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-   -   Issues Putting S5TII Engine In S4TII Chassis? (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/issues-putting-s5tii-engine-s4tii-chassis-654302/)

b18crx 05-20-07 06:21 PM

Issues Putting S5TII Engine In S4TII Chassis?
 
so i have a 10th ann. and im ready to order the swap but my friend is telling me i should go with an S5 engine for the minor benefits since the cost of the swap is the same so my question is will i run into any major problems when putting an S5 TII motor in an S4 TII chassis?

all help is much appreciated and i need answers as quickly as possible since im ordering my motor tomorrow. and please be as detailed as you can. thanks -mike

jdm12a 05-20-07 06:46 PM

yes do not get the s5. im sure everyone will tell you to stick with the s4, its much easier, the s5 into s4 swap is not worth the extra effort and money put into it

b18crx 05-20-07 06:56 PM

can anybody tell me why? i mean i can handle minor wiring.....what exactly would i be getting myself into?

stevensimon 05-20-07 07:35 PM

it will be a mess. you will have to switch every single wire in your entire car to the s5 setup. thats engine and body harness. computer. all sensors. everything. just keep it s4 and just port it or whatever you need to make the power you want.

staticguitar313 05-20-07 08:06 PM

just keep the S4 engine as is, but if you ever get it rebuilt then go ahead and have s5 rotors and counterweights thrown in ^_^

TehMonkay 05-20-07 08:08 PM

And the rear iron.

87 t-66 05-20-07 08:39 PM

this has been covered a million times

http://rotaryresurrection.com/2ndgen...o_s4_swap.html

NZConvertible 05-21-07 12:41 AM


Originally Posted by b18crx
... my friend is telling me i should go with an S5 engine for the minor benefits since the cost of the swap is the same

The cost is the same but the work required is not. The S5's electronic OMP won't work on an S4, so unless you plan to premix you'll need to swap the S4 front cover (c/w mechanical OMP) onto the S5 engine. This is not difficult, but you have to be careful doing it (read this). You'll also need to swap the S4 TB (c/w TPS and OMP actuator rod) onto the S5 UIM. It bolts straight on.

Mazda changed to a better style of electrical connectors when updating the car, so you'll need to swap in the S4 injectors or replace your injector clips with S5-style ones. Some rewiring of the S4 TPS will be required for the same reason.

If you're keeping the TMIC you'll need an S5 one, as the revised UIM meant different mounting brackets were required.

For all that work you get slightly lighter rotors, higher compression ratio, an intake manifold with longer and fatter runners and (assuming it comes with it) a turbo with a better exhaust housing and manifold design, plus it's a newer engine. Note that you don't get the S5's higher boost, as that was controlled by the S5 ECU. Whether these benefits are with the extra work is up to you.

Dp the question is, do you have the time/space/ability/equipment/inclination to do it? If so, get an S5. If not, get an S4. :)


Originally Posted by stevensimon (Post 6960332)
it will be a mess. you will have to switch every single wire in your entire car to the s5 setup. thats engine and body harness. computer. all sensors. everything. just keep it s4 and just port it or whatever you need to make the power you want.

Wrong, wrong, wrong. :rolleyes:

stevensimon 05-21-07 08:05 PM

i was talking about running the full s5 long block and sensors, needing the s5 computer

dwb87 05-21-07 08:41 PM

13B-RE :icon_tup:

b18crx 05-21-07 10:30 PM

i plan on using the complete s5 engine and ecu. like i said before im not afraid of wiring i just want to make sure there wont be any other problems....., that being said i wont need to change to s4 injectors or s4 tps etc. etc...

anything else i should keep in mind?

thanks -mike

NZConvertible 05-22-07 01:24 AM


Originally Posted by stevensimon (Post 6963883)
i was talking about running the full s5 long block and sensors, needing the s5 computer

You don't need the S5 ECU to run an S5 engine. It's ten times more work for very little gain. Many more wiring changes (and additions) are needed to do it properly, and for what? The S5 ECU has some nice convenience features but performance will be exactly the same.


Originally Posted by b18crx (Post 6964425)
i plan on using the complete s5 engine and ecu.

You'll have a much easier time doing what was described above, and you'll be just as happy with the result.


...that being said i wont need to change to s4 injectors or s4 tps etc. etc...
That's nothing compared to what would be required to use full S5 electronics.

b18crx 05-22-07 11:37 AM

your right with the "nice convenience" with s5 ecu, i like the idea of being able to pull my codes when i want, i dont want to have to write the codes down while im driving. thats just flat out dangerous. im not saying your wrong at all im just saying that convenience means A LOT to me along with the other minor gains.

StarScreaM2k1 05-22-07 12:22 PM

You guys do also realise that if you plan on running higher then stock boost applications its better to use the S4 Engine (mainly because of the Rotors are low-comp). It doesnt mean you cant use a S5 Engine, its just... i dunno... more of a cusion with lower comp and i think something along the lines of being able to handle higher boost better. Just a thought...

I would say stick with a S4 in your 10th AE, things are simpler, and if you plan on modding any of the stock benefits or well most of them will be nullified. Like ify ou plan on going higher boost, Aftermarket ECU and lets say...a different turbo/manifold.. then really you did all that work for a slight time of 'convenience'. Just a thought.

NZConvertible 05-23-07 01:37 AM


Originally Posted by b18crx (Post 6965905)
your right with the "nice convenience" with s5 ecu, i like the idea of being able to pull my codes when i want, i dont want to have to write the codes down while im driving. thats just flat out dangerous.

What the...? Why would you need to write codes down while driving? The S5 ECU has more error codes, which is good, but reading them is no more convenient than on S4's.

That's not what I was refering to anyway. I was meaning things like the improved idle control (needs extra ECU inputs), improved transient throttle responce (needs the full-range TPS), automatic fuel cut for de-flooding (also needs the full-range TPS), electronic boost control, etc. These things are nice, but not worth the grief.


Originally Posted by StarScreaM2k1 (Post 6966012)
You guys do also realise that if you plan on running higher then stock boost applications its better to use the S4 Engine...

That would only apply to very high-power engine builds. Not "higher-than-stock-boost applications". You don't think there are lots of S5's running around with higher than stock boost? They boost higher than S4's from the factory...

b18crx 05-23-07 11:42 AM

[QUOTE=NZConvertible;6968671]What the...? Why would you need to write codes down while driving? The S5 ECU has more error codes, which is good, but reading them is no more convenient than on S4's.

on the S4 you can only check the code as its occurring while the s5 will store memory of the code so you can check it later.

NZConvertible 05-24-07 02:25 AM


Originally Posted by b18crx (Post 6969709)
on the S4 you can only check the code as its occurring while the s5 will store memory of the code so you can check it later.

Yeah, that would be true for intermittent problems. But if the problem stays, so does the code. I have the LED's for reading codes mounted in the warning cluster, so I get live updates... ;)


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