Smaller ports equals more power?
03-24-2005, 08:48 PM
#1
3.0 BAR
Thread Starter
Join Date: Aug 2003
Posts: 1,950
Smaller ports equals more power?
I was browsing on another forum and found this link http://mototuneusa.com/think_fast_intake_porting.htm (interestingly enough posted by Gavin on this site as well) It's about how smaller intake ports makes more power and how flow benching heads is crap. My friends are in a dyno class at school and all they do is flow bench small block heads and now I'm wondering if it's all worthless. Really interesting read, check it out.
03-24-2005, 08:53 PM
#2
3.0 BAR
Join Date: Jan 2003
Posts: 4,438
Re: Smaller ports equals more power?
well if you over port or take too much material away from certain areas (ie... people tend to kill short side radius of the ports in hond heads) you will seriously kill the flow. Smaller ports will give you a bigger torque curve without limiting peak power too much, but for all out serious hp, serious flow numbers are needed. Most stock chevy/ford v8 heads especially from back in the day... look and flow like ***.
03-24-2005, 11:15 PM
#4
1.5 BAR
Join Date: Jun 2003
Posts: 824
Re: Smaller ports equals more power?
CFM doesn't really matter. If I wanted a high CFM all I'd have to do is hog the ports out. A sewer pipe will flow more CFM than a straw. If you can't deliver a nice atomized charge to the cylinder then no CFM will help you. Smaller ports equal more velocity, velocity helps to charge the cylinder and usually helps to suspend the charge.
03-25-2005, 04:23 AM
#6
0.0 BAR
Join Date: Dec 2002
Posts: 0
Re: Smaller ports equals more power?
Oh and a quality head will gian 20 whp w/ a stock cams done by an experinced head porter no your not one and no one else is here just becasue you read a article and buy a dremel tool. Dynos dont lie head porting makes power plain and simple.
03-25-2005, 10:52 AM
#8
0.5 BAR
Join Date: Mar 2005
Posts: 86
Re: Smaller ports equals more power?
Thats a great website. He claims it will work on any N/A motor ( I think he mentioned something about this not being practical with foced induction ), including a 2-valve which I don't really understand.. I was going to do that to my head before I caught the boost bug.
Check out the page on breaking in motors also.
Check out the page on breaking in motors also.
03-25-2005, 03:18 PM
#10
1.0 BAR
Join Date: May 2003
Posts: 326
Re: Smaller ports equals more power?
Originally Posted by FURACERMAN
Smaller ports equal more velocity, velocity helps to charge the cylinder and usually helps to suspend the charge.
Pressure difference is what forces air into your cylinders. High in your intake and very low in the cylinders. The bigger the difference in pressure, the more driving force (filling) of the cylinders. As air flows in it eqalized the pressure making the flow slow down.
Now the crutch.... A lot of cylinder filling is due to the mass (interia) of the air. It will continue to fill the cylinders because its moving fast even after the pressure almost equal. So the faster its moving the more you can jam in durring the last part of the intake stroke.
On the other side, the faster the air is moving the more frictional loss (pressure drop). Find the balance between the two and you get max air in the cylinders=most hp.
