2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Differences between s4/s5 and NA/turbo irons

Old 01-09-06, 03:21 PM
  #1  
Lives on the Forum
Thread Starter
iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,509
Received 1 Like on 1 Post
Differences between s4/s5 and NA/turbo irons

In case you don't know form my other posts, I'm going to be rebuilding my engine in the near future and I'm trying to get everything sorted out now so I know what to buy/get.
First of all, last time my engine was rebuilt, I was told by the first rebuilder that TII center irons would give me more power because the ports are bigger. Is this true, or BS? And if it is true, would it give me more high-end power at the expense of low-end power?
Second, what are the differeneces between s4 and s5 irons? I have a friend who is putting a v8 in his low milage s5 and he is probably going to give me the engine. I have no idea what condition mine are in, but I'm expecting the worst. I think the port openings going to the LIM might be different sizes, but I'm not sure about other differences.
Thanks in advance.
Sideways7 is offline  
Old 01-09-06, 04:29 PM
  #2  
Crash Auto?Fix Auto.
iTrader: (3)
 
classicauto's Avatar
 
Join Date: May 2003
Location: Hagersville Ontario
Posts: 7,830
Likes: 0
Received 1 Like on 1 Post
so do you want to use series 5 irons with series 4 rotating assembly?
classicauto is offline  
Old 01-09-06, 04:35 PM
  #3  
Carter 2.0
10 Year Member
 
jhammons01's Avatar
 
Join Date: Jun 2004
Location: Irvine Ca.
Posts: 6,263
Likes: 0
Received 0 Likes on 0 Posts
the only thing I have ever found is the front irons have a different milled area for an oil o-ring. Mazdatrix has a complete write-up pointing out the two and how to avoid loosing the o-ring after rebuilds. Once you read it you'll be able to identify the two different ones.

dDub also had something on his web page.

if you install the oil o-ring incorrectly or use the S5 o-ring on an S4 iron. The o-ring can move and cause you to have low oil pressure for a seemingly unknown reason.
jhammons01 is offline  
Old 01-09-06, 04:38 PM
  #4  
Lives on the Forum
Thread Starter
iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,509
Received 1 Like on 1 Post
Originally Posted by classicauto
so do you want to use series 5 irons with series 4 rotating assembly?
Actually I plan on using s5 rotors and was wondering about the irons in case mine were toast.
Sideways7 is offline  
Old 01-09-06, 04:39 PM
  #5  
Sharp Claws
iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,135
Likes: 0
Received 14 Likes on 13 Posts
T2 irons are 4 port and n/a irons are 6 port so unless you do a full conversion it won't work. the T2 middle iron does have a slightly larger port, the difference is a tradeoff of low end torque for upper end power but the differences should be slight.

it wasn't said if it was a turbo motor but the only difference in n/a is like Jhammons said, the front cover o-ring milling is slightly deeper on an s5.

Last edited by RotaryEvolution; 01-09-06 at 04:42 PM.
RotaryEvolution is offline  
Old 01-09-06, 04:46 PM
  #6  
Lives on the Forum
Thread Starter
iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,509
Received 1 Like on 1 Post
Its an NA motor. So I guess I'll just stick with what I have. It only ran with a popped seal for about 3 seconds, so hopefully the irons are fine. I'm planning on just buying new rotor housings. I'm prob going to get TII housings so they are easier to port and Ill just plug the coolant hole.
Sideways7 is offline  
Old 01-09-06, 04:50 PM
  #7  
Sharp Claws
iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,135
Likes: 0
Received 14 Likes on 13 Posts
you can use the irons, just use a slightly thicker o-ring for the oil pump feed line seal. with this setup you will have no EGR though and the EGR passage below the intake ports on the middle T2 iron will need to be sealed.
RotaryEvolution is offline  
Old 01-09-06, 05:00 PM
  #8  
Lives on the Forum
Thread Starter
iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,509
Received 1 Like on 1 Post
Well, this was mainly a just in case question. Its also a last ditch effort because my current irons have a street port.
Also, thank you very much for mentioning the front seal problem. I just read the page on the mazdatrix website and it was very good info, as I prob would have done it the wrong way. That also could have been the cause of my oil pressure problem. I had no oil pressure at idle, but I always thought it was a problem with the sender unit. I hope thats not the case because I might have more internal wear than I thought....
Sideways7 is offline  
Old 01-09-06, 05:59 PM
  #9  
Passing life by
5 Year Member
 
iceblue's Avatar
 
Join Date: Feb 2005
Location: Scotland, USA
Posts: 4,028
Likes: 0
Received 0 Likes on 0 Posts
S5 to S4 - S5 front IRON has a larger front oring casting and S5 front and rear had a larger port runner 1/8in and the port timing opens 10* later. S5 temp sensor hole is larger. S5 rear IRONS some were the same some had triangular reinforcement on the oil pedastool dowl, some had a larger casting same as the REW with the reinforcement.

The TII intermittent Iron P port is much larger then NA it opens earlier and closes later. This will increase top end HP and lower your TQ. However the port runners are identical. If you port the motor this will mean nothing. However if you have a USDM Iron the S4 will have a EGR valve and the S5 will not. The S5 TII wil also have a knock sensor on it.

All Irons are interchangeable though as well as housings.
iceblue is offline  
Old 01-09-06, 07:17 PM
  #10  
Lives on the Forum
Thread Starter
iTrader: (7)
 
Sideways7's Avatar
 
Join Date: Dec 2003
Location: Temple, Texas (Central)
Posts: 6,509
Received 1 Like on 1 Post
So basically any differences would be negated with porting, correct?
Sideways7 is offline  
Old 01-09-06, 07:57 PM
  #11  
Passing life by
5 Year Member
 
iceblue's Avatar
 
Join Date: Feb 2005
Location: Scotland, USA
Posts: 4,028
Likes: 0
Received 0 Likes on 0 Posts
Correct.

The S5 TII wil also have a knock sensor on it.
Should read
The S4 TII will also have a knock sensor on it.

Last edited by iceblue; 01-09-06 at 08:11 PM. Reason: Messed it up again lol
iceblue is offline  
Old 01-09-06, 08:02 PM
  #12  
Sharp Claws
iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,135
Likes: 0
Received 14 Likes on 13 Posts
what series aside from REW isn't threaded for a knock sensor in the middle iron?
RotaryEvolution is offline  
Old 01-09-06, 08:10 PM
  #13  
Passing life by
5 Year Member
 
iceblue's Avatar
 
Join Date: Feb 2005
Location: Scotland, USA
Posts: 4,028
Likes: 0
Received 0 Likes on 0 Posts
what series aside from REW isn't threaded for a knock sensor in the middle iron?
S4 is in the INT iron and S5 is on the front.
iceblue is offline  
Old 01-09-06, 08:13 PM
  #14  
Sharp Claws
iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,135
Likes: 0
Received 14 Likes on 13 Posts
front rotor housing but the middle iron can still accomodate the sensor.
RotaryEvolution is offline  
Old 01-09-06, 08:15 PM
  #15  
Passing life by
5 Year Member
 
iceblue's Avatar
 
Join Date: Feb 2005
Location: Scotland, USA
Posts: 4,028
Likes: 0
Received 0 Likes on 0 Posts
Can it? I think I should get me a S5 to take apart :-)
iceblue is offline  
Old 03-12-15, 12:00 PM
  #16  
Full Member
iTrader: (2)
 
Join Date: Nov 2011
Location: Reno, NV
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
S5 turbo Jdm center iron in 86 NA

I'm trying to use one of my S5 turbo irons in my 86 NA because the original blew a "water jacket rim". I saw a rotary evolution said you just have to seal the bottom EGR passage on the center iron if using the turbo iron. I noticed that they were different in a minute ago after I started taping the stuff up the paint it. I guess I can just stuff some JB Weld down there? Is there anything else that I'm going to run into you is using this iron? I'm using stock (s4 NA) everything else
Reddon is offline  
Old 03-12-15, 12:04 PM
  #17  
Full Member
iTrader: (2)
 
Join Date: Nov 2011
Location: Reno, NV
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Sorry for the typos, I just had a panic attack! Thanks in advance
Reddon is offline  
Old 03-21-15, 01:00 PM
  #18  
Full Member
iTrader: (2)
 
Join Date: Nov 2011
Location: Reno, NV
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
I stuffed it with red RTV. I hope this is enough..
Reddon is offline  
Old 04-07-15, 01:48 PM
  #19  
Rotary Enthusiast
iTrader: (23)
 
Join Date: Nov 2007
Location: san diego
Posts: 822
Likes: 0
Received 0 Likes on 0 Posts
Rtv will probably melt. But only really matters if using stock exhaust manifold.

Either way you shouldn't suffer from an exhaust leak, just a lot of carbon build up in the exhaust manifold to that opening
DR_Knight is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
stickmantijuana
3rd Generation Specific (1993-2002)
13
01-09-18 11:19 AM
NeilTee
New Member RX-7 Technical
13
09-15-15 08:46 AM
Ian_D
New Member RX-7 Technical
6
09-06-15 10:38 PM


Thread Tools
Search this Thread
Quick Reply: Differences between s4/s5 and NA/turbo irons


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: