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Messages posted by: GreenDieselEngineering
Forum Index » Profile for GreenDieselEngineering » Messages posted by GreenDieselEngineering

Is the CEL off? Any changes in starting the engine stock vs. tune? Were you using the additives pre-tune? Are the mileage figures hand calculated? and not EVIC as it has some accuracy issues on most KJs. Have you noticed an improvement in city driving, launching and passing? Hopefully the mpgs will increase for you, the extreme cold will rob a few %, but nowhere near where you are running. What driving mix is typical for your KJ, city/highway?

Thanks for the feedback.
The problem is the housing was never designed to be serviceable. It is made of die cast aluminum with the thermostat sandwiched between the top and bottom housing. The lower housing is pressed into the lip of the upper housing. This must be pryed apart to remove the thermostat and usually leads into cracking the housing or something so it will not reseal properly. 3 bolts and a gasket would be a dream for the CRD.
That is a nice alternative! The two t-stats inline will add some restriction, which will lead to a slightly higher head pressure and less flow to the radiator. The bypass, heater core, EGR cooling, oil cooling may see a significant increase in flow. The water pump should be fine, just a little more torque load on the engine, which may/not be noticeable in mpg. This would not be good if the CRD will be pulling a trailer up Davis Dam on a 100 F day, the system is already at capacity and the loss of flow to the radiator would cause a significant decrease in vehicle performance. All other conditions should be fine. Have you priced a replacement OEM thermostat, just for comparison?
Here is the link with the timing belt replacement procedure.

GDE Timing Belt Replacement Process v3
The following link will take you to a pdf file that details the turbo installation including step-by-step instructions and pictures.


The file is almost 2 meg and takes a little bit to download. This is a good review to know the workload and to determine if you feel comfortable completing the job or sending it out to a local mechanic.


The turbo kit can always be reverted back to the stock configuration and GDE will reflash the ECU with the proper tune if a need should ever arise. There are three changes that would require retrofit:

1. Weld the original exhaust downpipe back to the exhaust system.
2. Cut and solder the two wires that connect to the turbo EVM connector.
3. Weld the turbo heat shield back together.

The welding is very straight forward. The new exhaust downpipe has a slip joint that will slide over the exhaust pipe under the vehicle. This needs to be welded at the joint all the way around 360 degrees. One can use a MIG, TIG or stick welder to accomplish the job, it just depends on how pretty you want the weld to look. We just welded a couple inches at a time and then rotated the pipe to the next section. In total there is about 8 inches of weld and the metal thickness is about a 1/16 inch so it will be hard to burn through.
After making your provent, how much time did you give the engine to clean itself out? There always seems to be some residual that never disappears. Be careful with CCV mods if in winter climates. Having a longer breather hose increases the chance that water vapor will freeze in the hose and prevent the engine from properly breathing. If this happens you risk blowing oil out the front and rear main seals.
The higher temp thermostat will help combustion efficiency a bit and it helps to reduce some frictional losses slightly. It also helps with cabin heat in the winter. Most all new diesel engines have thermostats that start opening at 90 C, the KJ starts at 80 C. In 2008 all the new VM engines in Europe came from the factory with 90 C thermostats. Too bad the design changed, so they are not interchangeable with the KJ. The tune will work the same regardless of which thermostat you use.

For sure you can drive in for a tune, we would just need to set-up a time and place. You may want to check your fuel economy with some hand calculations as the EVID tends to be biased to the high side. Your vehicle sounds like it is getting decent fuel economy at the mement, but a tune will just add on top of that.

Look in our forum under "FAQ" and the topic "engine performance". It has the graph and numbers you are looking for.
The kits need some final welding and each one test fit on a vehicle. Availability is set for 01 February! We were able to get the price down to our target of $2500 and current tune customers will have an additional $300 discount for chosing the upgrade.

For any owner with a failed stock turbo, this kit is price competitive to that of stock replacement. Add in the massive performance increase and fuel economy bump, it becomes even more adventageous!

Those are some good numbers with the tires you are rolling on! A little brake torque makes for an agressive launch. Don't post this tank's fuel economy numbers...you'll make us look bad! ha ha
"Destructive" testing on a KJ CRD:

1. Increasing the engine output torque to find "shudder" with stock torque converter. Then backing off on allowable torque for customer vehicles to prevent shudder. The original TCs on our vehicles had a rough life and were in dire need of the Mopar TC upgrade.

2. Pulling a 7000lb trailer around to validate acceleration ability and being able to hold a steady-state speed on the highway. Not so destructive, but not good for suspension life and very hard on u-joints.

3. Repeating 0-60 performance runs until brake fade was very apparent. Warped a few rotors in the process!

4. Off-road validation caused a major issue with one KJ being stuck overnight in a river. We needed a track loader to drag it out. The sand bar wreaked havoc on the u-joints, front axle pinion seal, and another brake job.

5. We found that the front bumper assembly is mostly held on with little plastic push in fasteners...these readily fail if the nose of the vehicle comes down too hard after a small jump.

6. The CAC hoses are weakened by oil seepage and pop like popcorn with the stage II turbo kit. The Samcos fixed this failure mode.

Both vehicles are still going strong despite our best efforts. We will have these in our arsenal for a long time coming!
We concur with flman, there is no need for the provent or EHM with the tune. The intake may not fully self clean over time, but the build-up will stop occurring. Oil going through the engine is not a problem. You need to be aware that the oil will still bleed through the CAC hoses and weaken them over time. We would recommend the Samcos as a good fix due to the silicon lining so the oil does not bleed through.
The stock tune does open the turbo vanes in fast tip-out situations to protect the turbo. We modified the stock settings to make the response quicker and to allow the turbo to build boost back to the desired level faster after the tip-out event when the accel pedal is pushed again. It is safe to unplug the MAF sensor and it should slightly improve your fuel economy. The main issue is that your check engine light will always be on and if you have a real problem you will no know and engine damage could occur. We think it best to make sure the CEL is off normally and only comes on when a real problem is present.
The BCM is a separate module and will not effect the tune.
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