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Nailhead valves verses Tulip valves

  
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Nailhead valves verses Tulip valves

 
Fahlin_Racing Fahlin_Racing
I’ve been to a few races | Posts: 109 | Joined: 06/10
Posted: 10/09/12
05:21 PM

Have been thinking recently about the valves themselves and being used in stock or slightly 'buildable' racing classes. Which would be worth the money or would we be better off just modifying the stocker pieces if the ports are untouchable?  

pepsi1 pepsi1
I’ve been to a few races | Posts: 72 | Joined: 09/11
Posted: 10/17/12
04:28 PM

The tulip valves. The manufacturers go through a big expense to put them there. The swirl is a nice way to mix the air and fuel, the bigger plus it is tapered to help that flow mix in the combustion chamber. It shows up on the flow bench...  

Fahlin_Racing Fahlin_Racing
I’ve been to a few races | Posts: 109 | Joined: 06/10
Posted: 10/18/12
05:04 PM

What have you seen that benefit the most as far as rpm range with either valve?  

pepsi1 pepsi1
I’ve been to a few races | Posts: 72 | Joined: 09/11
Posted: 10/18/12
08:10 PM

The shape of the valve just flows better. Without any work that tulip will flow to 7000RPM or more.. How high are you going to spin your engine?  

Fahlin_Racing Fahlin_Racing
I’ve been to a few races | Posts: 109 | Joined: 06/10
Posted: 10/24/12
05:23 PM

Yeah, I am merely striking up some conversation is all. I was just was curious on if there is a'stock' engine that if on a budget would the flow of these out-weigh the cost difference from the basic nailhead design.

How have you been Pepsi?  

Fahlin_Racing Fahlin_Racing
I’ve been to a few races | Posts: 109 | Joined: 06/10
Posted: 11/25/12
05:53 AM

Here is a URL for a short video on Youtube for the tulip valve, however its not 'flowing' but you can see the velocity changes through the colors.

http://www.youtube.com/watch?v=HlzctVtCzyg&feature=share&list=ULHlzctVtCzyg

Here is a URL for a simulation of an ICE and looks like the standard nailhead style valve the OEMs use.

http://youtu.be/etXBD3u7nlw  

waynep71222 waynep71222
I watched NASCAR once | Posts: 17 | Joined: 04/12
Posted: 12/14/12
12:04 PM

just wanted to say thanks for linking those flow diagrams.

i have been thinking of the intake port flow for a long time...

but visualizing the stop and start of the flow as the intake valve closes and opens...

one wonders if the increase in volume around the back of the intake valve is a good idea or a bad idea for race engines..

as they are operated in a fairly high rpm narrow range of speed.. one could fine tune the bowl shape and reduce the volume to create a higher pressure area without reflecting waves going back up the intake port when the valve closes..

one also has to figure in the changes in speed of the piston into the stroke...

having a high pressure area at the back of the valve when it opens would seem to be a good idea...

so a tapered bowl area might be needed..  instead of a curved bend.  or even a flared bowl that might reduce speed of the flow as the valve opens and the piston moving down has to start the air flow moving again..

we are talking about HIGH SPEED engines here.. not a LOW RPM stocker.. super speedway motors..  

pepsi1 pepsi1
I’ve been to a few races | Posts: 72 | Joined: 09/11
Posted: 12/15/12
06:44 PM

Wayne:
  Actually if you could build a cylider head with  a triangular valve with the same volume and arear as around valve. You would see flow rates skyrocket....I played around with different designs when I was playing with valves back in the dark ages.To costly.
  What we learned the steepper the angle the cylinder head sits on the engine block we are getting the effect I was trying to explain....Angle milling but the bolt holes don't line up....Remember what we said about Minds....LOL...

Bob  

waynep71222 waynep71222
I watched NASCAR once | Posts: 17 | Joined: 04/12
Posted: 12/15/12
11:20 PM

bob and others...

i am not really talking about increasing flow numbers on the bench..

i am talking about tuning the intake port to keep the port velocities up while the intake valve opens and closes..

shaping the bowl behind the intake valve  to a taper. instead of an elbow.. so there is place for the air pressure to build up without slowing down the port velocities..  or having reflections back up the intake port..  less volume behind the intake valve head is less volume that has to stop and start flowing as the valve closes and opens again...

think of a plumbing water hammer.  where you close a faucet to fast and the inertia of the water flow slams into the closed valve.. builds pressure.. the reflection off the instant reversion wave rattles backwards through the pipe..   why not reduce the area where the reflection is created so there is less amplitude of the reflection.  since this is a cyclic happening.. careful calculations might create a higher pressure area right at the back of the valve face so when the valve starts to open.. the increased pressure there allows more air and fuel into the chamber.. creating more power...

this is beyond bench flow testing the ports... this is TUNING the intake port .  this would have to be measured on a dyno with the engine operating carefully measuring the actual amount of airflow into the carb...  and the power output..

again.. this is for HIGH SPEED TRACK motors..

it will have to be worked out in a CFD program.. to tweak the port size and shape..

but again.. not looking at the fixed open valve flow numbers.

would it work at lower speeds.. perhaps..  but who here wants to go slow..  

Fahlin_Racing Fahlin_Racing
I’ve been to a few races | Posts: 109 | Joined: 06/10
Posted: 03/31/13
06:14 AM

Wayne, you have posted some very good thoughts and have opened another window in thinking of flow. I am glad you posted your point of view.

It is seeming IMO that you could use this in a dry flow induction system as well from your wording.