PerformanceTrucks.net Forums

PerformanceTrucks.net Forums (https://www.performancetrucks.net/forums/)
-   INTERNAL ENGINE MODIFICATIONS (https://www.performancetrucks.net/forums/internal-engine-modifications-158/)
-   -   Which Springs? (https://www.performancetrucks.net/forums/internal-engine-modifications-158/springs-501461/)

Hivelocit 05-07-2012 09:03 AM

Which Springs?
 
Okay so quick engine specs:

2005 LQ4
317 heads stock
7.4 hardened PR
Isky Tripple 12 cam
LS9 Head gasket
ARP Head Studs
76mm turbo

The big question is what spring do I use, I like the added insurance for the duals... but I don't know what spring pressure to shoot for especially since this isnt a high lift cam! Patriot Performance 8401-B ? or are the Extremes a better choice? Any suggestions? Thanks!

Hivelocit 05-07-2012 09:42 PM

Basically anything tried and true for a turbo'd 6.0... Any thoughts?

Hivelocit 05-08-2012 07:32 AM

Not getting any feedback, so I looked up some older posts concerning Single vs. Dual Springs and looks like we have a winner...

Patriot Performance 8401:

Technical Specs:
Install Height: 1.800''
Max. Valve Spring Lift: 0.650''
Spring Pressure Closed: 135 lbs. @ 1.800''
Spring Pressure Open: 375 lbs. @ 1.150''
Coil Bind: 1.090''
Retainer Material: Titanium

They are drop in which are a plus, dual spring for a little extra insurance, and have great user reviews.. I know they have been used on a lot of motors out there, but they are new to me and Jeg's sells the whole kit for $256, pretty nice for duals with ti retainers!

With only 8-10lbs of boost I doubt I'll have worries of seat pressure, although just for the sake of this thread anyone who might look into a set of Valve Springs and what Seat Pressure to consider in relation to a Turbo/Supercharger build I found this in a thread from yellowbullet.com that might help:

The Crane Cams website used to state this;
"Selecting the proper valve spring for any performance engine is important; but it is critical to proper operation of supercharged engines. Consider the fact that when the engine is in a "boosted" condition, the supercharger (or turbocharger) is trying to blow the intake valve open. The boost pressure actually reduces the intake valve spring seat pressure. This is extremely critical on engines with hydraulic lash adjustment. Proper seat pressure (working through the rocker arm and pushrod) is necessary to keep the hydraulic lifter plunger centered in the lifter body to prevent "pump-up." If an engine has 2.25" dia. intake valves, there is 4 sq. inches of backside valve area. Now add 12 (psi) of boost pressure, and you have reduced your effective seat pressure by 48 lbs. (12 lbs/sq.in. X 4 sq. in.). If you started out with 120 lbs. of seat pressure (static), you now have 72 lbs. of operational seat pressure. There is no way that 72 lbs. of pressure is going to control a 2.25" valve! For street use, the answer is to select a tall, mild-rate spring that assembles at a high seat pressure, yet keeps the open pressure reasonable over the nose of the cam to assure long cam life. (For example; a great spring on a Big Block Chevrolet with a hydraulic roller and a supercharger is our #96879 spring, which will provide 169 lbs. at 1.880" seat and 432 lbs. at 1.280" open with a .600" net lift cam.) Exhaust valve seat pressure does not need to be raised significantly on supercharged engines. Racing applications with solid lash adjustment do not experience lifter "pump-up,” but still need the high seat pressure to prevent the valve from bouncing on return to the seat against the boost pressure. Consult our easy to use valve spring pressure chart at the back of our Valve Spring and Retainer catalog."

Entire thread at: BOOST & VALVE SPRING PRESSURE?? - Yellow Bullet Forums

Those guys run big motors with big boost but it still applies to us all I would think...

I'm seriously new to this so if any of the gurus on this site have anything to add chime in, this site could use a discussion on this topic.. and sorry if I missed it anywhere couldn't find much from searches :(

1989k1500 05-08-2012 08:24 PM

Those patriot duals will be fine. A friend of mine had them with a .551 lift cam and 19psi with no problems.

zero2sixT 05-08-2012 08:36 PM

I think you made a good choice.

I don't run FI, but I do run those springs. I bought them used from a guy with a .600+ lift cam. I think he sprayed on them too. Haven't had one issue with them.

Hivelocit 05-09-2012 04:43 AM

Thanks guys, yes I purchased them today from Racemart for $255 no tax, and no S&H great price IMO! :pimp:


All times are GMT -5. The time now is 03:38 PM.


© 2024 MH Sub I, LLC dba Internet Brands