Subject: Re: Driving impressions with the AFR heads by anesthes on 2009/8/19 1:14:28
Quote:
BeachBum wrote: Hi Joe,
Fair enough on your post above.
On the $ 800 head like a Sportsman vs an AFR 195 street ports, I think it is dependant on which one, in my opinion, the RHS is a pretty good casting and head for the price, I know some have done some good things with them. But, I think the Sportsman has been passed up in the market. (I ran the Sportsman head for many years both out of the box and then ported).... great head in the 80's and early 90's, fast forward 10-20 years and its outdated I think.
But, the real difference is a cast cylinder head vs cnc ported head...... on a street head, against a casting like the Sportsman, I think the difference is a solid 30 HP, probably more. Against a better casting like the RHS or Dart head, the difference is more like 20-30 HP.... but these are rough guess's. The only valid recent test we have is the $ 1485 AFR 195 street port vs $ 1460 cast Dart Platinum Aluminum Cylinder heads, which are probably a step above these other castings due to some bowl blending.... but not sure. I am going out of memory, but I think the difference in those heads were 25 HP on an rpm limited street car. (Wes's test is what I am referencing that I think you can still see in the C1 section)
I know some will say that this test was biased due to cam selection...... but thats just not true, that test was a 195 vs 200 cc cylinder head test... both in the same class in size.... I have no idea how one cam would benefit the set-up more than the next anything substantial at all..... whatever cam changes made.....would benefit both quite frankly. Besides it was just an off the shelf comp cams 230/236 cam on a 112...... extremely common street/strip cam. That test was about as average as one could get for the your typical street/strip applications.
That test gives us a clue on the difference, thus yes its probably 25-30 over the RHS and a bit more vs the Sportsman is my "Guess"..... cuz I don't know anything for a fact, just bench racing. But, if you're spinning your motor up towards 7k and beyond, I think those gains can turn into considerably more.
I agree, if thats not worth it to you, you shouldn't do it..... Nitrous is cheaper short term and will work wonders as most know.
good luck with whatever you chose ! :thumbright:
Sounds good brother. I agree with everything you said, and your estimates are probably spot on.
I'm looking at shifting around 6200 MAX on my 412, not spinning it at 7k.
I can see where an AFR head might outright spank another head due to a cam profile favoring higher lift where the AFR shines. But still, I was figuring around 30-35hp between the two.
You know, I've always been one to build supercharged engines. So for this car I started thinking build a big cube naturally aspirated motor. But you know, looking at the numbers. It takes a lot of agressive cam, and a hell of a cylinder head to push 550 flywheel horsepower.
However, a fairly mild cam, moderate heads, and 15psi of boost will produce the same thing potentially cheaper..
I agree on the sportsman comment. I was just using it for comparison sake. ya know, if my 355 sportsman headed motor in a 3600lbs car could trap 120, I'd think the AFR's would have much more edge.. But for 2-3mph it's not quite as worth it. (to me)
