OST-013: Massaging a virgin ;)

[oldeskewltoy]

NoHachi Wrote:

oldeskewltoy Wrote:I can do flow testing... BUT that usually costs MUCH extra do to time required to set up and then remove, port a bit, and then re-set the flow bench. In fact flow testing a head is often the difference in a $750 porting cost, and a $7500 porting cost (as in the cost of an Atlantic head)

Concerning 3 angle (or in some cases multi angle) I do not have the machining equipment to do this, I have Loynings do these for me. I TRUST Loynings work, they are an active racing machine shop who have built many hundreds of 4AGE engines... as well as others. Loynings has 27 SCCA championships accredited to their work, they are the shop that ported my smallport head... with which I've planted 145whp and 112#/ft, also measured @ the wheels... that is also emissions friendly

I have no doubt that Loynings know what they are doing. Similarly I fully believe that its possible to reproduce port work on another head that you know has been proven to work on previous flow bench tests. I was just curious how you developed your ports since all the old scool guys with flow benches say that it is easier to ruin a modern head (ala 4AGE) then to improve on it. (just to be clear, I'm not insinuating you ruin a head, quite the opposite, hence the curious questions... I want to learn.)

My secret.... isn't a secret @ all, I've studied a number of Loynings heads (ever heard of monkey see, monkey do?) I also DON'T promise I can match their work... because I can't. Just to be accurate, the 4AGE head is NOT as modern as some people would have you think. I promise a boost of 3hp to 10hp from my work (just to compare... my Loynings head makes 20+hp). All my work is taking a casting that is fair, and improving it - that is why I claim 3 to 10hp... some castings are that bad.

Finally, I've learned from a few friends that I have a talent when it comes to working with the equipment I use(mostly Dremel based). The owner of OST-007 is a close friend, and with all I was able to explain to him, he just couldn't operate the equipment with the same capability as I.

NoHachi Wrote:

oldeskewltoy Wrote:The ports you are seeing are intake ports, so the un-tapered part is away from the air stream - tucked behind the valve. The area behind this is very small and is very disturbed air, by not tapering the back more I'm minimizing this and minimizing the disturned airflow behind the guide. Part of the tapered guides is to "follow" the minimized guide boss, since the guide boss is minimized, the flow up to the guide would be more disturbed if not tapered.

This doesn't jive with the water drop shape idea, its actually the exact opposite. Many things happen inside a port so it probably isn't a straightforward thing. Do the Atlantic heads use similar profiles?

Hmmm, I use "drop tank" theory The large end of the drop tank is in the front - into the air stream. The back tapers to allow the air to flow smoothly past. Also placement of the guide in the bowl has something to do with it as well, some bowls (see link) are deeper than others, and allow the air to flow smoothly past(earlier in the radius). On a 4AG intake, the guide is very close to the bowls edge(later in the radius), the air is in mid transition from horizontal flow to a more vertical flow as it heads down to the valve

http://www.ws6transam.org/int_port_mod1.jpg - view showing guide in bowl center - early in the radius

Some Atlantic heads use very tapered guides, while others do have the guides removed. A significant difference in longevity(shorter) allows them to use techniques I can't use.