So, I've been toying for a couple years now about doing a P port 12a. I have had a full rebuild kit from Atkins for awhile. My engines running fine right now, just bored of it. Need more! Thinkin I should do it real soon. How many of you have seen a 12 p port? Think it would be worth wild? Anyways gonna happen. soon. will post pics and all with it to make it fun. Anybody have any numbers for a contraption like that? P-port 12a, holley 650dp, headers, exhaust? Oh yeah, gotta have a little juice with it also.

 

Sounds awesome Allan! If you need any help let me know Id be down

 

4 rotor or gtfo

 

A p-port with a Holley? Gonna build some sort of plenum for it? If I remember right, peejay tried something like that at one point.

 

I had one almost 10 years ago. It was difficult to get running right, had some ignition issues etc. I never really got it sorted out and it injested a piece of the filler material that was used to fill the side ports. After that i just gave up and lost interest. There are a lot of other ways to have a fast car that would be way more reliable and easy to handle and get more than 8mpg.

I have a friend that has one in Portland. His uses the MFR housing and its in an rx2. really nice engine. Like mine he is using a Weber 48 IDA. Pretty much the only carb to use IMO. I would highly recomend going fuel injection like a megasquirt would be cheap and really be worth it. A lot of time and money can be wasted trying to jet the carbs and different emulsion tubes etc. That is a really radical port and to really take advantage of it, it needs to run correctly and be jetted right. TWM throttle body with a a megasquirt would work good. Intake mainfold length also really changes the dynamics. Let us know once you start.

CJG

 

A p-port is going to be extremely sensitive to exhaust tuning as well, the rule for old school race setups was at least 102" before the collector. The longer your primary header runs the less reversion you will have, and the whole thing will run better.

Use a piece of flat steel to bolt over the side port intake holes with a piece of j-bolt protruding into the port in order to give whatever filler you use a positive hold, so as not to be sucked into the engine

Isaac

 

and your going to need WAY more then a 650 double pumper to fuel that thing. and stay away from the holleys, such a stupid carb setup in my opinion. ive had a carter 500 single pumper on my pretty much stock 12a for over 10k miles now, and it runs great, super easy to tune, super easy to rebuild. and it taught me how to work on carbs. if you want to go 4 barrel style carb with it your probably going to need at least a 750 double pumper, maybe even an 850 or a 900. i would say go with the bigger carb first, and start out with it a little extra rich. but with a periphrial port it would just be an all around better idea to go with a weber. that and your going to need stock shares in a spark plug company because your going to go through alot of them to get it tuned right. dont start with race plugs unless you have lots nad lots of $$$ because there going to be about 150 bucks a set.

 

hey, appreciate all your input. I am afraid of it not running too smoothly at low rpm's, but what the hell. I LOVE holleys!!!!! as most should know. I'm pretty good with tuning them up also. Only other thing i would run( yet no funds or will to spend the funds) would be fuel injection with the megasquirt. thought about that for the last 7 years now. just not willing to spend the money on it. Got the irons and housings down the other night, gotta soak and clean them up. then the fun stuff. will start a build thread when ready

 

Sounds like fun Allan, what about the predator carb. I think that is what is called.

 

na. have a 650 now. gonna keep it. should be enough. probably more than enough.

 

O_o Keep us posted, I'll have to come down there and check that out. I might be sharing a garage in Lacey this summer to work on mine.

 

Sounds like an interesting project Alan. I don't ever think Ive seen a 12A p-port with a holley. I'm sure you'll make it work. However, one of these days the boost bug is going to bite you ;-)

 

I think your going to be disappointed at the results if you use the holley. I knew an old guy that used a lot of PP engines in can am race cars in the 80's. They experiementd with all kinds of stuff and he said it took dual 750's to get the power up in around where a weber would run.
They did try predators and had some success. took a custom grind on the accelerator pump cam. Any ways, I would highly recomend at the very least dropping 600 bux on a 48 ida. There is actualy known combinations of stuff that has been tried with those. I dont think the holley will transition very well in the mid rpm range. Or save yourself the griefe and get the TB and megasquirt then you will have something that actually works pretty good.

Ultimately you could buy a $400 turbo, make a manifold and blow through a holley on a stock port and make more power and have something that is driveable vs the holley PP setup your considering. Just weigh the options...

CJG

 

Allen, I think your dream is quite do-able.

You can build your own PP housings - https://www.rx7club.com/forum/showthread.php?t=144200

Build your intake out of one 180 degree U of 2” aluminum tube - http://cgi.ebay.com/ebaymotors/Vibra...item5d2d9b5b18

Put a used 50 mm throttle body off of Z28 or Corvette LT1 - http://cgi.ebay.com/ebaymotors/90-92...item43a55ea1c2

Old megasquirt (fuel only) with some used injectors - http://cgi.ebay.com/ebaymotors/Megas...item3a63955e01

Stock ignition with an MSD and you are set.

The only thing left is time and a little money and your are there.
JEB

 

I agree with Jeb. The stuff he listed would get you the cheapest setup up that would actually run pretty good. I would recomend that. I think trying to make a 4 barell run on the p port is a bad idea. it needs to be either the weber or a TB setup with FI.

CJG

 

Kill No Cones... Forgive my OCD moment... I'm Allen, Kettlmen is Allan
Partlymazda used to use a stock intake manifold and run it through the water jacket into the p port opening. lots of "s" ing around for the air but it worked for the the guy runing the race car. can't remember how he stopped the water.

 

IIRC that was run quite a bit back in the day as a cheater intake. Looks stock from the outside for inspection, not so stock inside.

Isaac

 

i agree with that set up. just too many mouths to feed right now. will have to do some budget hunting and work for future. now i just need a little more time to get the parts clean.

 

Parts cleaned up yet bro?

 

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