Time to go Stage II!

[Alky V6]

What sort of fastener arrangement are those set up for?

 

[BlownV6]

Black ones are for standard 3/8 flat heads , alum 3/4" are for standard 3/8 SHCS. Mike

 

[Squid4life]

Figured either Mike B or Neal would have a set of plates laying around! That may save your time, although it looks like the ports would have to be opened up just a tad.

So, looking at the port to adapter diameter and size difference, do you plan to port the exhaust port to match (or come close to) the adapter plate/ flange size? IIRC, a small step smaller diam to larger diam is best? As in exhaust port being ~1/8" diam smaller than the adapter/flange?

 

[Alky V6]

Black ones are for standard 3/8 flat heads , alum 3/4" are for standard 3/8 SHCS. Mike

Thanks for the offer, Mike, but I think I'm going to make my own. The black ones look tempting, but they look to be lacking a tad bit in size for my needs. I checked, and I do have some material I can use.

 

[Alky V6]

So, looking at the port to adapter diameter and size difference, do you plan to port the exhaust port to match (or come close to) the adapter plate/ flange size? IIRC, a small step smaller diam to larger diam is best? As in exhaust port being ~1/8" diam smaller than the adapter/flange?

In the picture of the template laid over the drawing on the page of the powersource book, the opening in the middle of the template is the actual size of the exit of the exhaust port on the heads I will be using. The adapter will continue to follow that exact size and shape, and the angle of attack of the exhaust port.
I agree with you that a small step is best, but when I enter a stepped primary in the sim, LOTS of hp is lost in the calculations. Over 100.
I'm going to go with what the sim is showing to be the best and see what I get. The header flange and pipe openings will be oriented so that the roof of the flange/pipe opening lines up with the roof of the port/adapter opening. Like what is shown in the template with the different pipe diameters that I have drawn on it.
Another option would be to use a short tapered section off of the header flange to the pipe diameter I'm planning to use. The taper angle of the conical transition would need to be specific to prevent turbulence. Most likely 7-10 degrees, 14-20 degrees included.

 

[Alky V6]

I've squared up the blocks that will be the exhaust adapters out of 3/4" aluminum. I'm going to incorporate part of the ID taper that I'm going to need into the adapters. The other part of the taper will be incorporated into the header flanges. With the right angle of taper, I may be able to get the complete distance of taper into the adapters and flanges, and be able to come off the flanges with a straight pipe diameter.
I love making this stuff challenging.

 

[Alky V6]

Scribing the layout for the holes that need to be drilled using a precision granite block and a height gauge.

 

[Alky V6]

A great tool to very precisely locate and center punch the locations of the holes to be drilled.

 

[Alky V6]

The hole locations after center punching.

 

[Alky V6]

Drilling out the holes.

 

[Alky V6]

Using an endmill to finish the port shape through the adapter. The adapter is set up on a 7 degree angle.

 

[Alky V6]

One of the adapters is almost finished. All that's left is to add in the amount of taper to the ID, figure out what fastener I'm going to use, then countersink for a capscrew, or a flathead.

 

[Squid4life]

Jeez... That thing should be put behind glass or plexi and put on the wall. Very nice Donnie.

 

[SCOOBY DOO]

Almost too nice too race. I said almost.

 

[Alky V6]

I've decided to go with countersunk stainless capscrews to retain the adapters. The thickness for the adapters (3/4") that I've chosen is perfect for using allen capscrews.
Typically, the diameter of the countersunk hole would be 9/16" for a 3/8 capscrew. I'm going with a 1/2" diameter hole and will turn and face the heads of the capscrews to snugly fit the countersunk holes.
I'm going to taper the port opening in the adapter to a 1 7/8" ID exit (7 degree taper), maintaining the shape of the port through the adapter. The header flange, which will be .500" thick, will have a 2.00" ID entry (perfect circle shape) and a 2.125" ID exit (7 degree taper). The tubing attached to the header flange will have a 2.250" ID (2 3/8" OD).
The number 6 cylinder adapter is the only one that's close to being finished. The others are still very rough. The pics below show the adapters before adding in the 7 degree taper.

 

[Alky V6]

I have two options on the taper angle through the adapter. Still trying to decide on which one to go with. Red line, or green line? I'm favoring the red line due to the shallower angle.

 

[Squid4life]

Kind of hard to tell from the pics, but how much room is there for the nuts and washer for the head studs under/behind the adapters? I know the studs are usually flush with the tops of the nuts, but I would have to take a measurement to be exact. Might end up having to put a little clearance pocket behind there? Here is a pic of mine with the studs/nuts still there:

BTW, no re-torquing of those studs after a heat cycle without some disassembly, huh!? Looking great Donnie!

EDIT, ignore my pointing... That was just a pic for reference of something else and I am reusing it.

 

[Alky V6]

Kind of hard to tell from the pics, but how much room is there for the nuts and washer for the head studs under/behind the adapters? I know the studs are usually flush with the tops of the nuts, but I would have to take a measurement to be exact. Might end up having to put a little clearance pocket behind there? Here is a pic of mine with the studs/nuts still there:

BTW, no re-torquing of those studs after a heat cycle without some disassembly, huh!? Looking great Donnie!

EDIT, ignore my pointing... That was just a pic for reference of something else and I am reusing it.
View attachment 176528

Thanks, James.
I'm expecting that I'll have to clearance the adapters like you've brought up, but that will be a very minor operation.
Removing the headers for retorquing is to be expected, regardless whether adapters are used or not.

 

[Alky V6]

I'm starting to get jazzed up about putting together the new header system. Looking for inspiration.

http://www.racecar-engineering.com/articles/f1/renaults-radical-r31-exhaust-system/

 

[Alky V6]

The new design for the exhaust header primary entry.
edit: Another change to the angles was made after this post.