I'm thinking about swapping in a TII ECU in my car- for a few reasons.

1-Boost dependant fuel ratio (not just throttle position with my S-AFC)
When I floor it- the S-AFC is set very rich, to compensate for boost... but if I floor it at any given RPM, it runs really rich for a second untill the turbo spools up and soaks up the fuel. That power-robbing super rich condition has gotta be slowing the turbo spooling.

2-Timing retard while under boost (the biggie).
In order to avoid detonation at full throttle at high boost, I have the timing retarded by about 4 degrees.
This really kills responsiveness, especially at the low end.


Timing retard boxes are a little expensive, and I'm sure I could find a TII ecu for pretty cheap.

Question is- is there a difference in the wiring harness?
I know I'd need to replace the boost/pressure sensor with a TII one.
Any differences with using the N/A AFM I could tune out with the S-AFC.
I wouldn't be using the knock sensor... (doesn't it screw into the block? I'm not dealing with that...)

Any other issues? Are the harness plugs the same?

Emmisions aren't an issue either- To pass, I just hook up my cat, and install the air pump with a direct hose to the cat- it dilutes the exhaust so much it will pass.

I'm assuming I'll end up with an S4 ECU, since they are much easier to find. My car is 90.. Injector impedence isn't an issue- I'm already using low imp. w/resistors.
Any others?
Thanks.

 

If you have an S5 then you have to stick with the S5 series of computers since the wiring harnesses between the S4 and S5 are different. I don't know if your idea will work. I myself have questioned it though so I would like to know the answer. I know that on an S4 the part number for the afm's is different between the turbo and n/a's. I actually had a turbo afm on my n/a though and it worked fine so I'm not sure what the differences are. I'm not sure if the S5 afm's are the same way.

 

I've heard of quotes from the FSM's specs, that state that the TII AFM flows more max CFM.
The N/A one (apparently) bottoms out ealier, but that can be compensated for by the S-AFC.
Hmm... S4 and S5 harnesses are different.... that's going to be a pain to find an S5 TII ECU.

 

You need to find the S5 ECU. Don't try and put the S4 on since it'll be a major hassle.

The S5 ECU should plug right into the wiring harness and run the car, but you will not get all the benefits unless you do a "full" swap of the TII wiring harness and all the sensors.

I can't imagine how the TII AFM flows more then the NA. The physical construction between the two is the same.

 

Maybe the spring rate is just stiffer on the T-II afm and the computer is set up to compenate for this.

 

How about this.....I have a series 4 j-spec motor but it came with a series 5 throttle body and throttle position sensors (the duel ones). If I run series 4 wiring harness and ecu, will there be a problem with the series 5 tps? (I was told by an aussie that my motor probably came out of some mazda luxury car in Japan that came with the 13bturbo motor but used a few different parts on it.

 

The S4 plug wint plug into the dual tps and the ecu wouldnt know what to do with the other sensors imput anyways. You can still use one of the tpss tho. Use the one that has the red, green, black wires coming out of it. put the wires in a connector that will fit into the S4 tps clip on the harness.

 

Bambam7? If all you need is Boost dependent fuel ratio then you need the s5 turbo ecu with turbo boost senser??? Is your problem solved? What sensors will be effected with the turbo ecu and no harness to match? I would like to know for I will be trying the conversion soon.

 

cool, thanks for the info jahoo

 

if you look at the wiring diagram the s5 na and t2 are only different on 2 pins, the na has solenoids for the vdi and the 6 ports, while the turbo has wastegate and a knock sensor. the t2 will also use your 550cc injectors and a 2bar map sensor

mike

 

Nice... now all I have to do is find one!
S5 TII ECU, and the map sensor.... (I'm sure s4 and s5 sensors are the same)

It's almost plug and play. Man that would be nice.

 

Buy a haltech

 

Bambam7 2 ?s

Do we need the S5 turbo ECU for the wastgate? Hasnt yours been working fine without it?

Is is true that the FPR are the same for S5 turbos and na

Can timing retard be done with CDI box like MSD only on the leading and how much? Cheaper than a standalone or S5 ECU dont you think?

After these ? have been ansewered I feel no problems with doing the turbo-N/A conversion. Basically this means we dont need to use the S5 ECU unless theirs something I missed?

 

Bambam7 ANother ?

You said your fuel system should hold your power level tecknically BUT isnt the reason why your not getting as much fuel as turbo car ( no because of boost dep FPR) But because the ECU is only letting 460cc injectors run 65% duty cycle as oposed to Tubro injectors at 65% wich is why the S-AFC although maxed out still does not let the Turbo Injectors reach their fuller potential? Am I right? if so this would be a good reason to use S5 Turbo ECu

 

yes I know they both go more than 65% with S-afc but the n/a ecu will only let it max out so far thinking it had 460cc inj... I dought they go to 100% their must be a stock limit built in the ECU

 

bump,
I would like to know...

 

I don't know how people expect their cars to run perfectly when they are trying to get cheap...


-Ted

 

Bambam7

I am running a S5 turbo ECU with a N/A harness. I did change the map sensor and injectors. I did add a knock sensor (it screws right in the front housing. It is already threaded. 5 min job)
The only difference (pin wise) I found was pin 2m (knock sensor vs VDI).
S4 harnes is not the same as S5 (42 pin vs 52 I belive)