So on a higher lift cam, like a Kelford 272, GSC S2 (or if I'm really lucky, something like a GSC "S2R") spinning out to ~9200 RPM:
- What would you recommend as a service interval on dual springs
- Would you still go with Kiggly's - and why?

I am going to be looking to go to a higher lift cam when I finally get my paws on an EFR, so looking at possibly redoing the springs at that time wouldn't be that big of a deal. My supertech duals probably have about 10-15K miles on them.

l8r)

 

I don't think any of the other spring manufacturers put in the effort or Engineering time to develop a spring specifically for the 4g63... and their testing probably didn't include running those exact springs on their 8 second race car. As far as why I run the Kiggly springs, I know Kevin is a like minded Engineer to myself and I can see all the development and testing that he put into these springs and what he uses them for. I think I trust his work and the time he put in over an OTS option.... with maybe a vendor backing that brand.... which that vendor probably doesn't approach the problem with the same testing and engineering that Kiggly has put into these springs. That's not a quantitative answer or an answer based in Physics, but it's my honest answer.

Valve springs are service items, and their rates do change. A good spring will maintain its rate for longer than a poor spring.

If you wanted to go nuts, you could get some Titanium valve springs from RCS

 

lots of great advice in here regarding vavles etc, so i wont go there as it is not something I am very well informed in.

cams id go with the S2s and get some supetech Ti springs, seats, and retainers and call it a day! will provide goo mid range power but not drop off up top like some of the other cams. give you plenty of room to "grow" into a red or BBK, but wont be overkill for the street.

cheers and gl with the build brotha

 

Good info so far, so the S2's have a 11.2 lift? Isn't that the same as the Cosworth M2's? Or are they 11.0 flat? I forget

 

What did you decide to go with?

 

I also think you cant go wrong with gsc s2s Good luck with your choice