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Messages posted by: GreenDieselEngineering
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How fast were you going up the grade and what did you slow down to? Were you wide open throttle? With a 5000 lb trailer at 110 F we targeted runs at 55mph and settled in around 42-45mph up Baker grade. With a 3000 lb unit you should be able to hold 55 (we just push it to the floor with AC on until it shuts off on its own and keep going, the speed will gradually slow down until stabilization is found). Sometimes the trans will downshift to 2nd' if speed drops too much (used only during towing), it should pick up speed in that gear or maintain. With 3000lb or more we would recommend O/D off driving if the transmission keeps shifting up and down, 3rd lock-up keeps the mechanical fan spinning at the optimum speed for air flow through the cooling stack operating in high ambient temp/altitude conditions. Do you use trailer brakes? Definitely recommended on the KJ to help keep the best stability.

With a beefed up torque converter and tune to hold lock-up at peak torque, it might be possible to hold more grades in 4th or 5th lock-up in normal towing. This would improve fuel economy and ride smoother.

The target price is holding at $2500 based on the machining and parts cost. Our plan is to build in batches of 10 with first product available in the October timeframe. We will take reserves through email. If the interest is high we will try to increase the batch size to find any cost reduction feasible.

A 420 mile trip this weekend in 85-90 F temp, AC on, running 75-80mph with 30 miles at 45mph city driving produced 26.4 mpg. There were plenty of hard accels to exercise the foot and heart!
If the vehicle is functioning correctly there is no need for a lift pump. Our vehicles have been updated with the new fuel filter head assembly that fixes the fuel heater circuit wiring issue so the system will not pull air through the filter unit. It is important to change the fuel filter as recommended in the service manual to prevent a large pressure drop across the filter unit.

If one is having issues with hard starting, or engine shut-off due to fuel starvation there is a leak in the fuel system somewhere. We would recommend root causing the leak, but a lift pump would also address the issue. Our concern with the lift pump is having positive pressure on a fuel system that could possibly have a leak, there is a possibility that the pump could push fuel out the leak path onto the ground or in the engine compartment...this could lead to a potential fire hazard. The lift pump should be very low pressure, 2-4 psi would be plenty.

The system was designed not to need the lift pump, but the system also has potential for leaks so this is catch 22 and requires preventative maintenance.
The tune has several features that benefit towing situations. Here is a breakdown of what we have incorporated into the product:

1. Advanced injection timing and higher boost improves towing fuel economy in any gear, this also keeps the exhaust temps lower.
2. Engine torque limit while the transmission is in lock-up mode to minimize the possiblity of initiating "shudder" in the torque converter. This helps to prolong the life of the TC.
3. The electric fan is turned on when the transmission fluid is above normal operating temps when towing. The top three rows of the trans cooler are exposed to the electric fan in the cooling pack and we modified the tune to activate the fan based on trans fluid temp. This is not active in the production calibration.

Honestly, you do not have to be concerned when the coolant gauge starts to rise, only when it is in the red zone do you need to back off the throttle. The engine is self limiting based on coolant temp. The AC will automatically shut off when the heat load is too great. Check out our coolant gauge temperature breakdown on this forum for the 2005 and 2006 clusters.

We could change the the coolant gauge output that is displayed on the cluster to always point in the middle safe zone unless there is an emminant problem. We have not done this and want to gauge what the owners would prefer. If the gauge is moving toward the red zone when the engine is still in normal conditions it does not make much sense and only leads to unwarranted concern by the driver. What is your opinion about this option?
A fuel cooler is not necessary on the KJ CRD. The temps rarely get over 130 F and only in low fuel level situations. Towing a 5000lb trailer with low fuel one can see up to 175 F with less than two gallons remaining in the tank...ie. with low fuel light on. Not something most people would ever consider doing. A fuel limitation starts around 160 F and progesses up to 195 F at which time the engine will only idle. We have never seen temps near this high.

A fuel cooler can be a drawback if living in cold climates, there is more potential for line freeze with a cooler and the fuel heater on the vehicle does nothing for frozen fuel lines near the tank.

The improved coastdown goes help with MPG, but the diesel still has more inherent engine braking than a gas job due to the 17.5 to 1 compression ratio. Definitely understand your point about mountain driving, during testing we have cranked up the boost at zero throttle going downhill by closing the turbo vanes and the engine braking almost doubled...it would be a very nice feature for mountain driving with a trailer. We are investigating having minimal engine braking in 4th and 5th gears, but having higher engine braking in 3rd gear (when the O/D off button is engaged)...typical only used when trailer towing. If you want a specific setting in the tune we can always set it for your preference.

Is your CRD a 2005 or 2006? That seems a bit hot for daily drving...even in warm weather. You were very close to the thresdhold for when the mechanical fan would engage. If this happened you would be able to here an audible roar from the engine compartment as the fan is very loud. With the AC on, the electric fan is usually on low speed and with the high ambient temps it probably was on high speed due to the elevated AC head pressures.

If it happens again just keep everything on, don't turn off AC. Pull over and check the front grill area to listen for the electric fan at idle, it should be on. If not the electric fan may have an issue. Any chance you have build-up on the condensor or radiator from bugs, cottonwood, dirt or other particles? We do off-road mudding from time to time and have seen massive amount of mud and dirt collected in the cooling system on our vehicles...a good washing with the hose keeps the cooling pack clean.

Do you ever tow with your Jeep? If not, the gauge will never leave the middle mark. With a 5000 lb. trailer going up Davis Dam, Baker Grade or Eisenhower Pass the gauge will run toward the hot limits. This engine is designed to perform without issue with the coolant at 239 F (115 C), this is why the AC will cut out first (based on the cluster calibration). The engine will run all day at 234 F (112 C) with minimal fuel limitation. With the pressurized cooling system and bottle, there is plenty of expansion room for the coolant at higher temps. The coolant bottle cap was designed with a specific pressure setting to prevent cavitation in the cooling system, which would lead to hot spots in the cylinder head.

The only recommendation we would add when trailer towing is not to shut off the engine immediately after going up a grade at max GCW. This is referred to as a heat soak and will lead to very high temps in the cylinder head. It is always best to keep the engine running at idle after a heavy tow up a grade. If for some reason someone is pulling a trailer above 5000 lbs. there may be overheat issues pulling up grades in the desert, we have tried this and turned the heater on max hot with AC off and the heat rejection from the heater core was enough let us run up the grade with coolant temps around 235 F.
For those vehicles that have not had the cluster updated per TSB 08-043-05 to cure the mis-reading of the coolant temperature, here is how the gauge indicates and the relevant information:

(Click on the picture for the full-size version of course)

If you go to a dealer, the TSB should be applied for free. After the TSB, the gauge will read as it does in the first picture.
The optimum stall speed for the KJ CRD would be in the 1800-2000rpm range, right where peak torque is reached. The multiplication ratio is also important and you may have a hard time finding this type of information, usually only known by manufacturer. Lower stall speeds have a side benefit of reducing transmission fluid temps as there is less slippage in normal driving conditions in unlock mode.

Why would the 07+ hemi 5.7l TC have such a low stall speed? Most gas engines typically use converters with higher stall speeds since the torque peak occurs at higher rpms as compared to a diesel. It could be the multiplication ratio is very low on the hemi 5.7, which may lead to less aggressive launch performance if installed on the KJ CRD.

In our opinion the Euro TC is a good balance between stall speed and multiplication ratio and we are confident in its increased clutch capacity during "lock-up". As soon as these are off backorder we will have a couple of them for validating the hot tune and turbo kit. The hemi converter was designed with an 8-cylinder in mind for the lock-up clutch capacity. The KJ CRD torque is similar to the hemi in overall output, but the torsionals will be substantially higher due to having 4-cylinders. These torsionals are the prime driver in "shudder" and lock-up clutch failures.

Another thing to keep in mind, if using the GDE ECO tune or HOT tune, the torque peak is increased and the torque band is broadened. For comparison, stock KJ CRD torque range at/above 290 ft*lb is between 1600-2600rpm and with the ECO tune at/above 290 ft*lb is between 1400-3200rpm. With this broad torque range, the optimum converter should provide a solid launch, minimal slip for heat rejection and keeping the engine rpm in lower ranges to maximize fuel economy.

This is a breakdown of the coolant gauge and where the needle falls for a given temperature. All temperatures are in fahrenheit.

As long as you're running the car and the needle is within the black portion of the gauge, hammer down. The engine is self-protecting and you need only hold it to the floor when towing up hills and so forth.
The questions are good, we are here to help in any way possible.

Factory torque converters are rated by K factor. Stall speed is a factor of input torque, so the factory KJ 2006MY converter will have two different stall speeds if it is used with the stock engine cal or the tuned cal from GDE. Since ECO tune has more torque than stock, the stall speed may be 100-200 rpm higher.

The K factor for stock KJ converter and Euro TC is the same as far as we understand. It provides a good balance of transmitting useable torque to the wheels and keeping the rpms in check to have decent fuel economy. If the stall speed is too high, the engine will have to rev at higher rpms to keep the vehicle moving. Typically gas torque converters have higher stall speeds than diesel converters.
We would recommend a full NHRA top-fuel roll cage, chromoly exo-skeleton, Dana 80 axles front and rear, Rubicon T-case, 5-point harnesses, and a parachute for insanely-fast quarter mile times!

All joking aside, we've done all of our development based around the stock vehicle hardware. The kit is designed for the consumer to just unbolt their turbo and replace with the new one, make some slight wiring modifications, and enjoy their new-found performance and power! Of course, upgrading your vehicle certainly won't hurt anything, but running everything at their stated limitations hasn't shown any failures yet with the stock hardware.

Based on your list of modifications done so far, you should be good to go for further power enhancements.
The TCU is in charge of what engine speed/vehicle speed/pedal position dictates the upshifts/downshifts and when to lockup the torque converter (partial lockup isn't available for this application). However, the engine ECU is in charge of how much torque to allow at those various load points. This is how we can allow either "full torque" while in lockup, or our modified tables which eliminate the shudder while in lockup at the applicable load points.

Regarding the boost, the maps available on the Garrett website are only applicable to the wastegated version of the GT2056 and don't apply to the KJ's VGT version since it has different trims, A/R's, and wheel diameters. For VGT applications (and all turbo families for that matter), it's important to pay respect to three main constraints: compressor outlet temperatures, turbine inlet/outlet temperatures, and rotational speeds. For this application, the wide-open throttle performance is limited by the turbocharger speed - if you exceed the rated speed for too long then the turbo will self-destruct; however, the same goes for the temperature limitations especially in trailer-towing conditions.

The boost setpoint has been optimized at all engine points to provide the best fuel economy, which translates to both the lowest BSFC at each point and the lowest CO2 output. If you raise the boost setpoint too high in normal driving and thus close the vanes too much, then the engine has to work harder to force the air out through the turbine housing and the fuel economy goes down; conversely, if the boost setpoint is too low, there isn't enough air in the cylinder for complete combustion and fuel economy goes down and the engine smokes. Tuning for peak fuel economy isn't as simple as cranking the boost up all the way and going to town, each operating point must be optimized independently.

We spent considerable time in altitude earlier late spring/early summer to maximize the turbocharger performance in altitude. The tradeoff with higher altitude conditions is that with air of lower density, the turbocharger spins faster for a given boost setpoint so we have to pay respect to these limitations when tuning the boost system. At a given altitude, the boost setpoint was adjusted to give the maximum speed permissible so that performance would suffer as little as possible. This is mainly an issue at WOT throttle and load points slightly less, in normal driving we are able to mostly maintain the sealevel performance for boost and fuel economy.

Our tune (regardless of power level) at WOT from sealevel through 12000' is able to maintain a PR between slightly over 3 at sealevel to down to 2.7 at higher altitudes.

We currently have the new torque converter on order but thus far they are on backorder and should be available mid-september.
We cannot change any transmission behavior, but the engine will produce significantly more torque. The TCU is not sending torque signals on our vehicles. The customer can specify if one wants full torque in "lock-up" or just partial torque if using a stock converter.

We modify the code to raise or lower boost setpoint, which drives the vacuum level at the turbo.

For this tune we focused on maximizing the turbo speeds in WOT conditions running close to the surge limit and following to the peak speed line. In normal driving, the turbo is tuned for maximum efficiency zones that provide the best fuel economy. The fueling tables have several breakpoints and cover the full engine operating range. We only change the parts of the code that can be deciphered.

The euro TC part number is: 68037142AA. It is our understanding that this converter can be ordered through a dealer or mopar online (less $$$). The converter is on back order until 13 September at this point in time.
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