That is the fitting I used. I went with the sump due to sloshing. If I used just that, I could envision all the fuel going to the back of the tank under hard acceleration when around 1/4 or lower then sucking air. With the sump, there is a volume that is trapped in there.

 

That's a good point Mike.

 

Just talked to DI. It was them and it was discontinued as it was being put on street trucks. It was intended for racing/offroad and there are possible liability issues in the event of an accident.

I can see that as the entire tank will empty out in the event the fitting or line is busted. I will need to mod my skid plate and get it back on. I have thought about that many times, need to stop thinking and begin doing.

 

Measurements are always better than guessing and just hoping that everything works out ok! If you want to find out how much pressure your exhaust might be coupling back to your CC it can easily be measured with my gauge by hooking it directly to the hose from your tailpipe. I'll bet you that such a measurement might show as much as 26" H2O or more! This guess is based on the following quotes from this link.
1999upg2/-Cat=&Number=1173983&page=15&view=collapsed&sb=5&o= &fpart=1.htm


"My Ford, 2000, 7.3L Powerstroke Diesel Powertrain Control/Emissions Diagnosis Manual, page 4A-54, says anything less than 4" H2O, at WOT under no load, is OK. 4" and higher start looking for problems. The test is performed by sealing off the breather and putting an orifice restrictor adapter in place of the oil filler cap. I do not know how small the hole in the restrictor is but by the picture is not very big.(lot smaller than the breather hose) Any Techs have access to a crankcase orifice restrictor tool 014-00743 that can measure the restrictor hole for us?"

"Do you know if that test pertains to the conditions of the blow by past the rings?"

"Yes that was what the test is checking. The engine is run WOT for 30 seconds and if less than 4" H2O the engine is ok.Like I said before the restrictor has a small hole (smaller than the normal hose) so they can backup pressure and vent it at a calibrated rate."

The above leads me to guess that when vented to ambient with a 3/4" opening, the CC will probably always measure less than 4" H2O under any load. This tells me that your 30" H2O reading on the dyno was due to an extra 26" H2O or more coming back from the exhaust. Also, Tenn measures 0.5" H2O compared to your 2" to 3" H2O under similar conditions. Racor testing shows that CC pressure is increased by a X4 from idle to WOT under load. If you apply this to Tenn, he would see at most 2" H20 on the dyno.

A CC pressure of 30" H2O (1.08 psi) might not seem like much, but that means 50 to 100 lbs of force trying to blow the valve covers/oil pan off the engine! That's based on guessing their surface areas, my back hurts too much to crawl under the truck to take measurements.

 

The engine HP delivered to and measured at the surface of the drive rollers on a DynoJet depends on drive line losses, including those of the rear tires. I think the losses in the rear tires are effected by tire pressure! I think that 85 psi (like I always use for towing) provides less heat loss due to sidewall deflection and might give better HP on the dyno. Except for warming up the fluids in the tranny and diff, you don't have much control over those losses. I think that 3rd gear (direct one-to-one) has less loss through the tranny than OD does, at least that's how it works for manual gears.

I've not heard anyone mention their EGT readings? It seems to me that if you hit the EGT redline you've got plenty of fuel flow. I thought I read somewhere that the stock fuel set up returns at least half of the fuel back to the tank. Wouldn't that mean you could double the flow to the engine and double the HP without doing any fuel mods? It seems to me that the trick is to produce the most HP at the EGT redline, and the Diesel theory that I've read suggests that it's best to inject all the fuel (limited by EGT) in the shortest possible pulse so as to produce the maximum combustion pressure. I guess increasing the fuel pressure which fills the injectors can help some in this regard, but I did notice that most of the hot trucks (>350 HP) had either a FASS or Air Dog which would increase fuel density by removing the air and thereby deliver more fuel in a shorter injection time. Also, getting the maximum MAF into the engine is key, so you don't want to warm up too much prior to a run. The dyno guy told me that he almost always sees the highest HP on the first run, and he attributes lower readings on subsequent runs to heat build up.

 

After reading the first part of your post where you said i had 30", i stopped. It was 24" though, and i think you are confusing a WOT reading of 4" with a reading of 24" for a full load WOT run on a modified engine. I guarantee you if he would have put it on the dyno and slowly spun it up to 3400 rpm that it would not be over the "accepted" level.

Sure things would be different if it was stock, but i'm not stock and im not going to worry about it. I did install the gauge before i left, and do a run to 3000 RPM in park, and within a second of romping down on the throttle, the exhaust flow caught up with the increased pressure at the CCV tip in the exhaust, and the gauge came back down to less than 3", from 6" where it spiked when i pushed the pedal. I'm fine with my CCV and reading the gauge on the trip to gatlinburg confirmed that it was fine.

 

I'm talking about taking a measurement directly at the exhaust bung (without the CCV hose connected) to see if you have pressure or a vacuum at that point. I'd sure like to know what that reading is before I go drilling a hole in my tailpipe to try it for myself!