I am looking at installing some Tomei 260 Procams with 11.5mm lift soon and will also need to updgrade the springs to handle all that lift. A maximum rpm of 8000rpm will be set.


Would single springs be fine?
Should single springs be installed without updgraded retainers?
Does the titanium retainer wear out faster than the stock retainer?
At what point is it better to go double spring vs single spring?


There are a number of brands out there to consider:

Supertech
Ferrera
Crower
Revolver
Buschur


I am hoping to hear some feedback from members who have used any of these brands or others and have some recommendations as to which to use or avoid as there is not a lot of information about the different types of springs and retainers combos out there.

Note that Tomei suggest using their updgraded springs and keeping the stock retainers.

 

I know that AMS is using the double supertech springs and the supertech 1mm over valve and they are holding up well on the 800+whp shop car. Rule of thumb if I am right is use a double spring for higher RPM's and heavier valves themselves. The factory valves are very light and only require single springs from what I understand...always go with titanium retainers, its the hardest and best....someone jump in and save me....

Chris

 

Crowers are not very stiff, I consider them more of a factory replacement then an upgraded valve spring.

I've been very satisfied with the Supertech products I've used. There singles are stiff enough for most of the cams on the market.

 

You would be fine with either the Supertech singles or duals. We have used them time and time again and they are the best bang for the buck out there IMHO

http://www.z1auto.com/prodmore.asp?m...ne&prodid=1610

 

I just put in Tomei 260 procams in with their springs, their springs are straight and the stockers are beehive so the stock retainers are too small.
I used the Supertech retainers.
I got the parts from Z1 and Adam sourced out the retainers for me when I found out about the fit issues.

 

Bill - did you ever verify though that the retainers you showed me that day in NJ were from an Evo though?

 

Yes they were. I now have a bunch more of them in a box too!

 

Single vs. double spring:
The main things here are 1)solid length 2)stiffness and 3)life. There's a minimum stiffness which is determined by the critical freq. (set by the max rpm) and the loads/accelerations from the cam profile.
Double springs are 2 springs that total up to give the required stiffness as the required value. Since each of them is a more compliant spring than the single, their wires will be thinner (for the same number of coils) and therefore their solid length will _in general_ be shorter which allows for greater possible deflection, so you can use a more extreme lift. On the other hand, the stiffer single spring (with thicker wire) will have a higher critical frequency so it will be able to work at a higher rpm without problems (like unseating componets). The thicker wire in the single will also allow for lower stresses in the coil which should improve life, but this also depends on how much load goes on each of the springs on the dual spring setup.
Now the problem is that since the two springs sit inside each other, they won't really be reaping as much of an advantage since the one on the inside will have to be pretty fat to compensate for the reduced outer diameter. Some designs use the same wire for both, but the stiffness of the two coils still add up to the 'right' value.
Now, i'm saying this in a totally general sense. There are loads of variables that you can play with. For example you can play around with the number of coils, but I don't think you're going to be able to change a lot there cost the overall geometry is fairly limited. I beilieve also that people are using exotic materials and wires (Tomei, I think uses rectangular wires for reduced solid lenght) so there will certainly be exception to what I have mentioned. In any case, if the springs are well engineered, either a single or double will work. The most important thing is that they are engineered to match your application, whether they're single or double shouldn't make any real world difference. The point I'm trying to make here (and failing miserably) is that this is a very complicated topic (marred but the fact that you can only get wires of certain sizes) and there is no quick answer as to which one is better in principle.

Ti retainers
As for Ti retainers, if done properly, they will last as long as the steel ones. And are likely to last longer. Do use them, the reduced mass will reduce the loads in your valve train and as a bonus increase the critical freq. on your valve system so you can theoretically run at a higher rpm with the same spring stiffness. Whether or not you should replace the retainers is up to the spring manufacturer. If the springs are designed to fit the retainers then you'll have no problems. If they're a mismatch you won't get very far.

 

Thanks for the replies guys.

x838nwy - Thanks for the theory. I think I am more confused about which one to go for now!

I must admit that I was leaning towards the Supertech springs and retainers given the number of good reports I have heard about Supertech, but I was hoping to hear how the other brands I mentioned compared. If Supertech is what everyone is using with success then they must be doing something right!

Now to decide on single or double springs...


A bit off topic - BMan, how are the Tomei cams going?

 

I love them. Nice strong power all through the rpm range. I think it woke the whole thing up. In fact, the first time I showed the wife she jumped for the first time, and said "damn, now that made a huge difference".
I'll post numbers after I get it tuned (waiting for UTEC revision release).