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Messages posted by: GreenDieselEngineering
Forum Index » Profile for GreenDieselEngineering » Messages posted by GreenDieselEngineering
During the course of our development, we continue to improve upon various areas that we find to further improve upon the customer driving experience. As of Monday, July 27th 2009, we released what we call a “V2 Running Change” calibration that takes upon the GDE cal and adds further improvements to enhance the customer’s feedback. This process is similar to the OEM environment where as further refinements are made, they’re released to the customer after subsequent validation and verification. All ECU modules received on or after this date will receive our latest V2 calibration.

In addition to what you might have read and/or researched about the GDE tune, you’ll notice the following additional enhancements:
___•Fuel gauge linearization: The original fuel gauge display was biased towards the full side so that it would remain there longer, giving the customer the false realization that you were hardly using any fuel. We have modified the fuel linearization so that between full and ¼ tank, the gauge will (within a few percent error) display the actual volume in the tank not including the 2 gallon reserve. Hence, if you were to fill up at ¾ tank, it should hold (20gal capacity – 2 gallon reserve) * .25 = ±4.5 gallons, 9 gallons at 50% gauge reading, so on and so forth. We did this based on customer complaints that the fuel gauge was horribly inaccurate.
___•Off-road driveability in 4-LOW: While the T-case is in 4-low, we found that raising the idle speed from 760rpm to 800rpm allowed the vehicle to very slowly climb a parking curb without the use of the accelerator. Based on our testing, this resulted in a much more effortless off-road drive. Additionally, the accel pedal torque map was revised for the 4-low setting to allow for a more linear application of torque while driving in inclement terrain.
___•Vehicle driveability governors: This is just a refinement of our previous settings to have the drivetrain “clunk” less during aggressive tip-out maneuvers, especially in 3rd gear lockup.
For those living in Europe, you should be able to purchase the JK torque converter for use on the KJ. Jeep may not allow the warranty over there, at least until the part is officially released for service, not sure about it. Ask a dealer directly or ask for a unit as a spare so they don't question what you will be putting it in. The torque converter kit part number is 68037142AA and includes four bolts to mount the converter to the flexplate.
The torque converter must be purchased through Mopar and it is still not available for purchase in the US. If all the components become available, we could do complete installs for customers. We certainly recommend upgrading the TC with the turbo kit. This would allow you to have 30-35% more torque in lock-up leading to improved fuel economy while towing, less shifting on hills, improved passing, etc.
The "hot tune" has increased top end performance and it will allow maximum torque with the torque converter in "lock-up" mode. Even with the maximum trailers loads pulling in lock-up should not be an issue. No protection mode would be necessary for converter life. If shudder becomes evident in a vehicle, we can always back down the torque in specific cases.
Now that is funny! Far be it for us to use marketing to lure customers in...stock KJ 0-60 mph in 12 seconds. Stage II KJ 0-60 mph in 8.5 seconds and still improving...it is like buying a new vehicle for a fraction of the cost and still achieves an average of 28-30mpg overall. We had the KJ in 4WD part time at a launch with brake torque and all 4 tires spun!

We don't need no thought control...
On our 2006 KJ we installed a set of BFG All-terrain 245/70R16 and the fuel economy dropped about 2.5-3 mpg. We are seriously contemplating a second set of rims (as you know) to get a set of e-rated tires for summer use. The e-rated tires should increase fuel economy up to 2 mpg over stock. It would be nice to hear other mileage comparisons from KJ owners that changed tires.
The 1756 turbo has no issues bleeding off boost at any load/rpm range this engine operates in. With the vane mechanism on the turbine, we can open these up to bleed off boost. The vanes are just increasing or decreasing the flow area the exhaust gas passes through just prior to going into the turbine impeller wheel. The vanes also help direct the flow to be at the optimum attack angle to the turbine blades.

Long term we are investigating using the vane system to better control the coasting capability of the vehicle. For example, if you let off the throttle on the highway and coast it would be best to have the vanes full open so there is no backpressure restriction on the exhaust system and the engine will have less drag on the driveline. However, if you are pulling a trailer down the mountain, it would be adventageous to set the vanes to a 3/4 closed position as this will increase the exhaust backpressure and increase overall engine braking. Good to have going down a hill to save brakes. This is a similar concept to a jake brake (same end goal of increasing engine braking), just not as powerful as a jake brake because the intake and exhaust valve control is not changed.
The F37 lowered engine torque in several gears to prevent shudder initiation. Our tune will provide maximum torque in all gears with the throttle at 100%. However, in the operating range of 1650-2000rpm and with the throttle pressed to 70% we only deliver around 220 ft*lb of torque, right at the limit of shudder initiation. The transmission will "unlock" above 70% throttle and shudder will not occur if the TC is unlocked. This is th ebest balance we could find to still provide maximum torque when needed and save the TC from continued deterioration from re-occurring shudder. This is all accomplished with the eco-performance tune.

The "hot" tune will not have the same limitations built-in. We would expect to have close to 300 ft-lb of torque in lock-up conditions. It will be up to the customer to make sure he/she has the proper torque converter to handle the engine output.
This can be attributed to how the raw accelerator pedal position is filtered. We made changes to this logic so that on a tip-out maneuver, the filtering lasts longer so that, even though you removed your foot from the pedal, it still injects a very small amount of fuel for a slightly longer duration of time. We also made changes to the driveability governors that allow for an improved coasting performance.
Thanks for the inquiry, there is opportunity for expanding our range of services in the coming months. We have completed several timing belt changes and full engine teardowns, our team is very hands-on with the KJ powertrain. Providing full shop services may be a bit risky based on how few vehicles are in the Michigan vicinity, but it is always better to keep options on the table.

The yearly gathering is a very good idea and we may implement this next year once the product has gained market exposure. We are currently planning a 10-day test trip out west for stage II turbo development. We will post the route and days at location in case CRD owners want to do a meet and greet or have vehicles tuned on site. It is a start...


The first unit we pushed through to get the testing started, the second build we will take pictures and give detailed instructions for assembly. For sure, the kit will contain all hardware/software necessary for the retrofit. The intercooler on the KJ is respectable, we may test some alternatives if packaging is feasible. Would you prefer an intercooler tuned for peak power or peak fuel economy?

We appreciate the interest.

If a current GDE tune customer wants to upgrade with the turbo kit, we will have a discount to offset a portion of the tuning costs. In this way, if you get the eco-performance tune now, you will have some reimbursement with the purchse of a turbo kit in the future and not have to pay full price.
The SEGR will not add any value over and above the GDE tune. No need to install it if you are planning on the tune.

Continuing to run the SEGR won't have any negative impacts. With the GDE calibration, the only time the EGR opens is in a maneuver with potential surging of the turbo compressor so the SEGR will keep this function from happening.

In all honesty, the only time you really and truly risk surging is when the EGR is active and the throttle valve is partially closed (this is done to create a larger pressure drop and help to flow more EGR) because, with the plate closed, the system volume is artifically less and can cause the surging (sounds like a chortling sound coming from the airbox). Since we optimized the EGR to be shut (and hence the throttle plate is open), surging really isn't an issue.

So, in the end, the SEGR won't have a vastly negative impact on how the GDE calibration operates.

The reflash will be included in the price of the kit, but we don't have anything definitive for costs yet.

As for an exhaust, we've seen no benefit whatsoever by going to a larger/catless/mufflerless exhaust. You can spend your money much better elsewhere versus a new exhaust, unless it's something you just can't leave alone.
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