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MIGHTYMAX SWAPS

My truck, as seen on the shop cars page, was done in the pretty standard way many swaps are done. A lot of fabrication. DSM 4g63 engine, TH350 trans. Custom motor mounts, motor moved ~3 inches forward, trans cross member, extended driveshaft, engine adapter plates and custom converter, etc. That was a 1988 carbed manual trans truck.

 

For this 1990 injected auto trans truck, now often known as "Eric's truck," I wanted to do things a little differently. I came up with this plan in 2012 when we found the truck for sale locally, but it took a long time to get around to it. It ends up being a very clean, simple swap, as if it could have come this way from Mitsubishi, with only the wiring being more complicated. I get a lot of questions about this truck, so I'm putting this brief overview together to help explain the important points. 

The key to this method is to use the stock block with a kiggly crank sensor, and a 1995-96 DSM head and front cam angle sensor. This eliminates the need for the 1g CAS at the back of the head, and the need to push the motor forward for clearance (or firewall hackery that eliminates the heater core). The stock wideblock can be built internally with DSM-like parts to whatever power level you want, just as you would do with a stroked 4g63, or just like you would do for a stroked/destroked 2.4 block in a DSM. This truck is a fairly simple build, so it got Manley rods and Wiseco HD pistons. The head bolts right on with no need to fuss with plugging steam ports, etc. It was a perfect match to the DSM head gasket. The front of the motor will accept all 4g63 front end parts. Oil pump, water pump, timing components, and kiggly crank trigger. 

This was an auto trans truck, which was bought specifically for two reasons. One, the body comes with a much larger trans tunnel. Fitting a TH350 under my manual trans truck body was a pain in the ass, so this is an upgrade. And two, it can easily be built to handle a lot of power. It's all chrysler trans parts on the inside, in a case that bolts up directly to the wide 4G64 block. Since the motor did not move, the trans crossmember and mount are also unmodified. No adapter plates, no special converters or starters, all stock parts. I have not yet looked into converter options, but I'm sure this one can be restalled, or other chrysler cores can be found that will work well with some internal modification for stall speed. We had Accurate Trans upgrade several internal parts, including a manual valve body. It should be good for around 800 hp, which ends up going even further with the low 4 cylinder torque. The manual valve body is key, it eliminates the need for a throttle valve cable. One could be fabricated, but this saves the trouble. I also find that it's best to shift manually even cruising around in traction limited trucks like this. The column shifter has been removed, and it will get an aftermarket floor shifter. Any shifter that works with Chrysler transmissions will work here. It's an overdrive trans with a lock up converter, which is better for street use than the TH350 in my truck.  
The manifolds on my truck are both custom parts I had made, but this truck will use stock type manifolds to save some cash. The exhaust side will be the standard flipped turbo. For the intake side, we used an EVO8 manifold that was modified to work with the DSM head. The fuel rail mounts were removed, injector ports welded and cut, and then the whole thing cut flat on a mill. Some other minor changes were to the EGR setup etc. It clears the booster and puts the throttle body in a reasonable spot. I wouldn't expect this to have a whole lot of top end on a 2.4 liter, but it should get on the converter well.  
The next hurdle is the cooling system. With so little clearance between the head and firewall, no standard thermostat housing is going to fit. Clearance is about 2 inches. Jay Racing makes an adapter to run a thermostat housing, or an AN fitting, on the front of the head. Some feel that this will not provide enough coolant flow to the back cylinders. I've never tested it. The compromise I'm making here is to run the main water outlet on the front of the head (to a remote thermostat housing, like I use on my truck), and a small -10 outlet on the back of the head. This will feed the heater core to provide heat and encourage some flow across cylinder 4. I made a custom low profile -10 outlet for this, seen below. The radiator will be a spare race radiator from my car with AN fittings on it.  
To provide a return for the heater core, the DSM style water pump was modified with some AN fittings. A -16 out the end to go to the radiator, and a -10 out the back to run to the heater core. The head is still very close to the heater core ports, some tweaking is necessary there. 
The next obstacle, which might be the biggest for many people, is the wiring. Unlike the earlier trucks that had a separate engine harness, the later injected trucks combined the engine harness with the body harness. What I did here is remove all of the engine harness wiring, which is really not of any use with the turbo engine layout, and run all new wiring and connectors for the engine harness. The harnesses are still combined. While a separate "standalone" or swap type engine harness could be used, keeping them together serves two functions. The engine wiring and body wiring is tied together inside the harness, there is no connector to combine them like you find in the carb trucks and DSMs. And it looks more like it came this way. The stock ECU uses the same three ECU connectors the 1G DSM ECUs use, and some of the pinout is shared. New ECU pins were used as well as all new connector kits at the engine. Connections between the engine and body include the speedo, tach, CEL, etc. Everything will work like stock. I didn't keep track of the hours in this part of the project, but it was a lot. A turbo 1G DSM ECU will be used, with ECMlink V3, speed density, and flex fuel. I don't plan on using ECU controlled boost, but wired in a connector for it anyway. 
In preparation for some drag launches, the oil pan was baffled somewhat and I welded a turbo drain line fitting to it. It's just a simple barrier setup to allow oil to flow forward more easily than rearward. This is not quite as sophisticated as what's in my Talon (which works well to 1.16 sixty foots and wheelies), but has been good enough to 1.60 sixty foots in my truck. 

As with my '88, we're keeping the stock rear axle, with an LSD, and stock suspension, with some inexpensive slapper bars to prevent axle wrap and protect the rear u-joint and driveshaft. This has all worked well on my truck at 600 whp and mid 10 second ETs. The injected trucks can likely take a typical 255 upgrade in the tank, simplifying the fuel system. 

None of this has really been tested yet, but I hope this brief overview answers some questions and gives you guys some ideas for your own swaps. I'll update this when we get back to making progress on this project. 

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