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-   -   Another gutted NB intake manifold (https://www.miataturbo.net/engine-performance-56/another-gutted-nb-intake-manifold-38809/)

ZX-Tex Sep 3, 2009 07:33 PM

Another gutted NB intake manifold
 
As promised in another thread, here are pictures of my recently ported intake manifold. This is from my '99 engine. I'll be adding the water injection nozzles next.

For the pictures go here:
Picasa Web Albums - John - manifold porting

This is about 10-12 hours of work to get this far. Most of the material removal was performed with a die grinder and various attachments. The upper manifold is not too bad to port out. The lower manifold on the other hand needs much more material removed. Note that the upper is completely open now. The lower has the two round ports joined together so that the runner is now one large oval plenum for each cylinder, transitioning into the section that connects to the head. I think that this will effectively shorten the runners though it is difficult to say by exactly how much.

DMRider_10 Sep 3, 2009 08:33 PM

Nice. What are your expected gains from this?

UrbanSoot Sep 3, 2009 08:46 PM


Originally Posted by DMRider_10 (Post 450210)
Nice. What are your expected gains from this?

eleventy billion. didnt you know that thats how much you get for doing this mod?

ZX-Tex Sep 3, 2009 08:54 PM

It should improve top end torque a bit, though probably not as much as a full-up custom manifold with a larger throttle. We will see when I get it to the dyno.

The main reason has to do with the water injection system. I am installing port nozzles and the open plenum space will allow for better mixing. It will also provide some fail-safe redundancy by sharing some of the water/meth mix between cylinders should one of the four nozzles become clogged.

l_bader Sep 3, 2009 09:05 PM

Hmm... we're looking at a long weekend. All my women folk have the flu. I need something to occupy my time and keep them away from me.

Maybe some "quality time" with the dremel is just what the doctor ordered...

- L

(Looking good...)

ZX-Tex Sep 3, 2009 10:13 PM


Originally Posted by l_bader (Post 450225)
Maybe some "quality time" with the dremel is just what the doctor ordered...

- L

(Looking good...)

Go for it. There is something satisfying about removing all of that metal. Be warned though, it will probably take a really, really long time with a dremel. I was running the die grinder continuously for 15-20 minutes at a time, and used some aggressive cutting bits to remove most of the material. A die grinder has a lot more power than a dremel does. No slam against dremels, I have one too.

Die grinders also consume a lot of compressor air. My compressor was running continuously for an hour or two at a time trying to keep up.

l_bader Sep 4, 2009 02:57 PM

Then I guess I'll have to pay a visit to the fine folks at Northern Tool or Harbor Freight...

- L

ZX-Tex Sep 4, 2009 03:04 PM

I would get the die grinder from Northern by the way. The one I got is the Northern brand one with the red rubberized grip. It is holding up well with a dryer and some occasional lubing. The last die grinder I got from Harbor Freight went back; it was broken right out of the box. The Harbor Freight compressor is holding up well though.

Savington Sep 4, 2009 03:35 PM


Originally Posted by UrbanSoot (Post 450216)
eleventy billion. didnt you know that thats how much you get for doing this mod?


Have you ever made a decent post on this forum?

hustler Sep 4, 2009 05:30 PM

dyno your shit immediately.

ZX-Tex Sep 4, 2009 05:45 PM

Motor is still at the machine shop dang it so it will be a couple of more weeks at least :)

jayc72 Sep 4, 2009 05:48 PM


Originally Posted by Savington (Post 450533)
Have you ever made a decent post on this forum?

+1. Not only useless but possibly dangerous.

Stein Sep 4, 2009 05:51 PM


Originally Posted by l_bader (Post 450511)
Then I guess I'll have to pay a visit to the fine folks at Northern Tool or Harbor Freight...

- L

Throwing this out there. I had a $200 Sioux Tools die grinder. It was nice, but died after extensive use over a couple of years. I replaced it with an AmPro from Advance Auto. This thing was under $40 and has more power andhas so far lasted longer than the $200 Sioux. Highly recommended for The $.

jayc72 Sep 4, 2009 05:59 PM

The cheap die grinder I have is just brutal on my compressor (5hp, 60 gal). I assume that it is very inefficient and that something that cost more than $30 would have less requirements for CFM. The China unit uses way more air than my 1/2" impact. Better have a good compressor.

triple88a Sep 4, 2009 06:02 PM

:useless:

^S=multiple...!!!

ZX-Tex Sep 4, 2009 06:06 PM


Originally Posted by triple88a (Post 450625)
:useless:

^S=multiple...!!!

Huh? Did you even bother clicking on the link IN THE FIRST POST?

UrbanSoot Sep 4, 2009 06:49 PM


Originally Posted by Savington (Post 450533)
Have you ever made a decent post on this forum?

im drunk most of the time i post here. do you mind? if you have problems with me - you know how to reach me.

ZX-Tex Sep 4, 2009 07:09 PM


Originally Posted by jayc72 (Post 450620)
The cheap die grinder I have is just brutal on my compressor (5hp, 60 gal). I assume that it is very inefficient and that something that cost more than $30 would have less requirements for CFM. The China unit uses way more air than my 1/2" impact. Better have a good compressor.

Mine also uses more than my 1/2" impact. Die grinders just use a shitload of air; everyone I have talked to that uses one says the same thing.

You can reduce consumption a bit if you use a regulator set at say 40 psi, but then you do not have as much available power. It works OK if you are doing light grinding or polishing.

triple88a Sep 4, 2009 10:11 PM


Originally Posted by ZX-Tex (Post 450627)
Huh? Did you even bother clicking on the link IN THE FIRST POST?

my bad, didnt see the arrows there so i only saw the 1 pic that came up

Thank you.

leatherface24 Sep 17, 2009 10:08 AM

anything new?


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