My intake manifold fabrication thread, LOTS of pics

[The Aspirator]

I've had it done for over a month now and I haven't even made this thread yet! Pathetic, I know. So I had a few reasons for wanting to make this manifold, first off because I've just wanted to make one for years, they seemed pretty "simple" at the time (hahahahahahahahahahaha). Another reason is cuz I hadn't made anything new and cool and neat for my car in a long time, so it was definitely time for something off the wall that you don't see every day. I jumped in both feet first, trying to make it as cheap as possible and have it all done within a couple of weeks so that I could install it and drive my car down to the Carlisle, PA meet. I got it done in time but the flange was so warped that the car idled at 3500rpm and drove like poop, therefore I wasn't able to drive the damn thing to carlisle and had to hitch a ride, that SUCKED.

Parts list, lets see here, I made the whole thing out of mild steel with some stainless parts thrown in there. The plenum is 4" exhaust tubing and 15-16" long ($20), the runners are 1.75" tubing 3' long ($10), the injector bungs were machined out of 1" solid rod ($5), and the flanges are 1/4" steel plate (~20?). Then I needed the hole saws and some adapters, 1.75" and 2.25" ($35). O-rings, 1/2" ID x 5/8" OD (x4) and 5/8" ID x 3/4" OD (x4) ($5). Velocity stacks ($2). Surfacing flange flat ($30). Misc consumables, welding rod, gas (I used LOTS on this project), etc (~$35?). New fuel hose and misc junk ($25). I think that's about it, what's that then... Holy crap, $187 just in parts! I've never actually added it up till just now. I seriously thought I could do this thing for under $50. And I did EVERYTHING myself, except for surfacing the flanges.

I welded the entire project with a DHC2000, aka Henrob 2000, oxy/acetylene torch. www.cut-like-plasma.com
I decided to get that instead of a TIG because it was less than half the cost up front and it seemed more versatile. To be honest they over-hype it on the website at how easy it is to use, it takes a LOT of practice to get any good at it, especially with aluminum. Steel is much easier especially if you always use stainless rod, like a 308 or 309. Welding with steel rods SUCKS. I've had the torch for almost 5 months and I use it almost every day, and not to toot my own horn or anything, but I'm getting pretty darn good with it. Not quite TIG quality, but certainly good enough, I'm happy with it. But when I can afford a TIG I think I'll get that too. Ohh and this torch cuts through steel like butter, which is pretty neat and came in very handy while making this project (and many others).

I made quite a few mistakes while making this thing so lets hope I can remember them all and keep you guys from making the same ones. First mistake was trying to make my own flanges, that SUCKED. Sounded pretty easy, since I have a cutting torch and a hole saw. Even with cutting lube it takes forever and a half to cut through 1/4" plate with a holesaw, and it got dull quick. Next time I'm not even going to think twice about buying a flange that's been properly cut on a waterjet/laser/milling machine. Same goes for throttle body, I made a flange for a 240 TB because that's the only one I had laying around. That's my biggest regret, was not using a larger throttle, I really really really should have picked up an 850 TB first and used that. Ohh well, next mani.

Ok, on with some pics. These are the "velocity stacks" that I used. Very fancy, very high dollar.... 1 dollar to be exact. They're little stainless steel mixing dishes from the dollar store, and worked fan-frickin-tastically. They cost $1 for a 3 pack, so I bought two packs. The only downside is that they're paper thin, so welding was tricky. Great practice though. You can see them next to a piece of 1.75" tubing, which is several times thicker.



2 feet of 4" exhaust tubing, 3-4' of 1.75" tubing.


One of the injector bungs on the lathe getting bored out.


Be CAREFUL when holding things at a weird angle in a chop saw! I was trying to hold a 3" piece of 1" bar at a 45* angle and I think it slipped out, which shattered my chop saw blade and scared the shizzle out of me. I was wearing safety glasses but a piece still hit me in the face, no cut.



Next time I will either do these a LOT better, or buy some pre-made ones. I couldn't really find any steel ones for sale, only aluminum, so I made my own. The only bad part was that they were all slightly different heights. At the time I thought that would be fine, but once I welded them on and noticed that they really screwed up the injector placement, that's when I realized my mistake.


Lets see, to make these I cut two lengths of 1" solid steel bar, 3" long each. Then I cut those in half at a 45* angle (a bandsaw would have made that easy!). To figure out the depth to make all the steps you sorta just hold it up to an injector and use your digital calipers to measure all the distances. The center bore needs to be slightly bigger than the bottom part of an injector (I'm using CFI's), I think I drilled it for around 1/2". I'm not using the regular o-rings that they usually use, instead I'll be using 2 o-rings per injector, one in each of the following steps. The lower o-ring needs to be 5/8" OD x 1/2" ID 1/16" thick. Cut each bung to that ID, so 0.625", and make it as long as that section of the injector. At the top I cut a little groove 0.75" dia and 0.040" deep, this will house a 3/4" OD x 5/8" ID 1/16" thick o-ring.

These lower injector O-rings don't have to seal fuel, just air, so they're not as deathly important as the top ones. For the first few hundred miles I only used the upper 3/4" o-rings, 1 per injector, they leak air and cause me to idle high, so I need to install my 5/8" o-rings on the lower part of the injector, having 2 per 'jector should work great.


Here you can see how the injector fits in there nice and snug! And the lower part sticks out just far enough to clear the manifold tubing as well.


Plenum, injector bungs, and my horribly ugly flanges that I made. Also that other thing is a cone that I made on the lathe, I was planning on flaring my own tubing to make velocity stacks but the dollar store alternatives were just so much easier.






I love how SS turns gold when it gets hot! But it turns gray when it gets too hot, as you can tell around the weld area. It sure was tricky not burning through the cups, because the tubing is 0.065" wall and the cups are probably 0.02" or something. The thicker tube requires more heat to melt, but too much heat on the thin stuff melts a big hole, then trying to chase down that hole and close it up becomes a fun game. Luckily, this one turned out perfectly.


Here's another huge mistake. Do these welds LAST! I did them first and then had a bugger of a time lining everything up for the lower tubing and flanges. Trust me.


Now as I understand it, the purpose of velocity stacks is to help "suck" air down the port. Imagine if this plenum were filled with a heavy smoke, and there was a huge suction coming from the runner. At the bowl of the stack it doesn't just have to suck from straight up, but now it can also suck up the smoke that's below it. Imagine arrows pointing from the weld up around in a circle and into the mouth. Does that make sense? I guess that explanation only makes sense for N/A engines, not sure how to explain it for forced induction.


Hole for the throttle body. I chose to have it enter at a 90* angle because I've read that is a good way to do it. And easy. The other option is front mount, but then you're supposed to taper the plenum down. And this way let me use my existing intercooler piping, which rocked.


240 throttle body, home made flange, 2.25" exhaust pipe.




This idea is great in theory, but HOLY CRAP DID IT STINK! Don't do it, my garage smelled like burning carbon for a week. Especially with the oxy/acetylene torch, trying to weld those flanges to the runners, it got the factory manifold warm enough to start stinking up the place, it smelled positively nasty. Going to a spare head would be a much better idea, or if you had a one piece flange you wouldn't even need to bolt it down.

Here you can also see my DHC2000 torch and tanks, with my trusty fluxcore mig in the back (which I never use anymore since I got the new torch )


Runners welded, notice how #4 is at a hilarious angle, I had to do that to be able to kick it back over and line up with the port, I think the upper pipe got welded in crooked. Hence why you do those ones last! Notice how I did the runners in two chunks? That's because I needed the upper piece and velocity stack to be able to slip inside the plenum and down their hole. If the pipe was any longer it wouldn't have worked. I could have chopped the plenum in half then closed it back up again, but whatever.


Yikes, lots of tension already! Again, this is why you do the top runner-to-plenum welds last.




Fits onto the studs without too much drama, just scrapes the threads a bit on a few holes, I'm not concerned.



Injector holes, I think I drilled 1/2" holes then tilted the drill bit to ovalize them. I'd suggest drilling the holes to a size just smaller than the OD of your injector bung, because on some of mine the lowest body of the injector rubbed the tubing so I had to dremel it out.


The hole is for my idle motor and the bar is for 6 vacuum ports, all 1/8" NPT. I think that's 1/4" x 1" flat bar, a perfect choice for the threads.


Injectors installed.


Eeek, some misalignment issues for sure! Next time I will go through the trouble of making little bushings to connect the fuel rail to each injector bung, to make sure they get welded on straight up and down, and to the right height. Like mini injectors. Because injector misalignment leads to upper o-ring misalignment which leads to fuel leaks. I had to battle with the upper o-rings quite a bit to get them to seal well. Luckily the final misalignment was not nearly as bad as what you see here, I actually had to cut the #1 bung off and re-weld it over a little bit.


Had to bend my dipstick tube because the end of the plenum took the same place. This way works awesome.





During some of the first few test fits I realized that the plenum and my strut brace were taking up the same place, so I cut a chunk out of the plenum and welded in a slice of tubing to make a nice groove for the bar to fit into.


Notice how the fuel rail is on backwards, this is because the FPR hits the plenum if it were to go on the normal way. Surprisingly it works great backwards! Next time I'd make a custom fuel rail and put the FPR down below somewhere, but that was too much complication/expense for this project.


You can see how I did my fuel rail hold down, it works well but it bends the cheesy factory rail pretty easily, so be careful. But I figured that this hold down design could also work well when I eventually made my own fuel rail, so I like it.


Here's a half decent shot of the throttle linkage. I used a B230 throttle spool and bracket, made 3 little pedistals to bolt it down onto, and had to bend and weld the original bracket quite a bit to make it aim right. This was quite a little project in itself, I didn't put much planning into it, but it sure did take a WHILE.


More throttle linkage pics, and in the lower left you can see my idle valve hanging there and chillin, with a little breather filter on it. The brake booster vac line goes to one of the ports, wastegate to the second port, mapbomb (MS, boost gauge, vents inside) to the third port, then FPR, the BOV, then one left over for good luck.



Powdercoated my throttle body white, but you can tell that I didn't put too much effort into cleaning it first, all those yellow/ugly spots are grease.


The rest of the stuff turned out nice, canadian colors y0!


Since the flanges ended up being at quite different heights, and the car was trying to idle at 3500rpm all the time I took the manifold to a local machine shop, a cool old place out in the country where all the farmers go to, cash only. I think he just put it on a belt sander and took it all down, but hey, it's flat, it was done in 3 hours, and it only cost $30. He did the throttle body flange too.


Lots of crap inside this manifold now! I gave it a really good bath with hot water and lots of simple green in the laundry room sink (Meg didn't catch me!). For the white powdercoat to look good I wanted this thing completly grease free.


BLING!!! Couldn't be happier with the way the white powdercoat turned out, I just love it.


A few little cracks became very obvious under the white powder, I'm not concerned that they'll leak or anything, but they're interesting.





I made a new mount for my LS1 coils too (sequential coil on plug for those who don't know), out of 1/8" stainless steel rod. I'll powdercoat it white too eventually.





So there you go! That's my car, it's been so long since I've posted any pictures of it. Half the guys I meet think I'm still driving the old blue/red 244, which is long since gone. The yellow turbo in here now is a John Deere T3/T4, which was graciously donated by Vince (terribleone) when I was in a jam, something like a .44 trim 50ar with a .63 volvo turbine housing and wheel. Powerstroke intercooler, blueprinted and balanced B23 enigne, ported and polished 398 head, ported 90+ mani, A-cam at the moment, Megasquirt with the high res extra code running as many goodies as I can make it, 3" exhaust, M46 (still holding in there!) with a clutchnet 6 puck.

When this engine was in my 244 it laid down 235/250 at the wheels with a 60/63 turbo at 11psi and a stock IC. With this setup I should be able to pull 300whp without too much drama, but I'm not quite ready to have this M46 blow up on me, so I'm keeping the boost at 11psi right now. It probably makes 230-260ish, perfect for a daily driver.

As for the manifold, the car was off the road for over two weeks, and when I got it running again it didn't idle or drive right because of the leaks. So I don't have a back to back comparison for you guys. I'm sure it helps, but how much is the question. The 240 throttle body was a stupid rushed choice that I really wish I would have upgraded, it's probably the biggest restriction in the current setup. Ohh well, if I ever have the energy maybe I'll chop it out and slap a huge one on there, but for now I just don't care.

John

is the jelly for lonely time? looks great, you made me realize how many things you run into making a custon intake, it hurts my brain. whats the butt dyno say about it?

[The Aspirator]

I was like, wait, what jelly, did I make a funny and not notice it? Haha, the petrolium jelly, it's for lubing up the injector o-rings. And other stuff...

Butt dyno isn't sure, the car hauls azz but it did before.

[ovlover]

Looks awsome! any ideas on flow stats? did you do any testing to see better or worse power/flow figures for longer or shorter length runners? ..........any plans for a carbon fiber one?

[suterman]

Nice work, the powdercoating is interesting, how do you do that?

Originally Posted by The Aspirator

I was like, wait, what jelly, did I make a funny and not notice it? Haha, the petrolium jelly, it's for lubing up the injector o-rings. And other stuff...

Butt dyno isn't sure, the car hauls azz but it did before.

yeah you gotta lube up the bung so you dont break an o-ring

[Dr Dokeh]

That's awesome John, props for ingenuity!

[J2_]

Are you going to sell these ??

[Dauntless]

It would be really interesting to see before and after dyno figures!

[Rockmonton]

really? stainless rod with the steel? i should try that.... i've been having pretty good luck with mild rod still though. is the difference really that great?

[crazy0000]

So you finally you show the crowd! haha

As great as it looks in the pictures, it looks 10x better in person.

Are you going to start a project thread or what? haha

[gear whine]

great writeup man!

cant wait to finally see it in person.


edit: any progress on my sweet,, secret, totally awesome thing im giving you money to make!?

[Jerd]

WOWWWWWWWWWWWWWWWWWWWW

A+++++++++++++++++++++++

[linuxman51]

not as easy as it looks is it? ;)

[volvorsport]

without access to decent machinery , its pretty hard to a decent job unless you but a whole lot of stuff , then it doesnt turn out so cheap .

you could spin some ally ram pipes on a lathe , or press thtem on a 20 ton bottle jack/press , but you still need to makes some tooling .

if this were me i would have made a square flange to position thhe runners in and have a half moon plenum .

the purpose of teh ram pipes is to allow air to flow into the pipe without restriction or causing turbulence (which in itself reduces the diameter of the available pipe to flow air ), the best example of this is the radiused pipe stubs that fit SU carbs , the very shallow angle allows the air to turn nice and slow .

I think Mr Vizard makes a nice example of this in his tuning A series engines .

nice to see people having a go

[Captain Bondo]

Originally Posted by volvorsport

nice to see people having a go

+1, Sound like you learned a lot! The poweder coat looks wicked!

I would keep an eye on the weld to the flanges and those ones that are cracked though.

Cracked welds on a vibrating manifold assembly rarely just stay the same size- I would expect them to start leaking at some stage.

Also in the pic where you show the weld that pulled apart, it looks like the weld was just sitting on the flange, it seperated cleanly and didn't take any metal form the flange with it.

This suggests lack of/no penetration to the flange in that case.

Welding thicknesses that different will probably require some preheat on the flange.


I am jealous of the lathe- looks like you are getting a good handle on that too!

[The Aspirator]

Thanks guys! It's great to get positive feedback.

Originally Posted by ovlover

Looks awsome! any ideas on flow stats? did you do any testing to see better or worse power/flow figures for longer or shorter length runners? ..........any plans for a carbon fiber one?

Nope, nope, and nope. I did do a quickie flow test with my air compressor and the blowey nozzle, and when I blew air into the throttle body it felt like nearly all of it was coming out 1 and 4, with very little coming out 2 and 3. Not sure how that compares to what actually happens on an engine though, so ???.

Originally Posted by suterman

Nice work, the powdercoating is interesting, how do you do that?

I didn't read it, but this is probably pretty accurate.
http://en.wikipedia.org/wiki/Powder_coating
Powdercoating is awesome, you buy a kit for $100-300, hook it up to a 5-10psi air source, then bake it in a normal house oven (but not your in-house cooking oven!) for 10-30 minuted depending on the powder. Out comes a beautiful product that's very resistant to solvents and looks great for years.

Originally Posted by J2_

Are you going to sell these ??

No, this thing took way too much effort, and way too much welding time with the torch. If I had a TIG I'd consider it, but still I wouldn't count on it.

Originally Posted by Rockmonton

really? stainless rod with the steel? i should try that.... i've been having pretty good luck with mild rod still though. is the difference really that great?

TRY IT! You've got the same torch as me, the stainless rod flows out 1000x better than the steel junk. The weld bead will be fatter, but that's no biggie. Use a 2-3x carburizing flame to help shield the stainless rod. I haven't used steel rod for months since Captain Bondo suggested this. And now the welds will never rust .

Originally Posted by linuxman51

not as easy as it looks is it? ;)

You got that right! So much little fiddly crap, lining up the injector bungs, making the throttle linkage work, etc etc etc. Now I realize that the price you're charging is 100% justified, and yours is 10x nicer than mine.

Originally Posted by Captain Bondo

Also in the pic where you show the weld that pulled apart, it looks like the weld was just sitting on the flange, it seperated cleanly and didn't take any metal form the flange with it.

This suggests lack of/no penetration to the flange in that case.

Welding thicknesses that different will probably require some preheat on the flange.

Yeah that was just a quick tack, I didn't put enough heat into the flange to make it stick well. After enough practice it's easy to tell when you have enough pre-heat, because the weld area will start to melt into a puddle, if it doesn't then it needs more heat. Man I can just imagine how much easier it would be with a TIG, need more heat? OK, turn up the dial. For me it's holding the torch there for a few minutes trying to pre-heat it, or going to a bigger tip. This torch welds SLOW, since the materials require so much pre-heat, especially on anything thicker than 1/16". Ohh well, it was cheap-ish and just look at all the stuff I've been able to create with it, that makes me happy.

[Marek]

nice work man!

I would also like to see some digits with that TB

if you have a stock one it would be awesome to see before and after numbers :P



Gooooo Canada :D

[linuxman51]

Originally Posted by The Aspirator

Thanks guys! It's great to get positive feedback.

Nope, nope, and nope. I did do a quickie flow test with my air compressor and the blowey nozzle, and when I blew air into the throttle body it felt like nearly all of it was coming out 1 and 4, with very little coming out 2 and 3. Not sure how that compares to what actually happens on an engine though, so ???.

depending on how exact you got the nozzle pointed into the plenum it will greatly favor different things. I did the same thing with a water hose, funny off-center angles cause it to go one way, change the angle a little bit and it ends up on the other side. check your plugs closely after you do the test run and that'll give you a better idea of whats going on. I was hoping to crank mine this weekend, but I've gotta wait on some replacement ms parts :-/

[2fast242gt]

i love it john, but i gota ask, after all that work... what made you go with a 240 TB? i love your design though!

[MrBill]

wow looks great, it's too bad we couldnt see it at carlisle

[Poik]

Looks great John, I am envious! Also looks like a lot of work. You seem to be able to weld pretty good with that torch.

[The Aspirator]

2fast, I went with the 240 TB cause that's what I had laying around, and the local yard quoted me $80 on the phone for an 850 one. I rushed myself too much, I would have had plenty of time to order a bigger TB off someone here and get it shipped. Whateva.

Kenny I've had the manifold running on the car for almost a month now, probably almost 1000 miles? Even after decking the flange it still idled high, with the idle valve turned off and the thumbscrew in the lowest I could get it to idle at was just over 2000. This was re-using the old gasket. I bought two new gaskets and threw them on, that got the idle down a bit more, but still not perfect. Now I'm noticing that one of the lower injector o-rings (the upper 3/4" one) has popped out, and is spitting out a bit of oil on to the manifold, so there's my big leak. Once I install the double o-rings on all the injectors it should be back to normal. Though the car seems to run fine, even with the leak. I took the timing down 5* and that lowered my idle to just over 1000.

Thanks for the reminder to check the plugs! I'll do that and report back. They've always been very even on my engine so any differences will be obvious.

[shaved240]

wow I'm so ****ing impressed john! Welds look great, and manifold looks great! oxy/acetylene welding isn't the easiest, especially when it pops back in your face.

You keep rasing the bar on your projects. I remember reading your posts back when you were running 20 psi on your holset and your small rod b230f+t. I was so impressed with that, and now this!

I'm bummed though you used a stock 240 TB. I think to improve the manifold even more you could upgrade your tb. I'll sell you a q45 tb that i have lying around for the price i paid at the junkyard, which I think is about 15 bucks or so.

[245gti]

These might be a simpler option for injector holders...





Two-piece, self-contained with a 1/8" NPT fitting for fuel feed. I can get them made for the traditional Bosch and the newer compact injectors. I can also get the output end shaped however you need. They are aluminum so attaching them to a steel plenum or runner might be tricky but perhaps the next one will be aluminum?

Nice work John...