Hello there RX-7 community. Great day. in a great mood. hope everybody's doing well!
on to the point... I have two exhaust manifolds.. One of them has a hole next to the flange which goes back to the block.. The other one doesn't. What is the difference? And why does one have a hole and the other one doesn't? The tube that goes through looks kinda burned out already also..
Anyways.. I'm assembling my engine back together, Which one should I use?
Thanks!

 

the one with the hole and pipe is the 93-94 manifold WITH EGR. the one without the hole is the 95 WITHOUT EGR.

 

ah.. no way? That's nice to know. So the 95 models didn't come with a EGR? So which do you suggest I put back on my engine? The one with the hole is what came off of my engine. If I put the one from the 95 with no EGR will it affect me passing smog?

 

Also all the JDM cars had no EGR so they don't have the EGR pipe.

I *THINK* you can pass emissions without the EGR pipe there, but I'm not in emissions-land so I can't tell you for sure.

Dale

 

I'm sure u can pass emissions with the pipe there, that's what EGR is for right? I've passed with that Manifold.
But is it better to install the manifold with no hole?
And this thought: The pipe on the "with egr" manifold seems to be deteriorating and looks all burned out. This can be dangerous to the turbos can't it? Pieces will get burned off and chipped off and fly into the turbine and damage the blades and such..
But the other manifold is all rusted inside.. hahaha so which is better to put in guys?

 

With no EGR will in theory flow better. Rusty doesn't matter, just as long as the holes for the studs are good and sound. Exhaust doesn't care if it looks rusty.

I've never heard of turbos dying from the EGR tube breaking off or anything.

Dale

 

Ah I see. Well thanks for the help and info man! Yeah i haven't heard of anybody's turbos messing up cuz of broken off EGR tube.. but then again I've never seen other manifolds with such a crusty looking burned out EGR pipe.. haha and logically, if little pieces burn off and break off then they will fly into ur compressor wheel right?damaging the blades?..
And that Rust will not be bad for the turbos or anything?

 

every manifold has an EGR tube that looks like that by now.

the EGR system on the FD is like 1 grain of sand on the beach, AND its not even operating during an emissions test, so the valve just needs to be there, but it doesn't need to work. in other words you could use either manifold and it would have no difference in tailpipe emissions during an emissions test

 

The EGR on our 1994 is externally removed and blocked off; the CA emission results look like this with no EGR. This engine had >100K miles on it at time of test in 2010. (EGR mostly helps reduce NOx emissions.)