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

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.

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..

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

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.

Judge, what diameter is the partial peripheral?

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?

pics are gone (it was a long time ago!) but they werent very big

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

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

wtf? did u edit your post? i swear this is not what i read?

i was talking about the runners btw, not ports

we are on the same page, sorry if i misunderstood https://www.nopistons.com/forums/pub...R#>/unsure.png

Thanks for the pics kahren/ito!





I'm probably prying now, but I am also curious about intake manifold setup.. Throttle design.. etc...

na... non-edited. LOL

we all good though.



but now that i think about it, i remember the primary ports (port oriface) actually being smaller... i'll double check it as soon as i can tear that motor down. might as well do the comparison pics and post up just so people can have the reference anyway.

i forgot to take a pic of the overlay a stock fd port over the 13b-re one to show the exact diffrence of the port timing and shape.





like this

I really like the N/A set up I have. music to my ears.. that partial p-port gives it the extra melody I was looking for..

i'll try to do that.

Yah, I bet you do. Your makin good power. I cant wait to see what you get with both stages of Nos.

alrighty..



i didn't get the exact right angle on the pics, but it should be enough to give everyone who hasn't seen an idea of the differences and similarities between the cosmo and rew motors.



secondaries appear to be almost identical.



primaries are not only shaped differently, but the cosmo primaries open later for less overlap--good for low end.[attachment=34690:attachment][attachment=34691:attachment]



the cosmo is getting ported today, so if anyone wants any other pics, you've an hour or so to request them...

wow. this is almost scary. i haven't been on this forum in ages and i had this same idea last week. i'm really curious as to how many people run this setup (RE side housings with Renesis rotors) or something similar in a normally aspirated form.



i really don't think low end losses should be THAT bad. midrange and top end should be phenomenal though.