Help build a new intake manifold (long)
 

So I'm going to be building a new intake manifold and have a few questions that I'm sure some of you on here have already solved.

Details:
2.0L motor with 85mm 10.5 CP pistons, pauter rods, arp bits throughout.
99+ head with 270 deg cams, and other tasty bits. Headwork done by (now defunkt) replika machinen.

As a purchase of the motor I got an incomplete intake manifold. Starting from the intake tract:

https://lh4.googleusercontent.com/-d...0/DSC_0177.jpg
Flange (looking at the backside) for a mustang throttle body, will support a 65mm throttle with no problem. I have qty 3 of this. I'll be running a 59mm throttle to start, because I grabbed it from a friend for free.

https://www.miataturbo.net/attachmen...ine=1328751459
half round plenum intake, from ross machine, I need to buy this, looking at a 14" length, possibly 15" as a start point. If I cut off the flat section of the D, it will fit into my IM outlet flange (2 pics down) with little to no trimming. I will need to find a way to weld into the mustang flange. I'm not opposed to running 4" round tube for the plenum, but it would require more work to mate to the lower section.

https://www.miataturbo.net/attachmen...ine=1328751459
end cap, I'm going to lay this on an angle to prevent a perpendicular end to my manifold

https://lh3.googleusercontent.com/-5...0/DSC_0178.jpg
The output flange of the IM to the runners. I have qty 3 of these. The top flange shows output side, bottom shows input side, only one user per manifold. It is designed to slip fit a 2" OD aluminum tube into the output, and is setup to bolt on VW velocity stacks internally.

https://lh6.googleusercontent.com/-z...0/DSC_0179.jpg
The sexy and I know it. Sadly quantity 1 on this part. Also setup to slip fit the aforementioned intake runner. This was done to allow for the prior owner to dyno runner lengths in short order. The flange is setup to take o-rings to bolt to the head, have plenty of those in stock.

Now that I've shown the start point. Here is the list of "issues" I know I'm going to be tackling:

1. Throttle Cable routing
2. Fuel Rail Mounting
3. Vac lines/fitting
4. PCV?
5. Runner length
6. Supporting the IM with everything configured as a slip fit

For the throttle cable, I think I can figure that out pretty easily by using the bracket I took off my 1.6 motor before I sold it.

For the fuel rail, I'm kind of stumped on this one and open to suggestions, build standoffs on the head flange to replicate what was done on the OE piece?

For Vac lines I'm tempted to drill and tap one line and then run that feed to a vacuum distro block for ease of later upgrades. If I build future IM's with my spare parts, I won't have to do extra drilling/tapping on the IM. However, it does complicate the engine bay.

PCV I'm not sure I'm running, most others I've seen have this plugged IIRC.

Runner length, I'm going to have to futz with this and maybe pick up some u-bends to cut to replicate the longer runner length. Then again I may do that with rev-2 and just get the first IM up and running with straight runners.

Supporting the IM. Obviously the block has a provision for a bracket, but I don't have one on hand, so would need to source or build custom piece.

I could buy a 99+ IM and bolt it on, but the intake ports won't line up well, lots of other work, and I'm thinking that with some effort this stuff could be solved quick, I'm hoping that someone on here that has done some of this can point out the gotchas, what to look for, or possibly even help a fellow MT guy in return for homebrew beer, homeroasted coffee, cash, whatever.

Thanks,
-Greer

tl;dr: seriously, go read, pretty pictures and what not.

Naturally aspirated?

Yes. Naturally Aspirated. This car had an AVO turbo kit on it for some time, time for something "new".

-Greer

There's some interesting info here:

http://www.team-integra.net/forum/bl...culations.html

But unfortunately I've misplaced my math brain cells.
(Curly, of Three Stooges fame "I'm try'in ta think but nuttin's happ'in")
:vash:

I understand the need for runner length tuning and volume, that isn't my question.

1)What is the best method of building fuel rail supports that mimic OE
2)Has anyone run into throttle cable issues, if so, how did you solve
3)How many vac ports did you make and did you run a distro block or just tap/drill the manifold
4)anyone running PCV setup or just skipped?

-Greer

I'll be building an intake manifold for a 6 cylinder triumph in the near future, this is what I've decided on:

1) Why do you want to duplicate OE? Buy -6 fuel rail from Ross and roll your own
2) Custom cable, should be somewhere online that you can order these things fairly easily
3) As many vac ports as you need? Run your brake booster off its own nipple.
4) PC-what? Forced Induction guys have learned long ago crankcase ventilation blows (lol) on the BP series engine. Search "catch can" and "vented to atmosphere" or "VTA" and win. TL;DR? Vent both sides.

I plan on running one of these on both the Miata and the Triumph: Moroso Air/Oil Separator.

1. 1.8l heads have the injector port and rail standoff part of the head, not the manifold like 1.6's. You should be able to use the OEM rail, bolt-on aftermarket, or make your own rail easily. 94-97 rails are different than 99+.
2. You shouldn't run into any cable issue as long as you run a throttle body that uses a wheel and cylinder thing on the end of the cable like OEM. Either make a bracket or use the OEM stamped piece. I just got a 65mm Crown Vic throttle body off ebay for $40shipped including the TPS and harness. Uses a wheel and cable style like OEM miata and has a tang in the right spot to add return springs if needed; mustang stuff uses a different style cable end (ball socket thing). I will run the OEM IAC seperately like I did for saintfoo's car.
http://www.absurdflow.com/miata/acps...st2build14.jpg
3. I put a vac port for almost every thing that needed one, except for the boost gauge which was T'ed into my MAP sensor. The brake booster and PCV got big ports, the BOV got a middle sized ports, everything else got tiny ports.
4. I ran the OEM PCV with a catch can.


I like the idea about using commercially available vw velocity stacks. Where will you buy them from? Google shows cheap chromed pairs at ~$20.

Awesome. I have a 94 rail ready to go, but the head has been sitting tucked on a shelf long enough I must have forgotten that change. That saves a lot of work. I had a 1.6 in originally so I had that on the brain.

I've seen the 65mm stuff that cheap too, I may pull the trigger on one just for options. Since I'm running a tec-2, I already have a GM to ford IAC adaptor block to run a GM IAC that the tec-2 will control.

Okay, I was thinking running a single vac port to a block would be easier in the long run, but it looks like most people are running a plate with drilled/tap blocks that is welded in to provide the feed. Really I need brake, pcv, map.

Works for me. Easy enough to setup.

http://www.jbugs.com/category/vw-velocity-stacks.html

I'm going to use the 2.25" tall ones for the first rev of the manifold.

Thanks for the help!

-Greer

I'm glad I could help. That jbug site is what I found as well. If you google shop the Enco part number a few others pop up too.