Marine Intake

[L31MaxExpress]

36*F Cold Start was flawless this morning. On a whim I tried something, trying to figure out the lean tip-in. In normal blended mode the stumble is there. In Speed Density with the MAF disabled the lean tip-in is all but gone. In MAF only with the Dynamic Air Disable set for 400 rpm it was more pronounced. I set a PE delay back into it. Set it for 2,800 rpm and 5 seconds at 90% TPS. Still in MAF only, I snapped the throttle wide open against the converter. The fuel trims shot lean, indicating I still have a lean spot in my MAF calibration. I tried the same thing in speed density and the lean spot was nearly gone. Atleast I know what to fix now and can stop chasing the transient fuel ghost. I ended up adding about 10% to the MAF transfer in that area but have not retested it yet. Waiting on it to cool off so I can tighten a hose clamp on the bypass hose that started leaking. You can actually see Bank 1 02 voltage climbing during the initial part of the throttle transition and then falls flat to double digit lean after the throttle is already wide open. I really need to pick up a connector for my HP Tuners interface so that I can put Wideband Data directly into the datalog then do the fuel tuning in open loop off wideband data. On a side note the torque converter is now stalling 2,900+ even with the lean spot, meaning I have picked up a noticeable amount of mid-range torque that is now stalling the converter higher. The second throttle snap against the converter pushed me forward about 5 ft through the brakes while spinning the rear tires. Definitely do not do this procedure with anything close to the front of your vehicle or you might ram into it.

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[L31MaxExpress]

Coolant leak was an easy fix. One of the bypass hose clamps was not quite tight enough. I drove it around town a bit a couple of times with the engine cover still off, gets hot in there quickly even though it was only 50F outside and I had the windows down. Will attempt some longer drives in the next few days, once I am confident enough to get some distance from the house. I made a few quick part-throttle tip in tests loaded against the converter. Converter is brake stalling about 2,900 rpm at about 50-60% throttle at which point it couples and starts pushing the van with the front tires locked.

Warm Restart and Open Loop Tip-In

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Closed Loop Tip-In with the coolant temp still around 140*F.

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The lean spot is all but gone now.

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[Supercharged111]

2900 stall. . . with the B82 stall or did you go aftermarket?

 

[L31MaxExpress]

2900 stall. . . with the B82 stall or did you go aftermarket?

It is both. I had a converter company local to me build a B82 for it. Billet front cover, oversize lockup clutch, custom machined billet stator and all the fins were brazed/welded and the tolerances were tightened up. They basically created a performance converter that drives like stock until you get into the go pedal. It will move the van from a stop uphill at ~1,200 rpm. They pretty much nailed the stall speed. I asked them for 2,800 rpm behind ~500 ft/lbs @ 3,000 rpm and as much torque multiplication as humanly possible. I do not know if it was dumb luck or if the really know what they are doing that closely. Given most companies shoot for a number and offer a free restall within a year. They knew going in it was going to make 500 ft/lbs and I was going to lock it at WOT. They suggested the larger lockup clutch rather than a triple disc. They felt it would last longer at my power level while towing than a triple disc and what they shared with me made alot of sense. The single disc is made of a much thicker material than the thin discs of the triple disc.

 

[L31MaxExpress]

I purposely wanted a stock diameter converter as well. I tried one of those small POS converters and it was terrible. The small converter almost had nothing in the way of torque multiplication and even light throttle had it stalled up to 2,800 rpm.

This one was built by Performance Torque Converters of Texas in Kennedale, TX. I am not a torque converter expert, but JD took the time to fully understand what it was going into (power, weight, gearing, and use) before building the thing to match what I wanted.

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[L31MaxExpress]

The old converter was made by Phoenix in Weatherford, TX. 245mm and 2,800 stall behind the old 350. A truck used as a truck should never have a small diameter converter even if it "helps throttle response". The engine is quick to respond up to 2,800 rpm while the overheating rubber band slowly moves the vehicle forward from a stop. In a lightweight car with a lot of torque and a deep axle ratio the little 245mm would probably be a rocket.

 

[Supercharged111]

Man you have all the cool stuff local to you down there. I had actually aspired to have a smaller diameter torque converter to cut down on rotating mass and help acceleration but could never find one advertised with a low enough stall. Good to know they suck anyway in these heavy pigs.

 

[L31MaxExpress]

Man you have all the cool stuff local to you down there. I had actually aspired to have a smaller diameter torque converter to cut down on rotating mass and help acceleration but could never find one advertised with a low enough stall. Good to know they suck anyway in these heavy pigs.

245mm is basically a 60* V6 converter adapted over. Converter body is similar to the one you would find in a 3.4L Camaro or Malibu. Imagine trying to putting the 450+ ft/lbs you are making through a converter designed around maybe 150 ft/lbs at its 2,000 rpm OEM stall speed.

 

[L31MaxExpress]

I seem to have the stumble completely corrected in both open and closed loop as well as with or without a load on the engine. When I gave enough to drink my random 2-4* of tip-in knock retard also went away.

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[Reluctanse]

Oil pressure into the ecu would be fantastic, the gauges on these trucks aren’t exactly precise-