Who has a nice mild street port template for 12A?
 

Peeps,

I am rebuilding a 12a and like to port it. I have seen the Mazdatrix and the Racing Beat templates on their websites, both look a bit large. Anyone have a reccommedation of one they have used? Same for the exhaust port template. the car is going to be my daily driver and dont want to sacrifice driveability for a few more ponies at the top end.

Thanks!!!

I'd have to recommend '74 spec. It's the best port for daily driveability and great power. You don't really loose much in the low end and gain a lot in mid to high. You can also keep using a stock carb, saving some money. The ports respond very well to carb mods though, and are compatible with stock or very free flowing exhaust. '74 spec ports are all around excellent performers and by far the most popular port in my neck of the woods.

Someone needs to sell a '74 spec template. I made one out of paper, which I used on several engines. Then I used the plate in an engine recently so the paper template is the only one I have.

I might get access to another '74 plate at some point, and could make templates, but for now all I have is the one paper template and I'm hanging on to it. I don't want to make a copy of a copy because it would be inaccurate.

Here is a thread detailing a set ports ported to '74 spec and some other cool stuff. https://www.rx7club.com/forum/showthread.php?t=539579

Thanks Jeff. I think i will end up keeping ports stock since I cant find a decent template that is truly a mild street port. Eventually I want to make a 4 port 13B so I can play with porting then...

I think the RB template is pretty mild... you should get that

You got it all wrong. You can make even a monster streetport streetable by using smaller venturies/jets.

Wouldnt that be like training for a marathon if you are going to race in a 10K?

I'll revisit that one. Have you used it?

nope but just in case you wanna be competitive later on. So whats the point of going with a ported engine if you cant enjoy it. :rlaugh:

Jeff,
if you mount that paper template on a sheet of 4 grid, or any other grid (and specify) and copy it, I can make dimensioned autocad prints of it that would be exact replicas. That way you can have some spares. PM me if you're interested in doing it and I'll shoot you my email address. I'll send a set out to you and you can compare to make sure its good.

Send me one if you do!

^^+1

Im using it. Im porting right now. Does not change the timing THAT much.

Jeff, knowing how much respect these hooligans have for you and your opinion (not me, i don't respect nobody but mom and barry goldwater) i'd say we should stand and deliver. I do, however, trust your judgment and if you say so then the 74 spec should be made available to the public, if possible.

I'd like to see a more streetable peripheral port. Like a 42mm intake port placed at just the right spot so to minimize exhaust gas dilution but not go too far into the power stroke.

Yes
 

Yes i like the sound of that i can use one.

2nd, so maybe my dreams can come true :)

Wow a Barry Goldwater reference, gotta love it... I gotta read up on the runner up... Didnt a youg Hilary campaign for him... [Drifting off subject...]


[QUOTE=glewsRx;7410919]Jeff, knowing how much respect these hooligans have for you and your opinion (not me, i don't respect nobody but mom and barry goldwater) i'd say we should stand and deliver. QUOTE]

Come on Jeff, you know I'm getting ready to rip into my old girl. Something like this could sure be useful. :)

Down has the gauntlet been thrown.... (read in lord of the rings voice)

I took the S model for a 1st drive yesterday and wow those '74 ports are perfect. They have low end, mid and high up to 7k. You can't beat that for the street. I don't care if you have power up to 8k if your low end is missing. Have fun driving that daily. lol

I don't have access to any '74 port plates at the moment. If I did, maybe I could start making paper copies and selling them on the forum. It's easy to use paper to mark ports. Simply use a Sharpie, fill in the area above the port on the iron so it's all black, then lay the paper on the plate using dowel pins to align it, then take a center punch, leather punch, nail or whatever you have that's handy and pointy, and follow the edge of the port. Lift the paper and you have a small visible line through the ink. Port up to that and smooth the transition from runner to port. Also chop down any casting flash and harsh 90° edges. Then finally take a broken stone bit (garnet) in your dremel and spin it at the slowest speed to add a roughened finish to the port (press hard to slow it down even more). That's what I did in the 12A in the S model. It has a little over 2k miles and it freaking flies.

I totally agree. Without low-mid-range torque it isnt a pleaseant DD just because you are putting up an extra 20HP @ 8K

Unfotunately, I call that it a total bullshit.

Whatever works for you Wacky. I personally dont like to have to over-rev at coming off every light in a DD. Just not worth it to me. Now for a weekend/special occasion car...

Jeff, I'll lend you one of my unmolested 3B plates to copy from if you want.

Wacky, I've been driving my GLC with a large streetport daily for a while now. It sure is fun when you get on it, but just driving it around in traffic I sometimes wish I had a little more down low and that I was getting better than 13 MPG. Keep in mind that this is in a car that weighs some 500 lbs. less than an FB. Big ports are awesome if you have another car to drive daily, and it was worth the trade-off for me, but I can sympathize with someone wanting a little more low-range push and not wanting to completely trash their gas mileage.

I'll agree with Jeff that '74 spec makes a really nice mild port. It keeps your powerband within usable ranges and isn't a chore to drive stop-and-go. Combine it with a nice exhaust and carb, and you'll be very happy with the results.