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1971 VW Super Beetle
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Discussion Starter #1
So I have read around and searched around some but I can't seem to find the magic keyword combination to find what I am looking for.

For my high compression build I am going to use a z6 head with a y7 valve train in it. The reason I am going notec is because my car is non-vtec and obd0 so to simplify wiring, the swap, and tuning it makes sense for me and I get the equivalent of a ported y7 head. I am planning on using supertech valve springs since they're the cheapest I can find so far at $131 shipped and a delta 272 regrind (group buy ftw).

My question is should I use the d16z6 valve springs or the d16y7 valve springs? It seems the vtec valve springs have a softer intake spring because once vtec hits you have two springs instead of one pushing on the lobe. Where as the non-vtec springs are all the same stiffness. I am not ruling out going back to vtec with a obd1 conversion and all that jazz in the future so I was thinking just to get the z6 springs to keep my options open and I shouldn't have any adverse problems from the softer intake springs but this is speculation on my part and I would like to hear from someone more knowledgeable than myself.
 

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99 Hatch
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I'm confused, are you getting supertechs? If you are then problem solved, z6/y7/y8 are all the same. If your running OEM springs then get Z6/Y8 intake springs as Vtec springs are stiffer not softer. Run intake springs on the intake and exhaust
 

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Discussion Starter #4
Huh... I must have totally just blanked out the y7 in my mind when looking up these valve springs because I was thinking "vtec" and must have just excluded it.

www.IPG-Supertech.com - Supertech Performance Valvetrain

vs

www.IPG-Supertech.com - Supertech Performance Valvetrain

Hmmm. Both the seat pressure and the lbs/mm ratings on the d16a6 springs are higher than the d16z6 springs. Which is what lead my to the conclusion you want a softer spring for vtec because you have two pushing on one lobe.

Obviously, I can just get the y7/z6 springs which solves my problem completely but I want to learn a little more.
 

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same
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what do you mean 2 springs pushing on 1 lobe? all 16 valve honda sohc D series engines use 16 valve springs, 1 spring per valve. 4 valves per cylinder, 2 springs on intake and 2 springs on exhaust, 2 valves on intake and 2 valves on exhaust..... vtec or non vtec doesnt change anything about any of that.

you honestly dont need aftermarket springs for your 272 grind, they wont add power, and will add strain on the cam lobe, rocker pads, and timing components, so i'd follow the advice of using y8 intake valves for intake and exhaust and be done with it. the reason i say this is because the non vtec 272 wont move the usable powerband high enough to float the valves on stock springs. stock springs will handle 8000rpm even on a boosted motor....
 

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Discussion Starter #6
what do you mean 2 springs pushing on 1 lobe? all 16 valve honda sohc D series engines use 16 valve springs, 1 spring per valve. 4 valves per cylinder, 2 springs on intake and 2 springs on exhaust, 2 valves on intake and 2 valves on exhaust..... vtec or non vtec doesnt change anything about any of that.

you honestly dont need aftermarket springs for your 272 grind, they wont add power, and will add strain on the cam lobe, rocker pads, and timing components, so i'd follow the advice of using y8 intake valves for intake and exhaust and be done with it. the reason i say this is because the non vtec 272 wont move the usable powerband high enough to float the valves on stock springs. stock springs will handle 8000rpm even on a boosted motor....

This --^. When VTEC kicks the outer rocker arms lock to the center one. The center one then takes the pressure of 2 springs because there are 2 valves. Since with two springs the amount of pressure on the cam lobe increases as does wear etc. So to keep stress and wear down would it not make sense to use a softer spring since the combined springs rate should be enough to not float valves in my understanding of how valve float occurs?

Why does nobody talk about the fact that stock valve springs can handle 8k rpm? I am not waste my money on valve springs since I am never going to rev to 8k anyway...
 

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Discussion Starter #7
I sure do make it feel like summer lawl :dots:

It is purposefully a throw back but not to troll or anything I honestly would like to learn more and heck as it is going I may be saving myself $131 :)
 

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del sol
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video quote "isnt it funny that the vtec solenoid looks alot like the transmission solenoid" sir. i find it funny youd say that. anyways.

why dont you just run the z6 springs and that way when you do get vtec, youll be ready. and itll be prepared.
 

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Discussion Starter #9
Alright thanks to the input that I have gotten I was able to better tailor my searching. The general consensus on the internet is even with a "cam" if you don't go past the stock limit of about 7500rpm in the z6 there is really no reason to upgrade the springs. Being that the 272 is not the hottest full race cam ever, and that being non-vtec I won't be revving terribly high I feel pretty comfortable keeping the stock valve train for now. Though there are some brief mentions of people have successfully revved a stock head to 8000rpm and more without valve float (including the one in this thread) but I am yet to substantiate it.
 

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same
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What is VTEC and How Does it Work? - YouTube

This --^. When VTEC kicks the outer rocker arms lock to the center one. The center one then takes the pressure of 2 springs because there are 2 valves. Since with two springs the amount of pressure on the cam lobe increases as does wear etc. So to keep stress and wear down would it not make sense to use a softer spring since the combined springs rate should be enough to not float valves in my understanding of how valve float occurs?

Why does nobody talk about the fact that stock valve springs can handle 8k rpm? I am not waste my money on valve springs since I am never going to rev to 8k anyway...
i think i understand what you are saying but no it doesnt work that way, you need enough pressure to control EACH valve, even though they are working off the same lobe.

the reason you dont see much about springs in the D series community is because stock works for MOST cams, only the less popular more radical grinds really require them..... most people that run them most likely wouldnt need them but do for piece of mind.

i ran stock valvetrain y8 on 20+psi at 8000rpm (datalogged, not according to the factory tach) and didnt float them....
 

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stock vtec intake springs off a z6 or y8 all around and be done with it.
 

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Discussion Starter #12 (Edited)
i think i understand what you are saying but no it doesnt work that way, you need enough pressure to control EACH valve, even though they are working off the same lobe.

the reason you dont see much about springs in the D series community is because stock works for MOST cams, only the less popular more radical grinds really require them..... most people that run them most likely wouldnt need them but do for piece of mind.

i ran stock valvetrain y8 on 20+psi at 8000rpm (datalogged, not according to the factory tach) and didnt float them....
That's pretty awesome. Thanks for putting up with me.

stock vtec intake springs off a z6 or y8 all around and be done with it.
I think for now I will stick with the stock z6 springs and not bother with sourcing z6 intake springs for the exhaust side.

Thanks for all your help guys I hope that this thread will be informative for other people.
 

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what are signs of valvefloat btw.
on my 92 b7 after i put in A6 cam, and tuned it, rev limiter was reset from 6800 to 7600 and now about 7k u will fell a significant loss in power, and sounds like shits gonna explode, and it will puff out a small bit of smoke...its a bad sounding noise..u will be able to detect it right away...stronger springs here i come..
 

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Discussion Starter #20
on my 92 b7 after i put in A6 cam, and tuned it, rev limiter was reset from 6800 to 7600 and now about 7k u will fell a significant loss in power, and sounds like shits gonna explode, and it will puff out a small bit of smoke...its a bad sounding noise..u will be able to detect it right away...stronger springs here i come..
I have read that in like 93 - 95 Honda ran out of b7 valve springs and dipped into their a6 springs.

Yeah all I knew about floating valves is loss in power and smoke out the tail pipe. I didn't want to say anything though because I am not an authority on the subject because I have never had valve float issues before.
 
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