I'm new to 20b's but have been a rotard for 30 years. I still have my 75 RX4, 82 GSL, 85 GSL-SE, 87 TII, 91 vert, and a few parts cars.

Recently two Eunos Cosmo 20b front clips have come my way and I want to make an FC 20b driver. I am not planning to race the car (very hard or often) and want to hold the costs down as much as possible by keeping it an automatic and reuseing, when possible, all the original parts from the Cosmo. I do not plan to upgrade the ecu or turbos at this point in time or do any porting or other modifications to the internals; just keep it close to stock for now.

I've been following the bumpsteer thread but it seems to be weighted to FD's.

I understand that one may upgrade many items on the FC inorder to handle the increase in power that the 20b delivers, but again, I want to reuse the parts at hand from the 20b clip and the FC platform.

What are the "have to change/modify" and what can be reused from the Eunos Cosmo clip and the S4 TII or S5 vert?

 

i'm not positive on all the fc stuff since mine is going in an fd, but if you just got a front clip and need an engine harness (i dont see them often), there is an un-cut one on ebay right now. $115, buy it now is at $230. just trying to help, here's the url:
http://cgi.ebay.com/ebaymotors/ws/eB...sPageName=WDVW

 

For starters put the 20b in a Turbo II chassis because of it's stronger transmission.

Other parts are:

1. Aftermarket Flywheel and clutch(no counter weight needed because it's already on the engine).

2. Aftermarket engine mounts.(search the stickies in the 20b section for the Fc mounts).

3. Upgraded radiator.

4. IC piping to fit the Cosmo IC

There are other things but I'm not sure. I know more or less what to do with the Fd conversion.

 

Thank you Paximus and t-von for taking the time and effort to try to help.

The front clips are complete.

Harnesses and transmissions are all there as well as the Cosmo 20b engine mounts, radiators, and intercoolers.

I'm not planning to use the TII tranny because I plan to use the Cosmo automatic transmissions. I also expect to need custom tranny mounts and support brackets.

The engine ecu's are there as well as the transmission ecu's.

Both have the front suspension, dash and gauges.

I know it would be necessary to make sure that the radiators are flow tested, at a minimum, and replaced if they are bad or will not fit in the FC engine bay.

I imagine I will need to have a drive shaft built or have the TII one modified.

Will the rear ends need to be beefed up or can the TII LSD handle the increase that a stock 20b will deliver? Not knowing much about the Mazda 929, but hearing that they have some relationship to the Cosmo, would their rear ends be any stronger/better than an FC TII's?

Not having the front clips yet, I have not been able to look at the subframe in them. Will it be necessary to have one built/bought or can a stock Cosmo subframe be modified to fit and work in an FC? Engine mounts wear out as a normal concequence of driving and depending on the condition of the stock ones, new ones may very well be in order.

What kind of fuel pumping pressure and flow will be needed?

Are the FC fuel lines too restrictive for the needed 20b fuel delivery and return?

The battery relocation should not be too big a deal. There seems to be enough space in the compartments behind the seats to relocate it there. And the newer battery technology has smaller batteries with ample cranking power.

I know the devil is in the details, so any detailed advice is welcome.

Is anyone aware of someone that has done this "stock swap" to FC before?

I realize that most 20b swaps have a lot of customizations done to the engine and manual tranny's, but I am still planning to keep it as close to stock 20b as possible. It may not be as nimble or as fast or as reliable as a teardown and rebuild but that's my goal for now.

 

hope this helps... http://fc3spro.com/TECH/SWAP/COSMO/20b.html

 

You are really wasting your time trying to run the 20B stock at it's stock power levels and keeping the stock ECU and auto trans.

You're better off building a 400hp 13BT...
Cheaper and faster.


-Ted

 

gotta agree. . .keeping it stock is not the way to go. the auto tranny sucks, and you have to use EVERYTHING on the cosmo to use the ecu including emissions and other power limiting crap.

if you're going 20b, you've got to accept the fact that you're gonna spend AT LEAST 10K. . .AT LEAST. no matter what.

for cost effectiveness and lower horespower goals, definitely build a 13BT.

 

you will need to have a drive shaft built or have the TII one modified ONLY if the tail end of the 20B tranny is in a different location, but you might be able to keep this the same as the FC setup if you can live with the 20B motor reaching farther in the engine bay than the 13B does... it wont be too bad.

the TII LSD can definitely handle the increase that a stock 20b will deliver. the 1987-1988 TII LSD is the one you want for ultimate strength and durability but in your case of a totally stock 20B you could probably even get away with a N/A LSD rear end.

I would guess you'd need some mounting plates/stuff made up but I dunno... just a guess.

The FC fuel lines are NOT too restrictive for the needed 20b fuel delivery and return. I used the stock FC lines on my LS1 V8 swap with 330hp/350tq and fuel pressures at 60psi (constant pressure).

The battery relocation is not a big deal at all. I put mine in the pass. compartment and it fits like a charm... wiring was simple and the weight is in a much better location.

I dont think any guys run a 20B in stock form in an FC, there might be a few but good luck finding them... once you get that nice of a motor in the car you'll want to upgrade everything and costs just skyrocket.

 

Ted,

Thanks for taking the time to respond.

If I wanted a 400 hp engine in an FC, I'd just upgrade the small block chevy I have in my 88 GXL. https://www.rx7club.com/nw-rx-7-forum-33/88-gxl-chevy-v8-408671/

If I did a 400 hp 13BT, it would probably be lots faster than an FC w/stock 20b; but it still wouldn't be a 20b.

One mans waste is another mans treasure.

 

I think I understand where your comming from. We tend to do the things we want regardless of it being necessary or not.

 

So you want to do a 20B just because it's a 20B? Welcome to the club! I agree with everyone else that you shouldn't try to use the factory stuff. Just because it was originally in a luxury car doesn't mean you can't use a manual tranny and a large single turbo along with a tuneable aftermarket ECU. The engine will be so much better for it.

 

Thanks guys.

I guess I have to stick my fingers in the fire to learn that it's actually hot.

 

Hoof Hearted,

I have been playing with the cosmo chassis, and the 20b's for about 8 years now, and I will give you the best info I can.

go stand alone. I have wrestled with the stock ECU and all of its problems, and thats why I am parting out my cosmo because I am tired of the cash outlay required for anything associated with the 20b (hence my car being on ebay at the same time as the one you bought).

You will need to take the entire dash and all of its wiring, as it all plugs in through the TV screen, AT computer, AC computer, and the main ECU. (I am not bsing you) it all ties in to control engine RPM and load depending upon AC setting, and electrical demand (ac is controlled through the TV screen thats why you need it, and all of its associated parts to complete the circuit. the computer will go into limp mode if it does not see all of the computers hooked up and operating.
thats why everybody is reccomending you go standalone, even if you use the stock turbos.

you could cheat and use a 5 speed, and then send the ECU out to RE Amemiya or Pan speed, then can reburn the ECU to ignore the required auto tranny inputs, and AC-Alternator inputs that would probably be your easiest option, but you will still need the stock MAF and all stock boost sensors (CPU reburn will set you back about 1800 from japan)

the Cheapest option and I am honest here is a heltech, you could keep the stock injectors, sensors use the tranny out of your FC, tune it to stock boost and you would not have to upgrade nearly as much stuff. but that would limit you to about 300 HP.

kenn AKA mackthefatcat

 

i would say follow kenns advise.
but as far as stock 20b autos and ecus, a guy in canada did it, had a 10thae....hmmm what was his name. it was now i think. like "now". you can get mounts from quite a few people now. some are around $250, but you might want to research if any have any downfalls.
other than that save the automatic counterweight from the 20b. this will enable you to use any aftermarket T2 flywheel and clutch.

 

Yep, now is his name. I remember following his progress a couple years ago.

 

Whether I go stock or modified, will I need to have a stronger subframe for the FC or not?

 

Don't worry about the engine subframe unless you're making 600+ hp.
It tends to break everything else before that.


-Ted

 

Can I use the engine mounts from a stock cosmo or do I need to have custom ones?

 

Gotta go custom to fit it to the FC.

And as the others have said...

Dump the factory computer and automatic.

Go TII and stand alone.
You will still smell hell getting it all together.. BUT NOTHING like making the auto work properly.

There are a couple out there that thought as an electrical engineer that making the auto and factory ecu work was gonna be a breeze.....Well it WASNT. They took from a year to two IIRC. IIRC they both said they would junk the original ECU etc the first sign of a hiccup.

Listen to Ted. He HAS done most of the stuf to some degree or another. Not simply re-gurgitating info. Not that the other replies were.. but he really does know a thing or two.. and isnt just a internet poster. He gets his hands dirty.

 

Maybe I missing the piece that makes it all fit together about not using the stock setup from a 20b Eunos Cosmo. Is the stock Eunos Cosmo vehicle a dog? What are its flaws beside its not being fast enough for most rotary enthusiasts?

I listen to all the recommendations to junk the stock auto/ecu and go custom...but I have not heard the answer that makes sense to me yet.

I just don't get it yet.

If I am not too concerned about big horse power or racing, and I have everything from a stock 20b Eunos Cosmo (front clip, bumper to tranny), what is it that is the inherient problem with dumping it into an FC TII?

I may be crazy, but I'm not stupid. Help me understand why it won't work.

p.s. What is IIRC?

 

Stock Cosmo dyno:
https://www.rx7club.com/attachment.p...postid=1819419

It is a real pain to set up, and it is not capable of much performance, as seen in the above dyno. For the time you would spend rigging the stock ECU and/or auto transmission to work, you could have just worked at Burger King in your spare time and bought yourself a standalone EMS and coil packs that could produce over 400hp with the stock engine and turbos.

Here are some views on the subject:

https://www.rx7club.com/showpost.php...79&postcount=2

https://www.rx7club.com/showpost.php...09&postcount=3

http://www.computeruser.com/resource...nary/chat.html

 

EA,

Thanks for taking the time to help me understand.

I'm beginning to see but it is still not crystal clear yet.

1) There are limitations with the stock ecu and coils that don't let the 20b reach its potential hp/torq.

2) It is difficult to install all the components from the stock Eunos Cosmo into an FC.

3) Without the correct signals from the auto trans computer & all the other sensors you are going to detach.

OK.

If I am not concerned with the lack of hp/torq from a stock setup; then 1) above, is not a problem with me now. It may become one after I discover I want more hp/torq, but for now lets assume it is not a big deal to me.

Not knowing what specifically is "difficult to install all the components..."; I can not argue against that point. I will either discover them myself or learn from others experience of the specific difficulties.

If all the original sensors and parts are used from the Eunos Cosmo 20b, should I expect to "detatch"? Whatever detatch means, I can only guess at.

Again, I do appreciate you all wanting to see me do the right thing, I just need to understand it all clearer and resolve it in my own mind.

Thanks again.

 

IIRC If I Remember Correctly

Anyhow.. sorry if I ramble.. been a long day and got a race this weekend.

Some of the problems that are circumnavigable are things like the exhaust being monitored/controlled by the ECUs... they have cut outs that kick in at a speed.. IIRC 60 or something..
There are ECU's in the trunk as well IIRC..

The LARGEST problem as mentioned above that you seem to have missed...
EVERY COMPONENT must be connected to the ECU or it goes into LIMP MODE.
You will have no performance at all.
You are talking about putting $10K motor that will generate appx 220 to the wheels.
If you run the stock ecu and assorted hardware.

PLUS you will need to defeat the multitude of sensors and ecu's that will not be seen when you try to get it to operate peoperly. THat=TIME... a LOT of it. As well as knowledge that just isnt out there to pull from. There are a lot of tidbits of little things that will get you sorta there.. if you can find them.. 99.9 percent of the forum has no idea what these little things are. The IIRC TWO people that did a stock ECU successfully would prolly be good sources.... However I imagine after the year+ of hell they each went through I am pretty sure they dont wanna do the same for you.

But if you REALLY wanna put the aautomatic and the stock tranny in there.. go for it. Just dont expect people to magically snap off answers to problems no-one can answer.
The problems you will encounter are going to be jewels of mystery.. that will be a wonderful thing to fix.. if you can.. when you can. ANd the sense of accomplishment of being one of THREE.. will be wonderful.... Just plan for a year or so for the electrical.

OR.. you could spend X months to mate it up to a Manual and a stand alone ECU.. and cut out all the stock mating and troubleshooting. And have your car running in 6 months instead of several years.

Not trying to be a dick or anything.. just trying to give you a realistic idea of the project you are taking on. It is NOT a simple swap keeping the stock hardware. Not even remotely. Not even for a second.

Now all that said...

USE SEARCH.

A TON of the questions you are asking about subframes and mounts.. and ecu's and trannies etc etc etc are ALL out there if you spend a few minutes to couple hours searching the 20B forum for starters.. Then broden the search to peoples websites.. Start at the link Ted listed. You may wanna read up before you start.. as the subframe would be the FIRST thing you should know about before even buying the engine.... Cart before the horse and all that.

Night.. have to get up early to load the car and trailer.

Remember.. not trying to be a dick.. just realistic.

 

SPiN Racing,

Thanks, I appreciate the input.

I've done more searches and I still have a few questions.

Is the Motec m600 ecu the type I should be looking for? From what I've gathered the M600 3D is "sequential (6 ign groups / 6 inj. groups) STD". Does this mean that it can handle the 20b without needing one computer to run fuel and leading plugs, and one to run the trailing ignition?

The Haltech information I found inferred that you run a computer for leading, and a separate one for trailing (IG4), but there is a newer Haltech E11V2 which also appears to have the features needed for the 20b.

The Motec has a bunch of options like single wide-band lambda control option, dual wide-band lambda control option, advanced functions option, drive by wire option, over run boost (anti-lag) option, and a 512 Kb logging only option.

The Haltech price was lower, but is it a better value?

I'm now thinking of taking my 87 TII with zero miles on the rebuilt engine; selling the engine and using the corpse for the 20b.

An old post of Evil-Aviator, IIRC, said if he were to do it over again, he would keep the stock turbos and do the ecu upgrade (sorry EA if I butchered your advice).

 

The Microtech LT12 was recommended to me last night as a simplier setup than the Motech.