Go Back   Rotary Car Club > Tech Discussion > RX-7 2nd Gen Specific (1986-92)

RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.

Reply
 
Thread Tools Display Modes
Old 08-09-2011, 09:39 PM   #1
My5ABaby
Sigh.....
 
My5ABaby's Avatar
 
Join Date: Feb 2008
Location: Murfreesboro, TN
iTrader: (6)
Posts: 2,377
Rep Power: 19
My5ABaby will become famous soon enough
Default FCD question

Are S4 and S5 FCDs interchangeable?






__________________
1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles

Community Service Manual

RotorWiki

"Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel

Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."
My5ABaby is offline   Reply With Quote
Old 08-10-2011, 01:18 PM   #2
Boosted FC
Rotary & Boost Addict
 
Boosted FC's Avatar
 
Join Date: Feb 2008
Location: Dallas, Ga
iTrader: (0)
Posts: 203
Rep Power: 17
Boosted FC is on a distinguished road
Default

Quote:
Originally Posted by My5ABaby View Post
Are S4 and S5 FCDs interchangeable?
I don't think they are.
__________________


'05 Copper 6s, '87 TII RX7...248whp & 224wtq @ 12lbs
Boosted FC is offline   Reply With Quote
Old 08-11-2011, 09:54 PM   #3
Ender
rotors excite me
 
Ender's Avatar
 
Join Date: Mar 2008
Location: Iowa
iTrader: (3)
Posts: 372
Rep Power: 17
Ender is on a distinguished road
Default

seconded. you might find a store that sells one for each and see if they're the same or not (part number, or send support a question....). Racing Beat might sell them.
__________________
He isn't a killer. He just wins -- thoroughly.


'87 TII
240+ rwhp on my DIY streetport, ~13psi on stock turbo, Racing Beat REVTII exhaust
rTek 2.1 awaits a tune

Quote:
Originally Posted by need RX7
This is why I don't do politics, it's just one stupid thing after another.
360 gamertag: quick Tii
Ender is offline   Reply With Quote
Old 08-12-2011, 07:59 AM   #4
My5ABaby
Sigh.....
 
My5ABaby's Avatar
 
Join Date: Feb 2008
Location: Murfreesboro, TN
iTrader: (6)
Posts: 2,377
Rep Power: 19
My5ABaby will become famous soon enough
Default

Racing Beat lists them differently but HKS (albeit eBay) lists them together. I found an S4 one to use so I'll be fine, but maybe good to know for future reference.
__________________
1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles

Community Service Manual

RotorWiki

"Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel

Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."
My5ABaby is offline   Reply With Quote
Old 08-12-2011, 09:36 AM   #5
RETed
RCC Addict
 
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
iTrader: (1)
Posts: 1,813
Rep Power: 18
RETed will become famous soon enough
Default

Most of them are interchangable unless explicitly stated.
(This info is probably outdated, since I haven't messed with FCD's in years.)
The older Racing Beat ones (metal case) could be used on any model?
The only one that I know that doesn't work is the Trust / GReddy one - this unit is specifically listed as a Kouki FC turbo only application.
Trust me, I tried - I slapped one on my old set-up on my 1987 Turbo II, and it didn't prevent the overboost fuel-cut with the stock ECU. :P


-Ted
__________________
reted_2000@yahoo.com
Technical Advisor
FC3S Pro
http://fc3spro.com/



Quote:
Originally Posted by TitaniumTT View Post
because you're only as good as your backup
RETed is offline   Reply With Quote
Old 08-12-2011, 12:16 PM   #6
My5ABaby
Sigh.....
 
My5ABaby's Avatar
 
Join Date: Feb 2008
Location: Murfreesboro, TN
iTrader: (6)
Posts: 2,377
Rep Power: 19
My5ABaby will become famous soon enough
Default

Quote:
Originally Posted by RETed View Post
Most of them are interchangable unless explicitly stated.
(This info is probably outdated, since I haven't messed with FCD's in years.)
The older Racing Beat ones (metal case) could be used on any model?
The only one that I know that doesn't work is the Trust / GReddy one - this unit is specifically listed as a Kouki FC turbo only application.
Trust me, I tried - I slapped one on my old set-up on my 1987 Turbo II, and it didn't prevent the overboost fuel-cut with the stock ECU. :P


-Ted
Good info.

That's really weird considering how they work. I would think that if one worked, they all would. Perhaps the voltage is slightly different, e.g. 3.6 S4 and 3.7 S5 and the Greddy one activates at 3.65v or something.
__________________
1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles

Community Service Manual

RotorWiki

"Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel

Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."
My5ABaby is offline   Reply With Quote
Old 08-12-2011, 12:51 PM   #7
RETed
RCC Addict
 
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
iTrader: (1)
Posts: 1,813
Rep Power: 18
RETed will become famous soon enough
Default

It's probably due to the design of the FCD itself...

The older Racing Beat units were just resistors inline of the signal.
This basically shifted the overboost fuel-cut point to a higher boost level.
I think I was able to hit it *with* the older Racing Beat FCD at around 18 - 19psi.

Most of the new ones are voltage-clamp design, which just keeps the signal at a predetermined maximum *if* the input voltage exceeds that level.
Since the overboost fuel-cut boost level is different between the FC turbo series, this is why you see specific applications explicitly stated.


-Ted
__________________
reted_2000@yahoo.com
Technical Advisor
FC3S Pro
http://fc3spro.com/



Quote:
Originally Posted by TitaniumTT View Post
because you're only as good as your backup
RETed is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:06 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Hosted by www.GotPlacement.com
Ad Management by RedTyger