ZephyrS4

If some of you recall, I posted a couple of weeks ago about my first attempt at trying to install the bi-pipe to only to have it rub on the fan blades. Well, I decided to give it another shot today. I took my time and followed everything in the install manual only to have it rub again. The only way to get it to fit was to use larger spacers with the top 2 TB bolts. You see when the original spacers are used the bi-pipe seats perfectly to the TB, but it brings the pipe out where it rubs on the radiator fan. It's in now, but I'm kind of nervous to leave it in due to the fact that it's not fully seated on the TB....



APR, you need to contact me and take care of this problem...I have sent you emails in the past couple of weeks and you responded by saying that It wasn't installed correctly...well it is installed correctly, it just doesn't fit properly. I would be glad to get a new bi-pipe to try it again, but the way this one fits is terrible and not worth what I paid for it, only to have to modify the way it fits.

I'll take pictures of it tomorrow to show everyone what I'm talking about.

The R

with different tolerances from car to car. I have more than enough clearance from the fan blades.

Good luck and hope you get it solved quickly!

Imolavirus@BuehnEngineering

i dont see where the difference between cars is going to create that much difference

ZephyrS4

I lay it down on a table and it's not crooked...it just sticks out too far when fully seated.

ImolaRocket

Well, which is it....Good or Bad ???

Jason @ Streetwerke

The APR bi-pipe is merely created from a jig that follows factory part locations. Having installed countless bi-pipes over the years, I can tell you the part fits fine in most cars. The issue is a variance of how your car was built. The parts in you car (radiator support, plastic covers, fan, engine mounts, etc.) all rely on tolerances for each part and locational fitment as an assembly. From a design standpoint, each car can have a huge tolerance stack-up for the entire assembly.

Rather than discussing proper use of Geometric Dimensioning and Tolerancing (GD&T), I'll just say each S4 is built a little different so parts may or may not be in the same location as the development car.

APR's bi-pipe is not at fault, so please don't point the blame toward APR. Their part fits and works in most cars. Yours is an exception. Having said that, it's still not easy to get everything lined up right. It takes time and some effort. Sometimes the sequence in which you tighten fasteners will cause issues. Don't give up, it'll work in time. Oh, NEVER force the issue on the alignment of the fasteners in the plastic timing belt covers. Those are weak captive fastener nuts pressed into plastic, they're not meant to secure anything really. Leave the bolts out when in doubt. If not, you may cause the captive nust to break free and fall into the cam timing belt. Goodbye cylinder head valves after the belt skips a few teeth as it chews up the backed out brass nut!

Imolavirus@BuehnEngineering

well, scratch my reply : )

2000ImolaS4

after some gentle maneuvering, it seated perfectly with plenty of clearance. I wish I could remember what the issue was, but I do know I solved it with some gentle wiggling as I was seating the pipe onto the fitting adapter(that's all I can remember now - sorry).

ZephyrS4

I think the bi-pipe is a great idea. Speaking of the bolts in the timing cover...one of them did break off, but I was able to get it out. They really aren't necessary anyway with the bi-pipe. The way it is in there now seems to be fine, but the fact that it isn't fully seated makes me wonder if I could have a boost leak around the TB where the pipe bolts on. I'm having Matrix do my 60K service pretty soon...I wonder if there is a way to move the fan further away from the pipe with spacers?? I have heard of people shaving down the fan Blades, but that doesn't seem to be a good idea to me. I actually enjoyed installing it and messing around with it even though it doesn't fit perfectly. If it doesn't work out in the long run someone will get a grwat deal on the pipe. I bought it from Motopersona for $270, so someone won't have to pay $350 for it. I don't want to sell it, but if it doesn't work out in the long run, itdoesn't work out. I'll keep everyone posted on how it goes.

The R

Every part on the car has a certain allowable tolerance. That little tolerance difference may not be a big deal for OEM parts fitting properly......but when you're working with something aftermarket, it's very difficult to know what that allowable tolerance is without having the design drawings. That can create some serious problems when you're designing a part to go in a tight area like the bi-pipe. Ultimately, it's on APR because they decided to make the part. Can't blame Audi because they don't have that issue with their components.

There's always the possibilty that out of spec parts find their way to the assembly line and ultimately out the door to us...sucks, but that's what happens sometimes. It wouldn't surprise me if this is why some cars blow multiple sets of turbos while others haven't blown any as well as other little issues with our car.