Hey, I'm just curious, who all here has ported there intake manifold? I'm curious what exactly this entails. Do you enlarge just the runners that dump into the the engine block, or do you port the top of the lower intake as well? How about the dynamic chamber, do you port those as well?

What kind of bits did you guys use, or more specifically, what material bits did you use.

The reason I am asking is a finally got a craftsman rotary tool(same thing as a dremel) mainly for the purpose of being able to remove my inner bearings from the race, but I am also curious about tampering with intake porting. I figure I'll pick up a junk intake from a junkyard and practice on that first. So does anybody have tips on intake porting, such as what bits to use, and what surfaces to port, how HP can be gained if done properly, etc...? Thanks in advance.

 

hmmm...? Nobody's ported their intake out before?

 

I have a spare intake manifold I would like to have ported. Any info would be a great help to me too.

 

talk to MazdaSpeed7

 

hum-de-dum...one more bump.

 

www.geocities.com/rx_treme/intake.html heres a little write up on mine,

i sent Speedracer some more details he can post them if he feels the need.
Later
Jason

 

Alright...Hope you have lots of free time if you plan on doing it with an electric Dremel tool or such. They get hot very quickly, and need to cool down about every 30 min.

Bits - I dont know what its called, but theres this dremel bit thats made for grinding alum/non-ferrous metals. It has teeth that are twisted and pretty big too(its really hard to describe) and it does a very good job on aluminum. Ill get a part number for you in a few days.

The actual porting - Where the lower and middle intake manifolds bolt together, the runners narrow down to about 70% for the flanges. When you look at it, and what you can do to it, you will be amazed Mazda did something so poorly. That is on the secondary runners. Aside from that, all of the other runners you cant do much with, but make them a little bigger, and match port the 2 pieces that bolt together. Ill have some templates made in a few days if you want to wait for that.

The gains are awesome. I gained more seat of the pants power from that than the dual outlet headers/dual midpipes, no cats. And it sounds awesome.

 

Great info guys, but a few more questions if I may? How did you match the ports? Did you trace one of the finished ports somehow and make a template for the corrosponding port on the other side? Did you use any special measuring tools. I saw the that Rx_treme said he used a micrometer. Also, it seems that both of you only ported the runners on the top of the lower intake and the on the bottom off the dynamic chamber. I guess that makes since, because if you ported the lower portion of the lower intake, it wouldn't do any good unless you also ported the outside of the block, and that would probably require dissassemlbing the block?

I have a spare set of Fuel Injectors around, and I was thinking about sending them in and having them enlarged too 550's, and putting those in for my secondaries? Do you think thats overboard for an NA with ported intake and the mods in my sig?

I've heard of people porting the TB, but I don't understand that at all. Wouldn't you have to get bigger throttle plates if you enlarged the TB? And I would think you would need precision tools to port a TB to make the bores the right size in conjunction with the throttle plates.

Thanks again guys.

 

yeah i used a micrometer to measure left and right and up and down so they were the same.

550's wouldnt be overboard if you used a S-AFC. otherwise it'd be too rich.
Jason

 

I'm curious wouldn't it be cheaper to just buy some used TII injectors? If I'm not mistaken they're 550cc. *shrug*

Peace,
AJ ^_^

 

honestly, I don't know. I'll have to find out how much RC Engineering charges for enlargening injectors.

 

yeah there is both ups and downs to those.
buying TII injectors would be cheaper
you dont know the condition of them
Rc injectors are balanced etc.
if something goes wrong with them you can send em back.

jason

 

550 cc injectors are not overboard at all if you port your intake manifold a good bit. I had to get 550 cc injectors in the secondaries, because I was leaning out so bad with the stock 460's that power would fall off at 6K rpm. I put a pair of 550 cc injectors in the secondaries, and my car pulled hard all the way to the rev limiter at 8600 rpm.

RC Engineering charges $175 each to enlarge injectors. You can get a *pair* of 89-91 TII injectors for ~$75.

 

Well then...I guess I'll get a set of used 550's from T2 and then send them in with my used 460's and have all 4 cleaned at once, and then swap out my current injectors.

 

Today i started taking notes on what places could be improved on the 89+ middle and upper intake. The conlustion i came to was that there was some areas that could be cleaned up, enlarged, and matched. But over all, i doubt that there is more than 10-13hp at the very most to be found. I'm going to take my extra intake manifold up to Rob@Pineapple Racing sometime soon, and have him check it out, and see how much power he thinks is in there.

I forgot my notes and meauserments at work , but the area that could benifeit from porting the most is around where the 2nd set of inj. sit in the middle intake manifold. Also of concern is where the box of the upper intake, turns into the runners. Its not a very clean transition, in either the primary runners, nor the secondary runners. If anyone would like, tomorow, i can post my notes. Just let me know.

Also, if anyone would like to donate or sell cheaply a 89+ lower intake manifold to the porting cause, let me know.

Tomorow, i'm going to take a look at the throttle body.

CJ

 

Racing Beat sells a kit with all the bits you need for porting for exhaust and intake, but should work fine for the throttle.