Node

iTrader: (1)

Ding Ding Ding
Round One!

Well I figured since the 13B-RE (2 rotor cosmo engine) is almost the exact engine (besides lacking a rotor and some VERY small differences) as its bigger cosmo brother the 20B-REW, that this thread would do best in here.

OK, Well I know that the Cosmo is more of a stepping stone for the FD. It had almost all of the same features on the engine, but some stuff changed as evolution goes.

Here are the differences I've seen and noted so far.


1 Different engine mounts (REW mounts are bolted to the bottom of the end plate. RE mounts are on the side of the middle plate. RE mounts are very similar to FC mounts.)

2 Smaller Turbos in RE (REW has Hitachi 12s, RE has Hitachi 10s)

3 Different Exhaust Manifold

4 Larger Intake Ports in RE (very similar to 20b ports)

5 Intake is about 20% larger on RE

6 RE has smaller exhaust port insert
You can see pictures of it here: https://www.rx7club.com/forum/showth...threadid=53402

7 RE has lower power output of 230hp due to smaller turbos (on account of all cosmos being automatics, and possibly to not outshow the FD in HP figures)

8 RE has larger Throttle Body

9 REW may have stronger/different stationary gears, but I am unsure of this at the moment

10 REW may have better rotor bearings (but I am unsure of this also)


Here is a good thread on the differences
https://www.rx7club.com/forum/showth...ighlight=13bre


I can hope that some of you can alert me to corrections in what I've noted, or tell me of other differences.

Thanks

Node

iTrader: (1)

And here are some things I read from something that Dragon posted:

11 RE front cover uses a distributor type pick up instead of a crank angle sensor like the REW

12 REW has small runners to the Primary Intake Ports and has larger runners going to the Secondary Intake Ports

13 RE has both Primary and Secondary intake manifold runners that are the same size as the Large Secondary Intake Runners on the REW


I think that I interpretted it correctly, but I may have gotten some things confused.

j9fd3s

iTrader: (3)

thats about it, the fd's use the 20b main bearings (nf01 pn) i dont know about the jc 13b (i think it does not).
the jc motors have the aut-o-matic style rear housing, like the fd. the at fd's and the cosmo's share staters.
the power output between the 2 motors (jc 225 and 255 for rew) i think may be because of boost. i think the jc only runs about 8.5 psi and the fd runs 9.5. the jc shares secondary 550cc injectors with the 89+t2's, so 225hp might be about the limit hp wise, they went to bigger injectors when they raised the power. the primaries are both side feed, but they are not the same, the jc ones look like the 89+ fabricated tubes, while the fd uses an aluminum casting. the jc's do have a different insert for the exhaust. the jc 13b's share water pump bolt patterns but the fd uses a different housing on longer studs. the fd is also fully serpentine belts, while the jc is a mix.

mike

j9fd3s

iTrader: (3)

think about this too, mazda designed the 89+ t2 motor, then the 20b then the cosmo's 13b-rew (it is an rew) and then the fd rew motor, and had them all in production in the space of 3 years

mike

Node

iTrader: (1)

does the FD have 550s for primaries and 720s for secondaries?
And aren't all four FD injectors top feed. Oh nm, I see you said that primaries on both REW and RE where side feed.

j9fd3s

iTrader: (3)

the fd had 550 primaries and 850 secondaries. the fd injectors are all side feed, while the cosmo only has side feed primaries, and 550 secondaries

mike

Mister2sw20

whats the difference between side feed and top feed.
I know most people go to top feed for larger injectors and new fuel rails, and it looks like its easier to change them out.

BTW this is Node at a friends house

RETed

20B runs a 3-window slotted stat gear bearing.&nbsp The REW runs a 9-hole stat gear bearing.&nbsp You can argue which is more superior, but most people would rather use the REW ones.

I thought the REW uses the deepest (and widest?) rotor bearing oil groove out of all the bearings out there?&nbsp Hey, j9fd3s, I dunno what you meant by "main bearings", but are you talking about rotor bearings?



-Ted

j9fd3s

iTrader: (3)

i meant the stationary gear bearings. i think i ve read somewhere that they recotoured the fd bearings to match the race ones but ive never seen the 2 side by side.

mike