Porting-do's and don'ts
Posted 13 December 2003 - 10:53 PM
if you feel the need to reply, ask a question, or just make comments, please start a new thread as I will try to make this a running commentary.
Posted 14 December 2003 - 10:41 PM
Posted 13 December 2003 - 11:26 PM
No usable parts were harmed in the making of this thread.
Posted 14 December 2003 - 12:17 AM
First, you will need cutters. In the next photo you will see some of the cutters I use for this. On the right are metal cutters. These cost $20 to $75 each, so choose wisely.
In the middle are sanding cones. I use #80-100-220-240 grit. I use a long mandrel and a (not shown) short mandrel.
On the left are my own design polishers. These are made from med and fine grit de-burr wheels. You may use emery cloth attached to a mandrel and get good results. You may even run it without polishing if you wish.
I do not polish to a mirror finish for street use sence it will be covered with carbon after a few miles anyway.
So use whatever drive you have and remember,,
GO SLOW!!! Think ahead.
Once material is removed, it cannot be put back.
Posted 14 December 2003 - 10:05 PM
Posted 14 December 2003 - 10:16 PM
Never take anything for granted, check it all, mainly port match. I have seen some off by .200".
In this photo you see the inner radius of the port as the gasses enter the manifold. It is a 90 degree cut. THIS IS BAD!!! You will need to radius this as it is in the stock manifold. The stock ones are pretty close to being good. So just make it look and feel like the stock one.
And yes, I said FEEL. You need to stick your finger in there and FEEL it to see if there are any sharp edges. Your finger should roll right around the corner and into the manifold.
Remember, it you have any questions or doubts, STOP, and ask.
Posted 14 December 2003 - 10:24 PM
This is the "slip joint" from the inside. There is a miss-match here and it will cause a lot of confussion for the gasses as they try to find their way to the center of the manifold. Some are worse than others. BEFORE you put the manifold together, make sure this area is matched for better flow and lower EGTs.
Posted 14 December 2003 - 10:36 PM
But remember what I said before, you can run a ported turbo on a non-ported manifold, but you cannot run a non-ported turbo on a ported manifold.
Here we see a stock (yellow markings) and a ATS turbo mount flange. Notice the amount of material that will need to be removed from the stock unit to get it to match the gasket. SPECIAL NOTE; LEAVE 1/8" from the gasket to the port on the SIDES here. I will explain why later.
You want the aproach here to be as straight as possible the last 1/4 inch before it enters the turbo housing. (or leaves the manifold)
Posted 14 December 2003 - 11:02 PM
What you want in the manifold is, Volume and flow in the runners going from the head to the center, and Volume and velosity as you go into the turbo. Double standards for a fixed piece of metal. Plus you want the gasses to make a double S turn. The top and bottom become the sides and the sides become top and bottom. All this while excelerating. WHEW!
And here is what is making all this happen. The center section.
The pointer is showing you a turn the gasses from two cylinders must go around to exit. This radius must be made less dramatic but constant and smooth. On the inside (head side) of this you need to make sure the ramp is a smooth radius also. You will see that these gasses must fight for right of passage as the inner cylinder runs right into it. RIGHT IN THE MIDDLE OF THE BEND. So just make sure there is no interference here. Make everything smooth and constant. Don't be affraid to stick your finger in there and feel it. You must do this. Feel for any bumps or lips.
This is the place where the gasses are speeding up even though they don't want to. So you need to help them. Any confusion here causes heat and back pressure.
This is the most important part of the work you are doing so open it up and make it smooth. The runners and the center must be blended together before they exit the manifold.
I do not have a photo of the inside as it would not turn out for some reason. So if you have questions, ask.
Posted 14 December 2003 - 11:09 PM
But you can see the material that must be removed.
Remember me talking about leaving 1/8" on the sides of the manifold? This is why. If you open up the housing to match the gasket, the wall of the housing will be very thin and could crack. You loose a little CFM but you don't ruin a $350 housing. Good trade I think.
Posted 14 December 2003 - 11:28 PM
If you don't take the time to match this area, you are throwing away power and generating heat.
The whole idea here is to lower back pressure to release the parasitic drag on the engine and to reduce heat. Heat is good in the combustion chamber, but not good in the exhaust.
Also, if you have a 90 degree tool. you can polish the area where the gasses enter the turbine. This area is hard to see and if you can rework it, it helps a little also.
Ok, it seems the photo I had for this one is no good. But you can see what I am talking about by simply looking at your housing. I'll try to post it later.
Posted 14 December 2003 - 11:33 PM
Remember when I said to take it slow?
Posted 14 December 2003 - 11:42 PM
Ok, now here is the photo of the mismatch. Sorry
Posted 14 December 2003 - 11:51 PM
At this time I would like to say thank you to Rob Hansen for his help in making this thread happen. Plus I would like to thank Rip Rook for letting me use his products in the making of this thread.
If anyone has a question or would like to add something, please post it.
Thank you all
Posted 15 December 2003 - 08:51 PM
Post here and I'll Zap it :shocked:
Dave put a lot of work into this and provided a lot of excellent info so let's respect his wishes
Posted 17 December 2003 - 10:41 PM
Posted 22 December 2004 - 02:47 PM
I have a bunch of photos somewhere...I will dig them up and post 'em.
Posted 22 December 2004 - 08:31 PM
But then, ask John T. about his driveline.
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