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-   -   Where to start 13B Bport w/carb? (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/where-start-13b-bport-w-carb-64938/)

FrankenMini 03-25-2007 04:27 PM

I'm currently researching using a 13B for my project car (a mini, see below). Car is going to be used for road race and solo2. I've narrowed down my "spec" to a bridge ported 13B with carb, goal being 225hp. What I'm trying to figure out is where to start. I want to know which of the 13Bs is best to start with. Money is a concern, it always is, so if starting with a '93 turbo is ideal but I can save a few bucks going with '88 N/A that's the kind of information I'm after. I don't think my 225hp is too much to ask for from what I've read. I'm talking basics, do I use the engine from a turbo? What year? 4 port? 6 port? Or does such an engine become some kind of franken-engine with parts from various years etc?



I've read as much as I can here but there doesn't seem to be any one place that sort of brings it all together.



Thoughts?



Paul

j9fd3s 03-26-2007 11:56 AM

neat project!



you have plenty of choices here....



rotors: kind of a no brainer, you want the 9.7:1 89-91 na rotors. they are the most effective. renesis is not really proven to be better, and it takes a fair amount of work to even put em in. 86-88 are heavier and lower compression...



side irons: cosmo/fd have a better oil pump, but the center and rear irons are about the same as any of the turbo fc ones. cosmo/fd have a different intake bolt pattern than the fc engines.



rotor housings: if you're porting em, any 86-02 rotor housings are the same. only thing you have to watch for is the s4 engines have a different leading spark plug position (ive compared and it might not be all s4? or all s5?), so you need 2 s4 housings, or 2 s5+



e shaft: any 13b shaft is good.... straighter the better



stat gears: ideally you want the fd ones, cause they are hardened, and have the larger front needle bearings. renesis is good too, cheap new, takes a little bit of work to put em in. fc ones would be ok too, but wear faster

FrankenMini 03-26-2007 02:42 PM


Originally Posted by j9fd3s' post='865391' date='Mar 26 2007, 12:56 PM

neat project!



you have plenty of choices here....



rotors: kind of a no brainer, you want the 9.7:1 89-91 na rotors. they are the most effective. renesis is not really proven to be better, and it takes a fair amount of work to even put em in. 86-88 are heavier and lower compression...



side irons: cosmo/fd have a better oil pump, but the center and rear irons are about the same as any of the turbo fc ones. cosmo/fd have a different intake bolt pattern than the fc engines.



rotor housings: if you're porting em, any 86-02 rotor housings are the same. only thing you have to watch for is the s4 engines have a different leading spark plug position (ive compared and it might not be all s4? or all s5?), so you need 2 s4 housings, or 2 s5+



e shaft: any 13b shaft is good.... straighter the better



stat gears: ideally you want the fd ones, cause they are hardened, and have the larger front needle bearings. renesis is good too, cheap new, takes a little bit of work to put em in. fc ones would be ok too, but wear faster



Yeah, the car is unique, no doubt. I'm going to be running with the ford 4-banger this season, but want to get that engine out an replace with something in the 225hp range. The 13B seems like a good fit, plus it's small, which for a Mini is important.



So effectively an engine like this becomes a combination of parts spanning multiple different 13B generations?



How out to lunch is my goal of 225hp for a 13B bridge port?



The car only weighs 1400lbs (with current 400lbs lump) so it should be a rocket ship with the extra power and 200lbs less weight. My biggest worry is lack of torque, particularly for SOLO2 (autox).



Cheers,



Paul

j9fd3s 03-26-2007 06:14 PM

lol, well you CAN mix and match, but basically the simple way to put it is, an fd block with the high compression rotors.



a friend of mine had a BP 13B in an rx3, it did 231rwhp@9600rpms, which is as many rpms as the dyno would read.



it was a full bridge (3 fingers, into the water jacket), based on a 4 port block from a 74-85 engine. 89-91 high comp rotors, with stock seals. 750 holley (i think) on the RB manifold. exhaust was dual 2 1/4 or 2.5" car did 231rwhp, and was quiet enough to be streetable. oh yeah, with a tall 5th it would also get upper 20's mpg on the freeway.



so i'm thinking 225 is totally doable....

FrankenMini 03-27-2007 07:12 AM


Originally Posted by j9fd3s' post='865467' date='Mar 26 2007, 07:14 PM

lol, well you CAN mix and match, but basically the simple way to put it is, an fd block with the high compression rotors.



a friend of mine had a BP 13B in an rx3, it did 231rwhp@9600rpms, which is as many rpms as the dyno would read.



it was a full bridge (3 fingers, into the water jacket), based on a 4 port block from a 74-85 engine. 89-91 high comp rotors, with stock seals. 750 holley (i think) on the RB manifold. exhaust was dual 2 1/4 or 2.5" car did 231rwhp, and was quiet enough to be streetable. oh yeah, with a tall 5th it would also get upper 20's mpg on the freeway.



so i'm thinking 225 is totally doable....





So if I were to buy a rebuilt engine from one of the many 13B engine builders out there and stick to a 89-91 N/A 13B but go with new rotor housings I should be good?



Now I just have to find a dead 13B to do some measurements and a rough install.



Paul

RONIN FC 03-29-2007 11:12 AM


Originally Posted by FrankenMini' post='865544' date='Mar 27 2007, 08:12 AM





So if I were to buy a rebuilt engine from one of the many 13B engine builders out there and stick to a 89-91 N/A 13B but go with new rotor housings I should be good?



Now I just have to find a dead 13B to do some measurements and a rough install.



Paul

Any engine builder will gladly use some 89-91 9.7-1 non turbo rotors in an turbo block for you if you request it.







The n/a 13b (6 port) isnt as ideal as a 4 port in a carb application. But it can be done with some success

FrankenMini 03-29-2007 06:45 PM


Originally Posted by RONIN FC' post='865828' date='Mar 29 2007, 12:12 PM

Any engine builder will gladly use some 89-91 9.7-1 non turbo rotors in an turbo block for you if you request it.







The n/a 13b (6 port) isnt as ideal as a 4 port in a carb application. But it can be done with some success



So the turbo is 4 port and NA is 6 port?



Paul

ZeroRX7 03-29-2007 09:27 PM

in my car that is my everyday car i have the carb set up and everything i have a race port (6 port). the only think i am haveing isuues with right now is the timing and hopefully i get it right monday. and your torque issue thats where the high rev's come in just keep it up and u will do fine.

j9fd3s 03-30-2007 10:22 AM


Originally Posted by FrankenMini' post='865871' date='Mar 29 2007, 04:45 PM

So the turbo is 4 port and NA is 6 port?



Paul



yep.

FrankenMini 04-03-2007 03:18 PM


Originally Posted by j9fd3s' post='865946' date='Mar 30 2007, 11:22 AM

yep.



Got my hands on a dead 13B to test fit. We'll see how it goes.



Paul


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