Awd/ 4wd Fc
 

I know that back in the day there was a AWD/4WD FC that won the world rally championship. My question is more about the technical aspect of it. What gear box were they running, how did they do it basically. Anyone have any insight on it? I'm going to do some hunting about it, but if anyone knows anything it would be helpful. (technical knowledge, etc...)

It was Dag Bakken and Sal Dagens RX-7

It was a 3 rotor using a mazda MPV drivetrain.

I think.

Theres pictures floating around... have you had any luck searching?

Just bits and pieces of snippets about it. I'm still looking though

Rod Millen had a AWD FB back in the day.

True. But would his setup be the same as the FC's since they had both the 12A and 13B in them?

All they have on wikipedia about it.

https://img.alibaba.com/photo/502362...ansmission.jpg
Looking at the MPV tranny this is probably what he ran.. But I can't find any for sure sources that could verify that.

Now would everything mate up right? I'm going to guess no, it seems a little longer than normal N/A, but then that just might be a different bell housing. Not quite sure. but here's a link to an ebay one:
here

I was searching in the wrong section... I found some information on the suspension forum on here, here's what they have:
http://www.realautosport.com/pics/PPIHC/millen.jpg
That's Rob Millen's. Nothing about his set up though. Can reference this forum for more information.
although they don't have much infomation concerning the exact transmissino to use. They say a 626. Any one have any further insight?

I am pretty sure they used the driveline out of a 323GTX.

i know a shop owner that owns an awd fc that had a 12a. i believe he used a subaru tranny, but i may be wrong

Millen's FB was before 13b's were in FBs. I think he had a few though, so one of them probably had a 13b in it. It was like 82 up until 86 or so that he ran it. I'm not entirely sure.

lol, So basicaly any mazda made AWD tranny could work? I'm curious about how much modification he had done to it. IE, did he modify the back bone to support the transfer case, or did it fit lock stock and barrel? How did he get the front end to work? did he just use the respective front end pieces and mated them together?

Questions, questions, questions.

How about this from my '88 brochure.

Ramses666

and for those who can't read the micro print I put on my super eyes!
Thanks ramses666 for the post!

I can give you a better resolution if you like. I have my original '88 brochure & a scanner. I am on a primitive dial-up so I shrunk it down. The whole brochure is pretty kick ass with 20b's & everything!!!

Ramses666

I was able to read it and what not. It was just a pain trying to write it out and what not. is there any shots of the drive train?

Nope... no drive train but I think I might have something in my archive...

Check these out.. not much help

Ramses666

awd would be amazing.... are you planning on using a turbo? i might follow this up and make plans for a winter rx7.... even though rwd is fun in the snow... :)

nothing set in motion yet. I am planning on a major upgrade, but unless I get some input on exactly how to accomplish a mod such as this it will be rather difficult. I figure something like this will cost some dinero, so I'm trying to plan ahead as much as I can. First things first though i'm going to be doing a N/A->Turbo conversion. This is for "future" knowledge.

What i've thought of so far would be that if you have an AWD/4WD tranny with the right length on the shifter bit to align right and the transfer case is able to fit in the back bone without serious modification then it might be an easy bolt on to the motor (maybe an exhange or modification of the bell housing to accomplish it, but relatively simple). Considering that the RX7 has already an almost perfect weight distrobution it could really utilize the AWD to a huge benifite of power distrobution.

Thanks ramses666 for the pics. It's so close... so very close. I don't see any modification to the internal structure of the back bone, but maybe I just didn't look close enough.

seems to me the extra weight and loss of power thru the awd would not be worth the benefits on a motor that already suffers from zero torque...

I always heard 626 drivetrain, and he had to modify the firewall so the engine could sit back further.....there were also pictures of a 20B all wheel drive 7 floating around...that thing was awsome but the engine sat almost entirely in fron of the front axle...so no one seemed to approve...search around I knwo there is stuff in the internet about them

Depending on what the setup is it might not prove to be beneficial. If you think about it you're not adding a whole lot onto the car. the only addition to weight would be the transfer case and the front portion of the drive train. You'd have to figure out how to mount the engine in the proper spot but if you're laying down big numbers (read that as 400+) AWD would definatly prove more beneficial than not. Especially if you're able to maintain a 50/50.

i have these pictures but no info. all i know is that they look tough

NO.
The engine's power output would kill the 323GTX drivetrain in a jiffy.
If we're talking about Rod Millen's car, it was a ONE-OFF custom drivetrain that used a 626 FWD transaxle (don't ask me how) that Millen's shop somehow managed to get coupled with the rear.


-Ted

Those pictures were very illuminating.

Millen's 4WD FC used a custom tube chassis covered in a stock body. From the looks of the drivetrain, it (or something similar) *could* fit in a stock FC chassis, but you're looking at some fabrication. The transmission tunnel, front end, steering, and front suspension are going to need some custom fabrication. Chances are, you'll want to relocate as many systems as possible (the battery, engine bay fuse box, etc) to make room.

You'll probably need to chop off the front of the car's unit body and construct a tube frame; that'll give you more space to package the front differential. Maybe go to a dry sump pan for more ground clearance.

http://mrec.rotary.net.nz/millen/millen1.jpg
Seems kind of an interesting setup, while being fairly straight forward (not saying that it is an easy thing to do)
http://mrec.rotary.net.nz/millen/millen9.jpg

I think the tubular construction of the frame might have been to reinforce the chasis while not sacrificing tons of weight (as compared to straight forward reinforcment of the uni-body). It also looks like He changed over the rear to a solid axel--perhaps to handel excess power delivery to the rear?

the one thing that would concern me on that is you would have to tear up the interior because the 'shifter' for the 4wd/2wd looks pretty far forward on that setup and taking in consideration where the gear shifter is that would put the 4wd/2wd shifter up under the dash....

Needless to say U need a completely fabbed front end & engiine bay. I saw something in a picture I don''t have, but the firewall was totally relocated & engine moved to accomodate the front end. Radiators & all were relocated I think, but can't be sure.

Ramses666

interesting ..

I think you might be thinking of the 20B setup. As soon as I find it I will post up a picture. But as far as I can tell the tube chasis seems to reduce the total amount of space available for the engine to be placed in. (My thinking being, it's using the stock body panels, but the engine sits in the same place pretty much while there is a tremendous amount of space inbetween the radiator and the engine--Perhaps to allow the mounting of the front differential to mount as close as possible to the Rack). There also seems to be another set up where they change over from a single radiator to a dual radiator setup. Either that or it might be extra cooling pieces for something.

I'm an idiot, it was in plain sight! https://www.rx7club.com/attachment.p...hmentid=231905

Wow! thats the picture I was thinking of I believe. Pretty interesting.

Ramses666

Here is Amemiya's old AWD car, just sits in the back...probably still there too!

http://i106.photobucket.com/albums/m...r/DSC01380.jpg

And in that magazine picture, the car wasnt 100% finished, you can see the IC coupler not even connected.

Any input on how the AWD is accomplished with that 7? j/c

http://cp_www.tripod.com/rotary/pg15.htm just alittle more i looked up.. enjoy

This is really interesting, id love to see upclose first hand how exactly the FWD is set up..

And id love to feel how an AWD FC handles.. i can only imagine!

Man I hate these 4WD FC threads. They're 95% BS and ignorance, and it's the same BS and ignorance that's been posted in all the other 4WD FC threads that obviously weren't searched for... :rolleyes:

No RX-7 has ever won the WRC, let alone a 4WD one. The only significant record held by a 4WD RX-7 is Rod Millen's FC that won Pikes Peak in 1991. All of the RX-7's that completed in the WRC were RWD.

It should be pretty obvious that without moving the engine back (i.e. major body modifications) a 4WD RX-7 will no longer have a perfect weight distribution. This is a moot point however, as the engine must be moved either backwards (expensive) or upwards (expensive and stupid), as the front axle line currently runs right through the engine. A couple of minutes looking at your car instead of an internet forum would've shown you that...

And those items do weight a lot. You'll also need to replace the front uprights and strengthen the front suspension as neither are designed to transmit power.

Those pics are of Millen's FB drivetrain, not FC. The two cars were totally different. And not that it really matters, but since only half the power goes to the rear wheels, the loads on the rear drivetrain are not much greater than stock. The FB's PP 2-rotor made ~300hp (~150hp to the rear wheels, ~25% greater than stock) and the FC's turbo'd 3-rotor made ~500hp (~250hp to the rear wheels, ~40% greater than stock). There are plenty of 150hp FB's and 250hp FC's with stock rear ends.

That's Millen's original car, or what’s left of it. RE-A bought it and extensively modified it for circuit racing. It's been here in NZ for years and doesn't look much better than it does in that old photo.

Actually, they were searched for ;) otherwise I wouldn't have posted it.
I was going off of memory, and as I did research on it I see you are correct in the Pikes peak... But then again you could have also looked at the second page of this to see that too.
Weight distrobution would depend completely on your setup and engine location. IF you move the engine back you have shifted weight off the fulcrum to the rear. When the added weight of the FWD is put back on you shift the new fulcrum back towards the front. How much so depends on how heavy the pieces you use and how far back you made the engine sit. In theory the 50/50 can still be maintained, it would require fore thought and smart modification, but is possible.

I knew that modification like that would be necessary, especially considering that the steering rack sits right on top of the front subframe. Heavy modification was already known to me. It's the specifics that I was looking for that you seem to conviently omit from your critique. For instance you haven't confirmed the 4wd transmission He used. Nor the modifications to the front end (IE power delivery, but thank you for the specifics on chasis regidity for the front clip. That is something I hadn't previously considered and hence why I bounce it off the internet forum). However I do appreciate your information listed here:
Depending on transmission type and differential setup power distrobution to the wheels is different than 25% to each wheel. For example AWD transmission works by supplying power to the rear right and front left, once they break traction the other wheels pick up the slip. Hence why on some commercials you hear the slogan "...From the wheels that slip, to the wheels that grip."

It wouldn't be an RX7, but it sure would be a hell of a lot easier to drop a 13B or 20B into a subaru. There is a thread on here with some pics. Just seems like it would be a lot more feasable to drop the engine in to and AWD car than to put a AWD drive train in to a RWD car.

That's a possibility, however would the subby trainy handle the 13B? I'd imagine it would be okay during normal abuse, but once you start hitting the big digits like some people on the forum it would be a gamble. I've been trying to figure out other ways of trying to accomplish this besides throwing the engine back and doing the extrememly heavy modding. The only thing I can figure is a modified transmission with two front drive shafts that spin in opposite directions, each one running on either side of the engine. That may be able to work, but I still have some things to work out on it before I even draw up plans for it.

I think a big concern is some thing NZvert brought up. And that's the reinforcement of the front end to handle power. If too much power is transfered to the front then suddenly your front end will want to tear itself off from the rest of the car, throwing your entire suspension geometry out of whack. Not to mention the front hubs would need to be replaced or heavily modified to accept a transaxel.... Lots of things to think about.

If I had a subby to look at i'd probably focus on how they did their AWD, and more specifically how they have framed the front suspension to handle the load. /end random thoughts i've had on the subject so far.

Well, there are quite a high horse power subbies running around the web. And the one that has an REW in it looks like it came from a combied factory effort of subaru and mazda., really the install is great.

So thats what that hissing wuz!!

lol, i wondered why this thread got resurrected! *Phenoix down*
/and done!

https://www.rx7club.com/attachment.p...5&d=1176439253

Ok, if no-one is saying anything about this then I will.

WTF!

See how far up the engine is? Did no one notice that? Weight distribution must wierd, having the engine after the front wheels and all...

The engine has to be either moved far forward or far backwards to clear the front drive train components. No one has commented on that probably because it was covered in a different thread.