1.265" OD
.880" ID
130 Lbs @ 1.790" -Valve Closed, Spring Installed Height
355 Lbs @ .595" lift
Rate# 356
Average Coil Bind @ 1.145"
Maximum allowable lift- .595"

will these work with the cam? Also should I get the Trunion upgrade?

 

Yes get the trunion upgrade, well worth it. The springs should work. Depending on your highest CB height you may get pretty close.

 

I would get double springs if your planning on boost, just to be safe.

 

Should I get ones capable up to .650 lift? Like the Lunati doubles? This car will mostly be daily driven, and rarely shifted past say 6000-6500 rpm

 

IMO you do not need doubles. A good beehive will be more than enough.

 

Thank you!

 

1.790" (Installed height) - 1.145" (coil bind height) = .645" (spring opperating range)

.645" - .588" (cam lift) = .057" (tolerance)

.057" - .050" (recommended tolerance) = .007" (wiggle room on installed spring height)

1.790" - .007" = 1.783" (minumum installed spring height)

So you want and installed spring height between 1.783" to 1.790".
You should be fine.

 

Is that on the low side for tolerance? Basically is it worth it for me to spend an extra 115.00 to get double springs with a .650 max lift?

 

I don't think that it is worth it. Just run the springs that you listed. Just make sure that you check your installed spring height, and get it as close to 1.790 as you can. The closer to 1.783 you get the more stress you put on the valve train. If you go over the 1.790 installed height you won't have your 130lbs of closing pressure when the valve is closed.

 

A +/- 0.010" in difference in installed spring height will only give a +/- 4 lbs difference in spring force. I doubt the valve train cares much in a +/- 4 lbs difference.

Picking a spring with the correct spring rate is far more important to obtain correct opened & closed valve force than hitting the installed height dead nuts.

 

That cam isnt gonna be great for a turbo set up...thats a medium sized N/A cam.