Differences between the fc 13b and the fd.

[Brett]

I agree with you Grizzly, but over the past couple of years the FC has all but dissappeared fromt he UK roads, so those that are left are usually not too bad.  As for the FD - all I have to say is why o why did Mazda install that lovely rust trap called a power plant frame/brace?

[RotorHeid]

Grizzly, that\'s true about structual flame work., only in UK which\'s bad cos of salt on road in winter!.
 mine\'s store in shed until summer!
1st/2nd gen\'s more classic than 3rd gen cos it\'s racing pregreed!( spelling)

[Grizzly]

Yeh my Fd is really Classic at the Moment,i just blew the Motor in it about 30 mins ago.

I got a Question, Do Fd\'s Burn well!!!:mad:

[shaunwil]

How heavy is the donor car without engine ? I thought you where thinking about one in a 1st gen, I\'ve been impressed with the performance if an EGI 13b in the runaround

Shaun

[shaunwil]

Sorry to hear about the car, Major failure ??

I would say every time I see a mate with his sierra cossie he\'s always repairing it, the fd is more reliable at the moment.

The other question is what other engine fits

Shaun

[Grizzly]

Yeh afraid so, first thing i did was pull the plug out of the rear and turn it over, No comp at all so its goosed.

As for the engine transplant, i would be thinking about what i\'m going to use it for?? the only thing the rotary does well is track work, its not got the Torque for Drag and it gets a bit Unreliable at high Rpm for long periods (drift) but all said a rotary has a low COG which means you can mount it lower in the car and it has a Knock on effect (makes it handle better)

[mr.bishi]

OOps didn\'t read the thread properly.

For the love of God DON\'T use a Rotary as a transplant motor into a Heavy shell. .

The car weighs 940kg in standard trim with the cast block pushrod 1600 in it.....Less than my sa22c.

Thanks for your replys anyway.....Don\'t fear the rust people,embrace it!

[mr.bishi]

Differences:
 
13BT mounts are in the centre of the engine, on the 13B-REW they are on the rear housing.
 
13B-REW has better (more) oil passages and water ways so cooling is better
 
The 13B-REW castings are stronger - so utimately will take more power
 
The LIM (lower inlet Manifold) and UIM (upper inlet manifold) are different and the porting wider on the 13B-REW

Are they front or rear sumped?

[Grizzly]

The other question is what other engine fits

I had a look about and i\'d have to say the sr20det looks most promising if you can get one at the right money.

[m4drx]

Thanks for your replys anyway.....Don\'t fear the rust people,embrace it!

you keep saying that to yourself.............












and the mot people.

[Grizzly]

Are they front or rear sumped?

There all sumped in the same place (under the engine )

Ok.

The Four Variations of the turbo 13b, the 13Bt (as found in the T2 came in the S4 low comp and the S5),the 13bRe (this is found in the Cosmo) and the 13b-rew (found in the FD)

13bt Con\'s.
right this part you have to understand a Rotary designed in a manner where very little Twist can cause quite alot of Damage, The thing is the S4 and s5\'s main problem was they used the center plate to mount the engine so it was possible in theory for high hp cars to crack the rear plate where the Dowls locate the Rotor housing, this problem was worse on the S4 as the S5 had better rear plates to handle the Gearbox twist. The 13bt also has the Smallest Ports/Runners of the family (excludes the Primary inlet manifold runners for some reason being bigger then the FD??) the Inlet also included a Plenum so all of the Primary and secondary port Runners opened at the same time of a two stage Throttle body.
But the Biggest Con that springs to mind is the three peice Apex seals, I know they where trying to make a seal that sealed really well but if you can Imagen the seal is split down its length so the part with the biggest load (the bit that bridges the Rotor to the Rotor housing) is only using half the area it could have been, so what happens is the thinner Apex rounds off the corners on the Rotor then after a bit of time falls out killing the Motor and often the Turbo to.

13bt Pro\'s
The main pro that springs to mind is the S4\'s low Compression rotors which are the weapon of choice for the guys who run big BHP Hybrid Motors, I believe the S5 engine was the first to bring in Hardened Stationary gears which reduces the risks of a Failure when you start to raise the power. This option is properly the cheapest to get hold of, there are lots of T2\'s out there that suffer badly from structural rust and you can pick the hole car up quite cheap.



13b-re Con\'s
Realistically this one is not really an option.
Parts are becoming rare and as such expensive, there are not allot of Cosmo\'s left out there and i would be surprised if Mazda still made parts for them, the Enthusiast\'s would say Don\'t use this Motor because its like an Endangered species, so you may get looked at a bit funny by the Cosmo guys (maybe not as much as if you put a 20b in there though)  

13b-re Pro\'s
Of all the 13b Turbo series the RE/Cosmo was designed more as a Tourer there for they tried making the runners/Ports bigger in an attempt to get more torque for a smoother ride, but of course this was a big advantage if you wanted to bolt a Big turbo on the side so allot where used in High hp Hybrid Motors or T2 conversions (they use the same center mounts but with a strong rear Plate)

13b-rew Con\'s
The one that jumps out at me is the Seq Turbo set up/Vac assembly to run it, The idea is Sound and don\'t get me wrong when it works properly it makes the Fd drive like no other car i\'ve ever driven but there are so many Rubber pipes and Solenoids on a Motor thats Turbo\'d and runs warmer than most similar Piston motors in its class, what happens is the Pipes Dry out and crack causing boost leaks and Turbo spooling faults and all sorts of Problems. I would have to also say parts are expensive (they fall somewhere between the  13b-re and the 13bt)

13b-rew Pro\'s
Now next to the other 13b\'s i\'m not sure where to start, The FD was always going to be the "Track Day" car of the Rx7 Family so they have built it with fast Turbo response in mind with its Split Small Inlet Runners (the Primary and secondary Port Runners are kept separate and the Rew doesn\'t use a Plenum), Next the oil system had some revamp work done, the stationary gear bearing where changed in favor of the High performance Window bearings, the oil system also benefited from a Baffled Sump and higher Pressure oil regulators and i believe (not 100% on this) the Oil pump its self was Upgraded  as well as the main oil Galleries, Then there is the Fuel system where the earlier 13b\'s used 550cc top feed injectors all round the Rew used 2x 550 and 2x 850\'s which with a bigger fuel pump made the stock out of the box power go up from 200hp for the 13bt to 260 for the "out of the box" car and as you can properly tell the fuel system/Engine management on the FD was far superior mainly because of the massive R&D that was involved in the Fd.  

 
So having owned them all (well bar the S4) and rebuilt them, 300hp being the goal and it also depends allot on your Budget, if you where set on using the 13b i\'d personally aim for the Rew as it would be a very easy 300hp (it wouldn\'t take a to much to make that 300rwhp on stock Turbo\'s) but you have to look at what exactly you want?? if its just 300hp the 13bt will do that all day with minor mods and cost half what the Rew swap would but the REW is more expandable and it may be argued a better motor (due to evolution )

[mr.bishi]

There all sumped in the same place (under the engine )

Great info.....but,is the sump part of the oil pan at the front of the engine,middle of the engine or rear of the engine? You know,the hangy downy bit where the oil sits when not in use.

It\'s crucial to fitting the engine with my existing crossmember and steering rack you see

My other engine options are the sr20det,but it has to be out of the s13 silvia k\'s because of the sump position.

The ca18det which is pretty straight forward

Or keep it in the family and use either the 3s-gte from the gt4/mr2 turbo which is a bit of a mare to fit,or the rarer but easier to fit 3s-ge beams black top from the rs200 altezza which will apparently take a supercharged 300bhp on standard internals.

I figure the 13bt would be nice because i can keep it well back and low in the engine bay to reduce understeer and get better weight distribution and a lower c.o.g

[Grizzly]

Ok, the sump is basically covers 3/4 of the bottom of the engine an is approx 2.5-3" deep, I would say the T2 and FD are roughly the same size and shape but the T2 sump has a large section cut out so the center engine mount can bolt to the Plate. As you can see from the Pics below the Sump isn\'t that big and could be cut and Modified as its only Tin.

http://s32.photobucket.com/albums/d26/Grizzly30/?action=view¤t=Picture027.jpg

http://s32.photobucket.com/albums/d26/Grizzly30/?action=view¤t=Picture028.jpg

[mr.bishi]

Hmmmm,that looks to be right where my original crossmenber will be....



Thanks

[shaunwil]

You forgot about another option, Use a 12a front cover and a GSL Sump on a FC  13b engine. Although looking at the photos not sure if it will help at all !

Shaun