Day 20: Grandma is Getting Exhausted

Most racing sanctioning bodies require that you run some type of exhaust on your car, and it was no different for Project Grandma. We showed you in an earlier update the beautiful set of hand made Lemons Header’s that we made for the car, but that only makes up half of the exhaust system needed. Flowmaster Mufflers got the call for old Granny, and then we got everything coated using a Techline coating by Olympic Coatings.

For the mufflers, we tapped Flowmaster for a set of their Flowmaster Outlaw Race Mufflers, and some 4-inch exhaust pipe. Flowmaster Outlaw Race Mufflers are a reasonably-priced mufflers that flows monster air, and is in a very small form-factor that makes packaging the exhaust in your race car very easy.

Check out some of the feature below:

  • Incorporates sound attenuation rings along the inside of the case
  • Does not have a need for packing materials
  • Designed for race applications


Flowmaster calls them “Outlaw Race Mufflers”. We call them mufflers? I’m sure they do muffle sound, but the way they are designed, they are going to be loud and they are not going to restrict much, if any, horsepower.

These mufflers feature a straight through design that satisfies the guys at the tech pad, but don’t go trying to passing a police officer with them. They are designed to provide minimal sound reduction, and are more intended primarily for racing situations where a muffler rule is in effect with no specific decibel requirements. Flowmaster sent our mufflers with two straight pipes with a flange on one end for use of our Malibu along with some straight 4 inch pipe.

They won’t do much to limit the noise coming from our 555 Edelbrock/Musi engine, but that is exactly what we like about them! We picked ours up in a 4 inch in and out, but Flowmaster offers them in a 5 inch and 3 inch version to fit most race car exhaust tubing sizes.

First, we bolted the straight pipes up to the flanges off the back of our Lemons Headers’ Collector. It was then that we knew things were going to be tight. Because we had added a few extra bars under the car for more support and safety, getting even the small Outlaw Mufflers to fit was going to be a small challenge.

Mike Ryan wanted to run the car with no mufflers and just some turn out. Thankfully we talked him out of it. This ain’t NASCAR.

We added about 3 inches of pipping to each side of the exhaust after the collector, but before the muffler so that the Flowmaster Outlaws would clear the transmission cross bar.

Mike removed a little of the metal from the cross bar mount as well to give room for the massive 4 inch tubing.

We took a few measurements and shorted each muffler about an inch to fit in front of the large X-bar we had welded in.

Even then we still had an issue on the driver side of the car. So we decided to notch the top on the outlet side of the muffler so that it would clear with no problem.

Fast forward a little bit. We started Grandma up and you wouldn’t believe it. Car sounded fantastic. However, we also realized that we should probably do something to protect our headers and exhaust system for the long haul. Our Lemon’s headers and Flowmaster exhaust were mild steel.

To protect our exhaust system we made a call to Techline Coatings just down the street from us for a coating that would not only protect the metal, but help reduce the amount of heat put off of these components.

They recommended a Thermal Barrier Coating called CermaKrome for our G-Body’s exhaust. Thermal barrier coatings are designed, as the name suggests, to reduce the movement of heat by not allowing it to be absorbed in the metal. The coating can be applied to a variety of surfaces and metals, such as exhaust system components, valve covers, headers, or any other metal that can withstand the 500 degree Fahrenheit cure temperatures. It provides a smooth clean appearance that will not rust, and is effective as a hard protective coating for aluminum parts.


This unique coating is based on a water/solvent system, which requires careful attention to application procedures. To handle the coating, we sent the exhaust over to Olympic Coatings in Escondido, CA to make sure it was done right. We had used Olympic before, and we knew the quality of their work.


Once the exhaust was there, the team of Olympic sandblasted all of the components in order to prep them for the coating process. After a few quick shots with the spray gun, our system was set up to cure.


After the curing process was over, the headers and exhaust were polished to a chrome like finish. Makes sense – now we know where this coating gets it name from.

Now our exhaust is ready to handle temperatures up to 1600 degrees with no problem at all. Not that our system will ever reach that temperature given the coatings qualities. And because the coating was applied to both the inside and outside of the tubing, there are even more benefits. With the surface smoother inside, exhaust gas velocity is increased. Which means that scavenging effect that happens inside the exhaust is increased – moving more hot air out quicker.

That’s all for Project Grandma today, look for more next week!

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About the author

Tom Bobolts

Tom started working for Power Automedia in early 2008 at the young age of 20. Starting off as an intern spinning wrenches in the PowerTV garage, Tom cut his teeth helping us build the very project cars we feature. Since moving inside the office, most of his time is spent writing and shooting installs - but he still finds time to get out in the shop. Outside of work, Tom enjoys a variety of different motorsports from Street Bikes, Muscle Cars and just about anything that demands high amounts of horsepower.
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