I snapped a couple shots of what I have in the shop. The first is a 13B-REW from an FD. The second is a 13B-RE from a Cosmo.

 

That's an interesting case you made there Blake. Btw, Can I come live in your shop? I don't eat much, Heh.

 

Curious....I saw a 13BRE in a 85 GSL-SE that someone is trying to sell me...so, as I understand, this motor did NOT come in an 7?

 

Transplanting the 13B-RE into a gen 1 from a Cosmo rather than a REW from a FD is cheaper as these engines are frequently imported from Japan where the Cosmo tends to be scrapped early in life when it loses its status. Thus, several people have gone down that route, but some of them convert to one turbo. There is not as much power as the REW but more than enougth for the lighter SA/FB. It is an intermediate conversion between the 13BT and 13B-REW.

 

Now why would you say that?

 

The stock outputs are 235hp versus 255hp.

I have no direct information as to any difference in power for the engines alone without bolt-ons, but the different port shapes will give unique power curves which I presume Mazda optimized to suit the Cosmo and RX-7. Do you have any information on which has the best potential in a modified situation?

 

Stock power... Okay then.

Take the following information with a grain of salt. It is far from a
specific test/comparison - but it is interesting.

I have a mildly ported Cosmo engine, with FD Exhaust sleeves, and a 20B throttlebody. The large intake tract of the Cosmo actually makes the engine have more Air Capacity than similar setup FD engine.

I ran out of Turbo (63-1) to make 492rwhp at 20.5 psi. The Turbo won't give anymore boost towards redline.

I have a friend with the EXACT same setup:
FD engine/fuel/turbo/intercooler/porting/tune/A/F's/tuner - everything. Except his is an FD with a FD intake manifold.
He was able to make 520 rwhp at the same boost level, before his Turbo
ran out as well.

A difference of almost 30 whp. I discussed with my tuner (Crispeed) and he believes a good % of that power is that the Cosmo has more Air Volume within it. Thus I have more power potential than my FD friend, but I need a larger Turbo to keep the same flow as his. The FD has more velocity due to the smaller intake and runners.

Crispeed also made more power on his Race Car (9.20's in th 1/4) when he
used the Cosmo Intake over the 13BT and FD intakes.

Like I said, it's far from scientific, but it's interesting.

 

i'm not trying to come across as being hopelessly dense here, but just for the sake of clarity, is this confirming that the -RE front cover bolt pattern is the Gen I/Gen II type?

 

[QUOTE=Directfreak
Like I said, it's far from scientific, but it's interesting.[/QUOTE]

The problem is accurate comparison is difficult once you get above 400rwhp. Nearly every project is unique, while there may be a variation in dyno accuracy. Several people have also said the Cosmo design had potential, do you remember Mike-P-28 when we first joined the forum? Unfortunately he sold the car before it was finally sorted out, but then what rotary project is ever finished!

 

It's basically an S5 front cover...they are interchangable. S4 and S5 differ by a by an additional bolt hole, but you can get away with swapping them. S5 water pumps don't work with S4 front covers. Turbo and NA differ by a drain hole, but the NAs have the casting so you can drill them out. The usual stuff.

 

what are the exhaust sleeves?( not to sound like a noob)

 

I used the the stock GSL-SE front cover along with a TII (aluminum) water pump.
Every bolt and hole lined up perfectly. Just like a stock GSL-SE engine.

 

i am goign to add this the haltech E8 or E8X?

 

thanks. i didn't even know that the S5 engines had the additional hole, too. i knew about it on the -REW and that's why i was so curious about the -RE.

thanks, Alex. i figured they all lined up, but i was a bit worried about leaking at the extra hole. i take it you haven't had a leaking problem with yours? i'm not a huge fan of ham-fisted RTV use, but if that's what it will take then i'm sure i'll live.

 

D'oh! Wait a minute...I was thinking -REW. S4 and S5 have the same number of front cover bolts, though there are other minor differences. The extra bolt hole came later. Sorry. And, the -RE is the same as the S4/S5; not the -REW in that respect.

 

okay ... i guess there are no worries then. thanks.