M2 madness

[ray_]

Hmm. Mine runs out of oomph at 7000. ;-)

Sounds like you are almost sorted tho! What's the next project car?

;-)

Ray

well, it did develop an odd idle that varied in the last two sessions...have not tried to sort that yet....;-)

brakes sucked (slight pull to left and very hard to modulate), and i still need to dial out a push in the handling.

but...the Massive front track/camber spacers were worth it. getting the camber to 3.5 resulted in tire temps pretty even across the face of the tread. got more fender rolling to do though to run 205's.

i will start a separate thread on the real problem.....;-)

but for the most part the car made wonderful noises running up through the gears to 7500 and i took over a second off my previous lap times....

[M3M3]

first video...."teaching aid" demo video of the summit main racing line we made yesterday. sedate pace.

[M3M3]

here is video of one club trial session. all open track. if you look close you can see the speedo and tach. i was doing one hot lap, then a lap or two off the pace, then hot lap, repeat. these events use a qualifying strategy.

[M3M3]

Thought I heard an exhaust leak when putting the car in the trailer last weekend. so I looked for one during the post track weekend inspection. Sure enough, the hanger for the tranny mount cracked at the weld to the y-pipe. Will have to pull off and repair.

In better news, I acquired some tii front struts.

Besides the bigger bearings, I need more clearance from the tire to the strut. When ground control fabs struts up, they use a 50mm OD shock tube instead of the stock 45mm tubes. When the threaded sleeve is added for the adjustable spring perch, the OD increases even more. The widest part of this is right where the tire and wheel come closest to the strut.

Since I have gone to a shorter spring, the adjuster is well above the tire. I am not part of the “slam it to the ground” crowd, so I don’t intend to lower it much more than it is. (note - picture is with car on jackstands, not actual ride height)

So….i intend to send the struts to GC for conversion, but have them set the height of the spring perch 2 inches higher than normal. I will then use a two inch adjustable perch instead of the standard four inch one. this will raise the whole thing above the max tire width, allowing me to delete the 3mm spacer I am currently running. it all works in theory at least!

[jgerock]

That stinks about your exhaust crack/leak. Will the shop re-do it if you drop the parts off (or the car)?

[M3M3]

second day of track weekend the idle was fluxuating. was wondering why.

when taking the exhaust center section off i realized what was going on. i run closed loop fuel correction. the WBO2 sensor is in the loop and the AN computer constantly corrects fuel amount to get to a target AFR.

well, the WBO2 sensor is about 6in downstream from where the exhaust was broken. at idle, fresh air was being drawn into the exhaust and past the WBO2 sensor, making it think there was a lean condition. AN computer was added fuel to correct for the false lean readings.

here is the break..

note proximity to WBO2 bung

[M3M3]

exhaust fixed. had patch welded on to cover the hole. deleted the support bracket idea. good thought, but relying on the pipe wall for strength with a buzzy s14 probably was a bad idea. will use a more conventional approach and fab up a bracket that attaches with u-bolt around entire pipe this weekend.

[ray_]

I don't have a support there. But I'm not on a racetrack.

M10's certainly need one there, though!

Have fun,

[M3M3]

Went to put the exhaust back on today and got diverted doing close inspection of the things you can’t get to with the exhaust installed.

What is wrong with this picture?

Yep, the nut on top of the tranny mount is missing! Wonder where that went… took the opportunity to swap out the e21 mount for an IE poly mount. Been meaning to do that for a while.

Then noticed the arm supporting the shift platform was flexing…almost cracked all the way through. Time for some strengthening pieces to be welded on, then paint.

Now comes the “I am a dumb ass” part of the day. Ever since I built the M2, 5th gear has been notchy. This is a different 5spd than I used with the M10. I had replaced all the seals before I put it in the car. well, despite how many times I have posted to try to help others by reminding people to put the “short” bolt in the 1 oclock position on the output seal flange….. I decided to check to see if I had goofed it up on this one. dropped driveshaft and started pulling the cover bolts. They were all the same! No short one at all! The one in the 1 oclock position was clearly scraped off on the bottom from hitting something. I made one of them shorter with a grinder and cleaned up the treads with a repair die (not a cutting die!). DOH!!!!!

Next project was a hanger for from the tranny to the exhaust. Found a u-bolt in my junk bin that was the right size, then grabbed a piece of steel angle stock and started cutting and welding. This should work.

Waiting for paint to dry, will post pic of install tomorrow.

[jgerock]

D'oh! I SWEAR we have checked all the stuff under your car multiple times. SP must need some smoothing out on their courses.

Maybe I should send Nola over there with a bottle of Loctite and a Bluebook.

[M3M3]

we did, but hundreds of track miles at 7000+ rpm tends to vibrate stuff a bit more than years of street driving. its why pre and post track weekend inspections are important. well, they are needed after i get done with cars on weekends! :-)

yes, could use supervision. clearly the tech inspection done by Spritle and Trixie was insufficient!

[M3M3]

finished up the post track work.

installed the exhaust bracket.

free air cal'd the wbo2, adjusted LF wheel bearing, put the street tires/wheels on and put it back on the ground. hopefully tomorrow will be a nice day for a little drive!

[ifayeoh]

Nice work! hope you put some lock tite on them 2 under the trani, they always seem to be coming loose.

[M3M3]

While it is in the shop….figured after three track weekends I would take a peek at the cam timing to make sure nothing slipped. Marks looks like they did when I set it.

Then took it out for a spin on a beautiful sunny and 70 deg day. Over to JimG’s to find him further taking apart Oscar. That thing is looking great. Wrapped that up and the two of us drove the 02’s over to Grice’s. Grice and Eric were in final stage of putting the new stroker engine in his 02. Got a throttle linkage in, then with a few hiccups finding wires that were disconnected, stopping fuel leaks, jumping batteries and adjusting dcoe45 floats, it started. Another 20 min or so of timing, synchronizing, mixture adjustment and idle setting and it was alive!

There were a few red cars involved of course, it is the ISRCG after all!

[jgerock]

IT RUNS - Very well.