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

[FC3S]

Since V8s can produce more horsepower than rotary, why fear it then? May i ask how quick is your V8 1/4 mile run?

Who says rotary cannot kick vipers and corvette z06s ass? If a rotary engine is well-tuned i seroiusly don't think vipers and z06s are worthy opponents. Their tuning are almost at their peak so means not much room for improvements left. Also, given equal horsepower on both cars, a rotary have high chances of kicking the opposite's ass.

[Steel]

there's no replacement for displacement - unless its a rotary!

Listen man, a stock V8 wont be making you go much faster than a stock N/A rotary. But you want to make your V8 7 fast right? Well guess what, you're gonna be spending JUST as much money on that as you would if you were to mod a rotary. Plus, you're gonna end up sepnding a LOT to get that bitch monted in there, getting the tranny, making the different tranny fit under the car, getting a new driveshaft and rearend, getting a new computer to control your engine, fucking with the electronics because the tach's work different, and it'll be a general pain in the ass. Sure you can get a nice crate V8 for what was it, $400? but you're looking at 10 grand to make it fit and make it fast. If i had 10k's i'd jsut get a 3 rotor cosmo engine that STARTS with ~300 hp IMO and can EASILY hit ~700. Chew on that for a bit.

[Cbass]

Look, I have a free engine, and a tranny that cost me $100. I have a RX7 which will cost me $50, and has no engine. It has cost me about $500 so far, and I have everything I need to put the engine in the Rex with the exception of a fuel cell. I'm removing the stock fuel tank, to make room for the transaxle.

This engine is getting

cylinder heads ---------- $300
Rebuild------------------- $300
efi ------------------------ $400
crane 268 cam ---------- $120

The engine will make 400hp, and 500lbft of torque! As much as I love the rotary engine, show me a rotary engine that makes 500lbft, and then show me exactly how much it cost to build it. Could I build it in my backyard, like I can with the 400M?

[Kaneto]

Originally posted by Cbass
show me a rotary engine that makes 500lbft

Why? You looking to tow something with your RX-7?


Heh, seriously though. It's your car, do what you want. Sounds like you have a good deal on parts there, so just go for it. Sure, you'll get no love from the RX-7 community... but who cares? When it comes to your car, the only opinion that really matters is yours.

[FC3S]

Now look...since the engine you had is free, you can do whatever you want for sure coz' you won't be spending on another engine. Definitely a rotary will cost more than what you are getting.

That engine of yours make 400hp and 500lb/ft torque @ ???? rpm coz' the rotary engines are peaky and torquey by nature.

13B Rebuild kit price:
APEX SEAL ($6.00 each)
CORNER SEAL ($12.00 each)
SIDE SEAL ($12.00 each)
OIL SEAL INNER/OUTER ($4.00 each)
O-RING, OIL SEAL INNER ($4.00 each)
O-RING OIL SEAL OUTER ($4.00 each)
OIL SEAL FRONT COVER ($1.00 each)
OIL SEAL REAR ($1.00 each)
GASKET O-RING SET ($1.00 each)
INNER APEX SPRING ($6.00 each)
OUTER APEX SPRING ($6.00 each)
CORNER SEAL SPRING ($2.00 EACH)
SIDE SEAL SPRINGS ($2.00 each)
OIL SEAL SPRING-FRONT ($2.00 each)
OIL SEAL SPRING-REAR ($2.00 each)

[LS1 powered]

Found this thread, so I had to register and add my 2c's!

Until I can find a rotary that gets 27mpg daily, and has almost 400hp.....

[rogginator]

ok, have any of you looked into this?

the granny's website and the folks at torquecentral.com can really helped you with this. you will get a car that is almost just as light, has the same 50/50 weight distribution, will handle just as well (depending on how the weight issue goes), has way more power, and has a significantly power / reliability / MPG issue

some things i have read in this thread:

"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."

is that why honda motors rev so high? what about motorcycle engines, they have pistons. LS1's and many SBC's rev to 7 or eight every day and have no problem

"v8 is gonna be a LOT heavier than the 13b"

not really. aluminum heads / intake, and no PS / AC, and you have a car that is practily the same and has about 3 times the power

"if u do not have money to maintain the 7, then don't think of buying 7 at all "

what? i don't buy / build a car so i have to screw with it every 100 miles. a reliable 350hp small block is cheap and well documented. let me see that in a 1.3 liter rotary, and not well my friend has or mazda built one of....

"with an almost perfect 50:50 weight distribution you are going to throw that all off."

if you had bothered to go to the granny's site or torquecentral you would see how this can be maintained by moving your battery and a few other minor things

just do a little research instead of being so close minded, and you will see that it is a good swap that greatly improves the performance of the rx7

this will REALLY make some of you cringe - www.hinsonsupercars.com

[Cbass]

Wow, this thread turned ugly really fast...

If I had a FD, I would keep the 13B rotary...

but I don't, I have the 81, and the previous owner never changed the oil, this thing is hooped. I don't feel like rebuilding a carbureted 12A, because it's not worth my time or money.

It's still all in pieces right now, I'm rebuilding the 400M right now, and the G31 transaxle needs new synchros.

[philly fab]

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.

It is quite apareant that you dont really know what your talking about and you dont have 1st hand knowledge of what you say..Speaking from both sides of teh coin (yes i have had several rotarys including the 3rd ccartech 12a turbo kit many years ago before most here probally had a bike!) The V8 with alloy heads and water pump a relocated battery and removal of the needed 13B wires and coils and so forth will net 52/49 dist ratio as the case with my car..Thats on my scales in my shop..

You will never ever get a 13b to make relighable power no matter what you do..And after you factor in the cost of teh added support equipment to the turbo rotary and teh turbo you could have an all motor V8 with a solid roller cam and alloy heads with change left over..

[Devilbat]

You freak'n rotary PINHEADS!

What none of you seem to understand is that to have a v-8 RX-7 you most likely FIRST owned an rotary RX-7 which means that in addition to understanding piston engines (which are superior in every objective measure of performance) we understand in detail the workings of rotaries as well.

I have gutted the rotary out of my 3rd gen RX-7 and am installing an alum GM LS1 in it's place. The 13B-REW as compared to the v-8:


* Weighs as much as the vette engine.
* It gets worse gas milage.
* Higher emissions.
* Less torque.
* Less horsepower.
* Smaller powerband.
* It doesn't last as long.
* It is more maint intensive.
* It requires complex turbocharging to produce meaningful power


If you want to keep your wankler for emotional or subjective reasons I understand. But if you want a *RELIABLE* source of large amounts of responsive horsepower the v-8 is the better way to go.

[rxsskid]

Steel, you are an idiot, its official. Do the research before you open your mouth, ever again. I hereby revoke your right to speak to any intellegent human being ever again. To fill you in, you can build a 500hp, 600ft. lbs small block v8 for about $1500 with good parts and it will get prolly 18mpg and last forever. Then the ENTIRE kit with the motor AND tranny mounts, driveshaft, speedo and tach recalibration and everything is about $500. I wanna see ANY 13b get 500hp, and ESPECIALLY 600ft. lbs for 2g. I personally got my 87 NA for $100 with a blown motor and I spent about $1000 to build a 486hp, 574ft. lb. v8 plus $400 for the kit and my car runs ~10.40's ALL day on PUMP GAS. Also I put the battery in the back and put a hood scopp on and the car is a total of 22lbs. heavier in the front and will kill any of your cars immediately. SO with that I tell you that yes, rotaries are a great concept but until they became semi-budgetable to build, throw them in the parts heap.

[turbo2nr]

its a disgrace to the rx-7 all over to put a v-8 into a rx-7!
ddaaammm it, buy a 5.slow mustang den!
rx-7 can easily make 450+hp @ weels and do the 1\4 in low 10s.
my friends have 2 rx-7s that do 10s one is a 93 wit a worked 13b and it does 10.6
and the other is a worked first gen that also has a 13b and does 10.1, both of these cars are driven every day to work and back and driven to the track and bak!

so i think that the rotory engine is a very capabile engine!

[rxsskid]

Sr20, you have fallen victim as well, no more talking. No one ever said a rotary couldn't make 400hp or run 10's, ITS THE COST. The money it would take to put a 13b-rew into the 10's is LUDICROUS. It cost me 2000 for a complete fresh motor (specs in post above) and the swap. It costs you more than that for turbo upgrades, then you have to deal with injectors, cooling, all of that crap, ITS NOT WORTH THE HASSLE, especially if you're starting with a blown motor because a stock rebuild for a regular 13b is in excess of a $1000 in most places. But hey, if you have the money to waste on crap and one car, you do that, I would rather build my rx-7 how I did with the v8 for $2000 and smoke you and put the rest towards finishing my 1967 Chevelle (Blown 427) that will also smoke you. Hmmmm, two cars that will look better, run better, and smoke you, for the price of one that will self destruct at any given point. I think not.

[Devilbat]

This brings to mind a line that Dan Aykroyd used to say when he reported the news on SNL during it's original run in the 1970s;

"Jane you misguided ignorant slut."

A 13B can't EASILY make 450hp, rather a it is possible to make 450hp with a 13B in highly modified form, on racing gas, in a highly controlled environment, with expert tuning and no hope for reliability. It's just waiting to blow out and cost you big dough!

Now contrast that with a stock Z06 Corvette engine. 405hp and:

* Runs on pump gas
* Good gas milage
* Passes emissions
* Reliable as a brick factory warrenty on the crate engine
* More responsive (no turbo lag)
* Wider powerband
* Similar installed weight to a turbo 13B.

So again, tell me in objective terms why the rotary is better?

Originally posted by sr20det2nr
its a disgrace to the rx-7 all over to put a v-8 into a rx-7!
ddaaammm it, buy a 5.slow mustang den!
rx-7 can easily make 450+hp @ weels and do the 1\4 in low 10s.
my friends have 2 rx-7s that do 10s one is a 93 wit a worked 13b and it does 10.6
and the other is a worked first gen that also has a 13b and does 10.1, both of these cars are driven every day to work and back and driven to the track and bak!

so i think that the rotory engine is a very capabile engine!

[turbo2nr]

A 13B can't EASILY make 450hp, rather a it is possible to make 450hp with a 13B in

yea my boys both run about 400hp every day on pump gass and over 450+ hp at races ,
yes i agree that rx-7 take alot of $ to hook up but 2 me it is worth it come on having a 400+ daily driven race car..
its worth it... the fact that u can say i beat ur 5.0l+ wit a 1.3L thats enuff satification 4 me.

bty their rx7s are highly reliable