The Mighty 258 > Emissions/Vacuum Systems

EGR Valve questions

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Canoe:

--- Quote from: AMC of Houston on October 31, 2021, 04:44:32 PM ---New EGR tubes are down to about $45 now.   Used ones on EvilBay are ~$22.

--- End quote ---
Unfortunately, stock intake & 4.0 header -> custom size.
Plus prices in Canada.

Looks like I can get a stainless steel gas line FAC (Flexible Appliance Connector) that will do the job for under $20 CAD, all in.

How long it lasts is another factor... Need to compare wall thickness against getting CSST and connecting to my old connectors.

However, a longer length may offer some EGR cooling benefits. And CSST has larger diameters: for greater area for HX; and, for a given flow, a longer dwell time for HX.

Canoe:

--- Quote from: Canoe on October 31, 2021, 07:44:19 PM ---Looks like I can get a stainless steel gas line FAC (Flexible Appliance Connector) that will do the job for under $20 CAD, all in.
How long it lasts is another factor... Need to compare wall thickness against getting CSST and connecting to my old connectors.
However, a longer length may offer some EGR cooling benefits. And CSST has larger diameters: for greater area for HX; and, for a given flow, a longer dwell time for HX.

--- End quote ---

* FAC has a somewhat thinner wall than CSST. 
* FAC is more flexible, presumably more vulnerable to vibration fatigue. 
* FAC is supposed to be a one-time use: if you change an appliance, you should use a new FAC. 
* For the examples I've seen online where they're using FAC or CSST for EGR tubing, I've not seen anyone report back on longevity. Another odd observation: where I've found online diagrams or forums discussing an EGR cooler, the coolers are all water (coolant) cooled (Air-to-liquid HX), AND, the flow is Parallel-Flow, not Counter-Flow (which for a given size and flow rate, has the most heat energy is transferred due to delta-T). I suspect they're using water cooled as they'll get consistent results, whereas using air cooling, the air temperature varies with day/night, season and climate. No idea why Parallel instead of Counter-Flow.

 

TheBirdman:
Probably not helpful, but for what its worth, one of the first things I did to my eagle was remove the EGR and bolt a block off plate to it, and its never once given me any trouble, and also doesnt soot up my intake every 20k miles.

Canoe:

--- Quote from: TheBirdman on November 03, 2021, 08:44:07 AM ---... remove the EGR and bolt a block off plate to it, and its never once given me any trouble, and also doesnt soot up my intake every 20k miles.

--- End quote ---
With finding the garage installing the engine (fixed/updated after the head & a piston blew up), had not installed the EGR tube and had sealed the EGR valve closed, it's effectively a delete.

I've never had an issue with a clogged intake. Perhaps that's not an issue when the engine is running well, or depends on what the components and additives are in the gas in different regions. 

I want the EGR function back, to knock the toxic NOx emissions down, while getting the benefit of improved gas mileage. It's also illegal here to delete EGR.

Canoe:
Two things...

I now remember the garage telling me of the difficulty with getting a custom EGR tube. They suggested installing the engine without a tube and block the valve, so I could get on my way. I was to fix that later. Which I completely forgot... So my bad.  :banghead:

Apparently using air to cool the EGR gas, when that air can be < -30 C (-22 F) (and sometimes below -40 C (-40 F), even below -45 (-49 F), at some places I go a little north of here and up in altitude), may result in over-cooled EGR gas for mixing with the carb mixture, in conflict with the coolant-heated intake manifold.

* Below an air temperature, EGR usually is shut off. Perhaps that's not a big issue. 
* Or perhaps using a coolant-cooled EGR cooler means the engine can use EGR gas over a greater ambient temperature range. 
* Need to get more info before I can decide if I want to go beyond a simple EGR tube closest to the stock size. 
* And, apparently a coolant-based EGR cooler results in faster engine warm up (and the sooner one has a warm heater core for heated air in the interior - bonus in winter). I've no idea if that change in warm-up time is significant. May need an upgraded rad! lol(Self-inflicted can of worms...)

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