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Porting and a Daily driver?

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Old 01-24-09 | 09:49 AM
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Porting and a Daily driver?

I am wanting to have a very aggressive port job doen on the next RX7 I buy, but was wondering about how dailey drivable a j port or bridgeport would be.. I am use to radical Big block pro street cars so that is a norm..

How is a rotor car done this way? Issues?

Last edited by Sgt Fox; 01-24-09 at 01:43 PM.
Old 01-24-09 | 10:45 AM
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J ports are not reliable. Unless you are in a form of racing that bans peripheral ports, you should not consider them.

Is this car turbo or NA?

In general, a bridgeport makes a rotary act exactly like a piston engine with a radical cam. Loping at idle, poor mileage, some low end loss but a major midrange and top end boost. Bridgeports radically decrease turbo spool time. They are harder to tune and draw little vacuum at low RPMs.
Old 01-24-09 | 12:52 PM
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Well Ihave not yet even bought a car... This is coming next month.. Just trying to get I deas for the car and lay out a plan... I was thinking of going turbo on it and love the sound of a good bridgeport.. No racing organizations for me... Just want a radical rotor car,,,
Old 01-24-09 | 01:41 PM
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full bridgeport is the way to go
Old 01-24-09 | 01:47 PM
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Originally Posted by BlowenByTwins
full bridgeport is the way to go

I guess the next question is either to get a 1st gen 12a ,or 13b or go with a second gen n/a car and mod it... The first are lighter correct?

As you can tell from my sig I do not have a bunch of cash to start with...
Old 01-24-09 | 03:05 PM
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Unless you plan on porting and building the engine yourself, your budget is already shot at 2k. I have a 12A 1/2sp-1/2bp. Until I installed the Weber DCD carbs, it was a major pita to drive on the street. Time to start reading up on engine building and porting padiwan. Start with my sig line for links to the FSMs and other rotary reading. You may wish to concider starting with a street port for your first rotary adventure.
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Old 01-24-09 | 03:17 PM
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Originally Posted by Aaron Cake
J ports are not reliable. Unless you are in a form of racing that bans peripheral ports, you should not consider them.
Originally Posted by trochoid
Time to start reading up on engine building and porting padiwan. Start with my sig line for links to the FSMs and other rotary reading. You may wish to consider starting with a streetport for your first rotary adventure.
TwistedOne, these are the two best pieces of info/advice you should take from this thread.
Old 01-24-09 | 03:17 PM
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i had a 1/2 bridge frankenstien motor in my 84 that i drove nearly daily in the summer. it was loud as hell, made the whole car shake at a stop, poor low end, but great power abouve 4000 rpm. gas mileage really sucked *** though. all in all, i would have gone with a real agressive street port. but it was fun as hell!

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Old 01-24-09 | 04:16 PM
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Thanks Guys.. The 2k is just the budget to a get a stock driver... I will then buy a spare motor to have ported by a local racer from here. He owns a Mexican Resteraunt and has a 93 RX7 that runs in the 5's in the 1/8. Has a contact in PR for all his parts and is willing to help me out...

Thanks for all the advise... About the mpg and sound, I don't mind poor mpg ot loud.. I drive a 602rwhp diesel pickup daily to work... I want this thing to be radical and still be able to handle a bit of daily driving..

Just something diffrent to drive every now and then... I will check out those links
Old 01-24-09 | 07:02 PM
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power wise the 13B second gen would be your best bet, but being on a budget...
Old 01-24-09 | 09:05 PM
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I am only on a budget to get the car... Once it is home it is easy to spend money on it.. I was wrong on my buddies car... It went 4:80's in the 1/8th and 7:60's in the 1/4. I went nad had dinner with him tonight at his resturaumt. The car is in PR right now getting worked out..

He told me he has a 5 letter car that he gave $600 fot.. Has RB Intake, Holley and header already on it.. Said for me to come look at it and maybe we can work a deal.. So we will see...

Oh and his car is a P port turbo 13b..


The NA 2nd gens look to be affordable...
Old 01-25-09 | 01:40 AM
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A 13B P-Port, when done right, can put out 275+ hp NA.
Old 01-25-09 | 02:29 AM
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Why isnt a J port reliable?
Old 01-25-09 | 02:35 AM
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J-ports breach the main inner coolant seal and has to be sealed off. Does not hold up over time. Longevity estimates run 10-20k miles, if that.
Old 01-25-09 | 02:37 AM
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oooh. That sucks. So its more of a drag engine type porting?
Old 01-25-09 | 02:46 AM
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Yep, though some of those crazy Aussies street drive them.
Old 01-25-09 | 10:37 AM
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Originally Posted by old_skool
i had a 1/2 bridge frankenstien motor in my 84 that i drove nearly daily in the summer. it was loud as hell, made the whole car shake at a stop, poor low end, but great power abouve 4000 rpm. gas mileage really sucked *** though. all in all, i would have gone with a real agressive street port. but it was fun as hell!
This is the opposite way to do a half bridge. You've bridgeported the primaries while leaving the secondaries unbridged. That's very weird.

Anyone else reading this thread needs to know that it is supposed to be the secondaries that are bridged while the primaries are not.

Originally Posted by dazed_driver
Why isnt a J port reliable?
A J-port extends into the water jacket. Thus the water o-ring needs to be cut to allow the port and then somehow sealed up again. Silicone is the normal way and gradually through heating and cooling it begins to leak water into the intake port. J-port life is very short. It was developed as a way of getting around rules banning peripheral ports in certain classes of racing.
Old 01-25-09 | 11:24 AM
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Originally Posted by Aaron Cake
This is the opposite way to do a half bridge. You've bridgeported the primaries while leaving the secondaries unbridged. That's very weird.

Anyone else reading this thread needs to know that it is supposed to be the secondaries that are bridged while the primaries are not.
yea, it was done by the P.O. he explained the reasoning, but i forgot why he did it that way. either way, it runs like a raped OOT.

although, trochiods motor has 1/2 BP secondaries, so at least im not alone!
Old 01-26-09 | 12:11 PM
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You can't beat the sound of a full Bridgeport, a mate of mine has one and it sounds superb

Mark
Old 01-26-09 | 12:15 PM
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I was thinking the same thing Mark...

Here is a question for the experts.. What do yall think of the 6 port motor for a full bridgeport and a turbo add on later?
Old 01-26-09 | 02:07 PM
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That is the expensive way to go about things. Remember there is no turbo kit available for the 6 port currently, so you would be fabbing the setup yourself.

Honestly unless you have another reason, if you are considering going turbo, then start with the TII engine. It will save you a lot of work.

Or, start with the turbo first and don't bother bridgeporting. You'll make more power with a minor turbo upgrade and your fuel mileage won't stink.
Old 01-26-09 | 02:15 PM
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Ahh I see.. One of the cars I am looking at has a pretty fresh 6 port fi motor init.. Is a good seal and I hate to pass on it.. But I want a radicla rotary so I need to invest in the best route available...
Old 01-26-09 | 04:48 PM
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If you have tuning and fab experience, then a bridgeported turbo 6 port is a pretty radical combination. At least, I think mine is...
Old 01-26-09 | 04:53 PM
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Originally Posted by Aaron Cake
If you have tuning and fab experience, then a bridgeported turbo 6 port is a pretty radical combination. At least, I think mine is...

So how much fab work? Just a header and intercooling stuff?

I would love to see yours...
Old 01-26-09 | 04:59 PM
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I just looked on your site and saw them.. Nice car... Very Nice... I forgot to add.. Tuning part I am so so but my buddy Alex said he uses a guy out of Orlando so I guess we will take it down there when it is done..

That guys tunes his cars for him...

Last edited by TwistedOne; 01-26-09 at 05:03 PM.


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