I just got this seems like an 86 or 7 since it has the 4 lug and manual everything with no sunroof. I just took the engine out and it had an electrical mess but the n/a's usually have the egr on the top off the intermediate plate doesn't it? This one doesn't. It's a 6-port too so whats up with that? It seems this car has been messed with quite a bit and has a rotary7ven sticker on the front with some performance 4 wire box hooked into the MAF wiring.

 

Probably a 89-91 non turbo block. The 89-91 didn't have a EGR valve

 

Is there any markings to tell? I found some holes above the spark plugs in the housings that are blocked off, but it has S4 manifolds.

 

I think it might be two rear S5 housings because i heard that there is some sensor above the trailing plug that goes there. I still have to disassemble it though to look at the rotors, but they have the exhaust diffusers in there so.

 

While we're talking about EGR, what exactly does it do. I've searched and all I can find is that taking it off doesnt do anything and that the s5's were the only ones without it.

 

The EGR Valve is just above the exhaust pipe in the middle of the engine. It's purpose is to recirculate a portion of the exhaust gas back into the intake manifold, reburning it and keeping combustion chamber temperatures down, which aids in reducing emissions. I am just trying to figure out why this has S4 injectors and manifolds but the shortblock itself is not making sense.

 

it sound like the previous owner scavenged some parts. Most likely, he rebuilt it using some s5 parts because the stock housings were toast and he had access to an s5 with good housings.

 

So they are S5 housings and intermediate plate?

 

EGR also helps reduce spark knock/detonation...due to recirculating exhaust gases back into the intake. If it's trying to burn inert gas...it'll ricehen the AFR's a bit...cause exhaust gases are already burned once before.

 

Not 100% sure, but it looks like at least the intermediate one is, due to the lack of EGR. I'm not really sure of the differences between s4 and s5 housings other than that.

 

I hoping that they didn't make the extra holes for NOS or the inside could be pretty fubared, which would suck. Isn't the S5 plug holes different than the S4 ones for improved burning or something.

 

Not really sure, but I'm about to start a thread and thats one of the questions I'm gonna ask.