My daily driver is a 1993 Acura Legend L coupe. It has the Type-II engine (230HP, 210ishft/lbs, stock) with the six speed transmission. I had converted it to the 5-speed clutch and flywheel setup, as the 6-speed setup has a dual mass flywheel (YECH!) which weighed about twice what the 5-speed flywheel (22ish pounds) and clutch weigh. I knew it needed a clutch when I purchased it. The car was in pretty decent shape overall when I got it, but, it seems to attract people (idiots!) who can't park. You'll see all the damage soon enough. Anyway, a week ago, I was picking my mother up from work. On the way home, the car just nosed over. There was seriously no power at all, except for a few instances of about 2-3 seconds of normal power then just feeling like a late 80's Hyundai Accent . . .
Within a few blocks of home, my mother and I smell something burning. Uh oh . . . I decided (stupidly) to just limp it home since we were so close. I pulled into the driveway and started investigating. The entire midpipe was glowing orange! Not dull cherry red, not a little bit hot, but melt your flesh off, a few steps from melting down entirely hot. (I've done enough torch cutting and heating to know how close the pipe was to a complete meltdown.)
Ugh! So, I figured, OK the catalytic converter, after 184,600 miles decided to puke its guts, clog up, and go into meltdown mode. FINE! This past Sunday I set about taking the midpipe off. Of course, it wasn't easy. And, it was #)(*$()*#$ cold. The windchill in my area was down towards single digits (Fahrenheit), and I toughed it out and got the midpipe off at 9PM after a long day. After that, my fingers and toes had had enough so I called it quits until the next day.
Monday morning comes along and I look at the cat in the daylight.
Look at just how beastly the stock midpipe and cat assembly are! The stock cat was fine. WTF? I could clearly see all the way through all the honeycomb both sides. Just to give you a peak at what I was dealing with here:
That sucker is BEASTLY! I really didn't need the 2.5" flex pipe on there. I was overly worried about the midpipe. I will be taking it out soon enough, and you'll hear why in just a few moments.
Here's a crappy cell phone video of my car idling with open headers:
It sounds pretty gnarly! The best an worse is yet to come, though. I figured that since the cat was fine, and that the power loss was intermittent, that maybe the stock muffler had something come loose. Here's the stock muffler:
It's certainly seen better days, and what I didn't get a picture off, it had a fresh bonk mark on the bottom of it, so I figured that was the issue. I got a hold of something I thought would sound pretty decent and not be too annoying:
That's a svelte Dynomax Superturbo muffler compared to the stock muffler. Just a bit smaller, I'd say.
Here's a not about the stock piping. It is a VERY goo stock exhaust. It's a bit small for the breathing this engine can do, but, it's really not bad at all. It is about 2" ID, with very nice, large radii bends, and what I'll try to show (poorly) in the next pic is how it is even ovaled to accommodate the hanger for the midpipe! Overall, it is much better than many stock exhausts I've seen with crushbent, crap pipes that fall apart in a few years. This thing has the better part of 200K miles on it and, aside from surface rust and a few heat shield rattles, it is super solid!
Here is a pic of the stock exhaust mounting bracket, that had been slightly modified by the previous owner. (There is evidence the car had non-stock exhaust and suspension on the car at some point, though it was all correctly and excellently maintained and returned to mostly stock.)
Through the miracle of modern machine wizardry, the bracket came off lickety-split!
It took me a while to get something together that would allow me to use the stock piping and the stock exhaust hanger, since I really didn't want to spend even more time cobbling together some hackneyed system from bits of crap I had laying around. I'd rather use stuff I know fits and spend time making that stuff work.
In order to get the muffler installed to the stock pipe, I needed it installed at a slight bend. How does one bend a pipe without a bender? (#**(#$ Pie cuts! That's how! LOL! The best place, I figured, to make the pie cut was in the adapter itself. The adapter I got matched the pipes perfectly . . . but wasn't the slip fit I wanted. So, I first cut out a pie from the adapter, but didn't cut all the way through, and after some careful squeezing and the use of my carefully calibrated SWAG-o-meter, I got this:
That left me with the simple problem to solve of how to make something like this a slip fit. That was easily solved by slitting the adapter down the long side, thusly!
I didn't get any decent views of the welding of everything, as it was dark and starting to drop freezing rain all over. It was pretty effing miserable. I just welded the stock exhaust bracket to the end of the muffler, then used a spare scissor jack to line up the ends of the pipe after getting my modified adapter in place. I tacked it in place to lock in the needed angle and position, pulled the pipe off, and MIGed the sucker on.
The evening was pretty frustrating, as my dad had texted me to ask if I needed anything, and I did. I couldn't find the spare spring bolt things I had bought over a year ago when I originally intended to replace the midpipe. So, I asked him to find those and some 2 1/4" ID (to fit around the outside of the pipes) 3 bolt gaskets. The midpipe flange has a weird offset third bolt, but I just cut that part of the gasket off and it works just fine. (I've had the midpipe off several time for various things like replacing the rear tranny mount. This time it was rusted to heck and took most of Sunday afternoon/evening to get off because I forgot my dad had a Dremel, and mine is located conveniently at my "shop." heh) He graciously stopped at 5 auto parts places. Most parts stores don't seem to carry basic, generic exhaust gaskets anymore, or, they just don't )(#$(*$# know what you are talking about. My dad found some, but he brought 2" ID gaskets . . . which I didn't want to bother modifying to fit since they would be very thinned out and not even worth using at that point. I gave him a big hug, thanked him, then sent him on his way. He really is an awesome dad, but . . . sometimes all you can do is shake your head and smile.
Anyway, while I was waiting on the gaskets, I installed some new spark plugs. I found one leaking spark plug tube seal that I will need to replace this year. The plugs looked pretty decent otherwise. Gotta love COP and an excellent intake system that flows darn evenly to all cylinders. (The Type-II C32A6 has a variable length intake manifold. It actually switches twice, so you have three intake tract lengths, and MAN do they work! The engine sounds like it goes to 11 at about 4,500RPM!)
Here's an in the middle of the job pic:
I also took the time to change the tranny fluid and also changed the engine oil. I was so tired at that point that I forgot to change the dang filter, but . . . more on why that wasn't a bad thing at all, shortly.
I bolted everything together and in place, dropped the car off the stands, fully anticipating everything being fixed, and started the car up. I was greeted with a throaty idle, but it was still idling poorly. It had no throttle response at all. And . . . it was running pig, fuel drenched rich. Ugh. WTF? By this time, it was after midnight, the freezing rain was getting worse, so I just got everything out of the rain and went in to warm up and look through the manual. A friendly neighbor who is really awesome with cars was actually coming back from vacation and heard the car. (He's very good at troubleshooting stuff as he's been wrenching for his whole life.) He asked me if the car's MAF sensor was bad, as it sounded like a car with a bad MAF sensor. It seriously did. (I've helped fix a few MAF sensored cars before.) I told him it was speed density, as all Hondas pretty much at, and he said "OK, you probably want to check your intake air temperature sensor." So, I looked up the specs on the sensor in the morning and figured that it should read about 4-5KOhm at the ambient temperature, and measured it. 2.3KOhm. Oh, WTF? It was in the -20 to -30*F range. Duh. I also pulled the codes from the ECU and got a code for ignition signal output.
I had a spare IAT sensor from another manifold, and swapped it in. This is the old one as I pulled it from the manifold:
Yeah, maybe that is a problem . . . =( I also was asking myself how in the world it got that mucky. I soon found out. The car had come with a SRI (Short Ram Intake) and filter. I never paid too much attention to the filter as it looked OK. Well . . . that was stupid. It wasn't doing jackall. The intake tube had dust inside of it, especially the outside of the turn before the throttle body. The valve cover vent from the massensger side is also drawing too much oil through it. (It's good for crank case venting, but, not good to have that much oil getting drawn into the intake manifold. Oil vapors are bad for the engine!) The throttle plate was gunked up. Ugh. Shooting myself in the foot, for sure.
I reset the ECU, cleaned everything up, walked to the local parts store and picked up a K&N filter with a nice radiused inlet (much better than the old filter's crap design), installed the new air filter and then tested some vacuum lines (of which there are a surprising amount on a modern fuel injected car, as many of the sensors and actuators for systems are remotely mounted) and I found a few slight leaks that were corrected.
I had also taken the time to put up some shelter, since it was now raining:
After I started it up, I made sure it was running better, and holy crap did it ever feel and sound good! I then changed the oil (AND FILTER) again, and I was really shocked to see how crudy the oil coming out was. So, having all the fuel in the engine oil really did some good in cleaning up the insides of the engine a bit! Not that I recommend that at all . . . but unintended happy consequences are not a bad thing!
Here's a clip of the idle:
That leaves me with the last issue with the car from all of this: Drone. Holy )#($* does the exhaust drooooooooooooone at cruise and certain light throttle positions. Ugh. I HATE drone. But, I did what needed to be done, and will do what I need to do this coming month (have to wait for my next stipend to come in) and cut out the flex pipe, move the cat up as far as possible and install a 14" Magnaflow 4" round muffler as a resonator. That should help tremendously. If it doesn't kill the drone, I will purchase and install a Dynomax VT muffler, which has a flap inside it. Those things sound GREAT at WOT, but absolutely kill any drone at all when cruising at low loads. It's the best of both worlds!
I may have a couple smaller updates, but, I wouldn't expect anything major like this until early February.
Oh, and Justin, this is why your header isn't completely welded up yet. LOL!