Head Flow Bench Testing

[hubeerjw]

I had some bench tests done today on some VMax and Venture heads. I used VMax cams on both. My hopes were to use the Venture heads as a test set to play with and see where the most improvements can be made in regards to the flow on the intake side of things. As it turns out, the VMax and Venture heads are a little more different than I originally thought. Besides being made out of different material, the VMax intake ports have already been opened up quite a bit more, so it really doesn't help me too much to mess with the Venture heads.

Anyway, here are the results with the testing being done at 28" of H2O and testing only 1 cylinder:

Venture Head w/out a spark plug (oops) 198.94 cfm
VMax Head w/out a spark plug (oops again) 231.03 cfm

This was done with no intakes on the heads... and after we remembered to put the spark plugs in, here are the more accurate results:

Venture head - 183.26 cfm
VMax Head - 211.77 cfm

We also tested a 500cfm 2 barrel carb and it flowed close to 400cfm at 28"
I have also been told that a 4 barrel 750cfm will flow a 350ci / 5.7L motor up to 9k rpm...... I'm just trying to do some calculations and see what I can come up with for new carbs/intakes/.....etc.

Anyone else had some head work done with any flow #'s?

Jeff

 

[Birdoprey]

Very cool. Is 28" of vaccum the std? I've had some oil cooled GSXR1100 heads flowed(ported and stk). The stk GSXR heads flowed around 90cfm on the intake w/ stk 27mm valves(i think thats what size stk was). The ported head flowed 133 cfm on the intake with 31mm valves. Had another that Carpenter ported and it flowed right at 140cfm with a 30mm intake valve. Thats the max one can get from those heads w/o epoxy and reshaping port drastically. Had that last head on a 01 Bandit w/ 1340cc motor. Made 196rwhp with small sidewinder exhaust.
I'm not sure how many inches of vaccum they were flowed at. I'm guessing it may have been different than yours since your flow #'s are MUCH higher. Heck, they are higher than a set of Edelbrock RPM alum heads for a small block Ford flows!
You measured these flow rates with the stk valves? What was the max lift?

Great info! Thanks for posting!

 

[lankeeyankee]

Great info Jeff. If I have no luck of a trading my VMAX for a dragbike within a couple of months I would like to pull my heads and do some work here to help the MPH at the track.
I know a guy here in Nashville who is the master of headwork and bench testing named Robert Mcbride and has tons of talent when it comes to getting a head to flow. He made one of his flow bench testers it pretty much looked like a vacuum cleaner with some hoses to clear tubes with ping pong balls on a head jig. Doesnt sound like it would cost to much to make one for a VMAX. Would be interested in any thoughts of building a low budget flow bench tester..
I have 3 sets of heads so I could afford a screw up in the learning curve.. Mix up some epoxy and lets start testing...

 

[lankeeyankee]

http://www.diyporting.com/flowbench.html

http://www.kartingtechinfo.com/tech/flow.htm

 

[hubeerjw]

It would be cool to do your own testing, but on the link you posted Lankee, you wouldn't need all that digital measurment crap... it would be nice, but not nesessary. There are so many factors that can go into getting accurate flow numbers that my numbers probably won't help anyone else out much unless they went to the same guy that I did (to have the testing done). You could essentially use a vacuum, you just need to make sure you are "sucking" the same amount each time (kind of an adjustable wastgate idea with vacuum) and then some type of barometer to measure the pressure difference. As long as you have a baseline to start from, you should be good to go. I would really like to see some HP numbers, improvements, gains, of those that have done some head work. I think the biggest problem is that when someone has some head work done... there are usually other upgrades done at the same time, so it is difficult to say what
kind of improvements can be made.
Jeff

 

[lankeeyankee]

Yeah the software part of it is getting a lil to anal for me.
I would just like a simple setup to see an improvement or not in trying different things and what parts of the chamber have to be built up and what has to be taken away... Exhaust ports are easier than the intake..

Vac gauges are fairly cheap. And the vaccuum would have to be adjustable maybe with a variable control to adjust the AC current.

All in with all materials to build one I am guessing under 200.00