After a lot of reading on the subject it seems to me that the only good the EGR brings is that it heats your engine, be it through the EGR cooler, or the inert gasses reintroduced to the intake bringing up engine load to make more heat in the jackets. By eliminating the EGR you lose the heat put directly into the coolant, and the extra engine heat brought about by loading the engine down. I live in MN, and it is a little bit cold. I don't like that my engine takes forever to warm up as is, so an EGR delete in the traditional manner is out of the question for me. The other issue here is that the fact that the EGR is run at such a high amount I fear that it is causing some pretty severe coking.
On a tangent, something I learned about the priuses; they get the cabin heat from the engine coolant, and when the coolant is cold it'll run the engine just to heat the coolant, even if it is on battery and there is sufficient charge. This means that they want to scavenge the most heat possible from the engine during the short time it is running. They included an "exhaust heat reclaimer", which is more or less just like our EGR cooler, but on a bigger scale.
With that in mind I get to thinking that if I were to delete the EGR I could keep the EGR cooler to scavenge some heat from the exhaust. So to do that I'd need to get exhaust flow through the EGR cooler element, but without dumping the exhaust into the intake stream. To get flow you need a pressure differential, in the stock system the exhaust backpressure on the engine side of the turbine will always be higher than the impeller's output pressure, meaning some pressure differential and therefore flow when the valve is opened.
My idea of the alternate direction I can dump the exhaust would be back into the exhaust stream, just after the turbine. There should be more pressure differential than the stock setup, so I could probably get more flow and therefore more heat out of the system. The flow wouldn't need to be as precisely regulated to avoid choking the engine with exhaust into its intake either. Could probably even eliminate computer control from it altogether by using a thermostatic vacuum control valve from an old smog-era car. Coolant temperature is low, it allows vacuum to a vacuum operated EGR valve taken off of some other vehicle, allowing flow through the EGR cooler element, once coolant temp comes up the thermostatic valve vents the vacuum which shuts off flow. Simple as that.
The immediately apparent pitfalls of this setup would be that the exhaust gasses would be bypassing the turbine, so the compressor response might be a little different, possibly different enough that the computer would notice a discrepancy in incoming air. Unlikely, but possible. The orifice through any EGR I've seen is at most 1/2", and the iron log going into the turbine housing is 2" or so. Combine that with how much the EGR in its stock form would flow , and the amount this setup would flow and therefore bypass past the turbine is quite minimal.
tl;dr, remove EGR valve, reroute EGR cooler output to a repurposed EGR valve that dumps into the exhaust, post-turbine
What says you guys?
On a tangent, something I learned about the priuses; they get the cabin heat from the engine coolant, and when the coolant is cold it'll run the engine just to heat the coolant, even if it is on battery and there is sufficient charge. This means that they want to scavenge the most heat possible from the engine during the short time it is running. They included an "exhaust heat reclaimer", which is more or less just like our EGR cooler, but on a bigger scale.
With that in mind I get to thinking that if I were to delete the EGR I could keep the EGR cooler to scavenge some heat from the exhaust. So to do that I'd need to get exhaust flow through the EGR cooler element, but without dumping the exhaust into the intake stream. To get flow you need a pressure differential, in the stock system the exhaust backpressure on the engine side of the turbine will always be higher than the impeller's output pressure, meaning some pressure differential and therefore flow when the valve is opened.
My idea of the alternate direction I can dump the exhaust would be back into the exhaust stream, just after the turbine. There should be more pressure differential than the stock setup, so I could probably get more flow and therefore more heat out of the system. The flow wouldn't need to be as precisely regulated to avoid choking the engine with exhaust into its intake either. Could probably even eliminate computer control from it altogether by using a thermostatic vacuum control valve from an old smog-era car. Coolant temperature is low, it allows vacuum to a vacuum operated EGR valve taken off of some other vehicle, allowing flow through the EGR cooler element, once coolant temp comes up the thermostatic valve vents the vacuum which shuts off flow. Simple as that.
The immediately apparent pitfalls of this setup would be that the exhaust gasses would be bypassing the turbine, so the compressor response might be a little different, possibly different enough that the computer would notice a discrepancy in incoming air. Unlikely, but possible. The orifice through any EGR I've seen is at most 1/2", and the iron log going into the turbine housing is 2" or so. Combine that with how much the EGR in its stock form would flow , and the amount this setup would flow and therefore bypass past the turbine is quite minimal.
tl;dr, remove EGR valve, reroute EGR cooler output to a repurposed EGR valve that dumps into the exhaust, post-turbine
What says you guys?
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