View Full Version : psi 1511 with high lift?


Greg Fell
09-20-2006, 11:46 AM
Thinking of going with the PSI 1511's with TI retainers.

I'm running the GM TI intakes and GM Sodium Filled/Hollow exhaust with lash caps, and also with the stock GM rockers w harland sharp fulcrums. Also running morel lifters. 7.650 3/8 stem 5/16 tip pushrods.

My cam is .670/.650 lift.

If I shim to an installed height of 1.825 I get a seat pressure of 110 and an open pressure of 367 for the intake and 360 for exhaust. Is this seat pressure enough?

What would the safest minimum seat pressure you'd need for a 'light' valvetrain and 7k rpm?

Can someone give me a sanity check?


Endurance Spring: Single- Beehive LS1 & LS6 (O.D.: 1.290") (I.D. Outer: .630") (I.D. Middle: N/A) (I.D. Inner: N/A) (Seat Pressure: 120lbs.@1.800") (Open Pressure: 360lbs.@1.175") (Rate Lb./In.: 384) (Retainer Step: .000") (Max Lift: .625") (Coil Bind: 1.100")

Also, http://www.cvproducts.com/cv/products/specItem.aspx?prodID=161172&keyword=beehive&brandID=61 seems to have a much better price on these springs/retainers than other sponsors. Am I missing something?

1fastWS6
09-20-2006, 12:59 PM
CV has the best prices on PSI that I've seen. Just priced a set of DR1224's and they're $50 cheaper than my -discounted- Summit price.

Can't answer your question on seat pressure.....seems awful low to me though for a cam that size. Have you asked your cam mfg?

Craig

ChucksZ06
09-20-2006, 09:45 PM
Greg, I am far from an expert but I think you would want more seat pressure than that for the rpms you want. I would want to make sure those valves stay closed when they are off the ramp. I can envision it bouncing of the seat at the higher rpms at that low of a seat pressure.

gtovan
09-20-2006, 11:23 PM
Greg,
Jason @ TSP just came out w/ drop-in PRC springs for the LS7 that set up @ stock height. Check them out.

Greg Fell
09-20-2006, 11:44 PM
Greg, I am far from an expert but I think you would want more seat pressure than that for the rpms you want. I would want to make sure those valves stay closed when they are off the ramp. I can envision it bouncing of the seat at the higher rpms at that low of a seat pressure.
Thats the whole point with a beehive spring, they control the valves great and bounce less than a stronger spring. Beehives rpm better than standard springs.
The spring rate is not as linear as a standard spring, it sets it down gentler. Katech did an optron test and it shows better control than a comp 921.