I'm not pursuing the nth N/A performance for my engine build, so here's my $0.02 on a RELIABLE OEMish setup for ~500 boosted WHP. Most of my thought process begins here in my build thread:
http://www.nsxprime.com/forum/showthread.php?t=154927&page=9
Of course, everyone has different goals and how much money available to spend, so here goes my approach....
1. Valve guide = OEM or aftermarket?
With ~130k hard daily-driven 8k redline shifts on my engine (that's the benefit of a quiet OEM exhaust btw), my valve guides were in perfect shape. I had new OEM ones purchased to change out, but have decided not to. My engine builder was amazed. Valve seats are perfect too. Why mess with those if there's no wear as opposed to something that's fatigued like keepers or retainers or springs as discussed below?
Maybe I don't know the benefits of aftermarket valve guides? Is there some super-slippery non-wearing material out there that's cheap too? :smile:
2. Retainer = OEM or aftermarket (if aftermarket, I am going to stay with stainless)
This is related to your spring question below, but if you go with custom springs, you'll probably have to use their retainers too. In my Ti retainer search, there's various Ti alloys and heat-treating processes that make some a lot better than others. But of course, that's $$ too.
So, for my setup, I bought new OEM retainers to use with my new OEM springs. I also bought new OEM spring seats too, even though they're not "stressed" or wear. They were cheap....
I talked with Eibach about custom springs with lower spring rates than what they offer in their catalogue (since those rates are insanely high). Also talked with Comp Cams and Supertech....
3. Valve spring = does anyone what the OEM springs are rated to/at?
I haven't measured the OEM spring rate. The SM gives service limit height though. Since I'm not going for insane power, or big cams, I didn't want an increased spring rate for my rebuild.
However, due to 20 years of heat cycling, 130k miles, and the fact I want ~10psig boost, I bought new OEM springs. Had to wait on those from Japan :smile:
I'll ask my machinist to measure the old and new spring rates if the new springs haven't already been installed in the heads. I've never seen those numbers published on here either.
EDIT - I estimate seat pressure at ~56lbs from here:
http://www.nsxprime.com/forum/showpost.php?p=1543107&postcount=228
Eibachs are 80lbs seat pressure.
Alright, bored at work so I calculated Supertech and Eibach spring rates...
Supertech:
[email protected] seated
220lbs@12mm open
Rate = (220-67)/(36.4-12) = 6.2lbs/mm = 157.5lb/in
Eibach:
[email protected] seated
[email protected] open
Rate = (226-80)/(36.4-23.4) = 11.23lbs/mm = 285.2lb/in
4. LMA = I think I'll go ahead and upgrade to the newer spring style.
Yes, I bought the SOS kit about a year ago for my build. I would see how much they cost straight from Honda for the part numbers greenberet posted though.
5. Cotter valve = that is what most manufacturers refer to as a "lock", right? OEM or aftermarket?
I know of them as valve "locks" or "keepers." Yes, these are stressed too and can break. You'll get these from your valve and retainer people since they might have their own proprietary design and what angle they think is best....
I kept my OEM valves since they were in perfect condition. Just decarboned, polished and they were as good as new. Good enough for me and the $$ involved for aftermarket ones. So, I bought new OEM keepers.
I'm impressed with Honda's design and their mix of performance, longevity, and cost. Their engineers really are pretty sharp so I didn't want to deviate much from that :wink: Not saying it can't be improved, but I trust OEM Honda over aftermarket when trying to avoid dropped valves for another 20 years and 150k miles!!!
New OEM springs, retainers, keepers, and seats:
