Sunday, January 14, 2018

Insuring Domestic Tranquility

I'm not dead, I promise. I just haven't worked on any car stuff (recreationally anyway) in months. But that doesn't mean I haven't been working. As you know, we recently bought an old house. Houses tend to be a bit more expensive than cars.  For the price of a base model Ferrari you can have a house with a 1992 Chevy Celebrity interior (complete with jammed windows and that faint scent of cat urine).  So of course, that's what we did. 

Much like I browse the craigslist CTO section out of pure instinct, Jen does the same for interior design blogs. Well, she might have a slightly less addictive tendencies than me, but interior design is definitely her thing. She's wanted to do an old house remodel for a long time, so that was part of the deal with moving to Michigan. It's been a wild ride. We decided to gut the kitchen and both bathrooms, and repaint all the other rooms, in addition to replacing a basement wall that was bowing inward. We hired someone to to most of the work (don't worry though, my part of the work has taken ever weekend since we started), and he did pretty good work but went way over budget so we let him go and I get to do the downstairs bathroom by myself. We also had unpleasant interactions with the city building inspector who, on occasion, forgets the purpose of his job and uses it to fulfill his authoritarian urges.

Anyway, I'm not going to tell that whole story or show everything that has been done. If you want more of the story and design theory, follow us on Instagram at I'm just checking in on my blog because it has been feeling neglected (and Jen is out of town so I'm blogging to entertain myself).

To say that the change in our kitchen is drastic would be an understatement. I'll leave the captions off so you can play a fun game of "which is the before picture".

The kitchen is not completely done, there are about a hundred finishing touches we have to do, including a new door. We are pretty thrilled with it though. The old kitchen was cramped, designed to be as cheap as possible, and maybe just a little dated. The new kitchen is a really nice place to be and for a 10x12 kitchen, is incredibly functional.

While I've been busy building the house, Jen has been busy building a kid.

That's right, in June we will be having a little boy. Hopefully this means that in a couple years I have a garage helper!

Saturday, September 16, 2017

Drone Warfare

There is a deep primal urge within the lizard-brain of every car enthusiast. It usually surfaces when said enthusiast gets a new vehicle, but it can appear also when routine maintenance is performed on the exhaust system. The desire to undo countless hours of fine engineering work and replace the OEM muffler with something a bit louder is as strong as it is irrational. Rarely is anything besides a few decibels to be gained in doing so, yet we persist and do it over and over again.

One of the greatest risks in changing the muffler is that after spending a little time and often, a lot of money, the exhaust will drone. Drone is an unpleasant experience that happens when the sound waves from the newly loud exhaust resonates the body structure of your vehicle at it's natural frequency. It makes you feel like Manuel Noriega in your self inflicted NVH torture chamber.

I recently did this to myself. Not with Grace, but with my Jeep XJ daily driver, the TURD. The original 1998 exhaust system was on its way out and I got that urge. I picked up a glasspack from Summit racing for about $30, since my friend in high school had owned a glasspack equipped XJ and I remembered it sounding good. I paid an exhaust shop to bend up a new exhaust system and install the glasspack with a new catalytic converter.

Maybe I've just gotten old and maybe teenagers are immune to drone but as soon as I drove the Jeep, I knew I'd made a terrible mistake. The drone at 1500 RPM and 2800 RPM was unbearable, and it sounded so ricey I was a bit embarrassed to drive it. Remember, this is a beat up Jeep with a badge on the rear that says TURD, and the sound was the embarrassing part. I used an app on my phone called Sound Analyser to look closer at the problem areas, and found my biggest issue to be sound levels at 145 Hz.

Sound level readings with glasspack installed. Red areas show unpleasant drone.

After a bit of research, I came across the Flowmaster Super HP2 muffler. It would fit right in place of the glasspack and had a pretty good tone, from what I could find on YouTube. It wasn't cheap, but I figured I'd give it a try.

Top: Flowmaster HP-2   Bottom: Summit Glasspack

Inside Summit Glasspack

Inside HP-2 Muffler

The HP-2 or Hushpower muffler is not the traditional Flowmaster chambered "mousetrap" muffler design, it's closer to being a "straight through" muffler, without actually being straight through. It helped overall sound levels, as well as tone. While it took away the embarrassment of driving my Jeep, it didn't quite fix the droning when at 1500 and 2800 RPM. From my sound level 

Tailpipe as made by exhaust shop
Tailpipe after my modification

Over  the past couple years, I've done a bit of research on different types of noise cancelling resonators for exhaust systems. Most people thing of absorptive resonators when they think of an exhaust resonator, but those don't cancel noise, and they only absorb high frequencies. My issues were centered around 145Hz, which is a relatively low frequency. Of the noise cancelleing resonators, the most common is a Helmholtz resonator. A Helmholtz resonator is like an empty soda bottle that you blow across the top of. A wave resonates inside the bottle, and comes out amplified. If sized correctly and included in an exhaust system, this can actually cancel out sound waves of a given frequency. These are actually included inside many OEM muffler designs. 

A quarter wave  or branch resonator is very similar in function and can be similar in form. It is simply a capped pipe that is teed into the exhaust system at 90 degrees. At certain frequencies, depending on the speed of sound (influenced by temperature inside the pipe) and the length of the pipe, noise is cancelled. After doing a few fairly simple calculations and educated guesses, I chose 30" to cancel my 145 Hz drone. Link to my 1/4 wave resonator calculator. The construction of the resonator was simple and can be seen below.

This is where the resonator tees into the main exhaust system.

I was pleasantly surprised when I went for a drive after finishing. My calculations were correct, or at least correct enough to do what I wanted. The drone at 2800 RPM was completely eliminated, and the drone at 1500 RPM was actually reduced. This can be seen in the plots below. The first plot shows an acceleration without a resonator, the second shows acceleration with a resonator. In the color plots, you can see that the red spot is turned light green, and in the upper chart, you can see that the 145 Hz region was reduced from 74 dB to about 61 dB. A 13 dB reduction means that exhaust sound energy was reduced 20x. The average level (RMS) was reduced by 11 dB. That is an unbelievably large improvement.

I can't say enough about how effective this method is in reducing unwanted exhaust noise.  I was beyond pleased with the result. I've finally found an effective method to please my adolescent lizard brain with a loud exhaust while simultaneously using physics to appease my ever advancing old-man "get off my lawn" requirements.


PS: This blog post was done, and it sat in my drafts box for a couple weeks. I didn't want to post it without a video of what it sounds like. With the new (old) house I just hadn't had time to do it. Today I finished up the exhaust job and had time to make the video. First I'll show the downpipe fab and then show the video.

I had an exhaust shop do the rear part of the exhaust because it was pretty straightforward. At the front, it was going to be a little more complicated. There were two items to deal with:

  1. I didn't want to mess with a two-bolt flange on the header because the bolts always rust and then the nuts are impossible to get off. Instead I wanted to have a V-band connection. To do that, the header needed to come off
  2. I also wanted a large diameter, non-crushed downpipe. As you'll see in the pictures below, the downpipe was significantly crushed. It's a common issue on XJs, I guess as the springs sag, the front driveshaft's front u-joint smashes the downpipe and restricts flow. I figure mine was crushed to about 50% of it's original area
Now for the pics:

Crushed downpipe

Left to right: OEM downpipe size, crushed downpipe, new downpipe size

Expanding the collector to mount v-band flange

V-band flange mounted to collector

Manrel bent XJ downpipe
The new downpipe did just what I hoped it would and increased top end power. Previously, the power would die out above about 4000 RPM. Now it pulls very strong from 4000-5000 RPM. Mission accomplished.

For your viewing pleasure: This is what it sounds like. I like it. I think it brings out the inline-six sound nicely. It's not too loud, but it lets you know it's there.

PPS: This is my Michigan Garage V1.0. It's an almost 2 car garage. The structure is musty and starting to lean, so it will probably be torn down and replaced with V2.0 next year. Since most of my attention will be focused on the house for the next year or so, it'll do.

Sunday, August 6, 2017

The 5 Year Summer

Five years and one month ago I packed up my dad's pickup with my twelve belongings, and with my Ranger in tow, I headed for my new home in Bellflower, California. It was a long, strange trip complete with an exploded battery in the 106° Nevada desert. This past week I moved, this time to Diet Canada Michigan. I can't remember if I've mentioned it here, but my employer is moving my position from California to Michigan, and in the interest of having a job, Jen and I have decided to go. 

Grace has always been a cruel mistress, so it's fitting that we'll be leaving the world class canyon roads I built her for without ever driving her on them. Instead, we'll get to experience the potholes of Michigan together.  In reality, she'll be on the back burner for a bit, until our house is in order... By the way, we bought a house!

I like old cars, Jen likes old houses. Our house, named Old Sid (from a name that was on the property deed) was built approximately the same time Henry Ford was down the road cranking out Model Ts in any color you wanted, so long as it was black.  Old Sid will be getting a new kitchen, new bathrooms, some landscaping work and at some point (my favorite point) a new garage. So yeah, Grace will have to get used the the fact that she's not an only child anymore and Old Sid is mom's favorite.  

Today, I'm just going to try to get current with the work that was done before we moved.


Brakes, in their ideal form, will bring a vehicle in motion to a stop and very little else. Of course that would be far too simple, so my the brakes on my Falcon sometimes attempt to also bring the rear of the car into the direction of travel.  For some reason, the rear brakes had far higher brake force than the front. A tail happy brake system can lead to creases in the seat upholstery from the strong sphincter puckering action it can induce. In the interest of upholstery longevity, I began looking for a solution. 

Applying Occam's Razor, I attacked the simplest explanation first. It is my assumption that the brake pads that came with the suspension and brake kit were incredibly cheap. TCI, who sells the kits, most likely gets the cheapest pads available in anticipation of the end user purchasing a high performance pad after a short amount of time. I picked up a set of Wilwood Polymatrix E compound pads, which are a high performance street compound. A race compound would not work well when cold, and would have much more wear than the street compound.


In my last post, I wrote about the fuel system issues we had on the dyno. Grace ran out of fuel pump at about 350HP. I think the reason was two-fold. First, the pre-pump filter was not large enough, and second, the Bosch 044 pump was pulling fuel too far. 

To address these issues, I bought a larger filter, capable of flowing 400 GPH, up from the old filter's rating of 125 GPH, and I installed a Walbro 255 right at the tank as a feeder or lift pump upstream of the Bosch 044. 

Walbro 255 mounted to the front of the fuel tank.

400 GPH 40 Micron fuel filter from Robb MC Performance
Filter and pump installed

I also wanted to make sure that both pumps got full voltage from the battery, so I rewired the pumps to provide larger gauge wire and shorter runs of wire feeding them with fresh, high-grade, organic, grass-fed, amps and volts. The relays are in the trunk and have fuses built into them.


Cars without interiors are pretty miserable to ride in, and Grace was no exception. I felt it was about time to start working on the miserableness aspect of this car. The first big step was to install carpet. There are a lot of vendors that sell carpet for Falcons, but it seems they all have one thing in common: they all sell the exact same carpet. This is likely true for most makes and models, since there is one major manufacturer of aftermarket carpet, namely Auto Custom Carpets. I found a wide range of prices but the best price was through Rock Auto. I think I paid about $200 for a molded, mass-backed carpet.  

The mass backing adds a little shape to the carpet, and should help reduce interior noise a little bit.

mass backing and felt backing

Due to my raised transmission tunnel I knew no carpet kit would fit exactly. The rear carpet fit quite well, but when it came to the front, I had to do quite a bit of cutting to get it in. This is one of those projects that I'll definitely revisit. The front carpet will be modified to fit the trans tunnel properly, but for now, the noise levels are drastically reduced, so I'm happy.

rear section installed
felt backing installed on mass backing


When things get going too good, Grace is always willing to bring you back to reality. While on the freeway breaking in my fancy new brake pads in, for no apparent reason, the head gasket decided to let go while boosting at about 10 psi (or 275 hp on this engine). Keep in mind that about a week and a half ago on the dyno, this car was making up to 350 HP on E85 and 320 HP on 91 octane. 

At this point I had a follow up dyno appointment set to finish up the tune, now that the fuel system had been improved. I figured I could get the head gasket changed (I'm pretty quick at it by this point, I think I've done head gaskets or rebuilds on this engine about a dozen times by now... seriously, what's wrong with me??) and still make it to my dyno appointment, so I set to work.

Coolant bubbling out the #2 spark plug hole
Cylinder #2 pushed the gasket out

Shiny clean cylinders
But seriously, so shiny!
Luck was not with me, because even though I made good time thinks still went wrong. Any time you see someone using an EZ-out in the garage, step away, say nothing, avoid eye contact, and don't make any sudden movements. while trying to lower the cylinder head onto the engine, it slipped and I broke an oil fittting adapter, which wasted about two hours of my time that I did not have.

I wanted to make sure the head gasket didn't let go yet again so I went to the trouble of getting the correct assembly lube for my ARP head studs. After reading through an ARP technical presentation a few times, I was convinced that this was a necessary step if I wanted to actually achieve the correct fastener preload, or in other words the correct clamping force.

In the end it was all for nought, because the engine was still burning coolant after the head gasket was replaced. With the move coming at me like a freight train, I didn't have time to do anything but load a sickly car on a trailer and have it shipped across the country.

So here I sit in my barren house, waiting impatiently for my car and tools and real mattress to arrive (I've had enough air mattress for the next few years). I'll try to keep updating the blog when I can, but it might be a little less often until Old Sid gets the love he needs. Thanks again for reading, keep your stick on the ice!