lude98SH

I know there have been many people saying that the added compression is not worth the extra weight in the valvetrain, but I heard DonF mention awhile back about flat faced valves actually having better flow characteristics on the exhaust side if this is true it changes things alot.

squeezedeghatch

I definitely want to hear about this, as I have the supertech flatface valves. More info!!

Combustion Contraption

like so many things with engine building/cylinder head flow, "it depends". You probably wont get a real good answer from anyone on here that really knows. If you REALLY want to know, send me a set of flat faced valves, and $100 and i will flow them against stock valves on a stock B16 head that I have here. Ya gotta pay ta play!

egb18c5

i dont port heads, but thinking about does make sense. but then again, there's a lot of things that made sense and didn't make a difference.

i guess its back to the good old trial and error

GoldLudeRay

well aftermarket valves are lighter than stock ones so im sure
the extra material on the valve make them about the same weight as
a stock valve

squeezedeghatch

idk, i dont think companies like skunk and supertech would make products that they know are useless, im sure it has some kind of benefit. It just depends on the setup I suppose.

Combustion Contraption

How would it be "useless" if it flowed a few CFM less than stock? They still will seal, and enable you to add compression without changing pistons or skimming the head. Im not saying that any of them do flow less than stock, but if they did, they would still be far from useless.

lude98SH

anyone else have any info on this ? Or even the weight difference between a flat faced valve, stock aftermarket valve and a OEM valve. I think that would be interesting.

squeezedeghatch

What i was saying is that those companies would not make valves if they did not produce some kind of benefit, whether it be light weight or raise compression.

lude98SH

back from the dead bump

Lubo_25

grab a precision weighing scale to the 0.1 grams and check the static weights...

also depending on how many valve jobs you've had you might actually lose compression...so be careful...

lighter, dished valves for the win...


cheers

Lubo

Combustion Contraption

So youve done this then I suppose? What weighs more? A flat faced , standard sized SUPERTECH valve, or a stock ITR valve?

vinuneuro

Just curious, are there any OEM or factory race engines in the world (Honda or otherwise) that use flat-face valves?

d15Beta

steve, i may hit u up on that offer.. flowing flat valves vs oem valves hehe

lude98SH

Actually if anyone else is willing to put up some money I have a stock h22 head that I wanted to flow anyway. I have OEM h22 valves. I just need some flat faced valves, the only ones I have are in my motor. This will also help all stock head guys in camshaft selection.

00Red_SiR

I'd be up for CC doing the flow test and seeing the difference.

From what I know, it has to do with the way the air flows around the valve head. A dished (standard/stock style) intake valve allows the air to flow around it more quickly due to it's shape. The exhaust valve flows better if it's flat or even bubbled slightly since the air moves in the opposite direction over the valve head. When the valve is dished like stock, it can "cup" the airflow and slow it's exit speed.

I'm sure CC or don F could give a more technical explaination of what I'm trying to say.

mikesrex

seems like it would be pretty easy to model the system using some computer software to see what flows better

nikko_SOHC

so wouldit make sense to buy a set of flat faced exhaust valves and a set of dished intake valves? if this theory were true.

00Red_SiR

Yes. That is how my new head is set up, however I would go with whatever my head porter/builder suggested.

nikko_SOHC

does your setup have all aftermarket valves or a combo of oem and aftermarket?

00Red_SiR

All aftermarket but the intakes are just stock replacements to the best of my knowledge. Similar shape and design, nothing really special, just replacing them at the same time as the exhaust and are probably less expensive than the stock ones.