You guys are cracking me up. I WAS KIDDING ABOUT CHARGING FOR RESULTS.
I have completed phase 1 of testing and the results are very interesting.
As promised test one is on a stock head measured up to .450" lift only. This was done on purpose to give people an idea of what is happening on a stock motor.
Test 1 - no pipe or diffuser ---------- 106cfm
Test 2 - 6" straight diffuser ---------- 113cfm
Test 3 - Kooks longtubes ------------ 115cfm
Test 4 - Kooks short tubes ---------- 109 cfm
Test 5 - Mac shortie ---------------- 112 cfm
Test 6 - 95 Mustang header --------- 99.5 cfm
Test 7 - 96 T-bird header ----------- 92.5 cfm
Test 8 - Stock 89 manifold ---------- 95 cfm
Test 9 - Stock 95 manifold ---------- 103 cfm
So, for a stock engine, Kooks headers are clearly the winners. I was surprised to see that the longtubes were better than the short tubes. clearly collector design plays an important part in flow! More on this later.
The MAC shortie exemplifies how a short tube header with a good collector can outflow a long tube. The MAC's have a smaller primary tube but still out did the Kooks short tubes. More on that later too.
The 96 Tbird "header" is clearly no good, not even for a stocker. This example had been treated to a nice little clean up porting job but still performed dismally. Bone stock I'm sure it would have been worse. Two things contribute to this IMO. 1) the tubes are too small and 2) the way they join the plenum is not smooth.
The big surprise is how the stock 89 and 95 manifolds perform - completely stock. The 89 was very bad and I didn't expect much more from the 95 manifold but someone was burning the midnight oil on that one. It surprised me so much that I decided to flow all three ports to see what it looked like. To my amazement the front port actually flowed better than the middle one and actually nearly matched the real headers at over 113cfm!
So this started me to testing other ports and I started to realize that there can be great disparity between ports on the same header. The worst was the 89 manifold flowing only 94.5cfm on the middle port but 111cfm on the front port.
I have read things like this before and I know that BBK advertises an improved and symetrical collector design that is supposed to fix these problems. So my first round of testing was in no way comprehensive because I did not test all the ports on all the headers. I did notice though that the MAC has some awkward tube/collector alignments.
So that means more testing before we start to declare any winners.
Anyway, there is your teaser for the evening. Any comments?