Hi there,

I was wondering if anyone can tell me whether this is an s4 or s5 engine. From looking at it, I see what looks like the knock sensors above the trailing plug holes which should be an s5 but I also see an egr valve (it appears to be) just want to make sure:

 

s4

 

Seconded.

 

Thirded. S4.

 

S4 usdm.

 

Yep, Thats an engine ya'll have there. If your buying it be sure to turn it over by hand first, possibly put some oil in the chambers first... looks dirty...

Fifthed, Series four, found in 87-88 mazda Rx-7 TII's.

 

hey thanks for the replys everyone. I am just wondering how you guys were able to distinguish it from an s4/s5 engine. Was it because it had the EGR valve? What about the plug that looks like a knock sensor, is that just an expansion plug? I was hoping this was an s5, so I will keep looking out for one.

Thanks again

 

the egr valve and the turbo hotside give it away.

The S5 turbo has a much larger hotside and different manifold.

 

s4 has a mechanical oil metering pump..s5 is electrical.

 

also the S4 has a twin scroll actuator...that big guy mounted below the wastegate actuator.

that thing on the front rotor housing above the T plug looks like a sticker or a solder seal or something.

 

easiest way to tell by the pics you posted. also the egr.

 

no knock sensor holes above the spark plugs....

egr makes it US market