Eshaft

iTrader: (2)

I am thinking about picking one up to restore and make badass but what are the pros and cons of each and,
what are the body differances, i havent seen that many pic's so if you guys can show me some i'd appreciate it.
Thanks...

diabolical1

iTrader: (3)

don't really know much about the Rx-4 and how it feels. the Rx-3 is a nice car, but i guess it ultimately depends on what you want.

i started a thread in this board to get pics ... there are some Rx-4 pics on there.

Rotortuner

The RX3 is way lighter. Also somewhat smaller. Just give you an idea on the weight they are a good 400 lbs lighter than the 4. The rx4 might have a little better rearend set up for drag racing the way they come stock. If you want something that handles then the rx3 is the best choice since anti sway bars can be found that will stiffin it up a lot. Keep in mind rx3's do have rear leaf springs, where 4's I believe have a 4 link? I am very biased since i own a 3 and have never had a 4 but i have a freind who has a 4. He just sold it on e bay though. Rx3s are much more desirable due to the weight and size issues that i already mentioned. If you have any more questions just ask away.

CJG

repuguru

I guess the biggest thing that would keep me out of an RX4 vs an RX3 for street performance would be the lack of rear diff options. 3.6 or 3.9 open rear is sorta lame.
The 3 on the other hand has all kinds of options.
The 4 weighs more but just make more power with your motor, you'll never notice

rxtasy3

iTrader: (2)

Yes the rx4 also has leaf springs in the rear. All the early, pre-rx7 rotary cars had rear leaf springs. I had one several years back and they are 400-500 lbs heavier. An '82 rx7 LSD will bolt right in to the rx3, u'll also have to use the drive shaft.

Wankelguy

I have a '72 RX3, and a '74 RX4 right now. While the RX3 is indeed lighter and more nimble, I prefer the torquier performance of the RX4s' 13B, plus it's more comfortable. The RX4 is faster in a straight line, while the RX3s' suspension is fairly easy to set up for better handling. I like the "Japanese muscle car" looks of the RX4. Also, I have been told that a GSL rear end will fit in the RX4, that it is the same width, and that the spring perches just need to be cut off. I have not verified this, though. The '74-'75 RX4s are the ones to get as they do not have the Federally-mandated 1976 bumpers with their 60 or so extra pounds front AND rear. The A/C compresser is amazingly heavy in the RX4, so of course that had to go. I also saved quite a bit of weight by replacing the heavy power-steering setup with a much lighter and simpler manual box from a '74 parts wagon I had that only had 47K miles on it. I also installed a 1980 RX7 transmission, though I like the 5-speed ribcase also. The '74-'75 13B motors had the largest stock ports of any 4-port 13B motors and they definitely kick butt when the thermal reactor is replaced with a proper header/presilencer setup and the points-type distributor is replaced with a '81-up RX7 electronic ignition distributor with good wires. Just a neat car!
-Mike

rxtasy3

iTrader: (2)

I have a 13b out of a '74 rx4 that I'm rebuilding for my rx3. It's street ported and yes they have the center housings with the tall ports which is noticeable with the intake removed. These r the engines to have.

Rotortuner

Dont they only bolt into the SP's though? Or mabe they go into the older ones also but then the drivline has to be sized right. But i know that the 82 LSD bolts directly and teh the drive shaft mounts up and all into 77-78 SP. I think the SP had a longer pinion. Also are rx2 leaf cars also?

CJG

Wankelguy

A first Gen. GSL limited slip pumpkin will bolt into the stock RX3 rear end housing. The RX2s had a 4-link setup with coil-over rear shocks. It is next to impossible to find any decent replacements for the stock rear shocks as the perches are on the shock body.

Rotortuner

Ya they will all bolt in, but the axle sizes change. I know cus i tried to put an 84 gsl in my sp and every thing would have worked but the axles that it required were the large ones. And no this was not an SE pumpkin. I think you need the pre 83 to do it, that way it will use the small diameter axles.

cjg

Wankelguy

My mistake for not being more specific, you are correct, Sir! -Mike

Kick

Would that gls lsd swap work in an old rx3. LIke 72 to 76? IF so what all would it take..

Rotortuner

It should work as long as its a pre 83 rear pumkin. The difference as far as i know between 77-78 SP and early rx3 is that the pinion leangth is different. So basically that means your drivshaft is going to have to get reworked, i think it has to get shortened. also i am not sure if the flange is the same but i think it might be. Dont take my word as fact but i know for sure that the pinion leangth is different and i know that for SP you have to use the pre 83 GSL pumkin. Aside from the drive shaft issue it will just bolt in. To do the swap you have to take appart the rear brakes, pull the axles which sometimes can be a pain, also take the brake lines off the rear brake backing plates then remove axles and take out the pumkin. bolt new one in, put axles in hook up e brake, brake lines, re assemble brakes and hook drive shaft up and thats it.

CJG

repuguru

If you can dig up an SP drive shaft then it will bolt in your 72-76 RX3.

A 4 is a neat car, but a 3 with a B is much neater..

protlewski

Yeah I have wanted a 3 for a while and swap a 12a turbo into it or a T2. But I also like the idea of a Bp or pp 13B in it for an N/A ***-whooping. I'd love to get one severly modded but apears stock and beat up on the local ricers.

Wankelguy

The stock RX3 axles are a bit wimpy if you're going to go with a high-horsepower engine. Be prepared to replace them on a regular basis. Better to just go with a Ford rearend if you're going bridgeport or turbo power. My '72 RX3 project car has been completely seam-welded by hand for better rigidity and strength. You will also probably want to run a ribcase tranny, as they are stronger than the first Gen. units, although the synchros are a little weaker due to the notches cut in them. They like to deform where the metal is thin around those notches and then the rings get balky.

Rotortuner

I havent really had much of a problem with axles yet. Mabe its just me or my driving style, who knows. But the only time i herd someone having trouble was a guy running a 300+ hp turbo engine and he had the spyder gears welded and was driving it on the street, he said he had gone thru 3 axles, all on hard launches with semi slicks. When i talked to him he had the car and was still running the spool style rear.

CJG

Kick

Frist off, how hard is it to find and pre 83 gsl lsd diff?..
Next what would they ran about too, if I got one from someone. What is the gearing in them also. Could you be able to change the main gear in the gearing in the dff to something else and if so how hard would it be and what would be a good one to go with. I wanna have a nice street driven Rx3 with lsd.. heh

As for the drive shaft, the stock one would work, just would need to shorten it right?. H0w hard would it be to find an SP one, or would getting someone to do up the stock one for me be a better way to go..

Kick

Also what do I look for when trying to find a pre 83 rx7 gls lsd car. I am thinking about going out this weekend and give it a try to find one..

Eshaft

iTrader: (2)

What are the differances in looks between the rx-3 vs the rx-7, are ther both available in 4 dr and 2 door,
so far i've only seen the 3 in 2dr and the 4 in 4 dr,
Pics of both would be cool...

Rotortuner

The rx3 came in 2 and 4 door coupe as well as a wagon. I am not as knowledgable about the rx4. But if you just do a search on the google or something you can find a lot of pics.

CJG

Wankelguy

The RX4 came in 2-door coupe, 4-door sedan, and 4-door wagon versions. The wagon was the last to be discontinued, in '77 or '78 I believe. I've never seen a 4-door RX3, myself. Anybody got a pic? -Mike

Rotortuner

No pic but there was one at sevenstock this year. it was a right hand driver, race car from japan. even had the hex lights in it. It wasnt in very good shape but pretty cool non the less.

CJG

rotting in the garage

I actually own one of each

While the RX3 is a little skaty at high speds and does not have a long enough wheel base to coner with confidence over 130mph, it is lighter and the 1st gen LSD bolt in. I have only just got the suspension set up so you can take coners with confidence but even so it is still pretty scary getting sideways at 100 mph.

While the RX4 has a 28 spline diff the ratio's are not interchangeable but the rear end will take abuse and the center can be easily shimmed up. Mine was pretty much locked with the addition of shims just before it got the GEn 3 rear end. The cars additional with and length far outweight the additional 200kg's or so.

rotting in the garage

I have a set of the Hexagonal tail lights

If anyone is interested send me an email
or PM.