Max's 1st gen NV4500/4x4/dually conversion/upgrade

["Mad Max"]

These last two days have been a lot of fun - we just got back from a big charity dyno event up in Greeley, CO at GAM Motorsports. Took the diesel, and blasted out a couple of hot hammer runs. I'm now offcially in the '300hp club'!! ;D {beer} 8)



Last April the truck was in the mid 200's, but after installing a couple X-mas gifts (to the truck) it kicked the engine over the edge.

I already had big injectors and a sweet aftermarket turbo, plus a couple other things, but yesterday I swapped out the stock exhaust manifold for a monster ATS Pulse 3-piece manifold - basically a huge header for the engine, and swapped out the 16cm exhaust collar for a 14cm wastegated unit. The difference is easily a 300* decrease in exhaust gas temperature (engine exhaust heat measured at the manifold exit, pre-turbo), and a 5 psi increase in boost to a total of 40 psi. It pegged the 35 psi boost gauge by about 5, which is exactly where I set the wastegate.



Here's the old set up:



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Here is the new (probably final) set up:



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Heat is the power killer, especially on a diesel. Getting the heat out of the head is directly proportional to how much throttle you can give it. The more throttle, the more fuel, the more heat. Let the heat out and you can stay in the throttle. Let the heat out AND make more boost and you have a good setup.

To do it, I pulled off the factory manifold and replaced with a killer big-port ATS unit. The exhaust manifold gets super hot and it wants to grow(expand), but it's all bolted up tight, so ATS designed a 3-piece 'expandable' unit that can allow the manifold to grow wothout losing any exhaust seal, and eliminates breaking off bolts. The factory unit was totally stock and un-ported. The ATS unit came with a factory port job which wasn't bad but had a couple short lips insode the port area and I did some porting by hand to blend in the runners and help facilitate flow. It ALL adds up.



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The I port-matched the ATS to the new, smaller exhaust collar (hot side of the turbo)



Using steel gasket for porting template:



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["Mad Max"]

Then I ported the exhaust collar to match the manifold:



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The trick is getting the heat out and/or balancing the heat with lots of boost... all while trying to balance the engines craving for both fuel and air. The engine came factory with an 18cm exhaust collar, which I replaced with a nice 16cm unit, which gave me quicker spool up, and mated with a bigger turbo also gave me more boost sooner. A good set up, but I still was retaining too much heat inside the exhaust manifold, so the ATS unit had to go in.



The smaller 14cm collar accomplishes two things: faster spool-up, and it has a wastegate. A wastegate functions just like a rev limiter only instead of limiting rpm it is limiting/preventing overboost. Inside the hot side of the exhaust collar is a flapper valve which is controlled by a boost diaphram on the cold side that opens when boost reaches a preset level, which I have set at 40 psi. When the cold side reaches 40 psi it pressurizes the boost diaphram which opens the flapper valve. When it opens it creates an exhaust bypass from the pre side of the hot impeller to the post side, thus reducing the amount of hot, expanding exhaust gas available to spool the hot side of the turbo. This in turn creates a maximum exhaust level which, in turn, prevents the turbo from making any more boost.



This is a pic of the exhaust collar, wastegate controller solenoid, and flapper valve. You want the flapper valve very, very tight against the inside of the collar so exhaust gas won't leak past, robbing boost prematurely. To get a good tight seal you have to bolt the solenoid in place with negative pressure (pull) against the rod and valve - IOW, you have to pull the rod out a bit, set it, and release it with pressure against it, keeping the valve tightly closed. Doing this keeps the valve closed until very high boost, in my case 40 psi.

The wastegate solenoid is connected to the turbo outlet flange via a 1/4" rubebr hose. The solenoid can be adjusted to open at nearly any psi you desire - very low boost or very high, which is determined by where the arm is threaded up or down on the rod.

To make it easy, and using technical advice from Josh at PDR (thanks dude!) I made a little air pressure gizmo that I could use to simulate high boost. Simply pressurize with an air chuck and the rod easily extends to hook it on the valve arm. Once hooked, release the air pressure and the solenoid will try to close making the valve arm nice and tight... but you still have to measure the psi at which it becomes loose and bleeds exhaust pressure. So, hit the regulator with an air chuck, and based on how far the rod arm is threaded in or out will determine how much pressure is required to move the arm - the more it is threaded in the tighter the seal will be and the more boost will be required to open it, and vise versa. The further away the rod the looser it will be and the less boost required.

You adjust the rod arm in or out. On mine, at 40 psi the valve begins to loosen and open, thus bleeding off some exhaust pressure from hot side of the turbo (limiting the hot side from spooling any further) and preventing the cold side from making any more boost, saving your valuable head gasket.

So, pressurize, set the rod, depressurize, measure the pressure, adjust to your desired boost psi. Without boost on it the solenoid keeps a very tight pull against the flapper valve which makes a good seal inside the exhaust collar.



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Turbo and collar assembled and wastegate plumbed in



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With all of that assembled the engine gained tremendous exhaling capacity which allowed it to handle more fuel, or at the very least allowed me to not have to lift off the throttle because the heat gauge (pyrometer) was nearing red. It easily runs 300* cooler (crusing at ~600*-700* on the highway) wheras before it would be 800*-900*, especially under mild to heavy throttle. The beautiful part is under heavy throttle, say passing someone - the boost builds faster because the exhasut gas builds quick (smaller collar) but with the bigger manifold it can handle so much more volume that the heat actually gets out easier, so, I got mroe boost, with less heat, and way more power because I don't have to lift. At full throttle, on the dyno today, it still gets very very hot (around 1600*), and it pegged the boost gauge right around 40 psi... right where I set the wastegate. But under normal driving conditions it never went over 900* even approaching 30 psi, and the rig was haulin'. There is a huge amount of power available and it comes on right NOW. Cruising on the highway I'm guessing the rig only needs about 100-150 hp to maintain speed, but the other 150 hp is available for those times when you need it. It might make more boost, but much more than 45 psi and I run the risk of head gasket failure... and I don't want to pull the head any time soon.



First two pulls were in overdrive, from about 50 to 104 mph: Max power 255. 8 hp and 516. 8 tq actual numbers at the tires, at 6000+ feet. Crank numbers are a corrected 297. 3 hp and 600. 5 lbs of torque



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The second pull was just slightly under that. The third, however, we did in 3rd (1:1), and that kicked it over to it's all-time best of 308. 0 hp and 620. 9 tq (corrected) and a rear tire numbers of 265. 1 hp and 534. 4 tq



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Bottom line - diesels don't suck 8). Now if I can just get the non-lockup automatic transmission out of there and get the 6-speed in...



- M2

 

["Mad Max"]

... and the day after the dyno the injection pump in Trevor's '99 Cummins crapped out... so we hauled it up to ATS in Denver this afternoon.



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We yanked it onto the street and then using a snach block we used the Nacho's winch... for the first time... and winched it up onto the flatbed. It worked great and the winch and suspension performed perfectly {cool}.



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Then, we hauled it 1. 5 hrs North to Denver - 18,000 lbs... up Monument Hill... 60 mph... in overdrive... 1100*-1200*... and 30-35 lbs of boost... rollin' right along - I'm lovin' it.



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- M2

 

[Mopar_Tim]

what turbo are you running ? the pics of the manifold are very very informing ... ... between the buildup of your nacho on rcc and the buildup of your diesel over here ..... your making my 79 td/cummins swap much easier

 

["Mad Max"]

It's a PDR HX-35 (modified/improved by PDR), and it is fantastic. I'm hitting 40 psi at max throttle - the wastegate is set at 40. The 14cm collar is particularly suited for my altitude and works great, but also works great because of the amazing ATS 3-piece exhaust manifold. That manifold has moved up to the top of my 1st gen 'must-do' list... right next to a good converter (for the auto rigs) and the #366 spring.

- M2

 

[Mopar_Tim]

how close is your down pipe to your heater box? any melting issues

 

["Mad Max"]

- bump -



not sure but some of the conversion info on the first page might help with the manual conversions going on.



- M2