20B questions
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Joined: Apr 2001
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From: Omaha,Nebraska,USA
20B questions
I currently have a 1986 RX-7 N/A 13B.. I just rebuilt it 275 miles ago....
I was just wondering, for future reference, How streetable is a 20B?
How much would it cost to do a 20B conversion in my car with a N/A engine? Turbo ? Engine hard to find? anywhere as easy to work on as the 13b? How much power do you think it would have with minor mods and Normally aspirated? Any clue on MPG AVG ? Would it mess with the weight distribution much? Would you have to do any cutting of the firewall or anything to install it or does it fit pretty easily?
do N/A 20B's have aux ports like N/A 13Bs? Or only 2 ports per rotor?
I know that's a lot of questions, some of which are probably pretty stupid, but I couldn't find too much about them in the forums after a couple hours of searching... Feel free to point me to some posts about it... Thanks a LOT for your help guys!
I was just wondering, for future reference, How streetable is a 20B?
How much would it cost to do a 20B conversion in my car with a N/A engine? Turbo ? Engine hard to find? anywhere as easy to work on as the 13b? How much power do you think it would have with minor mods and Normally aspirated? Any clue on MPG AVG ? Would it mess with the weight distribution much? Would you have to do any cutting of the firewall or anything to install it or does it fit pretty easily?
do N/A 20B's have aux ports like N/A 13Bs? Or only 2 ports per rotor?
I know that's a lot of questions, some of which are probably pretty stupid, but I couldn't find too much about them in the forums after a couple hours of searching... Feel free to point me to some posts about it... Thanks a LOT for your help guys!
Passenger
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well first of all its not a simple swap, just ask the guys at www.k2rd.com . You will need the motor, special mounts, a whole new driveline and suspension, FD tranny, Standalone ECU, and a swell of other items 
As far as power goes its fast na and faster Turbo
As far as power goes its fast na and faster Turbo
Back from teh deadly!
Joined: Feb 2001
Posts: 1,163
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From: Louisville KY 40299
Originally posted by Jef Card
well first of all its not a simple swap, just ask the guys at www.k2rd.com . You will need the motor, special mounts, a whole new driveline and suspension, FD tranny, Standalone ECU, and a swell of other items
As far as power goes its fast na and faster Turbo
well first of all its not a simple swap, just ask the guys at www.k2rd.com . You will need the motor, special mounts, a whole new driveline and suspension, FD tranny, Standalone ECU, and a swell of other items
As far as power goes its fast na and faster Turbo
Last time I checked, you dont need an FD tranny. The guy that put one in his FC vert just used a T2 drivetrain
Rotorhead
Joined: Feb 2001
Posts: 9,136
Likes: 39
From: Charlottesville, Virginia, USA
OK, first of all, note that all 20B engines began life as a twin-turbocharged engine hooked up to an automatic transmission in a heavy, smog-friendly, luxury car. Given that, a 20B is as streetable as you make it. Engines are not all that hard to find nowadays, and are just as easy to work on as a 13B. The 20B has 2 ports/rotor just like all the other turbocharged rotaries. Once you get some custom engine mounts, a 13B water pump (or custom thermostat housing like I have), and a TII hood with a gutted IC scoop, the 20B engine will fit in the FC engine bay just fine. The MPG will depend on how you build the engine and how you drive the car.
Actually, the cheapest way to go for a 20B would be to keep the stock turbos, and run them parallel. You would get around 300 HP with such a setup, and up to 550 HP with appropriate go-fast goodies like FMIC, porting, etc. There are several ways to do a 20B swap in an FC, but here's an approximate list of basic items if running the stock turbos:
Engine: $2,000-4,000
Engine Mounts: $500
Aftermarket EMS: $1,500
Aftermarket Ignition & Crank Angle Sensor: $800
Larger Radiator: $500
Larger Fuel Pump: $250
Used 13B Front Cover, Water Pump & mechanical MOP: $300
Used TII Hood: $50-450
Flywheel & Custom Balancing: $350-500
Aftermarket Tachometer (set to V-6 mode): $50-350
Other stuff: $1,000
Obviously, it would be better to upgrade the transmission, suspension, etc. to handle the extra power, but your NA drivetrain would work if you kept the torque down and were extremely easy on the acceleration. If it is not yet apparent, it is much easier to start with a TII car, especially one that already has some nice suspension and drivetrain mods.
It would be just about as difficult and expensive to run the 20B as an NA, as you would need a custom intake manifold, carb(s), etc, and it would give you about 300 HP with higher compression rotors and porting. For an aftermarket-turbo 20B, you would need pretty much the same stuff that you would need for a 13B, except that you can't get bolt-on manifolds and such, so these and many other parts must be custom made. A 20B with a huge single turbo could get up to 1,000 HP on the street assuming that money is no object. I have put about $30,000 in my car over the last 3 years, and it's still not quite finished yet.
Hehehe, the weight distribution thing always cracks me up. The 20B only adds a little more than 100 lbs to the front of the car, and this weight is located pretty close to the front axle. I'm not a good enough driver to care about this, especially since I don't hear too many V-8 drivers complaining about their weight distribution. Besides, I think that the huge FMIC and radiator that I put up front probably have a bigger moment-arm than the extra rotor.
To be honest, you would get the best bang for the buck by forgetting about the 20B, and building yourself a killer 13B turbo engine. The 20B conversion is a real pain, requires a lot of time and money, and an incredible amount of skill (or in my case lots of skilled friends). I'm just one of those idiots who has always wanted a 3-rotor engine, no matter how little sense it makes. Oh, and for those wondering... no, I don't care what kind of HP or gas mileage I end up with.
Engines are not all that hard to find nowadays, and are just as easy to work on as a 13B. The 20B has 2 ports/rotor just like all the other turbocharged rotaries. Once you get some custom engine mounts, a 13B water pump (or custom thermostat housing like I have), and a TII hood with a gutted IC scoop, the 20B engine will fit in the FC engine bay just fine. The MPG will depend on how you build the engine and how you drive the car.Actually, the cheapest way to go for a 20B would be to keep the stock turbos, and run them parallel. You would get around 300 HP with such a setup, and up to 550 HP with appropriate go-fast goodies like FMIC, porting, etc. There are several ways to do a 20B swap in an FC, but here's an approximate list of basic items if running the stock turbos:
Engine: $2,000-4,000
Engine Mounts: $500
Aftermarket EMS: $1,500
Aftermarket Ignition & Crank Angle Sensor: $800
Larger Radiator: $500
Larger Fuel Pump: $250
Used 13B Front Cover, Water Pump & mechanical MOP: $300
Used TII Hood: $50-450
Flywheel & Custom Balancing: $350-500
Aftermarket Tachometer (set to V-6 mode): $50-350
Other stuff: $1,000
Obviously, it would be better to upgrade the transmission, suspension, etc. to handle the extra power, but your NA drivetrain would work if you kept the torque down and were extremely easy on the acceleration. If it is not yet apparent, it is much easier to start with a TII car, especially one that already has some nice suspension and drivetrain mods.
It would be just about as difficult and expensive to run the 20B as an NA, as you would need a custom intake manifold, carb(s), etc, and it would give you about 300 HP with higher compression rotors and porting. For an aftermarket-turbo 20B, you would need pretty much the same stuff that you would need for a 13B, except that you can't get bolt-on manifolds and such, so these and many other parts must be custom made. A 20B with a huge single turbo could get up to 1,000 HP on the street assuming that money is no object. I have put about $30,000 in my car over the last 3 years, and it's still not quite finished yet.
Hehehe, the weight distribution thing always cracks me up. The 20B only adds a little more than 100 lbs to the front of the car, and this weight is located pretty close to the front axle. I'm not a good enough driver to care about this, especially since I don't hear too many V-8 drivers complaining about their weight distribution. Besides, I think that the huge FMIC and radiator that I put up front probably have a bigger moment-arm than the extra rotor.
To be honest, you would get the best bang for the buck by forgetting about the 20B, and building yourself a killer 13B turbo engine. The 20B conversion is a real pain, requires a lot of time and money, and an incredible amount of skill (or in my case lots of skilled friends). I'm just one of those idiots who has always wanted a 3-rotor engine, no matter how little sense it makes. Oh, and for those wondering... no, I don't care what kind of HP or gas mileage I end up with.
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Rotorhead
Joined: Feb 2001
Posts: 9,136
Likes: 39
From: Charlottesville, Virginia, USA
Originally posted by Suparslinc
as soon as I saw that; my 20B hopes were dashed away.
as soon as I saw that; my 20B hopes were dashed away.
BTW, you have to make the mounts yourself, or buy some that RETed made himself. That's the thing that most people don't understand about a 20B conversion - there are VERY FEW bolt-on parts available, so you have to fabricate a lot of things. Sorry, but you can't mail-order a 20B conversion kit from Nopi.
Originally posted by RotaryMan88
just for curiosity sake....what do the Twin turbo, or just turbo, and NA 20B redline at...normally?
just for curiosity sake....what do the Twin turbo, or just turbo, and NA 20B redline at...normally?
Just Turbo: No Such Thing - You gotta make it yourself!
NA 20B: No Such Thing - You gotta make it yourself!
For more 3-rotor info, see this site:
http://www.3rotor.com
Originally posted by j9fd3s
i keep going back and forth on the 20b thing, and it fits in the fc the best but its still a pain, and still $$$
i keep going back and forth on the 20b thing, and it fits in the fc the best but its still a pain, and still $$$
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