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How would a 13B Cosmo RE motor do in N/A form?

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Old Oct 30, 2005 | 11:18 PM
  #1  
R.P.M.'s Avatar
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I have a JDM 13B Cosmo RE motor in pieces right now, I am almost finished half-bridge porting the front and rear irons using the RB template, so its not very agressive.



Now heres my question, how would the motor perform if I used 10:1 cr Renisis rotors and ran the motor in N/A form using the RE intakes?







Discuss
Old Oct 31, 2005 | 09:57 AM
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As you may well know the ports on the RE are very large, which causes that motor to lose a lot of air velocity at lower rpms. That is the reason for Mazda putting the smaller exhaust ports and smaller turbos was to get that velocity built up at lower speeds. I think if you are looking for lots of top end power it will fare well, but I think it will suffer considerably on the low end.
Old Oct 31, 2005 | 05:44 PM
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I don't think it will be that bad





The RE port timing is virtually the same as a 6 port with the sleeves removed, only the port is more "ideal"





I ran a 6 port with no sleeves, and TII LIM and upper, the 6 ports smoothed together. I lost low end, not alot.. But I did lose some. The motor was breathing awesome up high on the stock ports though, I couldn't believe the power increase up top..
Old Nov 1, 2005 | 04:06 PM
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the ports are about the same as the fd...it's the runners that are large.
Old Nov 1, 2005 | 07:04 PM
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My engine on my Rx3.. cosmo side housings bridgeported partial p-port. compression 9.7 to 1 on 103 octane is making well over 300rwhp. I'm looking to make 350rwhp N/A then I'll start tunning for nitrous. so far the best N/A set up I have seen. better then a full P-port. My friends racing beat peripheral port dynoed 278rwhp. with a super lean mixture(looking for power) I think it will work depending on what type of racing application.
Old Nov 1, 2005 | 10:11 PM
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Judge, what diameter is the partial peripheral?
Old Nov 1, 2005 | 10:29 PM
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Hey Judge, I'm glad you responded. That RX-3 of yours sounds crazy....the partial PP idea sounds complicated to me, but it sounds like it works great!!



Do you think having 2x50mm TB with a shorter custom intake manifold would work for a mild half-bridge Cosmo N/A motor?
Old Nov 2, 2005 | 01:46 PM
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Originally Posted by ColinRX7' post='774707' date='Nov 1 2005, 08:11 PM

Judge, what diameter is the partial peripheral?


pics are gone (it was a long time ago!) but they werent very big
Old Nov 2, 2005 | 03:18 PM
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Originally Posted by guitarjunkie28' post='774586' date='Nov 1 2005, 05:06 PM

the ports are about the same as the fd...it's the runners that are large.


they are not about the same, they are noticebly bigger.

the surface area of the RE secondary port is VERY similar to the

surface area of the aux and sec ports of the 6 port NA.

the RE would seem to have the flow advantage over the 6port,

and therefore the low end should be better, then running with no

6port sleeves



ito's partial pport with a bridge
Old Nov 2, 2005 | 09:04 PM
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Originally Posted by kahren' post='774899' date='Nov 2 2005, 01:18 PM

they are not about the same, they are noticebly bigger.






i've got one in the trunk of my car. i'll get some pics when i tear it down.



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