2ND generation rx-7 --- v-8 conversion kit.

[kcxox]

I'm thinking of purchasing a parts rx-7 with a blown motor and buying a conversion kit with a v-6 or v-8 to replace it. Is this a realistic goal, and is so, where can i purchase a kit. i know they exist, i have friends who have them. thx, KC

[Bryan8412]

im sure it would work by why retrogress to an inferior engine design??

A piston engine in V-formation is unbalanced, the pistons violently change direction, is unable to acheive high revs due to the mass changing direction so quickly, and it has many moving parts.

A rotary has 3 cycles per revolution due to its design, it has the best hp/liter ratio of almost any engine, its perfect for a twin turbo setup, it has THREE moving parts, it stays in one direction, and it revs high due to this.

if you're worried about having an engine problem solved: www.revolutionrotary.com

only a couple thousand. good luck

[Cbass]

Oh yeah, tons of people are doing this. Turns out when a rotary goes, people aren't willing to sacrifice the multiple limbs necessary to get it rebuilt/replaced.

I am doing this in an 81, with a 400CI Ford... I think the 5.0/early eighties first gens are the easiest, you just turn the engine/suspension crossmember around 180 degrees, and bolt up the stock Ford mounts. The tranny requires a custom fabbed crossmember, but grannys sells em for about $300.

Budget $2000 for parts if you do it yourself, including engine, new 4 core aluminum rad, and new crossmember.

These guys will show you everything you need to know...
http://members.tripod.com/~grannys/

[Steel]

or you can put in 1700 bux for a remanufactured rotary. Why bother getting an RX-7 if you aren't going to have the rotary in it? If you want a V8, theres plenty of Camaro's Firebirds and Mustangs out there.

[Bryan8412]

Originally posted by Steel
or you can put in 1700 bux for a remanufactured rotary. Why bother getting an RX-7 if you aren't going to have the rotary in it? If you want a V8, theres plenty of Camaro's Firebirds and Mustangs out there.

exactly my point: http://www.revolutionrotary.com

they sell reman 13b AND the king of rotaries the 3-rotor twin turbo 20b engine.

plus you can get the option of 3mm apex seals and other upgrades like street porting and what not. it's inexpensive and its like a new rx7 when you drop it in.

[Moppie]

Originally posted by Steel
Why bother getting an RX-7 if you aren't going to have the rotary in it?

Becasue the RX7 is a very light weight car, with competent for its time handleing (and when well sorted awsome handleing), and any small black V8 fits rather nicely in the frount.

You get the best of both worlds. Light weight Japanese car with lots of American V8 grunt.
Becuase lets be honest here, as cool an engine as the Rotory is, it will never make as much hp as a V8.

[Bryan8412]

Originally posted by Moppie
Becuase lets be honest here, as cool an engine as the Rotory is, it will never make as much hp as a V8.

not true. The reason most people baby rotaries is because mazda holds the patents to alot of the technology behind them, and they have ALWAYS skimped on power (miata, mp3, etc). They always go for low displacement engines. If another company would be able to make use of the rotary technology, they'd use more rotors etc. The 20b uses 3 rotors and puts out 280hp stock if you port the I/E, get a new pully system, new computer, and remove the old TT and put a quick spooling single turbo, it can touch 400+ easily. An experimental 6-rotor engine from mazda put out 900hp. It's just like an I-4 compared to a V-12 in the piston world, theres no replacement for displacement.

As mazda loses it's patents (i think theres a time limit isn't there?), maybe someone would make good use of the design. In fact i think i recall GM having solved some of the rotaries difficulties but couldn't apply it and never released the technology as they don't hold the patents.

[Cbass]

I like rotary engines. If I had a good 13B, or a 20B, I would drop it right in the RX7. I don't though. What I do have is a huge Ford smallblock, and it was free. I also have a Porsche transaxle from a 931, which is going to be my tranny. I can get a first gen second series Rex with a blown motor for around $300 CDN. I can rebuild the motor for $600 CDN with forged pistons, add $150 for a new cam, let's say a $900 rebuild with 400hp. With the Porsche transaxle, the car will weigh 2300-2400lbs, have 400hp, and a 50/50 weight balance.

Now I just need flares for wider tires.

[RXtony7]

Putting that V6 or V8 into a rex is totally nuts, you are ruining the whole concept of the car, with an almost perfect 50:50 weight distribution you are going to throw that all off.

[Steel]

yeah, that v8 is gonna be a LOT heavier than the 13b, totally screw your weight distrobution. Your rear end will be kicking out on you when you pull into the supermarket! unless you wight it down, bu then you will be the only owner of a 4500 pound rex.

[Cbass]

Well, thats one of the benefits of using the Porsche transaxle, it combines the differential and transmission, and only weighs 80 lbs.

I'm not replacing a 250lb 13B, I'm replacing a 350lb 12A with a 500lb 400M. The tranny is going to the back, and so is the battery. This will keep an optimum weight balance

Look, I don't mean to offend any rotary purists, I love rotaries as much as anyone else. I can't afford one though! Besides, this motor is a test bed for my shop, and it needs a home.

[jthompson02]

You all are idiots. the right V8 will overpower ANY rotory you have. Even a 20b turbo wont give out as much power as a modified v8. And you all must not read around. You can put a v8 in your car and gain MAYBE 150lbs. And that is NOt throwing off the balance. You can put a v8 in a TII and even make the car LIGHTER then it was stock. SO get off the V8's. Plus, i have a V8 in my 7 and all my fiends have a 7. I can either hang or BEAT them on the corners, and on the strait ways i can eat them all alive. one of my friends has a TII with about $15,000 of mods to it. Plus you all say its killing the car. Maybe some of us can afford to keep the rotory running. Stuff for those engines are expesive. You can go down to almost any autzone or pepboys to get what u need, (i recomend using summit for all your parts though). So get off this guys back. V8 will do just fine in a 7. A v8 will outperform any rotory. And like i daid the weight differance isnt that much. 150lbs...thats al. So before you all start talking crap...do the research. and if any of you are EVER in Ky, bring your 7 and ill show you what a v8 can do. BIOTCHES

[RXtony7]

Well any RX7 with a V8 is no longer a RX7 as far as I am concerned and alot of other 7 lovers feel the same way. 150 pounds huh?!? Yeah maybe after you strip the interior. But hey it's your car.

[FC3S]

What a joke!!! This is an absolute insult to every 7s out there. There is no place for a "piss-ton" engine or V8s in any 7s for that matter. Anyone who disagree can tell it to Mazda. I think it will surely disappoint Mazda, especially Mr. Rotary, Mr. Yamamoto will came out with rotary to complement the 7s handling and performance. Rotary is the soul of Mazda and 7s. If there is no rotary, then no RX7.

Let's put it this way, if u do not have money to maintain the 7, then don't think of buying 7 at all because if u have good money to spend, then the word piston should not even come into your mind. Also, if u are a true rotary fan, u will not sacrifice rotary for that crap for money's sake.

As for performance wise, v8 can overpower any rotary??? Then, why don't beat try on the RX7.com stock body street legal RX-7??? That's the fastest RX-7 @ 9 sec in 1/4 mile run.

To all rotary fans, cheers....long live rotary and 7s!!!

[jthompson02]

Riiiiight...hmmm the rx-7.com car. Let me think...im sure they dumped allot more money into there car then i will ever be able. But i will race ANY of you othat think this is a bad idea. And i bet i can still kick your ass around corners. I bet i will be able to take a corner faster now. So dont talk carp about peoples car just because they do something different. And i love the rotary engine, but it doesnt do what i want it to do anymore. I wanna be able to kick a vipers/ corvette z06's ass...and i will. Oh, if any of you are in the louisville,ky area. post it up...cuz i need people to check how my tail lights look on the road. BIOTCHES