Stredrotors RX4 Coupe "Project 20b"
Getting this thread back on track 
A bit more forward progress.....
Got the pipe layout sorted, think it will flow ok



Just got to sort out the transition piece on top
Couldn't help myself and did a test fit in the engine bay



Now have to have a think on how I'll plumb the wastegate.

A bit more forward progress.....
Got the pipe layout sorted, think it will flow ok



Just got to sort out the transition piece on top
Couldn't help myself and did a test fit in the engine bay




Now have to have a think on how I'll plumb the wastegate.
Nice to see this thread is back on track. Hey I was driving my RX4 and it only has a 13b with turbo and I am breaking traction bad with the stock diff. Prob a good idea for you to uprgrade the diff like we talked about earlier in the thread. Next thing to do in my project.
I'm subscribing to this. '74 RX4 was my first rotary back in 1976. And now I get to see someone put a 20B into one. I'm in heaven.
Thanks Stredrotor for allowing me to live out a dream through your work.
Thanks Stredrotor for allowing me to live out a dream through your work.
I once had a series 4 RX7 13bt in a RX4 hardtop in the late '90s but I got someone else to do the the install.
I do have someone to build the engine but I am trying to do all the fabrication and fit up myself.
Its a bit of a budget build hoping to get the engine in the car and running for $20,000 including $6,500 for the purchase of the car. $14,500 so far.

The previous owners of my Rx-4 started putting a 20B in it, they just never finished it. I have all of the mounts and everything still though. Maybe someday I'll be going down the same path. Nice work! Hang in there, the payoff will be amazing.
It's the first time I've done it all myself.
I once had a series 4 RX7 13bt in a RX4 hardtop in the late '90s but I got someone else to do the the install.
I do have someone to build the engine but I am trying to do all the fabrication and fit up myself.
Its a bit of a budget build hoping to get the engine in the car and running for $20,000 including $6,500 for the purchase of the car. $14,500 so far.
I once had a series 4 RX7 13bt in a RX4 hardtop in the late '90s but I got someone else to do the the install.
I do have someone to build the engine but I am trying to do all the fabrication and fit up myself.
Its a bit of a budget build hoping to get the engine in the car and running for $20,000 including $6,500 for the purchase of the car. $14,500 so far.

Finally got a few days to make this manifold
Tacked manifold to 25mm plate to help stop distortion......

Welded and turbo bolted on.....

Fitted to engine to see how it fits.

Now to fit the wastegate pipe!
Tacked manifold to 25mm plate to help stop distortion......

Welded and turbo bolted on.....

Fitted to engine to see how it fits.

Now to fit the wastegate pipe!
After a lot of thought decided to plumb the waste gate straight off the collector under the turbo.
I know it's probably not the best location for flow but there was really not enough room to run three separate runners.
Here's the pipe tacked up.......

...and test fitted in engine bay.

Pipe welded on and wastegate fitted

And bolted onto engine

Next is step is to send it off to get the mounting faces machined flat.
I know it's probably not the best location for flow but there was really not enough room to run three separate runners.
Here's the pipe tacked up.......

...and test fitted in engine bay.

Pipe welded on and wastegate fitted

And bolted onto engine

Next is step is to send it off to get the mounting faces machined flat.
Awesome build, i am also currently in the process of fitting a 20B to a 929 Coupe, looking at you pics has certainly been interesting. I was looking at using a 12a turbo front cover and mounting the engine on a Rx4 crossmember. Might have to reconsider after looking at the way you have done it looks a lot tidier. Although currently i am still in the process of fixing all the rust in the old girl. Basically its going to be a ground up restoration, the car is currently on a rotiserie. I also have a genuine Rx4 coupe that i have put into storage until the 929 is finished.
Once again nice work what you have done to date really looks great.
Being new to the site, once i have got it figured out how to i will upload a couple of pics of both of the cars.
Cheers Gus.
Once again nice work what you have done to date really looks great.
Being new to the site, once i have got it figured out how to i will upload a couple of pics of both of the cars.
Cheers Gus.
Awesome build, i am also currently in the process of fitting a 20B to a 929 Coupe, looking at you pics has certainly been interesting. I was looking at using a 12a turbo front cover and mounting the engine on a Rx4 crossmember. Might have to reconsider after looking at the way you have done it looks a lot tidier. Although currently i am still in the process of fixing all the rust in the old girl. Basically its going to be a ground up restoration, the car is currently on a rotiserie. I also have a genuine Rx4 coupe that i have put into storage until the 929 is finished.
Once again nice work what you have done to date really looks great.
Being new to the site, once i have got it figured out how to i will upload a couple of pics of both of the cars.
Cheers Gus.
Once again nice work what you have done to date really looks great.
Being new to the site, once i have got it figured out how to i will upload a couple of pics of both of the cars.
Cheers Gus.
The engine and gearbox is mounted 50mm (2inches) rearwards but the engine is 160mm (6 1/4 inches) longer so sits to far forward to use the original front mounts.
I am considering using a front mounting setup as well just for a bit of added strength. Working out how to go about that at the moment.
I'm keen to see some pictures of your car, always interesting to see how other people get around the same problems.
Cheers
Chris
Hi Chris,
Have included a couple of pics, as you can see i'm still in the process of getting rid of all the rust in the old girl. The redish orange one is the genuine 74 mod Rx4 which is currently in storage. Also have a pic of the 20b after it was dummied up after being dowelled. The Engine is basically ready to put back together. I have had all the rotors machined to 3mm and have SCR apex, side seals and corners seals all boxed up waiting for me to finish the car. While it was apart i also had South Coast Rotaries turbo bridge port it as well. If only i could stop finding rust it might happen a little faster. Good thing is when its finished i know that there will be zero rust anywhere in the car. Just cant wait to get the engine fired up again. Should sound sweet with the Turbo Bridgeport.
Cheers Gus
Have included a couple of pics, as you can see i'm still in the process of getting rid of all the rust in the old girl. The redish orange one is the genuine 74 mod Rx4 which is currently in storage. Also have a pic of the 20b after it was dummied up after being dowelled. The Engine is basically ready to put back together. I have had all the rotors machined to 3mm and have SCR apex, side seals and corners seals all boxed up waiting for me to finish the car. While it was apart i also had South Coast Rotaries turbo bridge port it as well. If only i could stop finding rust it might happen a little faster. Good thing is when its finished i know that there will be zero rust anywhere in the car. Just cant wait to get the engine fired up again. Should sound sweet with the Turbo Bridgeport.
Cheers Gus
Hi Chris,
Have included a couple of pics, as you can see i'm still in the process of getting rid of all the rust in the old girl. The redish orange one is the genuine 74 mod Rx4 which is currently in storage. Also have a pic of the 20b after it was dummied up after being dowelled. The Engine is basically ready to put back together. I have had all the rotors machined to 3mm and have SCR apex, side seals and corners seals all boxed up waiting for me to finish the car. While it was apart i also had South Coast Rotaries turbo bridge port it as well. If only i could stop finding rust it might happen a little faster. Good thing is when its finished i know that there will be zero rust anywhere in the car. Just cant wait to get the engine fired up again. Should sound sweet with the Turbo Bridgeport.
Cheers Gus
Have included a couple of pics, as you can see i'm still in the process of getting rid of all the rust in the old girl. The redish orange one is the genuine 74 mod Rx4 which is currently in storage. Also have a pic of the 20b after it was dummied up after being dowelled. The Engine is basically ready to put back together. I have had all the rotors machined to 3mm and have SCR apex, side seals and corners seals all boxed up waiting for me to finish the car. While it was apart i also had South Coast Rotaries turbo bridge port it as well. If only i could stop finding rust it might happen a little faster. Good thing is when its finished i know that there will be zero rust anywhere in the car. Just cant wait to get the engine fired up again. Should sound sweet with the Turbo Bridgeport.
Cheers Gus
What colour is the 929 going to be?
One reason I didn't start on the body of my car. I dread to think of what could be under the paint, I'll leave that for another time, just want to get the 20b running
.Chris







Great write up... Lots of valuable information. Great car for this build. Have you done anything like this before?