It's Alive! - Ironing out the last details

9-17-02

A few more days of work and things are starting to come together.  My second muffler should be in today.  I originally ordered a Summit Racing offset inlet / center outlet muffler, but it is VERY loud and buzzy.  So I put in an order for a Dynomax offset inlet / offset outlet.  I'm hoping that the extra space between the inlet and outlet will help quiet more.  I have actually considered sticking a catalytic convertor in the pipe to help quiet it down more and get rid of some of the smell out the pipe.

Also have to come up with a speed sensor for the VTEC and auto tranny.  It appears (at least in my case) that the 87 CRX sensor is just putting out +12V if the car is moving and 0V if the car is stopped.  I made a run with a signal generator last night.  The car shifted from 1-2 at a frequency of 45 Hertz.  So working backward, figuring the shift should happen at about 10 MPH under light throttle and given the diameter of my tires, I need about 18 pulses per revolution of the wheel.
 

A red letter date!  I actually pushed the car hard enough to get VTEC to kick in last night!  I got the Dynomax muffler installed but my hopes of a quiet system quickly evaporated as I pulled out of the driveway.  This thing still buzzes like crazy.  I feather footed it outside town so as not to attract the attention of the local pigs who would have nothing better to do than pull me over.  Once out of town I was a little more liberal with the throttle.  I headed down the ramp to a highway and decided to see what full throttle would do...."buzzzzzzzz-click-BWAAAAAA"  I suppose that is a good sign of when VTEC is on!

At first, I wasn't entirely impressed with the accelleration, but then I got to thinking...I really need to adjust my driving style for the car.  The performance I'm used to is in the Corvette which is a torque monster off the line, but pretty much all over at 4500 RPM.  The CRX is just the opposite...VTEC kicks in at 4800 and the fun continues up to 8000 or so.

The Dynomax was no help.  Still buzzing.  It was bad enough that I could picture any cop within earshot of even a half throttle acceleration spewing powdered sugar and donut crumbs across the dash as he slammed the car into drive to run me down, then not even having the decency to wipe his fat fingers of the grease as he handed me a ticket.

The solution, I installed a Thrush glass pack muffler (2-1/4" pipe diameter x 31 inches long... aka "da biggest one 'ya got) directly after the header and left the Dynomax muffler in the stock location. MUCH quieter! You wouldn't even know it was the same car. At idle the only thing that betrays my existance as a stock DX is the whine of the fuel pump and it takes a trained ear to hear that. Gentle acceleration up to about 3K RPM is also pretty uneventful, although the whine of all those valves and cams lets people know "it ain't stock" they just don't know what to expect in a clapped out 1G CRX. At 4K + you definitely know something is up, but what the hell...if it was dead silent, I'd forget it's running!  I still need to do a few mods on the "tailpipe" to the right side of the muffler in the photo, but the small extension was good enough for a test.