what are the differences?

 

a slight compression bump, I forgot the actual value but it was minimal. I would be concerned about the flat valves weight adding to the valve train, that would probably be minimal also though.

 

the face of the valves are flat causing a slight increase in compression. The stock valves are concave.

Some argue that the little compression you gain is only taken away by the added weight of the valve to make the face flat.

pretty common sense if you put a little THOUGHT to it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">the face of the valves are flat causing a slight increase in compression. The stock valves are concave.

Some argue that the little compression you gain is only taken away by the added weight of the valve to make the face flat.

pretty common sense if you put a little THOUGHT to it.
</TD></TR></TABLE>

i would say the compression bump is better then the weight.... what do you think 98vtec?

 

i dont know the differences in weight so i couldnt tell yuh. I plan on using regular valves in my motor. My compression is being worked on by the crank, pistons and head gasket/or head mill. Honestly rather have light valvetrain than a minute bump in compression.

this is all just my own speculation tho.

 

very marginal if any.. if anything if was NA i would get flat top valved.. i went with dished bc i wanted lower compression

 

Good advice on flat valves:
https://honda-tech.com/zerothre...08720

 

but if your going NA, wouldn't you want it to be light also? i have 12.0:1 cr pistons already, which one would benefit more?

 

why do you need any higher compression than 12:1?

 

flat valves dont flow as well as stock/concave valves. stick w/ stock valves

 

flat NA
dish TURBO

 

just going from what ferrea has told me:

the small bump in compression from the flat valves will not make up for the hp loss from the valves not flowing and pulling in as much air as a regular valve. they had just done some flow testing before i spoke w/ them. this was a few years ago.

ferrea offers both styles and they recommended their regular/concaved valve for my n/a application. they make a great product, but its hard to beat a stock valve for a mild application.

 

if that was the case why would they make flat valves?

 

just another option to offer people who are looking for something to spend their $$ on.

 

on a supertech valve the difference is around 2-3 grams or so approx...i have the dish faced ones they weigh about 48 grams...(approx numbers)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Missing Gears &raquo;</TD></TR><TR><TD CLASS="quote">flat valves dont flow as well as stock/concave valves. stick w/ stock valves </TD></TR></TABLE>



the concavity of the stock valves creates a low pressure pocket, pulling the intake charge over the edge of the valve....ps stock valves are very well designed, just get a new set of those and you'll be set.

flat vales cause no such effect

 

1st of all o'm not mechanic but i believe that my mind anderstunts physics verry good.

a. The way i see it with flat valves your motor makes more compression but are also hevyer. That means that if your valve springs are made to pull the stock valves to cutch up with the stock rev speed they will not be able to pull the hevyer valves with the same speed to prevent valve to piston contact.

b. I know that about 95% of the ppl that replce thier valves also replace the springs+retainers but as simple as my exsample above most of those ppl replace the spring+retainer package to be able to rev higher but again, with the hevyer valves, you will not be able to rev as high as the aftermarket spring made for.

c. There ARE some companys that offer ti flat valves wich are lighter than the oem dish type ones but they cost too much to worth it and you can make more power ,than the little compression upgrade, spending the extra money on other parts.

Once again, i'm not a mechanic, this is just the way i thing of it so if i'm wrong please correct me. We all have something more to learn.

p.s. my english are not so good, i know.

 

Skunk2 offer two types of valve, standard and high compression. The high compression ones still have a dish in the face, but not as big a dish as the standard ones (I've checked). They supposedly increase compression by about .3 - .4

https://honda-tech.com/zerothread?id=1542387

 

i had some skunk flat valves, they are not concave. they only have a flat round spot in the center.

not only that, but they are alot weaker than stock valves. i would never recommend buying a set. if you want aftermarket valves for some reason, go w/ ferrea.