After Market Headers, Cams, intakes
#1
05-17-2001, 03:43 PM
Join Date: Mar 2001
Location: Fremont, NE
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After Market Headers, Cams, intakes
[font size="1" color="#FF0000"]LAST EDITED ON 17-May-01 AT 04:45 PM (EST)[/font][p][font size="1" color="#FF0000"]LAST EDITED ON 17-May-01 AT 04:44 PM (EST)[/font]
I have a general question...
I know that some headers (short tube i think) are good for low end while others are good for high end power. The same with intakes. And I know that the cam and valve train of course have a huge impact on power. You want high port velocity, i believe, in order to get power. So i guess that is why low end cams dont open valves as long or far in order to get more velocity at lower rpms. I think all this so far is right but im not sure.
Assuming the above is correct, I know that certain things make power in different rpm ranges. **BUT** I dont know why. Why do short tube headers, low rise intakes, and high port velocities make low end power and vise versa? Is there someplace I can go that explains the physics behind these concepts? I am good with physics but I cant figure out why the speed of the intake air, the length of the headers, etc has the impact that it does on power.
Any help would be appreciated!
Andrew
'78 Ford Bronco 4x4 (351m, a couple of weeks and it will be a 460
)
ps: I got some headers from L and L products and they are NICE!! So I highly recommend them. (lifetime warranty against rust through)
I have a general question...
I know that some headers (short tube i think) are good for low end while others are good for high end power. The same with intakes. And I know that the cam and valve train of course have a huge impact on power. You want high port velocity, i believe, in order to get power. So i guess that is why low end cams dont open valves as long or far in order to get more velocity at lower rpms. I think all this so far is right but im not sure.
Assuming the above is correct, I know that certain things make power in different rpm ranges. **BUT** I dont know why. Why do short tube headers, low rise intakes, and high port velocities make low end power and vise versa? Is there someplace I can go that explains the physics behind these concepts? I am good with physics but I cant figure out why the speed of the intake air, the length of the headers, etc has the impact that it does on power.
Any help would be appreciated!
Andrew
'78 Ford Bronco 4x4 (351m, a couple of weeks and it will be a 460
)ps: I got some headers from L and L products and they are NICE!! So I highly recommend them. (lifetime warranty against rust through)
#2
05-21-2001, 01:12 AM
After Market Headers, Cams, intakes
Actually the long tube and tri-Y headers are best for low-mid range, whereas the shorties are better for top end. This is just a general statement and really depends on many factors. One book that was helpful was How to build horsepower vol II by David Vizard.
This site has some interesting info, I did have some other links but can't seem to find them now. The filling of the cyl and general design of the heads, engine stroke vs bore and carb cam choices have a big impact. One problem most people have is not matching things up properly and the other is not doing proper research before doing their mods and buying parts. Some of the cam companies like Crower and Crane as well as Ford motorsport offer some great advice.
http://www.bmw-m.net/TECHDATA/CYLINDER.HTM
This site has some interesting info, I did have some other links but can't seem to find them now. The filling of the cyl and general design of the heads, engine stroke vs bore and carb cam choices have a big impact. One problem most people have is not matching things up properly and the other is not doing proper research before doing their mods and buying parts. Some of the cam companies like Crower and Crane as well as Ford motorsport offer some great advice.
http://www.bmw-m.net/TECHDATA/CYLINDER.HTM
#3
05-27-2001, 11:47 AM
