Intake Manifold Modifications.....

[Installshield 2]

IS you're half right....what you said regarding airflow and top hp is basically correct, BUT psi is an important factor in determining eff. ranges...psi is also a function of heat, as we know air expands with heat. The psi is the work output of the turbo, that is the force representative of the energy required to produce a certain pressure. As you increase pressure you will always increase heat(laws of thermodynamics), thus as heat increases, eff decreases(covered in 100% eff combustable engines and such in physics II). SO though yes psi has nothing to do with airflow persay, it does have everything to do with intake temps and eff of the system at hand....the t25 will lose its eff at 18-20psi regardless of the cfm is flows at those pressures...the reason bigger turbos have higher eff boost levels is b/c it takes less energy(heat) to produce a given psi...but back to my question is there a particular year IM we should be looking for or will any fsde work?

Good points...I was trying to keep away from the 33% efficient gasoline engine theory, and all the potential energy of gasoline...If I would have included all that math, it would have touched more on the physics and chemistry behind air pressure...

I was just trying to illustrate that the turbo has two limits...and I only focused on the one...A) a given turbo can flow enough air for a determinable amount of hp...for any engine...and B) a turbo can build a certain level of pressure above the ambient pressure entering it...But depending on the engine the turbo is hung off of, maximum flow could be reached before the compressor trim bites it...My theory was that the turbo is pushing its maximum air in this dudes engine well under the graphs inefficient zone...as far as boost...

Leave me out of this though...ha, I don't even own a turbo...

 

[mspeed101]

take it off and bring it to me, ill do it..

You wanna do mine for me also? How long does it usually take to port the manifold?

 

[mp5jeff]

i won't be doin it for free, lol ill do it really cheap though, you would have to give me at least 2 days to do it man, it takes lots of time unfortunately...because if i do it i want the ports to be almost the same to each other(port matching) so each cylinder gets the same amount of air

 

[flat_black]

Yes, this process (Any porting/polishing job, really) will take a goodly amount of time. I did mine over two weeks, since I wasn't doing it constantly, and I took a lot of time to touch everything up and keep flow as laminar as possible. Fortunatly, Mazda didn't leave too much room for improvement, as the design is quite free of flashing and harsh corners, save a few.

Also, I'm N/A (And plan on staying that way), and as stated, it's beneficial to anyone, boosted or non; Let me tell you, too, that once you hit 4k RPM, you realize why you ported out your intake manifold. =) It pulls a LOT harder in the 4 - 6.5k range, for sure. Probably due to significant leaning, would be my guess, just due to the sound of the engine.

 

[DSMConvert]

for those of you that are too lazy or dont have the tools it should run you around $80ish to have a machine shop do it...well that would also inclue the IM being boiled if it was dirty

 

[EviLMaN]

hey just out of curiosity what if i just take the flap thingys off would i get any gain or no?

 

[flat_black]

You'll get a little gain, mostly at the high end, since it staunches flow a little bit. But you'll still need to plug the holes at either end.

The idea behind removing them, though, is to keep flow more laminar than anything else, really, which is why I patched all the pass-through holes as well, and removed all the burrs/bumps/ridges I could find, and made sure everything was nice and smooth.

 

[MSP Chris]

So as an update, I am still not 100% positive. The two piece manifold, the upper which is connected to the tb and the lower which is a shorter section that connects to the cylinder head. We are removing the shutter valves, which are in the lower manifold.

As per removal, I see about 10 or so bolts looking at the engine bay, is it possible to remove a section at a time..or at least seperate the upper from the lower to make removal and install easier or keep them together?

 

[flat_black]

I, too, thought it would be easier to finagle the two halves apart from one and the other. It actually is laid out the opposite of what you mentioned, though; The upper half is just runners, and contains both sets of butterflies; The lower portion is the plenum that attaches to the throttle body. The process of removal would be as follows, were I to suggest it:

- Remove the strut tower bar... No, really, it does make your life a lot easier.
- Remove all intake/intercooler charge tubing.
- Remove throttle body bolts(2 12mm bolts, 2 12mm nuts)
- Remove coolant hoses from throttle body
- Remove electrical connectors from throttle body.
- Extract throttle body.
- Remove PCV valve and leads to the intake manifold.
- Unbolt fuel rail and leave for now (4 12mm bolts)
- Unbolt and remove support bracket to the far right and unplug electrical connector. (2 10mm bolts)
- Unbolt and remove VTCS/VICS valve support bracket (2 10mm bolts)
- Unbolt and remove VICS actuator arm (The upper of the two, located further back in the engine bay. 1 10mm bolt and one circlip/e-clip.)
- Remove all vacuum hoses.
- Crawl under the car, and look up where your oil filter is. Unbolt and remove the intake manifold support bracket. (4 14mm bolts, one clip-in strap to support wiring harness.)
- Remove EGR inlet and bypass to the intake manifold (2 12mm bolts, one 23(?)mm collar. To the left of the support bracket.)
- Unbolt from head (7 12mm bolts, 4 upper, 3 lower. The lower ones are a little tricky, but you'll need a decently long set (3 - 9 inch) extensions, a 12mm deep and normal socket to allow you to change the length as needed. There are two bolts that you basically have to remove blindly; The lower one at either end. You have to shift the extension and socket around and get it onto the bolts, both of which are hidden away between the outer most runners, and the ones directly beside them. You'll see what I mean)

Installation is the reverse of removal. =) Hah! Oh, when you're taking the manifold off after all of this, be careful; you probably left the brake booster plugged in, so pull up slowly, and remove any remaining connections. Have fun, and don't break anything!

 

[peepsalot]

Good info. Seems this should go in the how-to section.

 

[flat_black]

I need to replace one of the gaskets on my furthest injector, so I'll pull the rail off and take some pics, then write up a real how-to. It's pretty self-explanitory, but it's a very time intensive task. Just take your time, and don't get frustrated, and before you know it, you'll only have one bolt to put back!

 

[DSMConvert]

wow so you cant just remove the upper portion...crap...I was hoping a simple removal like an exhaust manny or something...

 

[flat_black]

DSM: You can, actually; It's just KINDA annoying to do. I'll explain:

When you unbolt your upper manifold from the lower manifold, you can't move either, as the two studs in the lower manifold prevent the upper from moving. That being said, if you were to remove the brace underneath the manifold, then you could remove the upper; But the lower would fall down and/or bend/break something. So you have to loosen the bolts as much as you can on the manifold support bracket or remove the upper bolts on the bracket only, then scootch the manifold assembly back, and lift the top half off. This does, however, make it so you don't have to remove the EGR valve and bypass, which is a real b****. I have done it this way once, too, and it works just fine, but is a little less clear-cut as far as what you needed to do, so I didn't want to detail it in a straight-through set of instructions. =)

 

[peepsalot]

I need to replace one of the gaskets on my furthest injector, so I'll pull the rail off and take some pics, then write up a real how-to. It's pretty self-explanitory, but it's a very time intensive task. Just take your time, and don't get frustrated, and before you know it, you'll only have one bolt to put back!

And you won't be able to find that damn bolt. (laugh)

 

[DSMConvert]

flat- cool i might pm you when i get around to taking it off just to get a general idea if i get stuck....well that is if I ever figure out what year manifold will work....

 

[flat_black]

Cool, no prob. =) Drop me a PM if ya need anything.

What are you trying to figure out about the manifold, now? Maybe I can help.

flat- cool i might pm you when i get around to taking it off just to get a general idea if i get stuck....well that is if I ever figure out what year manifold will work....

 

[DSMConvert]

well I'm just curious what year manifolds will work....I have an IM off a 93 2.0L probe and I'm curious if I can use that or if they more than likely changed designs at some point...

 

[flat_black]

Hmm... It technically should bolt up... Can you take a pic of it? If so, I can tell you for sure if it could bolt up. But it won't have VICS, and it won't have the casting updates, so it'll be a little more like investment cast inside. IE, not as smooth, so less laminar flow. You'd have to extrude hone it or get a VERY good port job done on it, and even then, without VICS, you'd probably end up losing power.

 

[DSMConvert]

yea thats what I was afraid of...i guess I'm going to have to find out what year they did the casting update and the VICS addition...

 

[MSP Chris]

the upper half is just runners, and contains both sets of butterflies; The lower portion is the plenum that attaches to the throttle body

Alright I am confused because blkzoomzoom said the lower part (connected to tb) was the part with the vics system in it, I just want to claify we are removing the butterlfies, only one set of 4 which are on the upper (which connects to the head). These are the intake manifold facing the head, or are there 2 sets on the upper portion of the intake manifold? I am on the verge of being confused..