traviss

Flow numbers on my sheets have "open exhaust" and Exhaust with pipe". What is the differance between "open exhaust" and "exhuast with pipe"? Which was is better to look at for flow #'s?


Thanks
Travis

KAAMA

Travis, I am certainly NOT an expert in this area, BUT the only thing I can tell you is that when talking to AFR (Air Flow Research) they told me that the pipe on the exhaust side is to simulate a header primary exhaust pipe/tube which is supposed to give "real world" flow numbers and these are usually better flow numbers than without the pipe. Some may argue this point, however you Do have to bolt on an exhaust system though it may NOT always be a header type of pipe. I think AFR's theory is that if you're going to spend money on a good flowing set of ported heads that you are also going to install a good exhaust system as well in order to compliment the head work.

The cool thing about AFR is that they at least give you both "open" and "with pipe" flow numbers. . They painstakingly/exhaustfully hand port a set of heads as close to perfection as they can get it. Then they digitize all the ports and enter all the data into a computerized CNC machine and you get a perfectly (or close to perfect as possible) ported set of heads EVERY TIME, over and over again without them having to be hand ported again. No more tired hands. You get them relatively quick and a set price. The CNC ported heads really seem to be the thing of the future. There's one way of looking at it anyway.

traviss

Thanks for the info Kaama Thats helps knowing what they flow with a primary header tube.. AFR's flow #'s are impressive compared to all other heads in that catagory of around 190cc for a sbc. Who did you talk to at AFR?, i still have to call them and ask them a few questions.. I would buy them bare but they say on there website bare heads are not ported.. hmmm..


I got most of my ideas worked out for my this winters tweaking lets just say its alpha snappin time

Thanks bro

Travis

KAAMA

Traviss, I talked with a guy named "Dave". I honestly don't know if their porting numbers are inflated as they advertise them just to get the customer interested. However, I think that if you want fully ported heads that at least I would think the CNC machine does it CORRECTLY and CONSISTANTLY each and every time for every port vs hand porting them. I'm sure there are inconsistancies in hand porting and I'll bet the CNC machine has fewer bad days, doesn't need a vacation or a lunch break. It doesn't make up excuses for one reason or another----It just does what it's told and does it quickly! Plus you know what the price is going to be BEFORE it's done!

BTW, you CAN get them bare WITH porting!

traviss

cool , I found a website that tomcat posted with head flows on it and they flowed a set of the AFR 190 heads and it flowed a little more then AFR says I'll give them a call soon..

KAAMA

Traviss,

Like it or not, and as I have said; it sounds like that's the way the industry is going. It's the wave of the future---the new trend and it's at least worth checking into. Happy head hunting and let us know what you found in your search and how well it performs.