Non TDI VWs have head gasket issues at stock power levels, worse as you go faster. When you push them over 80 or 90 HP, they dislodge the prechamber liners. For 150 HP, better to get a TDI. A good TDI can put 250 HP to the ground on a wheel dyno & still get 40-50 MPG. The IDI head has a built-in efficiency disadvantage of about 10-20% due to heat losses & flow problems incurred by the prechamber design. Also, the Volvo diesels are VW-built, just have more cylinders. For the trans, you better get a TDI unit, or else it will be too low geared. Besides, a good diesel VW will shred an ordinary Rabbit gearbox as quick as you can say it, and probably quicker.
I have not heard anyone here in
land discuss IDI vs.DI heads, but I am guessing the same rules apply... Any thoughts on that?
I have an 81 Caddy pickup for just such a project. I already bought a new TDI motor, and I am looking for a 6-speed TDI trans right now. I will set it at about 150-200 HP.