attn: experienced porting people

[Cryptic]

I'm porting my wastegate to prevent boost creep. (which happens when you have full 3 inch exhaust). I am looking for suggestions on best way to go about porting this hole to 1.24" hole, which leaves enough to make a descent seal.

I heard the job can be done with an electric dremel, its just very tedious.

wastegate closed
http://www.brewcitymuscle.com/albums/MadTownRX-7/IMG_1090.sized.jpg

wastegate open
(you'll notice a slightly darker outline where I took a magic marker around the closed gate.)
http://www.brewcitymuscle.com/albums/MadTownRX-7/IMG_1089.sized.jpg

[Bad-TSi]

You don't wanna take a whole lot out of there, or it wont seal. Unless you get a bigger wastegate flapper. And to do it with a Dremel is extremely tedious, you wanna use some air power for this job.

Also what kind of boost do you plan on running anyway? If you don't allready know, the less boost you run, the more chance of creep.

[Cryptic]

no more than 12 PSI for now. From what I read already just by removing pre-cat and main cat (downpipe and midpipe upgrade), and upgrading to catback you will bump the stock 10-8-10 boost pattern to 12-10-12.

My stock fuel system really wont support more than that. I will already need a tune (which the Power FC I got is capable of)

The size of the port is highly discussed on rx7club.com. It's pretty much tried and true at 1.24 and no more than that.

I have an air dremel to (dad has one anyway). What kind of bits would you use on cast iron? carbide?


here's another shot of someone elses work (left before, right after)
http://crypticvault.com/ported_wastegate.jpg

[Cryptic]

haha... check out all the sh!t I had to take apart to get to it.
not to mention like around 12 vaccum lines
:stare
http://bellsouthpwp.net/f/l/flybye/TurbochargerBig.jpg

[Prince Valiant]

here's another shot of someone elses work (left before, right after)
http://www.rx7club.com/attachment.php?s=&postid=2751181Where is the Ray Charles "I can't see sh!t" picture when you need it? :rolf

[Cryptic]

bah fixed...

[Prince Valiant]

bah fixed...
very nice pic. How far did they extend down?

[Bad-TSi]

Yikes, that looked like alot of fun! :wow

A carbide bit would prolly be optimal, then smooth it out with a stone bit. And yes, 12psi is quite low.

Also are you tuning your Power FC yourself?

[Cryptic]

very nice pic. How far did they extend down?
varies from .5" to just over 1"


Also are you tuning your Power FC yourself?
I have yet to familiarize myself with it. Once the car is put back together and I have a chance to play around with it, I'll decide what to do then. If I dont feel 95% confident I can do it myself, I guess I will be taking the car to A-Spec for tuning.

[Bad-TSi]

I have yet to familiarize myself with it. Once the car is put back together and I have a chance to play around with it, I'll decide what to do then. If I dont feel 95% confident I can do it myself, I guess I will be taking the car to A-Spec for tuning.
I see, I have a friend with a power FC on his car and is looking to learn more about it. Where is this A-spec place and what's there deal? A Mazda shop I'm assuming.

[Cryptic]

I see, I have a friend with a power FC on his car and is looking to learn more about it. Where is this A-spec place and what's there deal? A Mazda shop I'm assuming.

They are in Addison, Illnois. A rotary specialist. http://www.a-spectuning.com/

I not positive but I believe there are base maps floating around the net that you can copy. Just match to the mods you have. At least then you should be in the right ball park since every car is different.


I just found this from here (http://www.scuderiaciriani.com/rx7/non-sequential.html#DIS)

You will *need* to open up your wastegate from the on paper 1" diameter to 1.24". Use a mill to do this, don't waste your time with a die grinder as some people who obviously have more time on their hands than common sense, or money to pay a machinist have done :)

The mill has the added benefit of allowing you to align the hole with the flapper, which is something the stock hole is not. (IE off center some which is not a problem with a 1" hole, but 1.24" would be)

so who does this kinda work?

[turbogarrett]

unless you are going to do a lot of autoxing just go non sequential while you've got all that out. while there is a little more lag, you get rid of some flow restrictions, about 70 vacuum lines and 8 solenoids. car is much more predictable than sequential as you don't have a 2nd turbo suddenly kicking in, boost control is rock solid and the car is much easier to work on without that rat's nest under the intake manifold. get a die grinder, carbide bits and some compressed air to port the cast iron, a dremel takes way too long.

[Cryptic]

I spent 2 hours last night reading up on the do-it-yourself non-sequential mod.
I got a little lost in the instructions, but it was pretty late. I probably could use a coach. :)

[scubastang]

get a die grinder, carbide bits and some compressed air to port the cast iron, a dremel takes way too long.


yep :thumbsup

this is what I have used in the past to port wastegates etc

[Syclone0044]

Same here; plus you'll probably burn out the motor in your Dremel if you're doing any serious porting on cast iron. Of course, not everybody has an air compressor and air tools, I certainly don't; but was lucky enough to find a friend willing to let me use his shop's.