E30 M52

[B C]

In case anyone else here doing a 24v swap, either now or in the future needs a solution for the y-pipe, this is mine.

-Vibrant 10356 Y-pipe (SS), 2.25” ID inlets, 3.0” OD outlet

-Vibrant 63004 3” Flex pipe

-Summit Racing M18x1.5 SS O2 sensor bung (SUM-G2990SS)

-2.25” OD .120” wall (2.010” ID) mild steel DOM tubing

-2.00” OD .065” wall mild steel DOM tubing

-2.00” Band clamps (butt-joint)

-3” SS V-band flanges (piloted!!!)

The rest of the exhaust system is carried over from my turbo setup and is 3” stainless exhaust pipe, a 12” Vibrant Ultra Quiet Resonator, Vibrant Streetpower muffler and actually because a 24v sounds like a bowl of raspberries I will be adding an additional 18” Vibrant bottle resonator.

The y-pipe is decently thin wall at .049” that isnt uncommon for exhaust tubing but considering that the inlets are nearly touching, getting a weld all the way around could be tricky. That isnt my main issue though. The main issue is the header outlets. They are 2.0” OD tubes but strangely one of them tapers down to 1.75” OD. I dont understand why.

I will be cutting the 1.75” section off so I can just have (2) 2” tubes to work with.

To adapt the Y-pipe inlets down from 2.25 ID to 2.0 OD I inserted the 2.25 OD .120 wall tubing in as far as I could (very snug fit, had to heat the y-pipe up in the oven a bit after deburring the edges to get them to slide together)

Once I did this I sawed the tubes flush (see the image below with one sawed off and one just about to be) and ground them smooth.

.

This leaves me with heavy wall inlets that are better for welding and has a 2.010” ID which allows me to telescope the tubes yet again by inserting the 2.0” OD .065 wall tube and weld all 3 tubes together with plenty of space to get a complete weld bead in the middle.

2.0” OD tube inside the y-pipe with the sawed off reducer (the edges are blended so it just looks like one heavy wall tube instead of the .049 wall y-pipe and .120 wall DOM tube together)

Next I will drill the hole for the O2 bung then crawl under the car to take some measurements, then I can drop by our favorite resident bass fisherman for some welding [emoji16]

[KaiserRolls]

They taper because the stock midsection is a slip fit with a clamp

[i_love_cars]

I have recently seen this engine bay in person and can confirm there is an actual 24v engine in it, and things do look as clean as the photos(hopped) suggest. There will be cruises soon, I just know it.

[Jdesign]

I second the size differences because of a slip fit. If you use thinner exhaust tubing/piping, you can buy an expanded kit from HF and I have found that to work wonders when making misc tubes fit together. It seems like you have a very good and ultimately better solution though

[HipMF]

Someone mentioned tubing expanders, so I'm posting this. Possibly NSFW...?

7hOXm1o.mp4

Attachments:

• 7hOXm1o.mp4

[B C]

That was awesome!

[Jdesign]

That's sweet. It reminds me of this CNC tubing bender.

[m42b32]

Jdesign said:

That's sweet. It reminds me of this CNC tubing bender.

Awesome! You could make some wild headers on something like that

[B C]

DANGIT, BOBBY!

I am installing my brake master cylinder right now and the charcoal canister wont fit anymore and needs to come out (okay, its out) and as im installing the two nuts that hold the master cylinder on, one of them is just spinning. 🤯

So I am inside cooling down so I dont rage and just stick an impact gun on it out of spite.

Im going to assume it is splined like a wheel stud and will try pulling the stud towards the front of the car before cursing up a storm and pulling the manifold and booster out.

*serenity now*

[KaiserRolls]

Jb weld

[B C]

I cut the spinning nut off with a dremel and ground away some paint for a tack weld. I believe I should have enough clearance for a small tack since the master cylinder has voids.

[Jeff]

Snap said:

I cut the spinning nut off with a dremel and ground away some paint for a tack weld. I believe I should have enough clearance for a small tack since the master cylinder has voids.

Depends on if the taaack weld you lay on there matches or has a smaller radius then the chamfer on the master cylinder. I suggest you get a set or these to make sure.

[HipMF]

also, aren't there meltable things inside the booster? Like a big diaphragm? Don't put a hole in it with a piece of weld spatter.

[GunMetalGrey]

Snap said:

 Between a reman. booster (not a 36 year old used one)

A 36 year old used one is probably sounding pretty good right about now eh? 

Looks like a bit of weld should help, or JB Weld!

[B C]

Right.
I squished a small bead of JB putty on this morning so we will see if that holds tonight when I try again.

[GunMetalGrey]

Have you ever tried the steel stik stuff? Like JB weld putty it seems.

[Earl]

Snap said:

Right.
I squished a small bead of JB putty on this morning so we will see if that holds tonight when I try again.

GunMetalGrey said:

Have you ever tried the steel stik stuff? Like JB weld putty it seems.

hmm...

[B C]

That is pretty much all I ever use. It is nicer to grind and smooth out

Back in the pre-Megasquirt era, the AFM to cone filter adapters I could find had a very poor transition between the round tube and the rectangular afm entry. The air simply runs into a wall. So I packed JB putty in the corners to make a radius, then ground and sanded it smooth as glass after it hardened.

I keep a stick of it in the car tool kit as it can patch an aluminum oil pan

[B C]

Good news: The micro bead of JB putty worked. The master cylinder is installed

Stupid News: its dark and everything is covered in humidity juice.

List of things you can do on a 24v swapped e30 without removing the intake manifold:

- install master cylinder

- change spark plugs

- change injectors

- rotate tires

- complain

[jc43089]

It's a joy removing the manifold, you will get good at it.  The extra joy in an e36 coupe is removing the wipers, cowl plastic, and blower motor cover firewall thingy so you can get the manifold lifted off of the studs.