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To port or not to port????

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Old Mar 11, 2004 | 03:53 PM
  #1  
pstnh8r's Avatar
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To port or not to port????

Hey guys,
Need some opinions on this issue. Sorry for the long *** post.
I just blew my second motor, I have RP putting in a reman as we speak, just one question. I have several mods that i will be transferring: RE intake,dp,mp,cat-back,fuel pump,triple race pulley kit,PFC,Front mount,lightened fly, street/comp clutch, 1600cc injectors, koyo radiator, efini y pipe, profec b, aluminum AST, while i am at it, do you think it is worth it to get the motor street ported with 3mm apex seals, milled rotors etc.... i wonder how much the reliability will be hurt (probably not much) if properly tuned, and if you think a $1,000 investment could be better spent. i mean how much HP do you think i stand to gain from a ported motor? i do plan on sticking with the twins, would i be better off saving my money???

Thanks for the help.
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Old Mar 11, 2004 | 06:19 PM
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If your look'n for an extra bit of power you might just consider porting the secondaries and leave the primary ports for low end.

Porting varies widely too. If you are unsure of weither you want to port or not that tells me your not look'n for a wild port.

A standard street port on the secondaries might be worth looking into.
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Old Mar 11, 2004 | 06:23 PM
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Why not port? Especially considering your mods...

However, how did you go through your second motor? Tuning? Lean?
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Old Mar 11, 2004 | 06:48 PM
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Get a nice sized street port but stick with the 2mm seals.

From what I understand, that should give you about 10-15% more airflow than stock porting.
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Old Mar 11, 2004 | 06:58 PM
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Streetport for sure, once the motor is closed up you'll wish you would have later. Also 3mm seals for sure why not have a little more confidence running higher boost when or if you decide to go with an upgraded turbo/turbos...?
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Old Mar 11, 2004 | 07:40 PM
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Get the port work done...you really will wish you had after the engine is all sealed up.

2mm vs 3mm seal debate rages on. Either one you choose, the best way to build confidence is with proper tuning for the boost you intend to run.

Plenty of cars run great numbers with 2mm seals.
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Old Mar 11, 2004 | 07:55 PM
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Porting can yeild as much as 150 Hp, but not by itself, of course... turbo etc... are all a factor... but a good street port is basically enlargeing the secondary runners and exhaust, the primaries, get a bit of work done, but not much, since it won't idle (as) smooth and it won't smog as easily (not an issue in TX).
But it's some of the cheapest HP when you factor out the price of the R&R (rebuild and reinstall).
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Old Mar 11, 2004 | 07:58 PM
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It's definately an issue in TX. Especially Dallas county, where you friggen Californians made our government as strict as yours!

Only thing we don't have to do here that you guys do is the CARB numbers on everything.
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Old Mar 11, 2004 | 08:23 PM
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Sorry I guess I was thinking West Texas / El Paso.. etc... ??? Dunno Never lived in Texas...
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Old Mar 11, 2004 | 08:41 PM
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I have a large street port and am very happy with the character of the motor compared to my old stock motor. The low end is a bit softer, but not bad at all, the mid range is very good, and when it hits around 5500rpms it rips to redline like a sport bike.

The change in character is similar to what I noticed in the lower gears when I upgraded to a light weight flywheel.

I did the same cost-benefit analysis that you are now doing. In the end I'm happy I did it. I bought a reman from Malloy and sent it to Carlos Gonzalez in FL. Upon disassembly he found that the E-shaft was pitted badly and corrected the problem. He also clearance everything, upgraded the oil system, and balanced the rotors to within 15 grams of each other. Finally he included a full disk of before/after pictures with the motor. All this stuff gives me a sense of security that I did not have with the reman. That plus the performance increase made it worth it for me.
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Old Mar 11, 2004 | 09:04 PM
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CCarlisi, im just curious after all that how much did it cost you?
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Old Mar 11, 2004 | 09:32 PM
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Zoom Zoom, anyone else bump that song in their 7? I do just to make the other drivers around me laugh...
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Old Mar 11, 2004 | 10:09 PM
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wait its going to cost you 1k to get a port job?
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Old Mar 11, 2004 | 10:29 PM
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I am a fan of porting, too. The stock ports tend to kill the power as you approach redline. After I got a street port, I kept hitting the rev limiter based on the "feel" of the engine still pulling hard. Since you have better compression after the new motor, the decrease in power at the low end (versus not porting) is not very noticable -- my car was actually stronger down low than it was before the rebuild. Get a street port... it just feels right.

-Max
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Old Mar 11, 2004 | 11:22 PM
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maxcooper-

did you have your primaries ported and was it a mild or wild street port?
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Old Mar 11, 2004 | 11:36 PM
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Is there such a thing as porting for more low end response? Something that gives a good kick with the touch of the throttel?
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Old Mar 11, 2004 | 11:43 PM
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Originally posted by spooledUP7
Is there such a thing as porting for more low end response? Something that gives a good kick with the touch of the throttel?

You drive an rx-7...........

There's no such thing as low end It's a high revving car, and that's where the revs should be!
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Old Mar 11, 2004 | 11:53 PM
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basically to increas low end you have to increase the velocity of the air.

making the ports smaller is not easy. So.....not really.

Adding back pressure helps but you lose the flow for your high end.

equivalent trade. Can't gain something from nothing.
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Old Mar 12, 2004 | 12:02 AM
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Originally posted by ooEfiniRx7oo
CCarlisi, im just curious after all that how much did it cost you?
I don't remember the exact price off hand but it was around $1,000 and included replacing all the o-rings that should not be reused after a motor has been cracked open. Turn around time on the project was about 3 weeks. If you want to find out more info drop him an email at RX3RX7@aol.com.
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