Trackmouse SuperDork
Aug. 16, 2017 2:47 p.m.

It's for the 1uz. Where's the place to get bends. How should I mock it up? What piping to get that won't rust apart in a year AND not blow a hole in my wallet? Summit has these

GameboyRMH MegaDork
Aug. 16, 2017 3:06 p.m.

I have a template for the 1UZ header flanges if you need it.

Stefan MegaDork
Aug. 16, 2017 3:07 p.m.

Local source for quality bends

For modeling the tubing bends and lengths:

Header Modeling kit

Building headers is an art form and to prevent them from rusting, get them ceramic coated once completed or step up to high grade stainless steel or another alloy. If you think building a fairly straightforward exhaust system is difficult, building a set of headers will be exponentially more challenging (with the upside that you'll likely not have to spend as much time under the car cutting and grinding).

Lots of info around on ways to build them, but expect to do a lot of practicing, trial and error and throwing it away and starting over again, so you'll probably want to start with cheap parts and work up to the final product. Modifying a set of existing headers is sometimes easier, depending on the application. I've heard of people using welding rod or similar stiff steel wire to mock up the runners, the plastic tubing is easier since it occupies all of the space required and you can pull it apart and build it one tube at a time.

The key appears to be getting the diameter, length, and pairing of the runners as close to ideal as possible, which is an available calculation. The collector has to be properly made, so don't skimp the rest can be roughly close, but the collector makes a difference.

oldtin PowerDork
Aug. 16, 2017 3:09 p.m.

I used a piece of plywood and some plastic hose to mock up mine. It wasn't perfect since the plastic hose can flex and lose the exact profile you may need if things are a tight fit. I then matched the profiles best I could using a box of bends from summit or jegs - I forget. There's some cool tools for header mock up like the Icengineworks stuff.

Dr. Hess MegaDork
Aug. 16, 2017 3:21 p.m.

"Sanitary Tubing." Google it up.

Driven5 Dork
Aug. 16, 2017 3:25 p.m.

Another good source for materials:

Cone Engineering

Trackmouse SuperDork
Aug. 16, 2017 4:03 p.m.

Thanks everyone. I'm venturing into the fray of learning to weld. So I'll start with cheap materials

bentwrench Dork
Aug. 16, 2017 8:42 p.m.

Tack it together with a MIG and then TIG or gas weld them up on the bench. If you do stainless or Titanium you will need to purge the inside of the tube as well as the normal welding gas envelope.

stafford1500 HalfDork
Aug. 17, 2017 7:00 a.m.

In reply to Trackmouse:

Mandrel Bends linked earlier in the thread is in your region. The have all of the bends you will need and the 1UZ flanges in their system. The head flanges are not quite right, but can be 'adjusted to fit. I have a set of mild steel headers I made for my application, but they probably won't work for yours. They are sitting on the shelf because I went with sidepipes on my second set (for foot clearance and cooling reasons).

A 401 CJ HalfDork
Aug. 17, 2017 8:03 a.m.

This will be a dumb question for sure because I'm a total noob at header building but why would somebody (as a hobbyist ) spend nearly double the money for the V8 modeling kit? Wouldn't it be just as easy to model and build one side then the other? Maybe it's really for the I6 guys and girls?

stafford1500 HalfDork
Aug. 17, 2017 8:33 a.m.

In reply to A 401 CJ:

Cylinder spacing is the same, but the cylinder offset from one bank to the other means the collector winds up with a front-back offset if you mirror the design. The ones I posted the picture above of had the collectors at the same location in the frame which meant a small but real design/layout change from left to right bank. Also, there MAY be items like steering/alternator/AC parts that are different from side to side.

NOHOME UltimaDork
Aug. 17, 2017 9:07 a.m.

Good video series on this task. Six videos from a header component supplier.

https://www.youtube.com/embed/j9knDsi-td8

singleslammer PowerDork
Aug. 17, 2017 9:33 a.m.
GameboyRMH wrote: I have a template for the 1UZ header flanges if you need it.

I want that template and will happily send anyone a set of flanges for cheap. Basically metal plus shipping.

SVreX MegaDork
Aug. 17, 2017 9:56 a.m.

I still remember Wheels777 giving a little tutorial on how he built his 180* headers:

10 or 12 people gathered in a circle as he explained...

Not-so-well-informed guy says: "So, you built you some long tube headers?"

Andrew says: "I built some right length tube headers, optimized for power for this engine. All eight tubes are exactly 32 5/8" long".

Not-so-well-informed guys says: (nothing)

Everyone else stands in awe with their mouths open.

It's an art, with a lot of science. Glad to see the effort, Trackmouse!

Jere Dork
Aug. 17, 2017 10:24 a.m.
Driven5 Dork
Aug. 17, 2017 10:30 a.m.

In reply to stafford1500:

Why would the second side have to be a mirror image of the first side when using the I4 kit? It can be taken apart and started over more than once, right?

kb58
kb58 Dork
Aug. 17, 2017 11:07 a.m.

Of all the tasks when building Kimini and Midlana, header fabrication was the most enjoyable. I won't do it for others due to the time, but it was really relaxing and allows you to be artistic at the same time.

Later I redid it due to switching turbos, using stainless "weld-els"

To stay on topic, go here, to late July, to see all the steps in fabricating the Kimini headers for the Honda H22A1, http://www.kimini.com/Diaries/2003Late/

A 401 CJ HalfDork
Aug. 17, 2017 11:52 a.m.

Precisely. That's what I was trying to say.

Driven5 wrote: In reply to stafford1500: Why would the second side have to be a mirror image of the first side when using the I4 kit? It can be taken apart and started over more than once, right?
Aug. 17, 2017 12:05 p.m.

In reply to kb58:

Would you mind explaining/describing the collector design/function in the top photo? It is very interesting looking.

GameboyRMH MegaDork
Aug. 17, 2017 12:10 p.m.
singleslammer wrote:
GameboyRMH wrote: I have a template for the 1UZ header flanges if you need it.

I want that template and will happily send anyone a set of flanges for cheap. Basically metal plus shipping.

I sent it to someone earlier today who PMed me. PM me if it wasn't you.

Trackmouse SuperDork
Aug. 17, 2017 12:21 p.m.

Why wouldn't somebody just use the flange that comes with the factory exhaust manifolds? It seems like that would reduce a lot of time.

Stefan MegaDork
Aug. 17, 2017 12:22 p.m.
WildScotsRacing wrote: In reply to kb58: Would you mind explaining/describing the collector design/function in the top photo? It is very interesting looking.

Looks like some slip connectors to allow for the expansion/contraction of the pipes with a crossover for an external turbo wastegate and the exhaust inlet for the turbo.

Oops, I was looking at the wrong pic. Sorry, I didn't scroll up far enough.

I believe he talks about the header designs he used on the Midlana build on his website. If I remember correctly, he made his own collector for the NA version of the car due to packaging and design challenges.

Stefan MegaDork
Aug. 17, 2017 12:25 p.m.
Trackmouse wrote: Why wouldn't somebody just use the flange that comes with the factory exhaust manifolds? It seems like that would reduce a lot of time.

You rarely can as most are made from cast iron. Those aren't easily modified. If they are already welded thin tube headers, then you could certainly look at re-using the flanges, assuming you don't warp them too badly cutting them up or welding on them.

Stefan MegaDork
Aug. 17, 2017 12:29 p.m.
Driven5 wrote: In reply to stafford1500: Why would the second side have to be a mirror image of the first side when using the I4 kit? It can be taken apart and started over more than once, right?

Sometimes you need to mock both up in the car to determine where everything fits or rather, interferes.

These are often geared towards people who build them for a living or who may want to keep it to make more of them down the road.

Driven5 Dork
Aug. 17, 2017 2:19 p.m.

In reply to Stefan:

Right, so in other words, a DIY/GRM type builder would still probably be fine using an I4 kit to build a pair for many/most V8 applications.

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