M2 madness

[jgerock]

You mention that the car is relatively quiet from the back. Could the noise be coming from your CF airbox? A lot of e30 M3 racers are getting into trouble with sound meter readings from racetracks like Limerock, and have come up with snorkel air inlets to dampen the sound coming from the airbox.

To me, Marshall's M2 is very loud in the front. He pulled out from an intersection and accelerated behind me and I thought he was right on my bumper but he was at least 4-5 cars back. I'm betting it is the CF airbox. The stock S14 one is most likely designed to dampen the intake noises.

WOW- I finally got this thread to the 13th page. Wonder why it has been showing (13) before, but not showing content??

[M3M3]

dunno. the intake sound is more of a roar that increases with rpm. the resonance i am hearing/feeling distinctly "turns on" at about 3300rpm. it is a raspy, unpleasant sound. i gotta do more diggin'.

[M3M3]

Nice toasty day, only cool spot was laying on the cool floor of the shop with a fan on….

Did a little on road tuning with Jim, than got the car up on jackstands to trace rattles and deal with the shifter issue. Jim confirmed for me that the shifter…..sucks….

Dropped the exhaust and the driveshaft for clearance and fixed a few potential rattle spots.

Then we got to the tranny. Decided to try drilling the coupler and shifter shaft out to ¼ in. 6.3 ish mm. stock is 6mm. first round was on the 4spd test mule. Drilled out an old coupler with a drill/reamer from mcmasters.

Then drilled out the shifter shaft.

Then use the hand reamer on the coupler and trans. Could not find my tap wrench, so used vise grips.

This kind of worked. very odd that the drill made a perfect hole in the shifter shaft that the pin fit perfectly in.

The coupler was a different story. Drill made a hole, reamer was difficult to get in smoothly. Pin would not go in hole. Tried freezing the pin. No go. Odd that same drill made perfect hole in shifter shaft, did not make big enough hole in coupler. Ended up getting pin in by sanding it with 400grit and using a bfh. Coupler was nice and tight after wards.

However, did not want to use bfh on the good 5spd tranny while it was in the car. decided to just use a new coupler and a new 6mm pin. Not quite as tight, but much better than it was.

Tomorrow track pads go on, brake system bleed and check over of nuts and bolts. Prep work for track days coming up.

[jgerock]

Must be a metalurgical issue with that coupler. Same tools, same pin but it wouldn't fit in the hole. Or as my dad always says "it's got hell in it".

Can't wait to hear how the revamped shifter works.

I'm getting more practice R&R'ing exhausts, driveshafts and shifters. The VW parts are relatively easy compared to the BMW.

BTW - thanks for letting me drive today. The M2 drives and handles like a dream - will be even better with the shifter fixes.

[M3M3]

Grice brought some killer brazillian coffee by yesterday, so after having a triple expresso this morning..

I caved.

I am a whimp.

I have retreated from ultimate performance.

I took out all the urethane engine and tranny bushings.

In an effort to quell the resonance, I decided to give stock engine and tranny mounts a try.

But not totally unmodified. I bent the tab on the drivers side down hard to try to reduce the amount of movement range.

Here is the test mule…new mount on left, bent mount on right.

Bent them using hydraulic press

I bent the new one even farther than the test one before installing.

Jim once again came over, that makes about 12 hours of labor in a 90 deg shop for him in two days. Thanks dude!

We lifted the engine with a hoist an inch or two, then swapped in the stock mounts.

A 320 mount went behind the tranny. Two hours start to finish, with breaks for lemonade.

Started it up. Wow. Engines sure move a lot on stock mounts. With the poly mounts it was rock solid. Rubber, well, not so steady. Initial look it appears it will not hit the strut bar, hood or brake booster, but will not know for sure until I get it on the road. I gotta find a way to make a right side engine brace to control the torqueing to the right.

Rear brake adjustment is a breeze with new backing plates and the stock bent 17mm wrench from a bmw tool kit. Even though I had just bled the system 1300 miles ago when I put the s14 in, doing it again today made a noticeable difference in pedal feel.

For those using Volvo calipers up front, here is the part number for the Porterfield R4 and R4S pads:

After I bumped into the hella lights for the 100th time knocking them out of alignment, I realized that I practically never drive the car at night, let alone in an area I can blaze them up. Plus they sort of block the air to the radiator, oil cooler and intake, soooooo….. wire snips and a 17mm wrench later, I have an empty bumper..

Wheels back on, off the jackstands and fuel map #9 loaded up. Will have to test drive later this week.

[M3M3]

test drive complete...

no surprise, but stock engine mounts make a car a whole lot more liveable on the street. the resonance at 3300rpm pretty much gone. sound level in the car down another few db's. car drives much smoother.

no evidence of engine hitting anything. yeah.

but....the instant response of added throttle making the car take off that is present with urethane mounts is gone. maybe most folks would not notice this difference, but i do.

bottom line...for track use, go with urethane. for anything else, including very spirited street driving, i would recommend stock engine mounts and a matching rubber tranny mount.

on to the shifter...yee ha! night and day difference after Jim and I reworked the linkage and put a new pin and coupler in. it is now precise and easy to shift.

fuel map #9 worked well. recorded another 30min of data, touched up a few more map cells, and produced map #10.

[Ian]

Marshall,

You might want to check out a set of urethane motor mounts from AKG. Their mounts have a durometer of 70, while the Ireland mounts are 80. From reading the S14 boards, they seem happier with the lower durometer. I think it is similar to the Motorsport Group N pieces that were made for the S14.

Here's the link for the AKG 2002 motormounts: http://www.akgmotorsport.com/catalog/catalog.php?category=2002%20Motor%20and%20Trans%20Mounts

I agree about the Ireland mounts. They were just a bit too buzzy for a car that I wanted to drive on the the street as well as track.

Ian

[M3M3]

Minor stuff today…

Replaced the straight fuel fitting on the front of the fuel rail with a 90deg piece that keeps the fuel line farther from the hood.

Then installed the new custom BLUNTTECH trim vibration dampers….wanted to see if the trim was adding to the noise.

Did last inspection on the car before track events next weekend. Will load up in trailer tomorrow.

[M3M3]

Went over all the critical systems one more time, then stripped all the excess stuff out of the car and loaded up tools, tires, and car into the trailer. Waiting for next weekend at Summit Point!

:-)

[ray_]

Woohoo!

Will this be the first time you've tracked the car? I think the answer is no.

Cheers,

Ray

[M3M3]

i tracked it with the M10 a couple of times last summer. a bit more go power now, and i bumped up front spring rate and both sway bar rates to compensate for some handling nuances i wanted to fix and the sllightly higher weight in the front. i am sooooo looking forward to this....

[jgerock]

March 2010 with the Rotas and M10

[ray_]

Needs S14.

;-)

Cheers,

Ray

March 2010 with the Rotas and M10

[ClayW]

March 2010 with the Rotas and M10

Hey, I recognize that ANSA.

[jgerock]

Clay - funny how your '67 has the muffler that my car originally came with.

We've passed that around like the proverbial "traveling pants" movie.

Hmm, Brotherhood of the traveling mufflers?