Twin Scroll Turbo

[squaab99t]

Dennis, what are you using for header material? 304L stainless steel? Tubing or IPS? What size and wall thickness? I am guessing you are going to use 1.625" outside diameter tubing. (Based on the 1-5/8" modeling kit.....)

Planning on 321 stainless tubing, 16 ga, 1 5/8" OD.

[squaab99t]

Was not happy with the way the first round turned out. Plate flexed too much and getting to the oil fitting with a wrench was near impossible.

Re-do with a second plate and single clamp design. Fastened hard on one side and bushed on the other. This is a proper clevis joint since you do not pitch or spread the ears. It also allows thermal growth or contraction.
In the end, stiffer because of the geometry and I have wrench clearance.
Mocked up with a cheap 1/4-20 bolt and nylock nut, but she looks good.

Next is the clevis for the upper attach. This will be the "tri-pod head" of the 3 legged stool.

Next step will be to mock up the legs that will go from the cylinder head to the tripod head.
1" OD tubing for the landing, so the plan to have room to place the 3 leg ends.

[squaab99t]

Swapped out the tripod head. That thin wall tubing and the orientation was not going to make the stiffness cut.
New hotness:

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Also made a new spacer for the lower tierod. The original was too portly.

[squaab99t]

Originally planned to use the stock turbo location to keep the intercooler, oil and water plumbing unchanged.
Started placement of the tripod legs and about ready to tack in place.

Then my buddy Kevin asks "With the turbo in its stock location allow enough room for the merge collectors to feed into cyl 4?"
Huston we have a problem...

Looks like it will find a her new home above the battery tray. Maybe a blessing as it will straighten and shorten the intercooler piping and the downpipe I had to make new anyways, will have less angle to turn.

Good news is that the hanger is pretty darn close to the CG.

I guess that is why they call it a project car.

[gmreider]

WOW Dennis !! I thought I was the one that could make up complicated projects and fabrications, but you have me beat. Very nice work . I wish I lived next door to you. Can always learn from others.

[squaab99t]

WOW Dennis !! I thought I was the one that could make up complicated projects and fabrications, but you have me beat. Very nice work . I wish I lived next door to you. Can always learn from others.

Thanks Gary,
The packaging is making this one complicated. Fact of the matter is that I use the car as a tool/object to focus my learning. Design, engineering, project management and fabrication are all put into play when you do more than simple bolt ons. The car is rewarding to drive it and see the gains, or losses
Having someone in close proximity is very nice. Kevin does not live next door, but only about 12 blocks away. We visit eachother's shop to keep the projects interesting, educational, and ourselves motivated. and drink beer....

[squaab99t]

Revised the hanger pickup relative to the CG since I have to opportunity.
Old:


New:

Does not seem like much, but there is no reason the header needs to support pulling the turbo into alignment. A simple relocation of the fastener location is all that it takes.

Change in direction on the truss. With the new location I found a how to place a horizontal tube and put a slug in the end. This will be the rod end attach point.

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[squaab99t]

So, lets get going.
2 of the legs in place.

close up of the attach point.

Mocked up downpipe helped dictate the placement of the turbo. The other factor was the boost outlet. Hope to have a short run with a single 45* and the existing 90* right to the intercooler.

Still need the 3rd leg of my tripod. Some where on the front end of the head should be good.

[squaab99t]

Tacked up the two upper legs first and then fit up the third. Took the turbo out for the final tack of the third leg.

Went to the bench and added tacks to have a minimum of three at each join as evenly spaced as possible. Took it back to the car for final fit check. Everything seemed to line up and the fasteners when in without too much complaint.
Back to the bench to weld all the seams. Took my time, back purged the sockets with argon and jumped from side to side to try to keep warpage to a minimum.

Free standing.

[squaab99t]

Added a temporary strut to keep the turbo from rotating about the rod end bearing.

Started adding the primaries with the modeling blocks. 1 and 4 onto one bank 2 and 3 into the other.

Need more 3"CLR blocks to place all 4 runners.

[squaab99t]

Did some more work this weekend. Mocked up the downpipe to reserve volume, so the headers do not encroach.
A 3" dia short bend so the flex pipe makes best use of the available space and will shoot between the cross member and the driveshaft.

A transition cone from 3" to 2 1/2" to pickup the existing exhaust.

I've also be trying this new tig cup with an additional screen to the standard gas lens. The thing is pretty expensive for a cup and screen, but the results are sweet.

[squaab99t]

Played around with the modeling blocks. First stab at my 4 cyl bundle of snakes.

Number 1 is not complete, but the others make it to their respective merge collector.

[KoogiA17]

Nice mockup of the exhaust manifold. Have you attempted to get each runner of a similar (almost equal) length?

[squaab99t]

Nice mockup of the exhaust manifold. Have you attempted to get each runner of a similar (almost equal) length?

That is sorta the plan. 1 and 4 will match and 2 and 3 will match. The theory of application will to have one set tune to lower engine speed and the other at high. The thought is this will widen the usable boost band.
The nice thing about the modeling block is they are 1" on centerline, so you will know if you have the right length even if the sections are curved or straight.

[Jon1]

What are the current lengths of the runners? Looks good, BTW.