Flow #s

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

I'm in the process of getting around to porting my head which will envolve some serious welding in each intake port to address turbulence by modifing the port walls near the short turn,thus reducing port volume in efforts of increasing the air momentum as it makes the turn to the seat and one port was some what butchered from the factory when they made the throat cut and in doing so,it cut away a bit of the short turn radius,so i'll need to try and over lay this section with aluminum to the combustion cap and then rework to the correct radious to match the other port.

I'll be flowing two types of valves to show a comparison of stock VS my modified version. I've flowed this particular valve before with excellant results but not with a well rounded port with emphasis of gaining the maximum possible CFMs on the XS head using a stock valve dimension.
I f ya wanna see the results,let me know................jack

chapmanmd · Posted: September 17, 2006, 4:20 pm Post subject: Re: Flow #s

I would like very much to see it Jack. I still need to talk to you about some head work.

royfisk · Posted: September 17, 2006, 4:49 pm Post subject: Re: Flow #s

Jack keep me posted,

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Well i finally got one intake port welded up, I concentrated in working the corners to radious the them upwards a few degrees cuz in previous testing where I reworked the corners to flatter profile,the cfm gains where a failure at 300 lift. In fact the XS head responds quite well to several port and floor shapes but don't get carried away with cutting down the corners,just round radius them and move on.

Hope to get the head sent off this week to be flowed with good gains i hope.......Jack

royfisk · Posted: September 17, 2006, 7:43 pm Post subject: Re: Flow #s

Thanks for the tip jack

RainLand · Posted: December 17, 2006, 12:55 pm Post subject: Re: Flow #s

Can you draw out a diagram, or give a good photo of where you took
away metal? I'm not seeing how I can relieve it without changing the
radius a bit...

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Got some #s in, there were slight loses at 200 and peak lifts but I was expecting this considering I completely reshaped the port to reduce port resistence rather than seeking a gain,just need to reshape the short turn a bit more to regain the #s. The mod valve will be flowed hopefully this week for a complete count and I'll post them,along with a peek of the port Wink

.....Jack

royfisk · Posted: January 19, 2007, 4:35 pm Post subject: Re: Flow #s

Jack thanks for the update

76xs · Posted: February 18, 2007, 12:25 am Post subject: Re: Flow #s

I'd like to see pictures of before and after porting as well as flow #.

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Is there anything else you'd like with that order :lol:... The imformation provided in the thread will give a flow ratio of 70% to 75%..........Jack

xs650temp.proboards29....1101587326

xs650temp.proboards29....1167445944

xs650temp.proboards29....1168793061

RainLand · Posted: February 22, 2007, 10:12 am Post subject: Re: Flow #s

I've started a 447 head, and I found that a Dremel with a pencil
extension works pretty well, although it takes a while. I've seen
three or four heads now, and they all look different. The shoulder
from the bore varies all over the place.

Will JB Weld work to smooth the pockets behind the valve seat?
I'm just going to leave the low spots rather than weld, because I
don't want to pull the valve seats out.

jayel · Posted: February 22, 2007, 11:45 am Post subject: Re: Flow #s

jb weld won't take the heat check the package it's only good to about 600 degree F

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Reshaping intakes ports by means of appling epoxies have been in practice for decades and to this day and JP Weld is the more commonly used two part epoxy for motorcycle heads do to it's chemistry make up and thermal expansion that's identical to aluminum rate, to resist cracking and lifting, if anchored properly and that's the trick.

Rainland...... I'm really getting burned out on these forums,you still have my email address? Contact me and I'll guide you through porting your head.............Jack

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Rainland..........When I rework a port,I go the extra mile to remove as much resistance as I can in the port, the port with the least resistance will always produce more HP. Air will always take the shortest route to get where's it's going and the floor is the critical area of focus.

The area that concerns you, is it the floor corners leading up to the short turn? Look at the picture I've posted where the arrows are..........Jack

RainLand · Posted: February 25, 2007, 5:37 pm Post subject: Re: Flow #s

The spot I have is just around the corner from the left arrow.
It's right behind the valve seat, after the turn. It looks to me like the
air's gonna slow there anyway, since it's the outer edge of the valve
pocket.

Where the bore ends, just before the guide enters the port, is a
shoulder. It looks like I could just cut that out completely from this
photo. Is that accurate?

Also, how do you finish the surface? I'm using a Dremel with polishing compound to get out the grind marks - is that going too far with this?

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

You need to blend the step your referring to down to the guide and to contour the pocket. Air velocity is slower in the roof section than the floor and by working out the step you reduce turbulance on the backside of the pocket to seat and valve to reduce resistance.

The area to the left are you saying ther combustion cap is exposed? Post a picture if you can.

When porting a head you're attempting to increase the volunmetric efficiency of the engine to boost power but what you also need to focus on is improving the combustion efficiency too to enhance both power and fuel economy. And to improve fuel economy will depend on the port barrier finish that's applied to enhance the homogenization process of the fuel mixture. The barrier finish plays an important roll in providing a high pressure point to create air pockets promoting turbulance to re-suspend fuel back into the main airstream and I generally apply a 24 0r 36 grit barrier finish,just depends on what abrasive grits I have on hand.

Post a picture................Jack

RainLand · Posted: February 26, 2007, 9:47 am Post subject: Re: Flow #s

Okay, so I should leave a roughened surface for the fuel/air mix...
The back of the valve seat is exposed for about 3/4 inch, about 1/32nd
deep. it's gonna be tough to get a photo - you can feel it with a nail
or a depth guage. I'm afraid if I JB Weld it, the steel will pop loose
from the putty, and I'll end up with it in my rings.

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Just go browse through the porting thread that I've posted above and pick a picture and save as is,then edit the area in question,then post the picture and we'll go from there.................Jack

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