Volkswagen TDI Powered Jeep Project by HPA Motorsports
After many years of building high powered VW’s, President of HPA Motorsports, Marcel Horn,went looking for a recreational vehicle that could support his thirst for torque, yet keep his three young boys safe during weekend adventures. Living in the Pacific North West, weekends are punctuated with routine camping trips into the great outback where endless miles of logging roads and trails are waiting to be explored.
Project Criteria:
• A chassis that was capable, yet affordable
• A powertrain that was simple and durable
• Fuel mileage able to support long range explorations
• A do-all platform that could transport a variety of equipment
Stumbling across a red 1991 Jeep YJ peeking out from a barn where it had been stored for more than 6 years; a project was born.
With 19 years of experience swapping motors and creating some of the fastest VW/Audi’s in the World, our team’s mind was swimming with thoughts of Volkswagen’s diesel offerings which reign supreme in Germany. The Jeep's 2.5L 4 cylinder motor left a load of unused real-estate under the hood; When you study one of our twin turbo Beetle engine bays you can only imagine how appealing the Jeep was at first sight.
The concept: to mate a VW TDI motor with the Jeep’s drivetrain from the flywheel back.
We chose to use the late model PD diesel from the 2003-2006 Golf/Jetta/Beetle which boasts 47mpg on the freeway. With a simple performance flash to the ECU it rates 165 crank HP and 265 ftlbs of torque.
Our in-house engineering team sunk their teeth into the project; using CAD to develop the power train interface and motor mounts while our expert tech team set out to integrate the electronics.
With the major hurdles now crossed we are down to the finishing touches and final installation before unveiling the completed project... We have received many questions about this build, and offer below some insight into the direction this project has taken behind the scenes:
Initial study and conversion:
We started with a 1991 Jeep Wrangler YJ with the 2.5L 4cylinder and AX-5 gearbox as there seems to be no economical rebuild path for the aging power train on this very common package.
The (PD) TDI engine we selected weighs in 55lbs lighter than the original 2.5L AMG motor we yanked out, and produces 45 lb-ft more torque that our Jeep would have done in its prime.
With the engine removed, the OEM frame mounts have been detached and our new mounting solution is bolted in. You can choose to either weld or bolt on our mounts, but our test mule will have these bolted on so we can stress test them long term.
We retained all original Jeep geometry from the flywheel back through a crank shaft adapter and bell housing adapter assembly. The OEM Jeep flywheel is modified to match the crank shaft adapter bolt circles allowing you to uses any off the shelf Jeep clutch kit.
We have had many satisfied years of working with SPEC for all our high performance Volkswagen/Audi builds and as such have chosen their Stage 3 clutch kit for our Jeep project.
The engine has now been in and out of the Jeep a number of times as we documented and patterned the widgets that have gone into this initial build. It is very exciting to see the cleanly installed assembly as it looks like it could have come that way from the factory.
Our TDI is rated for 100hp and 180 lb-ft of torque stock in its stock form but has even more potential with a few simple performance mods. Because our conversion retains the original engine ECU, a power prom flash can easily be added to bump this to 165hp and 265 lb-ft of torque respectively.
Adding to this package, we have designed our downpipe to mate up with an off the shelf Magnaflow 2.5" exhaust system for the Wrangler. As it happens, 2.5" is the ideal diameter for maximizing the power of the TDI.
We are also exploring a custom cam for our PD motor that will smooth out its idle and adds a proven 12hp gain and 22 lb-ft of torque as a stand alone upgrade (outside any power flash).
Our team is only weeks away from unveiling the finished project, complete with some new goodies for the body and chassis, and we will have pricing available after the Labor Day long weekend.
We will be offering three groupings:
Package 1
Grouping 1 is a bare bones package targeting the Do-It-Yourselfer. It will include everything required to take a late model TDI motor and physically integrate it with the 4cyl YJ driveline. Our team will supply a list of TDI engine codes that are best suited for this conversion.
As pictured:
- engine mounts
- bell-housing adaptor
- crankshaft adaptor
- Machined flywheel (exchange)
- Downpipe
Package 2
Grouping 2 will include everything in Grouping 1 and will expand it with our custom air intake solution and an air to water cooling package, along with the coolant line flanges we have designed to retain the OEM Volkswagen cooling system.
Package 3
Grouping 3 This package will be a little ways off but will include an entire engine assembly with the majority of the electronics prepared for installation; including radiator fan assemblies, etc.
*** For all three groupings, we will offer an "Immobilizer Defeat" service to those wishing to utilize the original VW wiring harness and ECU as we have done in our project. This will open the door to a variety of TDI power prom upgrades and retains access to factory VW OBD diagnostics.
Once the demo truck has been shot by JP magazine, we will bring in an AX-15 gearbox and start at the adaptor system for it, along with pulling in a 6 cylinder Jeep to verify that our current mount solution will cross over with no issues.
UPDATE: October 7, 2010
The past several weeks have been busy ones as our team has been working aggressively to finalize tooling and fitment for the Jeep TDI conversion while at the same time, augmenting our YJ’s running gear with a variety of upgraded parts.
To ensure our YJ was up to the task of transmitting the torque and HP of our TDI swap, both the Dana 30 and 35 axles have been torn out and beefed up. Precision Gear was called upon to outfit these small pumpkins with 4:10 gears and Alloy USA delivered unbelievable axles. The quality of these parts builds back our confidence in these OEM axles.
We have made some minor adjustments to our initial engine mounts to facilitate a seamless integration with the OEM rubber mounts. We have elected to supply a ready to install flywheel along with heat shields for the starter to protect it from the downpipe. Lastly, the downpipe has been re-routed to ensure it mates with off the shelf 2.5” exhaust systems. In our case, a Magnaflow has been strapped to the underside of the YJ.
Our Stage 1 Grouping is now finalized and is targeted to the “Do It Yourself” enthusiast. Take a browse through the product photo gallery to see detailed pictures of the installation. Note: Our engine mounts can either be bolted in or welded on. The installation images showcase the installation using the supplied bolts. Minor clearancing is required on the AX-5 bell housing to accommodate Bosch starter nose
The Stage 1 adapter set is as follows:
• CNC flywheel/crankshaft adapter
• CNC bell housing adapter plate
• Left and Right Male / Female engine mount set.
• (OEM jeep rubber mounts not included)
• Downpipe
• CNC machined Starter flange and heat shields
• (Bosch Starter not included)
• Flywheel and Crankshaft bolts
• Dowel pins for bell housing
• Turbo outlet adapter
Also included is a short OEM parts list to identify starters, engines etc. required for a successful conversion.
Stage 1 package $2599 USD
Our Stage 2 package’s intake track has been finalized. An air to water intercooler has been configured to optimize the space available under the hood, and sustain charge air cooling during low speed off-road applications. With off-road low gear terrain, air to air cooling intercooling as the factory TDI’s are equipped was simply not a good fit. Using a stand alone closed loop water system, our secondary radiator, cooling fan, pump and after cooler can maintain a steady state air intake charge best suited to feed our high torque output.
Our Jeep is bound for a debut at this years SEMA show. Once we return, we will develop the AX-15 adapter for late November release.
As always, we welcome your questions and feedback. Please contact us at info@hpamotorsport.com or call 604-598-8520.
UPDATE: November 9, 2010
HPA Motorsports' TDI powered Jeep makes its debut at 2010 SEMA show
HPA Motorsports' Volkswagen TDI Diesel Powered Jeep Wrangler garnered much attention at the 2010 SEMA show as it made it's debut outside the central hall at the Las Vegas Convention Center last week.
This unique Jeep YJ features HPA's 1.9L 4 cylinder PD Turbo Diesel conversion, enhanced with an air-to-water intercooler system and performance ECU flash to garner 165 hp and 265 ft-lbs of torque. The rebuilt Jeep AX-5 gearbox, Dana 30 and 35 axles with Eaton differentials, and Precision Gear 4.10 ring and pinion, and Rugged Ridge ORV 4" lift kit ensure the chassis is up to the task of weekend off road expeditions.
The impressive fuel economy provided by the TDI engine, combined with the 20 gallon fuel tank and extra Jerry cans from Blitz, means hundreds of miles of back country can be explored worry free. With Rugged Ridge bumper, stinger, and skid plates, Metal Cloak body armor, Garvin racks, and Hella lighting, the Jeep is right at home on the trail.
With numerous inquiries on the TDI conversion package flooding in, the HPA development team is setting to work on adapting the package to accomodate the TJ / AX-15 and other configurations.
HPA Jeep TDI as seen at the 2010 SEMA show
HPA Jeep TDI as seen at the 2010 SEMA show
Racking and Accessories
Smoked Lexan hood gave a sneak peak at the TDI engine bay
Special thanks to all of our partners for making this project happen:
UPDATE: November 17, 2010
TDI Jeep Complete Conversions now available!
We have officially released the stage 1 and stage 2 packages targeting the Do-It-Yourself enthusiast. These hardware groupings will allow you to adapt the 1.9L TDI engine from any Mk4 VW Golf, Jetta, or Beetle into the Jeep.
For those looking for a complete package, HPA has secured a limited supply of brand new 1.9L PD TDI engines to facilitate in house builds, and our workshop is now accepting bookings.
To ensure our YJ was up to the task of transmitting the torque and HP of our TDI swap, both the Dana 30 and 35 axles have been torn out and beefed up. Precision Gear was called upon to outfit these small pumpkins with 4:10 gears and Alloy USA delivered unbelievable axles. The quality of these parts builds back our confidence in these OEM axles.
