Water Injection on Corrado SLC VR6

Dude ... VR6.

The SLCs never had EGR valves, so there's none to put back on.

The VR6 has computerized timing based off of the knock sensors. There is no timing to set.

To the OP: Run some top-end cleaner like Techron or Seafoam. The engine probably needs it anyway. Put in new plugs. If the wires are the original black ones, put on new wires. Put in that guaranteed-to-pass stuff. You should be fine.

-Keith

Dude: I have a 93 VR6 Corrado SLC that is all original that has an EGR valve. The car I'm having problems with is a 90 Corrado that someone added a VR6 to and installed an exhaust manifold that does not have the port for the EGR supply tube. The intake manifold port is plugged off. The vacuum relay is in place as well as all the vacuum lines. I would have to R&R the exhaust manifold to install the EGR. I bought an EGR valve thinking it would be a simple install but nooooo.

You are correct about that. No timing adjustments available to the backyard mechanic.

I have done most of this stuff. The NO went down 75 ppm but is still

100 ppm too high. The plugs and wires are good. NO is formed by high combustion temperatures. The EGR reduces the temps to help reduce NO formation. The catalytic converter also helps to reduce NO emissions. I have not check the converter. HC is 119.3 (limit is 174 ppm) and CO is .73 (limit is 1.12%), well within pass limits.

You're totally right; I was mixing up the Passat and Corrado VR6s. The Passat only had EGR in California until 1995.

It sounds like at this point all you need to do is slightly reduce combustion temperature or add an additive that reduces NOx. That's not so surprising - isn't the intake on the Corrado rather warm to begin with? Anyway, a gas additive that reduces combustion chamber temperature should make that happen. Doesn't Techron include an additive designed to reduce NOx? If you do want to try the water injection, tap power from the far side of the fuel pump relay so you don't end up loading up the top end with water when the engine isn't running. You can probably, for a short run, use air pressure instead. In other words, get yourself something that can take a decent amount of pressure, fill it with water halfway, put a hundred PSI in the other half of air, then feed from that to a tiny nozzle positioned in the intake. I'm pretty sure you can get decent misting nozzles intended for micro irrigation. Still, an additive is probably going to be easier; the full-strength Techron might do the trick.

-Keith

Keith: That makes sense. I think this engine was originally from a 93 Passat.

I like your idea better. I have seen fuel additives that reduce NOx but never tried them. I will give it a shot.

Thanks for all the advice. I will report the results. Corrado Daddy