Interview: Horace Mast of Mast Motorsports

When the LS1 engine first appeared in the 1997 Corvette, it was a radical redesign from GM’s tried-and-true iron block engines. Many engine experts were skeptical at first that the aluminum block LS1 engines could hold up to the heaps of horsepower they had planned, but their doubts were soon put to rest. Today, the LS-series of GM engines are among the most prolific and popular in the racing world. A combination of light weight, strong architecture, and a devoted aftermarket have helped the LS engines make strong statements both on the street and at the drag strip.

Few people are as familiar or as handy with LS engines as Horace Mast, the 27-year-old founder of Mast Motorsports. A self-described “engine guy,” Horace got his start tinkering diesel engines in an effort to get as much power as possible out of them. He was always obsessed with horsepower, which carried over into his college career. He and a team from Texas A&M entered the Formula SAE contest in 2006 with a one-cylinder, supercharged engine that ran on ethanol. They took first place in the Western division with their race car, which helped to catapult Horace into a career as an engine builder.

Today, Mast Motorsports is an aftermarket company completely devoted to tuning the LS series of engines. They specialize in EFI hardware and software that has come to define 21st century engine tuning. From Variable Valve Timing to nitrous injection, Mast Motorsports does it all, and we got a chance to interview Horace and get his take on the past, present, and future of LS engines.

Mr. Mast himself, standing with one of his many powerful engine creations

powerTV: Thanks for taking time to talk with us Horace. Let’s start at the beginning: How did Mast Motorsports start?

Horace Mast: Well, I started it right after I graduated from mechanical engineering school at Texas A&M. I had been involved in some school projects where I was doing some engine design. I just saw an opportunity in the electronics field and I wanted to get into powertrain solutions for the automotive aftermarket. So, I started working on computers specifically for the LS engines because I thought they had the most potential and two of my engineers from A&M joined with me to get it up and running.

powerTV: What is it about the potential of LS engines that drew you to them?

Mast: I think what drew me to them was, first off, the amount of horsepower that was a foundation that the Generation IV platform provided. The foundation was so well suited for doing different combinations and making more horsepower out of them. It was very well positioned, I saw the market opportunity, as it was by far the fastest growing engine market. It had the newest technology and I felt like I was more up to date with fuel injection like VVT (Variable Valve Timing) and other things. So I felt like we would have a competitive advantage in the market place if we focused on it.

Mast makes complete wiring harnesses for a variety of engine combinations

powerTV: Can you tell us what you think are the best qualities of the LS engines versus the weakest qualities?

Mast: Some of the best qualities of that engine platform are how many combinations you can build from the base architecture. There is everything from a 5.3 to a 7.4 liter engine and they’re built from the same block architecture. There is so much GM provided with their OEM parts. I think its best qualities are not only its cost structure, which is competitive, but the range of products you can develop. It is very versatile. As far as the weakest, I guess compared to the market it doesn’t really have that many weak points. The cost structure is probably still a little high compared to the older small blocks, but it has come down in the last several years and it will come down more and be even more competitive in price.

powerTV: Why build your own EFI systems for the LS series of engines?

Mast: We worked on the fuel injection system first because we wanted to have control over all of the calibration and we wanted to have control over all of the harnessing and provide it to the end user, not only for our internal engines but to sell separately. And it kind of comes back to being able to control and the capabilities of having control over your own EFI system. It really comes down to being able to provide the best product for the end user, and if we’re working with the GM Delphi unit or an aftermarket system that isn’t as powerful but costs more money, we think we’re able to come out with a very cost effective and very powerful EFI system. It adds a lot of value to the power trains we provide.

powerTV: How do you feel about forced induction? Do you think more factory cars will come with forced induction?

Mast: It is a good candidate for forced induction in that it accepts forced induction very well. I don’t think forced induction is the future of LSX engines. I think its obvious direct injection is the future of LSX engines to increase efficiency moving forward with GM’s new Generation V platform. With the OEM front I think we’re gonna see even smaller displacements and more direct injection to keep the fuel economy up.

A complete engine setup from Mast is assured to work in perfect harmony, as every part has been tested to ensure it is the right part for the job

powerTV: As an LSX builder, what are some key musts when it comes to building an engine, and what are some common misconceptions?

Mast: I think one of the key musts, and it is something we really focus on, is the quality of the preparation of the building of an engine from the ground up. We put so much work into making sure our main and rod bearings are torqued down right and have the correct tolerances.

I think as an engine builder, it really comes down to the amount of time and effort and quality you put in to the shortblock. It is key that to build it really correctly, you have to get every little detail, the piston ring gaps, everything has to be right. I think a lot of people still have been throwing these things together, and they’ve been lasting for years, which is a good thing. But I think one of the key things is the time and effort you put into building the short block; the preparation and getting the specs.

powerTV: What are some key questions you ask a customer when you are building them an engine?

Mast: The main three points are you have to know what application it is, usually that is the first question, and you have to know what they expect for performance. RPM is one of the hardest things, the valvetrain with all the forces, so you have to know what RPM range. If they are going high displacement you have to keep the revs down. So, knowing the application is key, knowing the durability requirements, and knowing the environment. Is it going to sit in a garage for six months and then get thrashed like crazy for six months at the track. These are all things we have to know so we can really spec out the right engine.

powerTV: How do you think the new 2010 Camaro buyer might be different?

Mast: Well the 2010 Camaro buyer, obviously you have all sorts of buyers out there. They’ve been waiting a year for it to come out and they can’t wait to modify it. Then you have the people who just want to make slight changes. You know it’s a new generation of F-body, and at this time, its not so clear what the Generation 5 owner, who that is or what they want. So it’s very important to understand what your customers are looking for.

I think right now what people want, as far as performance, they are trying to get more performance out of their engine and still keep that every day drivability in a brand new car. And that’s what they are looking at smaller cams than people in a Generation IV might jump up to. Also, I think it really helps our cylinder head sales, our cylinder head sales have jumped up quite a bit, without having to go to a more aggressive camshaft. I think the new Generation V owners are looking for drivability as well as performance than Generation IV owners as that car is much older.

In addition to wiring harnesses and whole engines, Mast also has a line of cylinder heads they have been working hard at

powerTV: Can you tell us what is one of the wildest engine combinations you’ve ever worked on?

Mast: Well we’ve done several over-the-top ones. There are two that stick out of my mind. We built a championship off-road racing engine, a 396, that produced over 800 horsepower with a single carburetor and single plane intake manifold. That was a really interesting engine to build. It not only had to make a lot of horsepower at low RPMs, but it had to be real durable too because it would be bouncing around off road. That engine was very successful.

The other we built had to run on pump gas, it had to run on 90 octane. It was a 427 engine with low compression and it used our cylinder heads and it made something like 1,200 horsepower on nitrous. That was a very interesting build because it had to make a lot of horsepower on low octane and compression. Those are probably two of the most over-the-top, unusual applications that stick out in my mind.

powerTV: How do you think technology like Variable Valve Timing and Direct Injection will affect the performance of LS engines?

Mast: Well I think the effect of variable valve timing is the wider, broader torque curve we’re able to develop using it. And I think we’re kind of using it to its maximum efficiency with the products we have. It is already affecting the performance of these engines, and I think we’ve proved that with some of the engines and marine applications we’ve put out in the past couple of years.

I think Direct Injection is really quite intriguing. The power potential of Direct Injection in a small block is going to be very interesting to find because you’re really removing all of the fuel in the cylinder, which the unburnt fuel is taking up space, but it’s also fuel you lose over the overlap. You’re gaining efficiency of the vaporization of the fuel the way its injected. So it’s going to be interesting when that technology comes out and it goes mainstream to see how the torque curve compares against carburetors and regular fuel injection.

I believe the Direct Injection is going to be really efficient to this performance and fuel efficiency is going be much much higher from the factory and for the aftermarket when companies are able to control and modify it better. So torque and fuel efficiency are going to be improved a lot.

Some of the products in the pipeline include a set of Mast-built and designed roller rockers

powerTV: Can you let us in on any products you’re preparing to release soon?

Mast: As far as automotive aftermarket products, we are in the next four to six weeks, we’re going to start releasing and selling our line of rocker arms. Not just for all the GM OEM heads but for our own heads as well. It is a project we have been working on for two years now, it’s something we want to get right and not rush to market with it. We’re going to have a lot of combinations and a lot of applications as well for the rocker arms. It is not a totally unique design, but it has a combination of features you don’t really find as far as a roller rocker.

We’re also working on a plethora of new cylinder heads in the next few months. A lot of canted valves, cylinder heads designed for circle track engines from the circle track program we’re getting up and running for the circle tracker racers out there. We’ve really pressed hard to compete with using an LS engine in that market against the big boys and the smaller outfits that specialize there. We’re going to have a very respectable product when it comes out.

There is a lot of non-automotive aftermarket products we are working on too, some things that are really going to surprise people in 2011. There are some really great things to come from our company in 2011, so we’re really excited about it.

powerTV: Thanks for taking the time to talk with us, and we’re looking forward to seeing what is next from Mast Motorsports!

Mast Motorsports
Phone: 866-551-4916

About the author

Chris Demorro

Christopher DeMorro is a freelance writer and journalist from Connecticut with two passions in life; writing and anything with an engine.
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