BUYANDSELLRX7

I am wondering why NA 20b swaps are not that common. You can get about 250 hp from a NA 20b pretty easily and it would be reliable since there's not as much complexity and heat under the hood. And it wouldn't be that expensive if you sold your existing drivetrain and bought a cheap jspec pullout.

Just another option instead of going ls1 i think.

Cgotto6

iTrader: (8)

The motor is only a fraction of the total expense...Sub frame, ecu, drive train...

t-von

iTrader: (8)

It doesn't need to be NA to be reliable. Attila the Fun has over 50k miles on his TURBO charged 20b FC conversion. He is making over 350rwhp and the block has been totally reliable. In the end maintenance and great tune is what lengthens the reliability.

littlemilla3

iTrader: (1)

Seems like way too much trouble to me when you can have a perfectly reliable 255hp stock 13b-rew.

fastcarfreak

most people who go 3 rotor do so for the power and torque. If you want reliablility, buy a honda.

alberto_mg

there are lots of threads on reliability. try searching and reading those threads for some in-depth info.

shm21284

I think the question is a reliable for a tuned engine. For example, if wanting 400 hp, a 20b would be making less horsepower per cc than a 13b. If all things are otherwise equal, the 20b would be more reliable.

shm21284

Actually, the sub frame can be left unmodified without changing the position of the steering rack (no bump steer). GTORX7 did this... it's in this thread
https://www.rx7club.com/20b-forum-95/my-rx-7-done-cup-holders-3-rotor-semi-p-port-n-setup-stock-subframe-454580/

The ecu, when wanting 350 whp numbers, will have to be standalone on either engine, so no big cost difference there.

The 2nd/3rd gen drivetrains have consistently proven themselves for high hp applications, say 5-600 whp range, except for the clutch.

TwinGTR

Im planning on building an all race FD and I will use a 20B Bridgeport engine NA engine for that. It should produce 400 very reliable Hp for track/competition/endurance use. Engine is arriving in 2 weeks.

mono4lamar

iTrader: (32)

that 20b... boy what an engine! but you better be ready for the nightmare of working with it and respecting it. i once was bound set to do the conversion (rather than calling it a swap cause honda's do swaps that require very little work) but as i read on further and further i knew i could do it, yet i looked at my funds and realised that its quite out of reach for this year and the year after lol... maybe in the future but anyway do a lot of reading on peoples screw ups cause it will save you much more time and money. its very rewarding but you have to have both things going for you, money and the smarts. keep reading and good luck!

OneBadFox

My car is reliable, fast, and gets 24 mpg. But then I did do a ls1 swap. I know someone is going to say that a rotary motor can be just as reliable and that john doe has a 400 rwhp pump gas 13b that has over 500,000 miles on it. But what he will fail to mention is that he runs 8:1 a/f ratio so it won't blow a axep seal and gets 10 mpg if he stays out of boost.

When if comes down to it the LS1 swap is more that just power and torque. You will get better gas mileage, the handling will stay the same no matter what some people on this board will say, less maintenance needed (oil change every 5k, and plugs every 100k), aftermakret parts are much cheaper and the car is more reliable with a ls1 swap. I wouldn't think twice about hoping in my car and driving across the country.

Not trying to start a piston vs. rotary thread, just thought I would put the option out there. Some people just don't have the self control and discipline to drive and maintain a rotary powered car. I know I don't.

jacobcartmill

iTrader: (6)

come on dude... 500,000 miles? 8:1 afr's? 10mpg?

my TII was running in the 11's afr's (its a turbo car yeah) and got 23mpg. i even drove it 16 hours down to south florida!


there are many people on here that can claim that.

z28_SS

I dont' care, I would still do ls1

jacobcartmill

iTrader: (6)

cool

rx_obsessed

I think a piston engine has no business in an RX7. It has nothing to do with the original concept of the car. Remove the rotary and you remove the mystery, the quirkiness, the magic of what an RX7 is. If you want pistons, get a Vette or something.

blueskaterboy

yeah man that 20b bolts right up. just drop it in. that way you can keep it rotary so its still mystical, magical, unique and most of all, reliable



i want a 20b with a massive turbo because i want some massive power. it is kind of cool to drive a car that most people are afraid to even think about because of its reputation of reliability. if i wanted power and reliability i'd get a v8. n/a 20b? why the hell go to all that trouble for 250hp?

i did ride in attila's FC, the response and torque is pretty nice. i think jesus touched me when he floored it.

reliability and gas mileage? that's what my completely ******* stock civic is for.

TwinGTR

what do you mean by relaible BTW? Is my street car reliable? 500Hp+ on pump gas and if I drive legaly it gets 29 Miles per gallon. Havnt had a brakedown on any holliday trip, Track use on full boost for 20min, then cool down before giving it all again for 20 min. Been doing 190mph in some of the trips without thinking.

In my opinion its ok reliable. I would nog take the car out on track for 24 hours endurance race. Thats what I seek.


BTW. It should be a death penalty to put something else then a rotary under the hood of a Seven.

blueskaterboy

29 mpg you mean miles not meters right?

TwinGTR

haha. No Miles per gallon. I checked it again and it seems like I calculated a little bit wrong. In sweden we calculate with km/liter.

26MPG is more correctly. Were talking legal speed here, or almost. 75Miles/hour.

ReadyKW

I think you calculated wrong again. Unless you were going downhill with a tail wind and in neutral.

No, putting all those tacky ugly body kits should carry that penalty. The guys that have the imagination and innovation to do stuff like that (engine conversion) are what "drive" automotive development to make all our cars better and faster. Not someone putting on bolt-ons for purity sakes.

This is from someone that is an original owner of a stock 93. I like rotary powered RX7's, I like LSx powered RX7's (or LSX7 if you will). A V8 will make your car faster. There is no way a rotary can deliver torque like a V8, and that torque curve is what makes you go fast. I would bet that the ones that slam the V8 conversion cars would leap at the chance to ride in one or drive one. I know I would.

TwinGTR

I tried this one this time. http://www.onlineconversion.com/fuel_consumption.htm

0.9L/km=26MPG. But as I said calm driving legal speed. But I had to without o2 sensor and tune it well to get there. Full Boost and very hard track use it was 3MPG last time I checked


If I were to ride in a v8 RX-7 it has to have extremely good silencer, and a very nice speaker system making rotary sound.