I'm still alive...
 

I know I haven't been posting here in a while but got too many non car related things going on that I have no time to do anything... My 1.9 is now at half service: motor mounts are shot & the stupid idlers from DA keep on going, so I get to drive the 2.8... This weekend I should settle some things and have some free time to play soon.

Here's what's on the list:
1) Replace engine & tranny mounts with IE urethane: these should last...
2) Retrofit S52 idlers or custom aluminum idler with better bearing than Fenner Drives Chinese crap...
3) I've got a set of midpipes sitting in my garage with no cat. It's just a matter of fitting a pipe where the cat was and bolt it up. Basically remove all the cat backpressure. I've also found a trick to foul the post-cat O2 sensor which involves a diode (apparently the "spark plug anti-foul" trick works only if there's some cat, but not if there's no cat at all... the diode takes care of it)

Stay tuned...

Oh, and btw: my oil cooler project is done and over: works perfect!! Pushing the car real hards keeping up with an ///M coupe on the twisties and oil was at 220-230... I love it!!!

A good metal matrix cat has no back pressure to speak of.... I've flow tested several on a flow bench. Its kind of a myth left over from the old pellet cats of the 70's and 80's, and the crappy eastern import ones with ceramic cores and cardboard liners.

Just sayin...

Dave

Well, the only datapoint I have is page 295 of "Supercharged! Design, Testing and Installation of Supercharger Systems" by Corky Bell.

They present a supercharged Z3 M44 with a custom twin screw SC intercooled running about 7PSI, a tad less than the DASC.

They added 3 pressure gauges in the exhaust: 1 before the cat, one between cat and resonator and one between resonator and muffler.

They measured 5PSI beckpressure before the cat dropping to 2.5PSI after the cat.

Everything eles, is just "my buddy told me his bro read on the Internet that..."

i've gone for a race hi-flow cat, but i haven't finished the rest of the exhaust so i cant comment on its performance yet.
the race cat is meant to flow 85 % better than a standard cat.

i'll have it back on a dyno as soon as i can get it all finished

Yep I was looking at your work: very nice stuff!!! Congrats

Keep us up to date with the idlers, mine are always squeaking and falling apart! Even genuine BMW ones cant take the strain...

If you don't already have these, consider going wth something different. Mine didn't last that long, and the design is such that if they completely fail, the mount will rip apart and completely separate. I've gone to the Vorshlagg competition mounts as they are a complete bolt through design, but they are much harder than the IE motor mounts. I wouldn't run the Vorshlagg mounts in a street car. Which leave the only real solution to be the OEM mounts.

Were you able to use regular 6-ers mounts? Cuz AKG has bolt through, but they are advertised for 6 cylinders only and when I called they said they wouldn't fit the 4 cylinder. IE on the other hand said theirs fit. AKG has a street & race version which uses different urethane.

http://www.akgmotorsport.com/catalog/catalog.php

No, they are four cylinder fitment only. You don't want to use the really hard I6 motor mounts on the m4x motor. The little four cylinders have a ton more vibration at idle, and the I6 motor mounts are way to stiff. I definitely would not use the AKG race ones, even if they do fit.

The Vorshlag ones are expensive, but they are the best aftermarket mounts I've seen for our motors. Terry at vorshlag said they tried using higher durometer urethane and after a certain point it just wasnt tolerable the amount of vibration they put into the car. I definitely don't want to sit in my car with it just idling any more.

What BMW idlers have you tried?

I think the problem with the idlers is twofold. First they are crap: the seals on the bearing fails dirt gets in, grease gets out and the thing seize. The other problem is that they are small thus they spin fast. IIRC I did the math and at redline they spin close to 15K RPM which is too close to the limit of the bearing used. You should go smaller bearing to be able to spin faster, but then they would probably be overloaded.

Anyway, I took 'em apart hand here's how they look:

http://i259.photobucket.com/albums/h...s/DSC03466.jpg

The bearing is standard and can be sourced from amazon:

http://i259.photobucket.com/albums/h...s/DSC03467.jpg

The problem now is that the idler itself being made of plastic deforms easily and now the bearing doesn't sit tight in its housing anymore.

My plan is to machine a idler out of a a block of aluminium so I'll be able to service bearing in the future without problem. FAG & SKF are top quality parts, so that would also add some life. Additionally I'm considering to add a cap in front of the bearing (similar to what BMW did) to already take away dirt from the bearing...

I know it's got to be an acronym for something but why would they name the company FAG?? :eek: :lol:

LOL!!! On Roadfly it get's Ops'ed out... eheheheh

Here's fyi:
http://medias.schaeffler.de/medias/e...ang=en&x=9&y=8
http://www.skf.com/portal/skf/home?_requestid=2326925

Nice work, I wont be able to turn new pulleys out of ali, so I think I am going to keep going with new BMW idlers every year or so.