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Unread 04-12-2014, 02:35 PM
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Default Re: Vorshlag Scion FR-S LSx Alpha Project

continued from above

The saving grace of the FA 20 engine is the height: this lump is a lot shorter than an average upright inline-4 or V-configuration engines, with the bulky DOHC cylinder heads sitting very low down in the chassis. That is all this engine does add - a lower center of gravity. But low weight isn't what this unusual engine layout offers, not hardly. As you can see below, we've already weighed the stock FA20 engine and transmission at 480 pounds. This is, by far, the heaviest 4-cylinder aluminum engine we've ever weighed.

Weight of 2.0L engine and 5-spd transmission is 493 pounds with a 13 pound dolly; the aftermarket turbo was removed

There are other things about the Subaru flat 4 engine that are unusual. With only 4 cylinders it still has an inordinate amount of parts and complexity: 4 camshafts, 2 cylinder heads, lots of cam drive chains and tensioners, and the block has to be split in half to disassemble the connecting rods and other internals. The compression ratio of the FA20 engine is also very high at 12.5:1, an uncommonly high value for a production gasoline engine. This means you have to run Premium (high octane) fuel and adding forced induction (super- or turbocharging) is a very risky proposition. The saving grace is the Toyota designed Direct Injection fuel system, which uses very high fuel line pressure and injects fuel directly into the combustion chamber (diesel engines went to this type of direct fuel injection a long time ago). These new "Gasoline Direct Injection" (aka: DI) systems tend to add 5-10% more power and 10-20% extra fuel efficiency over a more common "low pressure" (45-60 psi) port fuel injection system, and its how they can get away with that much cylinder compression. But since these DI systems are so new they are difficult to tune, upgrade and modify. Even the factory Toyota system used on the 86 includes a second set of "port fuel injectors", to help with low engine speeds and cold start problems (see this video for a better explanation of the factory DI and PI systema)

All this high tech wizardry doesn't magically make this 2 liter engine produce awesome levels of power, however. Even the 1999-era Honda S2000's F20C engine made 240 hp with 2 liters, normal pressure EFI, and 11:1 compression. The 2013 FR-S makes 200 hp with the same displacement, Direct Injection and a higher compression ratio. When measured the FA20 is making about 160-170 whp, and the chassis dyno measurement shown below on one of our tester's stock 2013 BRZ is typical.

The stock horsepower numbers are something an FT86 owner is never going to brag about

The blue test car we worked with in 2012-13 made a best dyno pull of 167 whp (measured at the rear wheels on a DynoJet chassis dyno) in stock form, and with a measured curb weight of 2775 pounds (+ 200 for a driver like me) to push around, that makes for a 17.8:1 pounds per hp ratio, which I'll round up to 18:1. Pounds per hp is a common number that racers look at, as many road racing classes have strict limits there. Our NASA TT3 prepped 2011 Mustang has to conform to an 8.8:1 pounds per hp ratio, giving us twice the horsepower for each pound we haul around compared to an FR-S/BRZ.

That 18:1 power to weight ratio is more inline with an early 1990s 1.8L Miata. For some folks, that's perfectly fine. For others, they need more power to create the higher acceleration rates that lead to more thrills, and on a road course this is amplified dramatically. Tens of thousands of people have made the comment about the 86 twins that they need more power. We've had dozens of owners ask us here at Vorshlag "When are you going to make an LS1 swap kit for the 86?" So we had been quietly looking for that perfect "Alpha customer" for the past year and a half.

Each time I have driven these cars on track (see video above), the immense grip levels were notable simply because of their inherent lack of forward thrust the 2 liter boxer engine provides. It goes fairly well, and you can terrorize stock Miatas in a BRZ or FR-S, but that's about it. We've seen so many aftermarket parts pop-up to try to rectify the limited power levels: all manner of headers, cat-back exhausts, cold air kits and other bolt-on doo-dads, custom tunes and even E85 ethanol fuel conversions. All sorts of manufacturers and shops have been trying to unlock more power - but most solutions seem to come up short. There just isn't a lot of "easy" horsepower left to untap on the FA20 engine, and many of the claims of "300 whp!" end up being a bunch of internet hype or turbo ticking time bombs. Even a 200 whp FT86 build is somewhat legendary.

Weight of a bone stock 2013 BRZ Premium package car came in at 2775 pounds on our scale

Why I Hate Boosted Track Cars

The main power solution now coming to market for this chassis includes forced induction kits using either a turbo- and supercharger. I lump both of these Forced Induction (aka: "FI") solutions into the same category, which I often label with the derogatory term "boost buggies". This Alpha build FR-S came in to our shop with an turbo kit installed, and was one of the first Ft86 car's in Texas with this particular kit. I don't know what brand of kit this is, but it almost doesn't matter - as these FI kits will all suffer the same fates in the 12.5:1 compression ratio FA20 motor. Detonation and premature engine failure until the engine is modified with new pistons that can lower the compression ratio.

When the lowest part of your track-built car is the turbocharger and engine oil line, trouble awaits

The layout of this particular turbo kit was less than ideal, in my opinion, especially for track use. The turbocharger was mounted low, underneath the engine, and both the turbo housing and the oil feed line to it were the lowest parts on the chassis. There was also an electric oil pump for the turbo oil feed. This would mean than an off-track excursion could easily rip the oil line off or damage the turbocharger first, which could turn into an expensive mistake. This car was supposed to be built as a reliable track car, but this kit pretty much precluded that, as you have had to make the bottom of the car safe for "offs" by adding skid plates, thus making ground clearance even worse. This turbo package and associated tuning also ended up killing two motors - first the stock 12.5:1 motor then a lower compression motor - both of which died on the dyno, according to what we heard. Before the final race prepped turbo motor was ever able to take a single lap on track, the car's owner went looking for a better solution.

There's not going to be a blame game here - it was a commercially available turbo kit, but something obviously went awry. Several times. Even without multiple engine failures on the dyno, I think adding a turbo system to a high compression stock motor with cast pistons was always going to be a recipe for disaster. Maybe it would have lived with the final race built motor it received, but we will never know because that motor is no longer in this chassis. There were too many other things wrong with the installation to document, but needless to say, we're going to put it back together the Vorshlag way - with a big naturally aspirated V8 making a reliable 400 whp, a beautiful exhaust system that has a sound that will make you crave it, proper cooling and sub-system solutions, and a distinct lack of zip ties and bailing wire.

A Pikes Peak team we sponsored with some suspension bits had decent luck with a turbocharged set-up on their FR-S race car, but it had some serious tuning hiccups and teething pains to deal with before it got to the mountain. For that extreme hill climb you see over 14,000 feet of elevation at the top of the 12 mile race course, and the only way to maintain horsepower at the top of the mountain is with FI or electric power. FI can make up for the lack of air density and electric motors don't ingest air, so they don't care.

But most of us don't race at 14,000 feet, and in most cases a larger displacement naturally aspirated engine is much MUCH more reliable than any FI engine, especially engines that were not FI from the factory. I'm personally not a fan of turbo and supercharger "kits" installed onto stock motors, and I have seen and experienced a lot of bad examples of this first hand. I worked at a tuner shop that specialized in supercharged V8s back in the day and customers were always breaking pistons, head gaskets, and more. The only way to make them live, even on drag/street cars, was with very mild boost levels + a GOOD fuel system + a conservative tune + a very well built motor. That hasn't changed.

Vorshlag has worked with FI engines for road course and hill climb use and we understand the REAL challenges to making these reliable

The problem is exacerbated when the car/motor in question never came from the factory as a turbo model. You see, there is a LOT of engineering and development that goes into building a factory turbocharged car, with all sub-systems getting upgrades to deal with the extra power and HEAT of a boosted engine. To make a non-turbo car into a turbocharged set-up is a lot of additional work to get it reliable. It is so much more than "bolting on the turbo". All sorts of things need to be insulated and re-routed, all fluid systems need beefed up cooling, and heat soak becomes a major issue.

And don't get me started on what it takes to make a turbocharged or supercharged engine car live on a road course. The things you need to make a turbo engine live in drag racing or street use pale in comparison to what you need to do for track use. Everything heat soaks... the turbo housing, the intercooler, the intake manifold, the oil gets cooked... you almost cannot make an intercooler big enough to shed the heat from a turbo to run on a road course for more than a handful of minutes. The intake air temperatures on most turbocharged engines used on a road course keep going up, up, up.... to the point where the pistons eventually melt or something goes BOOM. Even short road course use set-ups like Time Attack and Time Trial face huge hurdles and challenges to keep the motors together and reliable.

Road course competition in any FI car includes a lot of extra prep and maintenance

So we've explained why an FI build doesn't make sense for this dual purpose street/track car. What is our solution? If you've heard of Vorshlag then you already knew what we had in store before you read anything on this post - swapping in a lightweight V8 engine that will nearly triple the stock displacement. That is a common answer we have to the question of "I need reliable horsepower". Our plan is to use this particular 2013 FR-S as our "Alpha" or first prototype build, then perfect a bolt-in LSx V8 swap kit for FT86 owners to be able to swap in this aluminum V8 motor with as much ease as possible. We always start all new swaps with an Alpha build, which includes the following cars...

Vorshlag is well known for LS1 swaps in chassis, as well as our production kit components that make installing these V8s easy

If you do some research you will see that Vorshlag has developed and built LS1 V8 swaps for a number of different chassis, and our E36 swap kits are extremely popular with new sub-system parts and products released from 2007-2014. We released our initial "Stage 0" kit (the parts necessary to mount the drivetrain) for the BMW E46 chassis last year and those have also been received very well. We have done a number of other "one off" LS1 swaps such as the BMW E30 LSx that we built for the Grassroots Motorsports $20XX Challenge, which we won overall with in 2011. Then there was the BMW Z3, and we're also need into the development for an NB chassis MX-5 Miata V8 swap kit.

The beautiful engine bay of the Z3 LS1 was worth opening the hood to see!

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