Audi R4R

Hey Guys, is the crankshaft on the Audi A4 1.8T's forged or cast? I hear they're cast. If so,... would you advise getting a forged crank? If so, are there any you know of and approximate pricing would also be appreciated.

I was also thinking of the RS2 tranny. I'm not sure where to get one and the cost on it (used will suffice). Also I assume that the clutch would be differennt. If anyone can give me more info about it, I'd appreciate it. I've blown the OEM tranny once already with the last set-up; this one will surely be more potent. Any suggestions appreciated!!! =)

smallTTs

I don't know if 1.8T crank is forged or cast, but just because an OEM uses a cast crank does NOT mean it is inferior to a forged crank. There are a number of reasons for this:

1) "Cast" when used for cranks, rods, etc. doesn't mean "cast iron" like a cylinder block. It means "ductile iron" or "malleable iron" which is iron with very specific range of elements which has been heat treated. It bends like wrought (forged) steel before breaking, unlike (gray) cast iron which is NOT very bendable (ductile). Ductile iron has strength properties equivalent to many forged steels.

2) Modern casting techniques produce, on average, more consistent parts than does hot forging. Inherent in the forging process is the chance for voids, inclusions and under- or over-worked areas.

3) It costs very little extra to produce the strongest ductile iron, but to produce the strongest forged parts from 4340 AQ (aircraft-quality) alloy (aka nickel-chrome-moly steel) is much more expensive than common low alloys usually used in forgings. The stuff that makes 4340 superior also makes it harder and more costly to fabricate. As in most things mechanical, there is no free lunch.

4) In some respects, ductile iron cast cranks may actually have better resistance to fatigue cracking than do many forgings.

5) It sorta depends upon how much power you want your 1.8T to produce. Obviously if you are going for more than 350-400 you are going to need all the parts to be stronger; crank, rods, pistons, maybe even the block. Here you'd want a purpose built AQ 4340 forged crank from one of the premier aftermarket crank builders.

6) Bottomline: IMO (which is never humble) a mediocre forged crank is inferior to an OEM cast (ductile iron) crank. Unless other folks running 1.8Ts of similar power to what you plan are breaking cranks regularly, I wouldn't change. I would, however, inspect/prepare my crank very thoroughly before I doubled the rated power. You could do that when you are putting in the new rods and pistons.

7) My guess is that VAG use forged cranks in the 1.8T. I'd really like to know.

My $.02

Audi R4R

I appreciate your time and effort in writing all that out for me! My mechanic and I never really thought about upgrading the crankshaft so I've never done any research on it.

Everything seemed to hold fine on the last set-up what was around 380-420hp. I'm going for about 450-500hp this time. I never had aftermarket internals with the old set-up: it never felt like anything was really stressed. But this time around, pistons, rods, valves, valve springs, mechanical valve train, etc. are getting an upgrade. I'm not sure if I should bother with the crankshaft.

So that's why I'm on the forums asking for experienced people's advice! The OEM crank seemed pretty rigid to me and it never seemed like there was a good reason for an upgrade.

Thanks again,... would you have any thoughts about the tranny. That is a bigger concern due to the fact that I've gone through one already on the old set-up.

xr4tic

at least the one out of my 97 A4 was. There is a rumor that the 225 TTs had forged cranks.

Anybody want to lend me thier 225 TT so I can tear it down to find out

My 2.0 conversion will be using a forged crank.

xr4tic

but the clutch is the same

Here's some info on the 01E trans:<ul><li><a href="http://elektro.cmhnet.org/~charlie/photos/cars/01E/trans.html">http://elektro.cmhnet.org/~charlie/photos/cars/01E/trans.html</a></li></ul>

PanTTher

seam lines.

PanTTher

You've got mail.

PanTTher

2000 and earlier don't according to John S. But I've only seen mine 1st hand.

smallTTs

Metal parts, much like women, remember every time they were stressed. When they have been stressed hard enough times they tend to fail catastrophically and with little warning. A stock crank enduring near-stock power output has a very long fatigue life (almost infinite if oil is kept relatively clean). Putting 400 hp through it a few (or many) times cuts that life considerably.

IMO, you have already used up much of your crank's life. Buy a new one from Audi, or get one from a used stock engine and prep it. Don't buy a cheap forged crank. If you go that way make sure it's 4340.

Sorry, I'm not familiar with trans. At 400 hp I would expect it to be overtaxed. What failed, and was it during a shift? If you've upgraded the clutch, the trans is the next weakest link. If you have a 1.8 A4, is the 2.7T 6-sp trans compatible with your engine and chassis? I'm sure it's good for lots more power than the stock 1.8 trans.

Now if you were asking about American Iron, I could be more help.

Good luck.

quattro5

"no way dude, then i can't put 'forged crank' in my sig.". seriously, great REAL info.