Talk me through serious VW power

I don't mean to thread-jack, but this question is along the same lines.

I have a line on a free short block( included upgraded forged rods ) that came out of a 1992 Audi S4. I think this a 5cyl engine, so I'm almost sure it won't fit in my mk2 golf. Is it worth re-using the pistons in an obd1 aba engine? Would it be an upgrade? Or would it even fit, w/o machining the block?

mrwillie wrote: I don't mean to thread-jack, but this question is along the same lines. I have a line on a free short block( included upgraded forged rods ) that came out of a 1992 Audi S4. I think this a 5cyl engine, so I'm almost sure it won't fit in my mk2 golf. Is it worth re-using the pistons in an obd1 aba engine? Would it be an upgrade? Or would it even fit, w/o machining the block?

Actually that engine is the same size internally as the PL (1.8L 16v) block. Those pistons and rods will bolt directly into a PL, and make a sweet turbo 16v engine. I actually have that exact same combo sitting on and engine stand waiting to go into something.

In reply to 16vCorey:

So wait, is it really as simple as swapping the rods into the aba?? Do I need to change out the crank or anything? Which head would you use for this combo, and what did you use for a exhaust manifold?

No, the ABA won't work. Wrong bore and rod length. The best fit is the PL 1.8L 16v. They fit perfect and are designed with that exact same head profile, so they're pretty much factory turbo pistons and rods for a 1.8L 16v.

I haven't put an exhaust manifold on it yet, but you could use the S4 exhaust manifold and either cut the extra runner off of it and weld it up, or block off the extra port. Any 16v turbo manifold will work though.

Ok. Thanks. I'll keep working on getting the aba installed and running. I'll keep an eye out for PL and 9A blocks. They don't last long in the yards here.

Thanks for the info.

Are there different flavors of the 16V heads?

Looks like all the recipes include them.

I know 16v heads have been around a long time. Much difference in them?

Is the 16v on the 9A significantly different than others?

Is the 9A a 2.0L or a 1.8L?

The 9A is a 2.0L 16v, the PL is the 1.8L 16v. The heads are slightly different, but interchangeable. For a budget turbo build either head will be fine. 9As are easier to find cheap in the Pull-a-Part yards, but the PL is easy to find cheap on the Vortex (because a lot of people swap them out in favor of the 9A).

So, 16v heads are interchangeable over a 20+ year span?

That sounds like 60's vintage Chevys!

Actually the 16v head was only used from '86-'93 in the US. But seriously, these things are like small German SBCs. I put an ABA block from a '98 GTI in my Brother-in-law's '83 GTI, bolted the '83 head directly onto the '98 block, and didn't have to fabricate much of anything. Same thing with my Rabbit. It's a '77, with the transmission from an '86 Scirocco, the block from a '93 Passat, and I don't remember where the head came from (I think the '86 Scirocco), and it was all a bolt on affair.

Corey, you're making the turbo 16v thing sound too easy by glazing over things like plumbing fuel rail/intercooler piping and the agonizing hours of megasquirt tuning. Knock it off and lead me not into temptation.

edited for smiley icon because I'm calling you to tune the damn thing if I do it.

SVreX wrote: Thank you. That's what I needed. The trans I'm planning is the Audi longitudal 5 spd FWD with the side outputs. The power target was based on what I thought this trans could handle. See any issue with that?

Make sure that a 4-cylinder will bolt up to it. A lot of older Audi transaxles are 5-cylinder only. The bolt patterns are maddeningly close but different enough.

The ones that were 4-cylinder only WILL break at those power levels. Easily. There's a local making about that much power in a Fox, and IIRC he's given up on it because, while the car is psycho-monkey-fast, he can break transmissions at will.

The 01E from a 968 would probably work out for you. I'm fairly sure the 016 from a 944 is 5-cylinder pattern only.

16vCorey wrote: I haven't put an exhaust manifold on it yet, but you could use the S4 exhaust manifold and either cut the extra runner off of it and weld it up, or block off the extra port. Any 16v turbo manifold will work though.

Or sell the S4 manifold on eBay and buy a 16v manifold for less money.

By the way - mrwillie, what's wrong with that shortblock? To hear people talk, a 20v five with upgraded rods is a sky's-the-limit engine. Stock rods = 400hp max. Upgraded rods = how big is your turbo, and do you have a strong enough transmission?

Knurled wrote:

SVreX wrote: Thank you. That's what I needed. The trans I'm planning is the Audi longitudal 5 spd FWD with the side outputs. The power target was based on what I thought this trans could handle. See any issue with that?

Make sure that a 4-cylinder will bolt up to it. A lot of older Audi transaxles are 5-cylinder only. The bolt patterns are maddeningly close but different enough. The ones that were 4-cylinder only WILL break at those power levels. Easily. There's a local making about that much power in a Fox, and IIRC he's given up on it because, while the car is psycho-monkey-fast, he can break transmissions at will. The 01E from a 968 would probably work out for you. I'm fairly sure the 016 from a 944 is 5-cylinder pattern only.

Good point. I will check further, but I'm pretty sure it will work. This particular trans made it's way through a Fox, so I think it's already been bolted to a 4 cylinder.

I can probably work with "maddeningly close". I just can't work with "Holy crap, that's not even in the same ballpark!"

Oh, I looked into it already. I wanted to go the same direction you did - 4 cylinder engine onto wrong-species trans.

From what little I remember, one of the bolt holes was right. The ones at the "top" (deck surface) were nowhere near right, and at least one of them was flapping in the breeze instead of meeting the engine. The kicker is that 4-cylinder models mounted the starter to the transmission, while 5-cylinder models mount the starter to an ugly, beefy-thick ring cast into the block.

I don't think the particular 4-cylinder block I wanted to use had provisions for the lower block brace (essential for longitudinal) on the oil pan rails, but I'd been hoping to solve this with a newer cast aluminum oil pan, which would have bosses for attaching to the transmission.

Another thing I found out - 4-cylinder and 5-cylinder engines cant over at different angles! The fives are laid over more than the fours.

I wonder how strong the FWD manual trans was from the A4s. We probably didn't get many V6 FWD manual trans A4s but that might have the strongest US-sourced box. (I doubt very many, if any, of the rare front-drive A8s had manual transmissions...) A rule of thumb is that any longitudinal trans made after ~1992 is going to be dual bolt pattern. They started filtering in sometime around 1990 but the single-pattern units stayed in use until the end of the 5000/200 range.

The trans I'm working with mounts the starter to the trans. Perhaps that answers your question.

I am capable of fabricating an adapter plate. What you are describing is not impossible with an adapter plate.

Mounting a Chrysler with a flywheel/ clutch that is about 12" in diameter inside an Audi bellhousing that is more like 10 1/2" in diameter is a completely different animal. It involves cutting off the bellhousing and custom fabricating one from scratch.

I appreciate your insight, but it's not going to stop me.

In reply to Knurled:

Not sure about the details. I'm getting the block free. I have a friend that used to have an S4, and this is one of his spare blocks. The car is gone, and he wants his garage space back.

SVreX wrote: I appreciate your insight, but it's not going to stop me.

I never thought it would. Just sharing what I've learned.

In my case, it was simpler to just source another 5-cylinder and keep the four-bangers around for other projects.

Thanks!