Sunday, April 28, 2013

Mmmmm Magnaflow

I've had a Flowmaster 2in 2out on my car since I bought it.  It's been a little bit of a love/hate relationship.  I had one of the outflow pipes plugged in an attempt to quiet it just a little as it would drone something awful on the highway.  I liked the mean sound it had but at the same time it's always seemed a little too "American Muscle Car" to me (too many Flowmasters on Mustangs imbedded in my head maybe)

So having had a Magnaflow on a previous car I really wanted to try one on my 911.  I came across a used one the used parts classified for a nice [your author is a cheap-ass] price and decided to try it out.  I'm quite pleased with it after a day of cruising around.  It's a little quieter all around but not by much, its got a very nice tone to it that may just completely be a personal preference thing.

It's hard to capture the true sound of a muffler on video it seems, and I think it sounds a little sweeter in the cockpit (engine sound mat taking some of the mechanical noise out and not facing the tailpipe helps I think).  But here is a video of the newly installed Magnaflow:



And for reference here is the video I made of my car alive again with it's fresh engine rebuild.  It doesn't have any revving in it but you get the idea:

CIS Problems may be solved

So I find myself once again patting my own back (if not me who else will right?)  I spent bits of free time reading up on CIS Troubleshooting threads this week then I hooked up my gauges Friday afternoon.

Current state/symptoms:  1) must re-adjust mixture/air-bypass as weather changes to maintain starting.  Car still starting instantly all the time with no driver interaction 2) Initial start from dead cold (overnight), after warm (5 min) idle at ~2000-2200 rpm, this remains as long as the car is running or restarted quickly (i.e. gas fill up).  If left for ~20min restart idles at ~500-700rpm, highway trip for 10-15 min has it idle at ~2k rpm again.

I established my current control pressures and my "WUR profile", this confirmed something I came across that made me wonder about the electrical connection to my WUR and AAR.


Neither my WUR or AAR had any voltage going to them, the specs for my ['78] engine say that pin #10 should have 12v when the fuel pump is running [my '75 chassis has the fuel pump running at all times when the key is on].  For whatever reason (mis-match of parts I'm guessing) I had nothing going to that pin #10, well I rectified that the next morning and I get the new data below:



As of 1 day, a spirited drive and several restarts later she starts up, quickly gets to 1k idle, stays there, restarts are the same.  Waiting to see how varied temps affect this but I may have checked off another annoying box :).

Sunday, April 7, 2013

Rear suspension I have conquered thee! (well, for the moment)

I have found a miserable job, I found myself trying to think if any of my engine rebuild caused me nearly as much cussing as I have done this week at the ass-end of my car (and I couldn't think of any point).

First, as I tend to do with all of these projects I pour over my books, then internet threads, then I go out and start getting filthy.  As I approached my now elevated and de-wheeled automobile I notice (for the first time in 3 years) that there are no covers bolted onto my spring plates (that was step 1 in all my reading, I was somewhat disturbed my step 1 wasn't available for doing).  Now logic (and evidence) tells me that I have blissfully, ignorantly bobbed down the road in this puppy for all this time it's obviously held together pretty well by all the other bolt-age but still, those in the know insist these are very important metal pieces.

So I trudge on, get the spring plates off of the trailing arms without injuring myself (always good) and proceed to tinker with rotating those plates on the splines of my torsion bar (I found out here I have a 28mm bar instead of the stock 23).  I ultimately made a 5° change (down) which by my calculations and on-line research bumped the backside UP by ~1.5"

Thence commenced the profanity....and the bruises....and the blood....and the general questioning of my decision making paradigm in the true love of this 37 year old German mistress of mine.  I tried for 2 hours to get one spring plate back on it's swing arm to no avail, exhaustion and exasperation won that night.

With a fresh head, a few tips I drudged up on the internet and some re-assuring knowledge that seems everyone accepts touching the rear suspension to be nothing less than a royal pain in the ass I went back to work.  This time after 2 hours I had both sides fully re-assembled.

What's funny is a post on the internet got more than a few "why don't you just take it to your local Porsche race specialist shop" replies.  Well 1) I never leave myself enough play budget for labor (I do well to sweet talk the wife into ignoring the plethora of UPS deliveries that show up :D) and 2) Lower Alabama is not exactly a hot-bed of Porsche specialists, [outside of the dealer's master wrench, @ $1xx/hr]  the only one so far I've found, lives and works several hours North of here.  If someone has to "figure out" how to wrench on this old beast, it might as well be me and not pay crazy rates for their education.

With the addition of a new set of slightly higher profile front tires I now have my car (if I'm not mistaken) at about 1/2" lower than "Euro Height" with tires that are still low profile but not nearly as small as what came on the car.  It certainly does ride better.

Next I revisit my alignment lessons from a couple of years ago as I just don't trust anyone around here.  I did ask where I had the tires mounted, and got the usual "uuuuuhhh wayuhhl brang it on een and we will see if we can figer out how to do it"  To which my thought is no thanks, I'll do it myself, save some coin and likely do a better job than they manage  (see above thoughts on local monkeys).

Before:

After:

It may look like a small change but it matters to me and the car's driving dynamics are SOOO much better by this little addition of rubber and suspension travel.
..............................................

I did my 500 mile oil change & valve adjust this weekend too, happy to be able to leave the valves alone for another 10,000 miles, not a hard task but not particularly enjoyable with the motor in the car. I found nothing but clean oil when I strained it and everything is purring beautifully.