Hey guys tell me what you think of an '83 Mazda RX-7 with a 4 block with 3.25 in crank in a 4 in bore block.
T5 and granny's engine conversion kit obviously?
This isn't a 3rd gen but it's a swap I'm helping my brother do.
He's new to V-8's.
Anyway give me feed back.
By the way the RX-7 weighs in at 2,300 to 2,400 Lbs.(HEHE)

 

I think those are too ugly to mess with

3.25" crank? That's a 327 ya? should be fun.

 

Fun...
Not really difficult once you get the motor mounted in there. It'll fit. Might end up blowing the rear after a while though with that 350 in there.

 

I had an 88 Convertible RX7 that I wanted to put a V8 in. Weighed out costs and sold it and bought my 91 RS convertible. But from my research on Granny speed the rearend is tougher than our 10bolts. The swap should be pretty much straight forward if you have all the granny speed parts that you need to swap engine and transmission. Getting the guages functional again looked like the hardest part. With grannys mounts it the engine and tranny pretty much just drop in there.

 

No, 327 (3.25" stroke, he said). 331 if .030" over.

Sure fits the "unique" criteria. Hope you both have plenty of time for this. And he has plenty of money.

 

My bad... I was thinking about the car I worked on. It killed the rear.

 

There was a guy on here awhile back that installed a 305TPI into his RX-7 I believe. Do a search maybe. He had a website too.

 

That's going to upset the old girl a little. That's a lot of weight in the front of that thing compared to the 50 lb roto motor that came out of it.

 

No it all comes out to about 100-150 pounds more.
Which is going to be offset by relocating the battery to the back and all the aluminum I can get on that sucker.
In terms of time that's not a problem cause the whole car is getting the treatment.
The engine is just the best part of the car.
We already have the driveline except for the engine takin care of.
It consists of granny's custom drive shaft,Junkyard T5,aftermarket torque arms, and the mounts for the tranny.
It's really is a pocket rocket and it will most likely be a real mean son of a bitch.
But my $500 '87 firebird will be holdin more than it's own against it.

 

I'm gay.

 

Ok point made.

 

lol!!! foo!!!

 

maybe the aluminum LS1 would even the potential weight issue out. I say go for it, LS1 or good old fashioned 350. I hope you plan to replace the drivetrain as well.

 

the drive train is all taken care of.
the latest improvement would be the World Class T5 we just got from an '88 RS.
Those T5's have better synchro's and a lower 5th gear I believe.
Custom aluminum drive shaft and the rest I'm not sure of.
Those suckers come stock with 3.91 rears, But that'll just get blown to peices probably.

 

By the way they don't have an LS1 conversion kit yet, but yes that would definetely be a plus.

 

Nah the WC T5's just have the better synchros; same gear ratios.

 

Ohh ok I was just told some stuff but thanks.
Later when the money situation is better My brother is gonna buy a T56 and the T5 is gonna go into my firebird which will be nice.
Peace

 

There are several v8 rex's around. I have done a lot of research on the subject. I've heard a small block weighs almost exactly the same as a rotory w/two turbos, intercooler, and all the piping. You just have to be really carful about placing everything(more than one v8 rex has burned to the ground) Don't forget there wil be a cooling issue, possibly hood clearance problems, speedo/tach recalibration, and several other difficulties. I've also heard granny's kits aren't that great, and they have ****ty customer servece.

Make sure to look up everything you can about the swap before you do it.

 

I know of an RX7 with a SBC in it.
It's in RI, and all the guy could tell me about it is that it was a "Corvette engine."
Can't give you any swap details, sorry.

 

I guess I havent heard of " Grannys" Fill me in please..

 

http://members.tripod.com/~grannys/rx7.html
That is the address, you should check it out.

 

thanks for the link..

 

what about an lt1 swap? with no rear mounted distributor could you move it back in the frame to help offset the weight? I mean it would still be heavier than the original engine but I think it could help out the handling a good bit.

 

Yes they do have an LT-1 swap and actually we were gonna do it but we figured we'd just go with the gen 1 engine and later convert to EFI.

 

The mission here is to stomp alot of those imports in the area with some good 'ol V-8 power,there's none better for the common gear head.

 

here is the test mule.
it needs a new paint job after the swap.
We are currently swapping in a ford 9 inch rear. this is before we started.

 

I drove a newr ('90-ish) RX7 with a 302 and auto trans in it. It was amazingly fast and agile. I don't think the added weight is an issue.

 

A 302 is also lighter than a gen 1 350. It has a shorter deck height so it fits better too. If you thought that was cool you should check out some of the Miata 302 conversions. Now that a rocket on a roller skate.

The 9" in the back of this thing will offset the front end weight. Those things get to be a little heavy. Not as bad as the Dana 60 in our drag car. That thing almost weighed as much as the rest of the car.

 

some other conversion company just came out with an LS-1 kit, but it's for the third gen RX-7's.
GODDAMMIT!

 

:nono:

 

fella down the road from me had one, he broke the original rear fairly quickly, but the turbo rear held up very well.

It had a very mild Vortec headed 350 in it, and a T5, and flirted with the 11's once it got nailed down.

Lotta motor in a lil car, they are really kinda nifty, and his had more room around the engine than a thirdgen by FAR.

Was neat hearing that rumble from that lil car

had a decal on the back that went something like this
the standard mazda badge

mazda....... with (insert bowtie) stuff

 

I've seen a guy with an 84 RX-7 with a 305 Chevy in it. That car hauls as*. Much more powerful than the Rotary Engine.

 

and does everybody know why? repeat after me -

There is no replacement for displacement

 

You got something against Wankel? All you do is port that rotary till it will barely idle and you will be shocked at the power. Rotary was a brilliant idea. I hate this "no replacement for displacement". I have an 81 RX-7 with the 12A 1.1 liter Wankel. It makes around 130 horsepower. I think this is Damn good for 1.1 liters of displacement (it's carburated too). If you do the swap I might be interested in buying your rotary. Mine has a chipped apex seal. I admitt you could make a hell of a drag car from the RX 7 since it weighs nothing and it is rear wheel drive. Good luck anyway.

P.S. There is a replacement for displacement. It's called a turbo charger. Rotaries respond well to them (the 13B version, 1.3 liters)

 

there is a replacement for displacement

displacement is a tool for making power yes

but.... those who think displacement is the only way to make power for the most part only have that thinking to use it as a crutch

yes a 305 might be faster then the stock 1st gen 12a rotary but the stock 12A was nothing special in stock form

though you can port them to make around 250-300hp all N/A
you can turbo them to make least 400-500hp on stock interns

also step it up to a 13b and you have even better setup due to better port timing. lighter parts. and quite a few other things.


no replacement for displace = crutch

finding ways to make power without resorting to bigger is better = auto tuner

 

just curios as to what you have done to the car to make 130hp

stock is not near 130 for a carb and with a chipped apex isn't going to help any

 

no, there is no replacement for displacement. if you mod a 4cyl and then do everything the same to the 8cyl, the eight will make more power. having more cyl isn't the only way, but in the end it makes all the diff.

 

you guys are talking about how turbos make up for lack of displacement

iam building a 350 for around 2k that puts out over 300 horse N/A

now if you put a good turbo on that you will have a good starting point

i dont have anything against mazda but turbo chargers will only get you so far if you have no power to start out with

so yes i do think there is no replacement for displacement

 

anyone ever put a big block in one of those little cars?

 

my next door neighbour obviously thinks the way you do. he got a 1975 datsun 280z. it used to have a 327 which threw a rod n' piston earlier this summer and now has a totaly new, except the block, 350 engine. its a crazy car. low 12's i believe on some street tires, not even street slick. the car is awesome and he hade to make alot of stuff himself, but i'd say it was worth it.

 

not thirdgen related but...
The RX-VO project it is an rx7 with an american motor in it.

 

Checkout http://www.rx7club.com/index.php there's a guy there named Jimlab and he is currenly doing the similar project. He's using a Corvette engine, I think. But he spent around $10,000 or so on insane mods creating a 600 some HP N/A engine for his RX-7.

 

This may not be an RX-7 but it's one bad, bad, bad 240Z. This guy had a ton of money and about 550 RWHP in that car. This guy can break the tires loose in all 6 gears.(T-56). I have a bunch of vids of this guy from this site


http://www.taner.net/movie-dir.cgi/darius/


Look at the "full" video for a shot of the motor.

 

The site is jacked at the moment...

 

I was able to get through earlier. It's really slow sometimes but you have got to see that movie. I'd post it but it's like 12mb.

Try this link. Right click and save the file. Check out the "full" clip first.

http://www.lbjhs.net/~cliff/movies/darius%20movies/

 

Check this out cool

http://www.rx7v8.com/

 

you say that if you do all the things to a bigger displacement motor will make more power then a smaller motor


what if I do all the things you do to your bigger motor to my turbo motor... which would make more power?


now who is right

you saying that adding a turbo to a bigger motor is the only way

or adding more motor to a turbo car?


which way is the right way?

again those who say displacement is the only way to make power I would say your wrong.
I would rather have a more efficient motor with a turbo that I can make a little smaller then some big hunk of iron in my car
I like the power band that a turbo gives... very usefull on a highrev motor. also with less wieght I think I could get my car to handle better then I could if I plop a 502 in there


no replacement for displacement is just a crutch to get away from tuning and extracting every bit of power you can from a smaller motor that might work just as well....

all in all I would say there is no replacement for proper tuning when it all comes down to it.... again not displacement

 

if you take a motor built up for turbo use and put it on N/A duty you are going to get **** no matter what....

turbo motors run on sub 9:1 compression most the time. also with the port timing that they have it doesn't help also.

again no replacement for displacement

could build up a wankel of a whole 80 cid for 350hp on just motor alone for about 2000k myself.....

also it would prolly have a little bit of a flatter torque curve then your car would

wnakel is not the only way just my choice as a 350 would be yours, but I'm sure I can get my hands on a little 3.8 v6 that I could make over 400hp with in under 1000k... but I could also do that I would think with a N/A motor also if I could get ahold of the right motor where things don't cost arm and leg.... a.k.a. honda



oh and by chance has anyone ever ran a GN or TTA without the turbo on it.... I wouldn't be shocked if it was real slow... lot slower then the stock v6 motor

 

I hate to post coming off as an a$$hole so let me just say that this is in no way a flame post aimed at you. "I'm a big believer of the no replacement for....." saying. I've seen a charger (yeah so what if its mopar its still american) lift the tires up off of the street by about 6 inches. All i know is it had a big block dodge engine in it. Man that thing could run. Seeing that car run is what got me into american cars and drag racing. But to back up the replacement statement check this link out.
427 turbo
What it all really comes down to is speed costs money.... how fast do you want to go? I think i have a formula for figuring out how much you have to spend on your car. C is for the amount of money you have to spend on your car. M is the amount of money you make in one month. V is all the bills that come into play during the month. x is the amount of money spent on regular maintance of the vehicle. So C=-2[¼(M-V²)]-X. Also this formula applies to 82% of amicans living in the united states during the past ten years and the next five years with a growth of 2% (of V²) for 60% of americans that have major credit card debt. In other words most of us dont have 35000 to drop on a turbo 427 but look at the amazing numbers that engine pulled!!! Imagine how much fun it would be to drop the bomb on a brand new viper!

 

I was waiting for this to happen...

No replacement for displacement? Hmmm... I dont see any Top Fuel cars running Wankel engines. Nuff said.