place here locally has 2 jspec TII motors. i went and looked at them today and i wanted to know how can you tell the difference between the S4 and S5 motor. i know the radiator fill on s4 motors in near the block and one of the motors had that so i knew it was an s4. the other he said was an automatic. i looked at it and no radiator fill off the engine. i was wondering if auto s4's had different radiator fill spot than the manual and how can i tell the difference between s4 and s5. thankls guys.

sorry tried searching but got lazy.

 

Quick down and easy things that you should see right off the bat.

S5:
- Upper radiator hose pipe that houses the thermostat and is connected to the water pump housing is a black plastic one piece unit.
- Electric MOP
- Turbo manifold comes straight out and there is NO solenoid/actuator bolted to it.

S4:
- Upper radiator hose pipe is aluminum and has a coolant cap on it.
- Mechanical MOP
- Turbo manifold curves slightly up and there IS a solenoid/actuator bolted to it for the twin scroll activation.

There is more differences, so go ahead and use the search feature it is a wonderful thing.

- Dana

 

the knock sensor is in a different place, one has it on a rotor housing, the other in a center housing, but I DO NOT REMEMBER WHICH! augh... sorry! The OMP/MOP/whatever will let you know without a doubt though.. if they're both mechanical, they're both s4..
If it doesn't really matter to you get the one that is in better overall condition instead of just looking by series.. the s5 motor could be crap and the s4 a jewel, or vice versa...

 

Knock Sensor on Rotor Housing = S5
Knock Sensor on Intermediate Housing = S4

Ted, Icemark, Kevin L. correct me if I am wrong

- Dana

 

is there differences between auto and manual though? i mean for the radiator fill spot.

 

oh, and i heard only the s5 series would work in a s5 car. is this not correct? i heard if i found an s5 TII motor i could still use my stock harness and ecu for the time being till i found a tii ecu. could i put a s4 motor in my car?

 

Short answer is any thing is possible with enough money . But it is easier to keep the motor the same series as the chassis. I can’t stress enough how good the search feature is on this forum. Check this link it might start you in the right direction. http://www.rotaryresurrection.com/ click on the tech button on the top of the page. You will find a lot of useful information.

- Dana “happy motoring”

 

i did search. all i found is to look for the omp. i dont know what it looks like though. i was looking for an easier way to tell. or does anyone have a picture of an s5 omp and the s4. i know the s4 is mech. and the s5 is electrical so where do i look?

 

blk fc3s- if you get a s5 turbo engine to swap into a s5 gxl you can't use the stock gxl n351 computer. it won't handle boost. the only s5 non turbo that has a ecu that will handle a turbo engine is the n352 convertible ecu. because in japan the verts are turbo and in aspec verts it used the same ecu as the verts in japan. so you will need to get a n370 or n374 ecu and matching boost sensor. you can use the non turbo wiring harness but it will need to be modified to accomodate a knock sensor and longer leads to the TPS. also the duty turbo solenoid if you decide to use it. and there shouldn't be a difference if it's auto or manual. jspecs rx7s are all turbo and had the auto option. if it's a s5 turbo it will have the black plastic thermostat housing and electric OMP and the knock sensor is located on the rotor housing. also check the TPS, s5 TPSs have 2 plungers, full range and narrow range. s5 t2 engine only have a one plunger TPS. the only difference an auto s5 t2 engine will have is the flex plate instead of a flywheel.

 

the OMP is located on the passenger side of the engine, look below the lower radiator hose. it has 4 clear plastic lines that are attached to it and a wiring harness if it is a s5.