My Car


How To





Proj. Cosmo

Nate Bowen

Arturo Chia

Old Updates

Project Cosmo Pictures now on a different page.   CLICK HERE:)

Bad Center Housing

Good Center Housing

Bad Rotor

Dented Rotor Pic 1

Dented Rotor Pic 2

Kanji on Rotor

FD Port

Cosmo Port

Side Port Comparison

Top Comparison

I have created this page to somewhat document my trials and tribulations of my engine swap project from a 1990 Turbo motor to a 1993 13BTT Cosmo motor.  I do not have a Redwood money tree in my back yard and I have other, more important things, to save money for so this project will try to use as many stock parts as possible.  I will be keeping the twin turbos that came with the engine and run them non-sequential via my Haltech.  Running them sequentially would be too much of a pain and would leave a bunch of solenoids and vacuum lines on my engine and make it a mess.  I like things simple and the non sequential modification does exactly that.  So with that in mind, here are some notes and pictures for you to enjoy, at least I hope you do.

Latest Updates:

Well, I have not updated this in quite a while so I thought it would be a good idea to:) Somewhere around the end of May I got the intercool plumbing finished so the car was fully turbocharged! When I left the car was running great for the most part and on low boost, about 5.5 psi I was getting 210 rwhp with about 190 rwtq. While this was not exactly what I was looking for it was nice none the less since my car actually worked! It was reliable, never overheated, and ran nicely. The boost controller does not seem to be working right, probably because I did not reset it, and the wastegate seems to be sticking occasionally so I need to fix that. Right now I am still in Japan so the car is resting at my mom's house but when I get back I will finish some of the things I kind of half-assed as well as tune it better so it runs smoother and with more POWER!

Now, if anyone is wondering whether or not you can fit a Cosmo 13BTT into a 2nd gen body without major cutting and hammering, you CAN. It FITS. Period:)

Take it easy!

Old Updates:

As of Sunday, May 13th Project Cosmo has become road worthy.  Some of you may remember me having an oil leak from the OMP block off plate and I realized that the plate was not even covering the hole completely so I turned the plate sideways and trimmed it and then slapped some JB Weld on there and then an aluminum plate so now it will NEVER leak:)  I also tightend up a few bolts here and there to fix a few more leaks and then I tested the cooling system and installed my electronic fan controlled by the Haltech.  The fan works great now and the car stays nice and cool so the cooling system is working just dandy as well.  I have no boost right now because I need to plumb the intercooler and my little test pipe didn't work and I also think my stock BOV is not sealing properly so I am loosing boost.  Soon I will have things all worked out but for now, I am happy to be able to drive it:D

I do not know if the engine will fit with the twin turbos because I have heard both sides of the argument and I have not test fit the engine yet so I can't tell you for sure.

If you are running a manual tranny, if you aren't SHAME on you, you will need to change the flexplate to a flywheel and clutch.  If you are buying a lightweight flywheel you should get a counterweight with it that you have to use.  If you go that route you will NOT!  I repeat NOT, need to remove the 54mm shaft nut, whoa getting personal again, and that WAS a PAIN IN THE BUTT!  Did I say it was a PAIN?  Just making sure because I removed it for NO REASON.  The clutch and the flexplate are held on by 6 bolts, NOT the 54mm nut.  I cannot recommend using a stock flywheel from a different year motor because the counterweight is stuck on the flywheel and I am not sure if it would balance correctly.   If you get a lightweight flywheel from a different year Rx-7, you can use the auto counterweight that is on the Cosmo motor.  I have not tested this out but 3 very prominent tuers have told me that it will be fine with my OS Giken Twin Plate clutch with a 12# flywheel.

You will need to make new motor mounts because the 3rd gen and Cosmo motors have the mounts on the rear endplate and housing.

More notes:)  86-88 turbo water pump housing will fit but there is only about 1mm of room for the hose to attach between the stock turbos and the turbo coolant return hose and the lower radiator hose so we will see if I can make them fit:).  The Cosmo water pump will NOT fit the 86-88 housing!  Damn engineers:)  I did the TB mod so the turbo coolant sending line is the one that used to go to the TB.  The 1990 turbo tranny fits fine but has one less bolt to hook up because the stock drivers side mount for the Cosmo was acting as a bolt hole and since I do not use the stock mount, I do not have that hole.  This should not be a problem, however, you will need to block off the hole that the old mount covered.

Even more:)  If you plan on making your own better oil cooler lines you can order the metric to AN fittings through Racing Beat and get 1 16mm and 3 18mm to 10 AN adapters.  The part #'s SHOULD be 11901 (1) and 11902 (3) but they were messed up when I ordered so make sure to tell them you want 1 16mm for the front housing and 3 18mm for the rear housing and the 2 oil cooler hook-ups.   Then you SHOULD get new washers or use your old ones for the cooler and put some sealant on the threads which is what I will do because I am getting lazy.  Then order 6' (will have extra) of Aeroquip -10 AN stainless steel braided hose (http://www.bakerprecision.com/earls1.htm) from Baker Precision and some Aeroquip fittings (http://www.bakerprecision.com/aqp5.htm).   Get 3 90° -10 AN fittings and 1 60° -10 AN fitting if they have it, if not get a 45° fitting.  Then thread the small 16mm into the front cover and tighten and then one 18mm into the rear housing and the others into the oil cooler.  Cut the hose to length and follow the directions on how to hook up the fittings (http://www.bakerprecision.com/aqp12a.htm).

And more:  Paul Ko and Quartermaster recommended using a "radiused" TO bearing rather than the stock version because the stock can bind and not put even pressure on the pressure plate.  I have ordered the Quartermaster TO bearing and collar from my local dealer but you can find a dealer near you by calling them, Quartermaster.

And more: Well, I did some more work and found out a few things.  First it would be a good idea to relocate your battery, as I kind of descibe here, becuase the IC piping will fit easier if you want to leave it stock Cosmo style rather than cutting it.   Also, if you are running the stock twins with a modified water pump housing you will need a lower radiator hose because the old one doesn't fit.  Another problem I ran into was the clutch fan and the stock fan shroud.  I think it is because of my mounts being low and slightly to the side because I have seen swaps that use the mechanical fan just fine!  It is too far to the passenger side of the engine so I got an electric fan. I have not yet installed the radiused bearing because the motor is already in but I have a feeling I will need to soon because it is physically longer and my stock one may not disengage the clutch all of the way.  I will find out soon.

And more:  Here is the 1993 Cosmo CAS wiring info below as well as the J&S Wiring on a 1990 T2 ignition (should be the same for all 2nd generation cars, a.k.a. Series 4 and 5.

Inside CAS wires.Cosmo CAS wires.Haltech wires.
RedBlackYellow (Trigger)
WhiteGreenRed (Input B)
GreenWhiteGreen (Home)
White/BlackRedBlue (Input A)

Some random part numbers.

  • "Radiused" TO bearing = 236520
  • TO bearing = G561-16-5108 "Clutch Release Collar"
  • Pilot Bearing = N326-11-D03 "Needle Bearing"
  • Oil Seal = 1881-11-404 "Oil Seal"