CNC heads VS hand ported?

[nw_guy4_fun]

Check this AS CAST port tw26 Andrews baby cam low compression dyno out.
2006%20CAST%20PORTS%20SAE%20edited.jpg
Thunderheader! 9.5/1 175ccp

[YankeeBob]

Originally Posted by nw_guy4_fun

Check this AS CAST port tw26 Andrews baby cam low compression dyno out.
Attachment 44905
Thunderheader! 9.5/1 175ccp

Very typical curves for that cam. But, I think the numbers are too high....by about 4%.

[BVBOB]

Looks like here we go again, everyone worried about high peak dyno numbers, does anyone actually ride their bike in the real world anymore?
Seems to me that some of the high HP/TQ builds in the rpm we ride in make more sense than sacrificing low end power with the use of bigger cams just to get that big number(high rpm) on a sheet of paper.

[YankeeBob]

Originally Posted by YankeeBob

Very typical curves for that cam. But, I think the numbers are too high....by about 4%.

But what do I know. I'm just a lowly plumber.

I'm not trying to start a fight, nor do I wish to witness one. I'm just saying all the typical 26 builds I have seen posted are around 95tq and 80hp...give/take.
But, like I said, the curve appears typical.
I had a 26 in a 95 for a while and it was a blast to ride. I am sure this one will be too.

[compressor#v]

Arn't CNC ported heads initially done by hand, then digitized to be copied by the CNC equipment?

[nw_guy4_fun]

I posted this because I have been saying for awhile that I distrusted the approach many were taking relying so heavily on flow bench numbers and looking for great curves and shiny numbers especially from .500 - .600 lift. These heads did have special seat and valve work and minor deburing under the seats and high tulip valves, 1.900 Intake and 1.575 Exhaust. They are not heavy breathers especially at .500-.600 lift (take a look at where the piston is at between .500 and .600 in both intake and exhaust cycles) but they do have some very impressive .300 and .400 numbers. A little differant approach to porting and giving the motor what it needs where it needs it based on the CI and the cam. BTW this dyno is on an 8 year old 250 and the numbers are SAE and Winpep software is version 7, for the sake of honest disclosure. This is a new paradigm as we typically were used to 10.5/1 high lift cam 95" motors reaching these levels. The Thunderheader will make good torque but not low and at the top is probably costing a few HP IMO. FatCat would be even stronger.

BVBOB this is a baby cam with specs close to stock and only 18° overlap.

Regarding CNC
The machine removes metal by program 1st, hand blending afterwards. If there is core shift concievably places in the port could never be touched and others would have a very heavy cut. The HD heads late model can have up to a + or - tolerance of .040. The guys like R&R have all this dialed in when they use their own ports developed by Reggie.

[BVBOB]

Originally Posted by nw_guy4_fun

I posted this because I have been saying for awhile that I distrusted the approach many were taking relying so heavily on flow bench numbers and looking for great curves and shiny numbers especially from .500 - .600 lift. These heads did have special seat and valve work and minor deburing under the seats and high tulip valves, 1.900 Intake and 1.575 Exhaust. They are not heavy breathers especially at .500-.600 lift (take a look at where the piston is at between .500 and .600 in both intake and exhaust cycles) but they do have some very impressive .300 and .400 numbers. A little differant approach to porting and giving the motor what it needs where it needs it based on the CI and the cam. BTW this dyno is on an 8 year old 250 and the numbers are SAE and Winpep software is version 7, for the sake of honest disclosure. This is a new paradigm as we typically were used to 10.5/1 high lift cam 95" motors reaching these levels. The Thunderheader will make good torque but not low and at the top is probably costing a few HP IMO. FatCat would be even stronger.

BVBOB this is a baby cam with specs close to stock and only 18° overlap.

Regarding CNC
The machine removes metal by program 1st, hand blending afterwards. If there is core shift concievably places in the port could never be touched and others would have a very heavy cut. The HD heads late model can have up to a + or - tolerance of .040. The guys like R&R have all this dialed in when they use their own ports developed by Reggie.

I have a set of those Babies right in front of me on my desk right now, yes, numbers close to stock, ramp angles anything but close to stock.

[nw_guy4_fun]

Bob
I think you got my point though...
Heck 203s have a lot steeper ramp than stock
My point is, this is a torque not top end build and the cams are the second to the smallest made by Andrews other than stock replacements. The HP just comes along for the ride because it is in the equation. Airflow / CFM is not in the torque and HP equation. The bottom could be pumped further with a simple pipe change away from the Thunderheader.
If we could get White Bros E pipes this thing would really have everyone scratching their heads wondering and the FatCat would not be bad either.

[Hillsidecycle.com]

Our approach to headwork, has always been to concentrate on the mid-lift numbers, as the valve is there more than anywhere else, for the longest period of time. A flow bench is great tool that shows alot of information, and not only inside the head either, as manifolds, carbs, pipe diameters, etc. can be scutinized.
Monster flow numbers at .750 lift, are absurd to chase, for most normal street applications, although we have been there before.
Just comes down to experience.

[KingofCubes]

Originally Posted by compressor#v

Arn't CNC ported heads initially done by hand, then digitized to be copied by the CNC equipment?

Many cnc porters do it that way as did Reggie Sr back in the day when he started but he has since switched to a probeing process so he can identify and adjust core shift on the fly because what he found was the core had shifted .030" to the left and the machine was taking out material on the right that the velocity would be down on that head so he uses the dowel locators, the seat, and the port window as reference points and the probe to adjust the machining.
On his billet heads he didn't hand port and digitize because there was no port there to begin with so he designed the whole port in Mastercam. I've watched him make and modify ports a couple of times and now he writes macros and probes them.

[nw_guy4_fun]

A good time to mention that some of the class acts have spoken to me (now not just another guy but competitor) and we have shared ideas, disagree some and agree some but are all gentleman. This would include Hillside, R&R, King of Cubes, and another that remains cloaked under a screen name of Redpanhead. All classy guys and have been decent to me. Thanks for that.
And now with that said.........
Nothing back to the scheduled programming.

[FLHR2000]

New guy, be careful using that Dyno, every FL with a 95" will flock, and those that do not get the 105 HP will want warrenty work.

[FLHR2000]

KOC, just so I am not confused I am going to ask you to clarify the probing thing, you make it sound as if he probes the port and makes adjustments based on the shift or position of the port, correct?

[wfolarry]

Originally Posted by FLHR2000

New guy, be careful using that Dyno, every FL with a 95" will flock, and those that do not get the 105 HP will want warrenty work.

Or their money back.

[nw_guy4_fun]

So what are you saying? Distrust the dyno? Others are posted here from the same dealer, same dyno, same operator, same software. This is an honest build and was very well documented on the net with photos of the ports as-cast. Pretty low drama. Same skeptics voiced disbelief before hand. There will be more of the same.