DIY Turbo exhaust manifold for my Tacoma's 2.4L 2RZ-FE

[ToxicGumbo]

Before year's end, I'm planning to liberate my Toyota Tacoma (Hilux) with FreeEMS and immediately move towards forced induction. I haven't seen too many turbo exhaust manifolds out there for the 2RZ-FE engine which aren't prohibitively expensive, so I'm hoping to MIG weld my own and toss on a TD05 16G turbo for modest boost.

Here's an example of a typical design which fits the available space.

Flange:
I've seen some people on here go from CAD designs (for laser cutting) to chopping the flange off a header. Regarding the latter, I only have the stock cast iron manifold available. The former I know I won't be able to find the time to draft up. This guy on eBay is selling a couple of cut flanges: 1 (more expensive), 2 (less expensive)

Tubing:
I have a pipe bender and chop saw back in Louisiana, though am planning to purchase pre-shaped tubing pieces. The tools needed for grinding and cutting are here with me in Kansas.

Turbo mount:
TD05 16G flanges and gasket sets are easy enough to find through online retailers and eBay for under $20.

Extras:

• O2 sensor bung

Worst case, I can take all these parts to a cheap fab shop in town and have them do it, but where's the fun in that?


-Jeff

[Fred]

I don't like the typical design. Please provide a set of pictures of "the available space" on your truck (not downloaded) for your distributed design team to consider :-)

Flange, steer clear of the stainless one.

Tubing, use thin wall tube, not thick wall pipe.

Turbo mount, hang the turbo off of steel rods/brackets, let the tubing just be tubing, NOT support the turbo.

Extras, O2 sensors go AFTER the turbo in the down pipe, but you likely knew this.

Design: Consider that the flange will be cooled by the head, but the piping to the turbo will be super heated (below melting point, but..) and expand substantially more than the flange. IE, in the example design, it'll tear itself apart through heat cycles and/or snap off studs. A friend of mine did a worst case setup on a BMW 6 like that, and it just kept destroying itself. I know mine is big and wild, but consider the stresses in it when it gets hot, that's right, there are few, and the thin-wall mild steel tube can move to accommodate them, and the turbo is hung from a bracket, the pipes are just pipes. This is no accident.

I did a wire frame model for mine, I suggest you do the same for yours, it was very helpful to visualise it first:













Which is not actually what I ended up doing, as I found a better way when I got the pipe in my hands, or perhaps before I bought the pipe. I don't recall. Reality of steel:











End result you can find in my truck thread, see sig.

Fred.

[ToxicGumbo]

I don't like the typical design. Please provide a set of pictures of "the available space" on your truck (not downloaded) for your distributed design team to consider

Will take a variety of photos tonight. I rarely see anything decent online anyway and have yet to see two Tacoma engine bays that look the same (anyone who takes a photo of a stock 2.4L Tacoma engine isn't likely to post it online unless it's been pulled and put up for sale).

Flange, steer clear of the stainless one.

(2:25:11 PM) Jeff: Burning question: is raw steel really okay to work with? If I paint the exterior, less chance of rust. Is it safe to assume that the heat and carbon buildup will protect the interior from rust?
(2:25:39 PM) Fred: mine sat for 2.5 years and didn't rust
(2:25:46 PM) Fred: not enough to care about
(2:25:57 PM) Fred: if you REALLY care, get ceramic coating
(2:26:09 PM) Fred: otherwise spray with zinc paint (special one) and hot paint, and get it hot
(2:26:13 PM) Fred: won't rust then
(2:27:03 PM) Fred: re zinc paint, good stuff melts and galvanises once hot
(2:27:34 PM) Fred: steel will rust eventually...
(2:27:37 PM) Fred: but fuck...
(2:27:40 PM) Fred: you're growing old faster
(2:33:14 PM) Fred: you mustn't coat the inside with zinc or anything... it will fuck up your O2 sensor
(2:33:23 PM) Fred: s/s will crack
(2:33:28 PM) Fred: ceramic is ok
(2:33:30 PM) Fred: or straight

Tubing, use thin wall tube, not thick wall pipe.

Absolutely. I understand that you can pack thin tubing with sand and use a pipe bender with fairly decent results, but don't plan on going this route. Definitely not "pipe" from the hardware store.

Turbo mount, hang the turbo off of steel rods/brackets, let the tubing just be tubing, NOT support the turbo.

I like this idea a lot.

Extras, O2 sensors go AFTER the turbo in the down pipe, but you likely knew this.

Yes. Will need to accommodate the change of location for the pre-cat sensor on the exhaust manifold.

Design: Consider that the flange will be cooled by the head...I did a wire frame model for mine...End result you can find in my truck thread.

Excellent! Thanks.


-Jeff

[Fred]

I understand that you can pack thin tubing with sand and use a pipe bender with fairly decent results, but don't plan on going this route.

Wasn't suggesting to. You can buy U and 90 and 45 and whatever you need in thin wall pieces and weld them together. eg:

http://www.ebay.com/itm/1-25-1-1-4-mild ... fc&vxp=mtr

You can get different radii etc too.

Fred.

[ToxicGumbo]

Every so often, Car Craft has a good writeup on DIY headers. This one's pretty good and on that vein of thought:

http://www.carcraft.com/techarticles/11 ... ewall.html

[Fred]

Thing with NA manifolds is they rarely crack, because they are naturally long-tubed all the way to the first collector (2:1 or 4:1). With turbo manifolds, people want to put them close, and it causes issues. You need to think it through up front to keep the tubes a bit longer on purpose.

Question: low mount or high mount?

I went low mount to keep CG low. Most go high mount to keep turbo visible (ricers!). Going low mount also means exhaust has a straighter path out the back and less bends = less restriction. Low mount recommended. If so, you have lots of room above to do spaghetti tubing :-)

Fred.

[Fred]

https://www.facebook.com/ToxicFab < Your future work ;-)

[ToxicGumbo]

https://www.facebook.com/ToxicFab < Your future work

Liked! At first I thought you set it up as a gag/encouragement page, but then was surprised to see it's genuine. Hopefully the name doesn't come from excessive zinc-plated welding.

Here are some photos from my engine bay:



^ This was taken a few days ago during the sparkplug swap. Wish I would have taken more while the intake clutter was off. That flat plate holds the intake resonator above the exhaust manifold and can be removed of course.




^ Engine overview




^ Zooming in on the left




^ You can see the exhaust manifold below the intake resonator




^ Now zooming in from the side




^ Closer...




^ Looking down from the side


As for how to mount the turbo, my main concern is water level. I drive this truck through a lot of deep water pockets...or at least did. I'd like to not worry too much about that.


-Jeff

[Fred]

Looks pretty roomy to me.

You have a power steer or air con pipe there that needs to be protected from heat.

You also have a bunch of silly intake stuff that will go and/or change with boost. You need to think about intercooler placement and cold side plumbing routing.

The turbo's intake will be routed in a sealed pipe anyway, so it'll run submerged, no stress. Feed it to a snorkel, if you want.

Once you get it FreeEMSed you can rip off all of that intake shit and put a small filter directly on the throttle so you can see what you need to. Then you can design your manifold.

I also noticed your ex manifold has the flange welded on, cast stuff usually has it cast in. I don't know what the process used for that manifold is, but it's not traditional casting, that's for sure.

Perhaps you could reuse it and just change the output direction with bits of 3mm plate/tube to direct the flow to where ever you put the turbo.

Fred.

[ToxicGumbo]

I dropped by the local community college today to sign up for a welding workshop series that now turns out to be cancelled. Sucks. Having a span of 3-hour blocks with good facilities, equipment, and reasonable wall voltage was something I was looking tremendously forward to.

That class was originally how I planned to pace this project, but now I'll work on getting some equipment, practice, and parts together.


-Jeff