Matt's 1.8T dune buggy side project
Posted: Tue Oct 24, 2017 7:01 pm
I started this project a little over a year after being inspired by a buggy me and a friend built that was converted to run on a 2.0 ABA engine and digifant 1 engine management. The one i built is a bit more elaborate than that one but i wanted to use a 1.8T for more power and the old aircooled transmissions fall short on holding such power and abuse without dumping a ton of money into them. This is my mid engine 1.8T buggy. i will have better pictures posted up eventually.
Its a normal 70's/80's california style buggy chassis that was originally based on using all OG beetle parts. i have since modernized most of it with common and readily available VW/audi parts. it still retains the original beetle front suspension and steering box along with the beetle rear torsen beam. it has custom made swing arms in the rear for the mid engine setup. the arms where original beetle IRS arms with a box arm kit installed on them.
The engine is literally built out of the junk pile in my garage. its running an 03 audi A4 1.8T bottom end with a head from an 02 jetta engine. it has stock turbo/manifold but the manifold is modified to use a tial 38mm external wastegate with 15psi base spring. its running a stock AEB intake with MK3 0BD1 throttle body. on the fueling it has an 8 gallon ebay fuel cell, ebay bosch 044 knock off, 4bar FPR and stock AAN 20V injectors. the transmission is stock from a 1999 VW passat 1.8T with a southbend stage 2 endurance clutch set including single mass flywheel. axles are modified late audi A4 front axles with tripod joint inners and 100mm outer CV's from MK3 VW. custom machined adapters allow the 100mm CV to bolt to the original 90mm CV stub axle. the stub axles and outer hubs are modified with custom machined parts so that the rear is now 5x112 bolt pattern for using modern VW/audi wheels. the brakes are URS4/URS6 rotors and G60 dual piston calipers on custom made caliper brackets. for stopping and clutch i have an OG neal pedal set from the 80's that was NOS along with an empi throttle pedal. the throttle cable is a PTO cable from an international tow truck as well. the cooling system for the engine uses a radiator from an XJ jeep cherokee, fan is from a W123 mercedes benz, thermal switch is from a URS4, and all radiator hoses are custom made. the fuel management system is digifant 1 from a 1990 corrado G60 that uses a 250kpa MAP sensor from a URS4 ECU with a custom made harness to fit the buggy specifically. for the ignition system it uses a custom made distributor that drives off the intake cam where the original cam position sensor was. for plug wires it has old school NGP high output 16V plug wires with custom 3D printed covers to go over the coil holes in the valve cover so no water gets in there. over all im sure there is plenty more im forgetting lol.
Over all its running at 15psi but can run 20psi max before the limit of the MAP sensor is met. it is scary fast at 15psi although i have had it at 20 and its about useless with severe traction issues on pavement or dirt.
here's a few videos off my youtube of it in action. i will upload more later there as well.
This is a hard spark cut launch control, sucks you cant see the flames and fire in the day light lol. i will have to post the night launch videos.
i kept shearing off engine mounts at one point so i made a whole new solution and decided to stress test it the fun way. also you'll notice it has a hard spark cut RPM limiter, i had problems with it pushing over the stock fuel cut one so i created this in the ECU to make sure it stops. puts on a great show for people lol.
This is a trip on my favorite trail in the woods behind my shop.
Its a normal 70's/80's california style buggy chassis that was originally based on using all OG beetle parts. i have since modernized most of it with common and readily available VW/audi parts. it still retains the original beetle front suspension and steering box along with the beetle rear torsen beam. it has custom made swing arms in the rear for the mid engine setup. the arms where original beetle IRS arms with a box arm kit installed on them.
The engine is literally built out of the junk pile in my garage. its running an 03 audi A4 1.8T bottom end with a head from an 02 jetta engine. it has stock turbo/manifold but the manifold is modified to use a tial 38mm external wastegate with 15psi base spring. its running a stock AEB intake with MK3 0BD1 throttle body. on the fueling it has an 8 gallon ebay fuel cell, ebay bosch 044 knock off, 4bar FPR and stock AAN 20V injectors. the transmission is stock from a 1999 VW passat 1.8T with a southbend stage 2 endurance clutch set including single mass flywheel. axles are modified late audi A4 front axles with tripod joint inners and 100mm outer CV's from MK3 VW. custom machined adapters allow the 100mm CV to bolt to the original 90mm CV stub axle. the stub axles and outer hubs are modified with custom machined parts so that the rear is now 5x112 bolt pattern for using modern VW/audi wheels. the brakes are URS4/URS6 rotors and G60 dual piston calipers on custom made caliper brackets. for stopping and clutch i have an OG neal pedal set from the 80's that was NOS along with an empi throttle pedal. the throttle cable is a PTO cable from an international tow truck as well. the cooling system for the engine uses a radiator from an XJ jeep cherokee, fan is from a W123 mercedes benz, thermal switch is from a URS4, and all radiator hoses are custom made. the fuel management system is digifant 1 from a 1990 corrado G60 that uses a 250kpa MAP sensor from a URS4 ECU with a custom made harness to fit the buggy specifically. for the ignition system it uses a custom made distributor that drives off the intake cam where the original cam position sensor was. for plug wires it has old school NGP high output 16V plug wires with custom 3D printed covers to go over the coil holes in the valve cover so no water gets in there. over all im sure there is plenty more im forgetting lol.
Over all its running at 15psi but can run 20psi max before the limit of the MAP sensor is met. it is scary fast at 15psi although i have had it at 20 and its about useless with severe traction issues on pavement or dirt.
here's a few videos off my youtube of it in action. i will upload more later there as well.
This is a hard spark cut launch control, sucks you cant see the flames and fire in the day light lol. i will have to post the night launch videos.
i kept shearing off engine mounts at one point so i made a whole new solution and decided to stress test it the fun way. also you'll notice it has a hard spark cut RPM limiter, i had problems with it pushing over the stock fuel cut one so i created this in the ECU to make sure it stops. puts on a great show for people lol.
This is a trip on my favorite trail in the woods behind my shop.











