Welcome to the SR20 Community Forum - The Dash.
Register
SR20 forum logo

Thread: Franklin vs supertech valve springs *pics*

+ Reply To Thread
Posts: 11-17 of 17
2014-08-13 23:14:22
#11
Originally Posted by Doctor
Originally Posted by KillerKrossover


On my current build, I did some mix and matching. Ran the Franklin main springs with the factory inner springs.


I recall hearing of people using the factory 20v outer with a stock inner as a good compromise on the ve motors yes, hence my question.

What spring rates did you end up with using that franklin outer and stock inner combination?



Here's the original thread with all the different spring rates: http://www.sr20-forum.com/vvl/24460-20ve-vs-n1-vs-20v-spring-pressures.html

I never had the Franklin springs tested. The numbers were given to me. I would say with the Franklin outer and factory inner springs, the seat pressure would still be greater than stock, N1, and 20v with the two springs setup.
2014-08-14 21:13:20
#12
Anyone know the installed height of the springs on a 20ve head or does it vary by spring manufacturer?

Had to guess today, but all things being equal the supertch 93lbs came out a bit stiffer at open pressure than the franklins. I didn't take note of the seat pressure. Heading back tomorrow.

I'm assuming you want to aim for lowest pressure that will suffice for the valve lift and rpm, but how do you know what is enough? Seems easy to go overboard here and loose hp for nothing.
2014-08-14 22:04:05
#13
Originally Posted by Doctor
Anyone know the installed height of the springs on a 20ve head or does it vary by spring manufacturer?

Had to guess today, but all things being equal the supertch 93lbs came out a bit stiffer at open pressure than the franklins. I didn't take note of the seat pressure. Heading back tomorrow.

I'm assuming you want to aim for lowest pressure that will suffice for the valve lift and rpm, but how do you know what is enough? Seems easy to go overboard here and loose hp for nothing.


Originally Posted by KillerKrossover

No, the inner spring sits higher. It's a shorter spring than the outer spring.

20VE/16VE
Inner Spring free/uncompressed length: 42.02 mm
Outer: 48.49 mm

Installed Length
Inner: 32 mm
Outer: 37 mm

Max Open Length
Inner:20.44 mm
Outer: 25 mm

N1 Springs
Free/Uncompressed Length
Inner: 38.76 mm
Outer: 44.50 mm

Installed Length
Inner: 32 mm
Outer: 37 mm


Max Open Length
Inner: 19.64 mm
Outer: 24.64 mm


20VE/16VE Spring OD/ID
Outer Spring: 1.145" OD, .830" ID
Inner Spring: .797" OD, .615" ID


Test the spring rate at the seat/installed height of 37 mm (main spring) and 32 mm (inner spring).

To test the open spring rate, take the max lift subtract the installed height/length.

Example: N1 camshaft = 12 mm lift

12 mm lift - 37 mm installed length = 25 mm open length

Test the valve springs at 25 mm compressed length to get the open spring rate.
2014-08-15 08:35:02
#14
Test inner and outer together or separate and combine readings?

Since valve lift can be measured differently, is it not better to use the lobe height x rocker ratio? And also account for lash?
2014-08-15 19:20:10
#15
I don't know how serious you are about the spring rates.

If you don't have the equipment and are giving it to someone else to do it, then just give them the seat and open #'s I posted.

If you are doing it yourself, then yes you need to test the inner and outer springs separately. Compress each spring individually to the length, posted above, and add lbs # together.

If you want to be anal about the valve lift, measure the lift right at the retainer. It's the end result of lobe lift, lash, and rocker arm ratio. Change any of those variables and you will change the valve lift.
2014-08-15 20:27:18
#16
You don't want the spring combo to be too stiff.

When i had my VE head work done, the cylinder head shop showed me what happened to rockers & cams when too stiff of a spring was used. He had a engine there from an end of season tear down. SR20VET with brand new rockers and cams, both had major ware in the hardening like if it had done 200,000KM. They were using 130LB seat pressure. He highly recommended the supertech 93LB which he said proved to be a performer and wasn't as harsh on the valve train.
2014-08-15 21:05:26
#17
Ok had them checked again at the engineering shop.

At 37mm this is what I got:

Franklin 52lbs
Supertech ~93lbs

At maximum lift for my cam I got:

Franklin 180lbs
Supertech 170lbs

Interestingly the franklin is shorter than free uncompressed length of the 20ve and n1 springs. At 42mm.
+ Reply To Thread
  • [Type to search users.]
  • Quick Reply
    Thread Information
    There are currently ? users browsing this thread. (? members & ? guests)
    StubUserName

    Back to top