And for fine grinding I will be using Dremel #84922

 

Not sure what andre wanted me to see but ehres my input:

IMO a dremel will take MUCH longer than a heavy duty power drill with the saw bit.

the bit is pERFECT, it never got hot, adn would nicelywear away the metal.

the guy with the red painted manny, i think you need to do MORE porting, you only made them round, we made them egg shaped.



a good rule is to take off the gasket, and line it up on both sides, you WILL notice that on one side the metal is SMALLER than the gasket opening

just take a scribe and folow the inside of the gasket holes, then cut away the metal thats within the scribe lines.

THAT will help free up the intake

 

well i did this mod on a turbo II, and can say it worked effectively, tho when i get my boost back i will know just how effectively... right now i have no turbo, but doing this mod unleashed almost as much power as having my turbo functioning properly before i did the mod... the car idles pretty high, need to adjust that, but it runs so much stronger, especially in the top end, i did a little bit more than this mod too... but i don't know how to describe it, i'm trying to find pictures so i can illustrate what i did, since i don't know much about part names etc

 

Hey Guys,

IMHO a Dremel is just not the right tool for this job (but it will work). If you have access to an air compressor. Go buy a small die grinder (it is about the size of a dremel but spins abou 1/8th the speed with about 5 times the power.) You can usualy get an el'cheapo model for $20.

I gasket matched my lower intake manifold (the block already matched the gasket). It took me (seriously) 10 minutes. 7 of those were prep and clean up, 3 minutes of actual grinding. You have to be careful, it isn't likely you will cut through the manifold but if you don't do it right you will not have round ports or matched (the only thing that is important is that both rotors get the same amount of air (or else one will be richer / leaner than the other).

If you lack the skill of Andre and protege man, just take the gasket lay it ontop of the manifold, and use an awl to etch the edges of the gasket onto the manifold surface, If you realy want to do it right, go buy some machinists dye and dye the manifold surface first, then you can easily see the awl marks. Then remove material up to the line you etched. If you realy are picky, you can get some sand paper and polish it, but porting adds most of the power, polishing is like grasping for straws (and some may say the rough sides helps the fuel / air mix better, although I don't think so). So with the die grinder, you are looking at an hour to do the porting, 45 minutes to etch all the surfaces and then 15 minutes to do the actual cutting.

Well I was thinking about it tongiht, and I decided I just couldn't live with myself unless I go get another gasket, pull the lower intake back off and port the whole manifold. I will take some pics and post them ('87 GXL). then everyone will know what their 6 ports are. I wish I could get Pine Apple racing sleeves here by wednesday.. hmm.... Perhaps I will try. That sure would complete the job right.

Joey

 

I look forward to your pics. How soon?

 

kf4oij/// It seems I am getting alot of heat for using a Dremel to port my Intake.

Although It will take a little bit longer, It will be uqually effective. The bits that I will be using are madeout of Silicon Carbide. These bits are tolerant of long standing grinding and are heat resistant.

Finally, who wants to be holding a big *** grinder when porting the Manifolds? It requires steady and smooth grinding that can be achieved with the Dremel, or the like, due to It's size.

*note* When I used the term "puny", In reference to the Dremel, I was just refering to It's size.

 

i put it back together too quick to get any pics:P sorry, i didn't think about that...

 

I agree with kf4oij. Use a die grinder. I have a dremel. I wouldn't dream of using it for anything other that polishing your newly ported work. My die grinder with the carbide bit rocks! They aren't that big and are very easy to control. The added size and weight make it easier to control than the dremel. It doesn't jump around as much. I've seen those saw bits. Whoever used those is far more brave then I am. I could do almost everyones manifolds on this post with a die grinder in the time it would take to do 1 with a dremel or a saw bit.

Has anyone done a dyno comparison of the before and after affects? I would like to see it. I am somewhat sceptical since my butt dyno has lied to me before. Not saying that it doesn't work since so many people here have said it does. I would just like to know some actual numbers across the whole usable RPM range.

 

I had my 87 na intake manifold ported when I was having some preventive maitanace work done about 3 weeks ago. I could really notice the diffence in hp no matter what rpm's.

 

Yes dyno numbers would be great.

 

Damn Dremel sucks towards this application. The carbide bits wore out completly, In less than 5 minutes. I know, I told you so.

I'm ordering the Beaver Saw Drill Bit that came highy recommended. No Home Depot stocks It here. So I am taking It to the states. They are going to mail It to me - express.

 

I was wondering if you know anyone who have done intake porting on a 86-88?

 

If you are asking me then no one that I know of personally. Just myself, soon.

 

rotary 13b- I did the intake on 86-88, I wrote about it earlier on this thread, look for the pics of the painted red manifolds a few pages earlier. very very worth it. pm if you have questions

 

Heres a ? for someone? The lower intake manifold has the two holes on each far end. Can I dremel off that bridge piece so I can enlargen the hole more?

 

Oh hell no! That will destroy airflow into the engine. The engine runners are that shape. You need to keep the transition as smooth as possible. You could grind it out if you also grind the port entrances together on the engine itself but you will be losing the all important velocity through that region.

 

I just got my VDI intake manifold to adapt to my GSL-SE. I can definitely see why you would want to do the egg shape on the lower part when you port it. Interesting design Mazda gave us.

 

The manifold narrows with right where the secondary injectors fire. They did this to help the fuel atomization at lower rpm's. But I have never had any problems with it in my car, but I also have a lot of mods. But I dont think it would ever be significant to affect even a stock motor.

And porting extends your powerband another 500-1000 rpm depending on your other mods with a VDI manifold. Youll love it.

 

Since I only have 2 injectors on my car I am filling the secondary injector holes on the manifold and grinding the inside to a nice round shape. Mine should flow much better.

 

It worked great for mine. Did you use the proper cutting oil with your carbide bit?
(Do you even know what cutting oil is to be used on aluminum? I'll give you a hint... it's not 10W30...)













Answer: Kerosene

 

Thats hillarious. I'm being quizzed. Anyway, yes I know of the cutting oil but as you said "cutting" would/could be used for that particular application. With the porting of the Manifolds, we are shaving or trimming the Manifolds. I guess you could use Keresone oil however, the bits I was using was not suited of the duration of this project and MAYBE Keresone oil could have spared a few more moments with these particular bits.

 

Any Dyno comparisons, please? im woried the porting would screw up the nice presure wave tunning on the s5 manifold

 

I used a dremel with coarse sanding drums. Went through about 7 drums for the whole job. Took about 2-3 hours tops. Came out real good. Won't know how well it runs until I get the car back together though.

 

well now it looks like its time to port the TII intake mani ; O )

 

About to port a friend's TB, so I picked up one of these saw bits. Looks like it would work well, but I didn't like even thinking about moving a heavy drill effectively, so I bought a flew shaft kit for my drill for $24. It's a lot like the one for the dremel (which I will use for final polishing), and is a lot easier to handle.