How about a turbo VW?

Since going to the Challenge as a spectator I've got the bug to participate. I'm spending way too much time on Craigslist looking for a likely candidate vehicle. I have seen a turbo diesel VW Beetle for Challenge money. I was wondering how hard it would be to cheaply crank up the power for the drag portion of the Challenge. How much boost can one of those engines accept and what else could be done to it?

I'm assuming you mean a late model Beetle TDI, which are definitely the bargain of TDIs if you're willing to be seen in one. You can add some power, but you quickly overpower the stock clutch, good injector pump rebuilds are expensive and a lot of guys start to bend connecting rods in the mid 200HP range anyway. The platform is not well-suited for handling either, or at least doesn't respond to conventional mods much like the other A4 platform cars (IIRC, the roll center is super high or something). For a Challenge car I would skip it, though they are a cheap way to get into a TDI daily driver. A 1.8T with a tune would be a much better way to go fast.

Just look around here a bit... kermatdi.com

Buy a pre-ODBII MkIII and put 1.8t setup into it. That is what I was considering. I got all of the way to the "time to turbo!" part and decided I hated the car.

You can certainly make double the stock 90 hp and still have it be reliable and get decent mileage, but it will be more than $2k just in modifications to do that, not including buying the car and doing the maintenance it will need (mainly timing belt and related stuff, and suspension bushings).

In reply to DeadSkunk:

The boost limit on TDI's is mainly restricted by the turbo itself. The factory turbo is integrated with the exhaust manifold, so swapping out for a larger one is no simple matter. The long block itself can handle quite a bit - stories of 200 hp and 400+ ft lbs on stock internals is not uncommon. Then there are the required larger injectors(~$500) as well as having somebody dyno-tune it (also roughly $500). Plus a larger inter-cooler and hoses (not cheap through vendors, but could probably pieced together for less). And yes - the OE clutch won't live long under those conditions - even faster if driven hard - so figure on another $500+ for a clutch and flywheel kit.

And we haven't even touched the horrid suspension yet...

So I agree that while it's a neat idea, a TDI Challenge car would be very difficult to do unless you have access to experienced TDI-modding knowledge for free. Even then, I have a feeling even the mod-happy guys who have been fiddling with these cars for years would say it can't be done.

Ian F wrote: The long block itself can handle quite a bit - stories of 200 hp and 400+ ft lbs on stock internals is not uncommon.

See, that's why I'd love to see a 16v head plopped onto a TDI bottom end. The 4v chambers are huge - the same pistons that make 9:1 in a 4v are about 13:1 in a 2v, so it'd probably be around 8:1 with TDI pistons.

Sure you wouldn't be able to rev it much over about 6k because the rods and pistons probably weigh a ton, and you'd have to turn the crank nose down to fit gas engine timing components, and it would probably cost more than just buying good rods and pistons since TDI blocks seem to go for stupid money (if they never break, then why do they cost $2k for an engine??) and... hmm.

Actually, this is a pretty stupid idea unless you happened to have all of the parts. And you still have the problem of finding a VW transaxle that won't explode on contact unless you go longitudinal, and if you were to do that, an I5 or 32-valve V8 will make more power and ft-lbs for less money...

Knurled wrote: See, that's why I'd love to see a 16v head plopped onto a TDI bottom end. The 4v chambers are huge - the same pistons that make 9:1 in a 4v are about 13:1 in a 2v, so it'd probably be around 8:1 with TDI pistons.

8:1 diesel bottom end? You think that would make compression?

crankwalk wrote: 8:1 diesel bottom end? You think that would make compression?

Who said anything about compression ignition? The idea is bulletproof bottom end and airflow for a gasoline engine.

Corrado G60 bottom end bits should also do the job but then you wind up with about 6:1 with the 16v head.

I was wondering how hard it would be to cheaply crank up the power for the drag portion of the Challenge.

It would be HARD.

1/4 mile is about HP/Weight. NOT torque/weight. It is HARD to get a tdi to make real HP.

If you double the HP of a stock 1.9tdi it might end up as fast in the 1/4 mile as a 1.8T with a cone filter.

Vigo wrote: If you double the HP of a stock 1.9tdi it might end up as fast in the 1/4 mile as a 1.8T with a cone filter.

Pretty much. You can make a TDI into a half-decent track car where you can stay within the relatively narrow powerband, but it'll always have a disadvantage in a pure drag race.

As far as putting a 16V head on a ALH block, it would easier and cheaper to simply install stronger 16V internals. I'm not sure the piston centers are even the same or if a 1.8T cam profile would work. The bore is fairly close and possibly within overbore limits: 79.9mm for the ALH and 81 for the 1.8T. Compression ratio is more than double: 19.5:1 for the ALH vs. 9.5:1 for the 1.8T, although much of that is in the very flat diesel head profile. Plus, there is the piston design. The ALH has chambered pistons (recessed cavities) meant to control burning diesel vs. typically flat or domed pistons in a gas engine.

thanks for starting this thread... yet another search for CL.....

I think I'll be starting threads every time I see a cheap car that I think might be a Challenge candidate, right up until I actually buy something.

^I for one am completely fine with this!