Here’s the new address:

http://beyondthehorizon.cz.cc

           //Drive on.

Part 1 is here.

Part 2 is here.

Part 3 is here.

     It’s as simple as the title of the “most victorious racing car of all time“.  1,436 victories in just 1,628 days.  Imagine that.  Over the course of four and a half years, the E30 M3 achieved a win every-day.  Every single day, whether it was a weekend, a vacation, or any day without a race (which is pretty often).  Against a competition that furiously improved their race cars to have more power, more grip, more everything, the E30 M3 only had two small revisions during its four year reign where its power increase was summed up to only 60 horses.   The road-going version featured a 2.3 liter engine which pushed out around 200 horses, but the race-going version peaked at 300 horses with the same 2.3 liters and without forced induction.  Weight was also reduced to 960 kilograms, or around 2110 pounds.  This gave the racecar a power-to-weight ratio of 3.2 kilos per hp.

     BMW’s first major race was round one of the first World Touring Car Championship in 1987, featuring the legendary Ford Sierra RS Cosworth, Maserati Bi-Turbo, and Alfa Romeo 75 Turbo.  Judging by their names, the opposition featured turbocharged engines, while BMW decided to stay “au natural”.  This decision usually gives engines better durability due to (relatively) lower engine temperatures, something needed when running a race-car at full throttle for up to twenty-four hours straight.  Round one started with a Ford taking pole position while six M3s took second to seventh place on the grid.  Unfortunately, while all six M3s finished 1-2-3-4-5-6, they were disqualified due to illegal lightweight bootlids.  And while round one gained them no points, it showed the world that BMW was ready to dominate the world.  That year (1987), the M3 won the Australian Touring Car Championship (ATCC), European Touring Car Championship (ETCC), German Touring Car Championship (GTCC), and the World Touring Car Championship (WTCC) all with different drivers.

     What made the victories more amazing was the fact that the M3 ran with 300 horses throughout the season, while the Ford Cosworth started off with 360 ponies and ended up with 460.  That’s a 160 horsepower difference, or a 2 to 3 power ratio in favor of the Ford.  And with the introduction of the legendary RS500 which took the power-to-ratio crown away from the M3 later on in the year, the M3 had only superior reliability and handling to rely on to win.  By the end of the season, BMW recorded four wins, while Ford took five, but BMW took home more class victories which added to their point total to give them the outright victory of the World Touring Car Championship.

     The victories kept piling up in 1988 as well.  The cancelling of the World Touring Car Championship just let BMW focus their attention on other touring series’.  They won the ETCC again with three straight race victories for total domination of the 2.5 liter class.  The Asia Pacific Touring Car Championship and British Touring Car Championship added to BMW’s list of trophies.  In ’89, the ETCC was cancelled, and BMW decided to focus on the German, British, and Italian podiums instead.  The same year, while the Evo 2 was released giving BMW a six-gear transmission and a small bump in power, the outright performance numbers couldn’t come close to that of the Ford RS500.  That year, BMW only won the German Touring Car Championship.

     With the turn of the decade, the E30 M3 was starting to show its age.  Even so, BMW bagged the Italian, Dutch, Swiss, and Belgian Touring Car Championships and finished second in the German Touring Car Championship.  The Evo Sport debuted in 1991 with 360 horses, but it was the newly developed 2.0 liter that BMW put into their M3 that won the BTCC in their new 2 liter class.

     1992 was the last year the E30 M3 raced in Europe due to new regulations and the introduction of the E36 M3.  BMW’s last season running the E30 M3 was in Australia in 1993 where they were allowed to run against V-8s and the new regulations.  Though they didn’t win the Championship, but the few podium victories against the newer V-8s was testament to the aging M3′s prowess.  The end of the season ended on a high note though, by winning Macau Ghia Trophy Race, one that BMW won 4 times prior with the M3.

     All in all, BMW recorded over 1,400 victories in almost as many days.  The M3 toiled against superior technology, massive amounts of horsepower, and AWD traction, but still came out on top.  They routinely passed Sierra Cosworths, Audi 300 Quattros, Holden Commodores, and even Nissan Skylines on their road to the top of the podium, which seemed to happen quite often.  This clearly shows that a well developed balanced car is more important than one with all-out horsepower or AWD traction.

Part 1 is here.

Part 2 is here.

     Let’s move on to the fun part: the numbers.  Ain’t no room for opinions here, it’s all hard numbers and tests.

     When M started development of the M3′s then unnamed engine, they decided to go with the high-revving 4 pot route instead of a lower-revving 6 cylinder.  They based the block on BMW’s 1.8 liter M10 engine which was powering the rest of the 3 series lineup at the time.  The head however, was based on the M88 engine (cut down to 4 cylinders of course) which powered the street version of the M1,the E28 M5, and even some second generation E34 M5s.

     The stock 2.0 liters of displacement wasn’t enough for M, so they decided to both bore and stroke it to 93.4 mm and 84.0 mm, an increase of 4.4 mm in bore diameter, and 7 mm in stroke length.  They then adapted the M88, which featured double overhead cams, onto their 2.3 liter block by machining both the intake and exhaust ports for better flow.  They added eight counterweights to the crankshaft to deal with the increased rev limit, and also added individual throttle bodies (ITBs) to help each cylinder breathe with maximum efficiency.  This combination gave the S14 around 200 horses (197 hp i believe ) in production form.  While being powerful and efficient all the way around, M also wanted their S14 to be seen as clean and fuel efficient as well.  Thus they added a catalyst converter, which when tuned with their engine management, would return over 30 miles per gallon.  While the inclusion of the catalyst converter would lower the maximum output, it only sapped around 5 ponies in all, leaving the final power output at 192 hp.  The more powerful special edition M3 EVO2 which arrived in 1990 sported a larger power unit, both bored and stroked again to 2.5 liters by increasing bore diameter to 95.5 mm and stroke length to 87 mm to produce 238 hp.

     The chassis was also modified to accompany the increased power figure.  Lightness and stiffness was the goal.  The chassis was stripped down to only its bare necessities and then some.  The front windscreen and rear window were bonded to the chassis for improved stability and handling.  The front and rear bumpers, sidesill, boot lid, and spoilers were built from plastic to reduce weight.  Brake disc sizes were increased, while the front disks were exchanged for ventilated ones.  Stiffer anti-roll bars and springs/dampers were also included.  At the end of the diet, the stock weight was around 1200 kilos, or 2646 pounds, giving the car an impressive 6.15 kg per hp.  (Keep in mind that the E46 M3, which ended production in 2006 sported a 5.50 kg per hp ratio.)

     In the area of aerodynamics, you can definately see the improvements.  A large front spoiler was installed to reduce front axle lift by one-half, and the loud rear wing reduced rear lift by two-thirds.  The larger wheel arches helped increase track length by a bit, and could hold larger wheels and tires for increased grip.  The rear C-pillar was shortened and widened to allow better airflow to the wing and the front windshield was raked back as well.  The coefficient of drag was a low 0.33, which probably attributed to its efficient fuel consumption and high speed.

     As for real world performance figures, zero to sixty was found in 6.5 seconds, and reaching the century mark was done in 19 seconds flat.  The top speed was an impressive 143 mph with the catalytic converter, and 146 without.  Remember that this car was released in 1982, and those numbers were very impressive at the time.  If they seem tame to you, we’ll take a look at the motorsport variants of the E30 M3, which featured increased power figures, and even more madness.  Stay tuned.

Part 1 is here.

     In 1989, the next generation M5 was released by using a modified E34 535i chassis, and used an evolution of the E28 6-cylinder.  Each M5 was hand built by either one technician or one team throughout the whole process (of appromixately 2 weeks), and rumor has it that the test drivers of the M5s could tell which team, or which technician built that M5 due to the quirks resulting from the hand-built nature.

     Six years after the release of the E30, in 1992, BMW decided to roll out a new M3 with the recent introduction of their improved E36 chassis in 1990.  M went with a more subdued exterior this time around, and this was the first M3 to receive a 6 pot engine in the form of the S50.  Unforunately, the new chassis also gained an extra 500 pounds due to sacrifices of raw performance for a broader appeal.  This was evidenced by the plethora of options available to the consumer and the fact that  BMW even released a sedan version of the M3 to bridge the gap between the end of the E34 M5 and the arrival of the E39 M5.  Even after a power bump to 320 horsepower and a few special editions, many E30 enthusiasts still felt like the E36 was “soft”.

     In 1995, BMW decided to take a jab at Ferrari and started a project to create their own ”Ferrari killer” in the form of the M8.  Luckily, BMW realised there was no market for such a product, and dismantled the project before it was fully realized.  Some of M’s hard work did trickle down though, and the E31 8 series CSi receieved the only BMW production V-12.  Outputting 380 horses, the CSi was never labeled as an “M”, but the engine clearly had the badge.  Unfortunately, the 8 series never sold well, and that’s the last 8 series in production.

     Then in 1998, BMW introduced two M models in the same year.  They decided to do something new, and released an M version of BMW’s Z series roadsters. Two versions were released, one based on the roadster, and one on the coupe, which shared many of its parts due to the need to reduce production costs.  The whole project had a hard time getting green lit due to this, and their answer was to share as many parts as they could between the two models.  The other model was the third generation M5, based on the E39 chassis 5 series.  This M5 used a V-8 to power itself, and is probably the most loved M5 in history.  It was comfortable and luxurious, yet you could push the M5 damn hard on the track and have a fun time while doing so.  Part of its charm was the huge 4.9 liter V-8 that produced almost 400 horsepower which let you swing its large rear end with ease.

     And finally, with the arrival of the new millenium, we saw the introduction of the third generation M3, based on the E46 chassis 3 series.  Based only on a coupe and convertible this time, BMW wanted to keep this M3 as a pure sports car.  Though still beating with a 6 pot in its chest, BMW increased their new M3′s power to over 330 horses.  This gave the M3 over 100 horses per liter with the S54 engine, which also went on to win numerous awards.  This M3 model returned to its harder-core roots somewhat, as special editions included a CSL version (Coupe Sport Light) which shaved over 300 pounds and had its power increased by 30 horsepower and a GTR version which sported a 4 liter v-8 that had a limited run of only 10 due to its main purpose of endurance racing.  The third gen M3 definately had better success as a sports car (viewed as one of the best of all time) than the previous generation, which was partially due to its aurally breathtaking engine note.

     Everything past that point I’ll consider modern since the newer models have yet to stand the test of time.  In other words, I’m too lazy to keep on writing about them.

     Let’s take a quick detour from the E30 M3 and explore the history of the BMW M GmbH itself.  BMW M was created 14 years prior (1972) to the release of the E30 M3 to help facilitate BMW’s racing program.  They started out as an 8 man team, and their first project was the 3.0 CSL (based on the E9 chassis), the spiritual predecessor to the E30 M3.  It was the success of the CSL in the European Touring Car Championship that started BMW’s sports car image; with the help of M no doubt.

     Their next project was supposed to be developed solely by Lamborghini as a pure race car due to the financial problems BMW had at the time.  Ironically, Lamborghini also fell on some hard times and had to hand the project back over to BMW to finish.  The problem was that it wasn’t completed on time for the German racing championships due to the delays.  The next choice would be to enter the Procar Series, which required their racecars to be based on a production car.  It was beecause of this that the thinly veiled racecar was released to the public in 1978 under the M1 monikor with a small run of only ~450 cars.  So far, it’s the only M1 model ever created, and the only mid-engined BMW as well.

     A year later in 1979, BMW released an M version of the E12 5 series for everyday use under the M535i model.  It was basically a performance tuned version of the stock 535i, but basically for those enthusiasts who lusted for M1 power yet wanted everyday drivability.

     The next M model was released in 1983, and still wasn’t a fully badged BMW, but rather an M tuned 6 series.  Based on the E24 chassis, BMW M turned the 635i into the M635iCSi by using a modified version of the M88/3 engine they stuffed into the M1 six years prior.

     So what was next?  A racecar, a 5 series, and a 6 series were already “M”odified by M-Technik.  Unfortunately it wasn’t the M3, but rather another 5 series.  But not just “another” 5 series; this time it was badged as a “real” M car, under the first M5 monikor.  Based on the E28 chassis 535i, this M5 breathed through an evolution of the M88/3, dubbed the S30.  Pushing 286 horses, this wasn’t just any family four door, but it was the fastest performance saloon in the world at the time (1984).

     It was two years later that the E30 M3 was released to the public in 1986.  And thus the first M3 was born.  Designed from the ground up for the tracks, this road-going version was released only due to homologation purposes.  And we could tell.  It was a perfect mix of racecar and sports car, to the point where you could almost smell the burning tires seeping through the bulging wheel arches and feel the wind rushing through the massive front spoiler and over the rear wing.  It was hard.  It was mean.  It was ugly.  But it was beautiful.  Function over form with no compromises.  This was what the M3 was all about.  By the time 1988 came around, demand for the M models was high enough to persuade BMW to release an M version of every new generation 3 and 5 series.

Part 1 is here.

     ///M.

     The M badge is the symbol for the BMW subset now named BMW M GmbH (shortened from BMW Motorsport GmbH) that was created within the company in the 1970s to support their own racing efforts.  BMW M (also known as M-Technik) is the subsidiary of BMW that modifies and produces all the ///M versions of their parent company’s stock models for sale to both the public and to the motorsport world.  For their full history, click here (part 1) and here (part 2) for a full article on their history.

     As I’ve stated before, the E30 M3 was the first M3 ever, and may still be the most loved model even after more than two decades, three evolutions, and numerous technological advancements.  Just like how the M3 series is considered the “best” sports car in the world, the E30 model was, and still is considered to be the “best” out of all the M3 models (E30, E36, E46, E92).  Why?  Well let’s start off with the history lesson (you can skip this all of course.  The next post will be on the fun part: the engine and the specs).

     Three years after the launch of the E30 model (1982 -> 1985), the greenlight for an especially dynamic engine solely for the 3 series was given by the Chair of the Board of Management to BMW M (still BMW Motorsport GmbH at the time).  BMW M immediately began work on the power unit, deciding against a larger 6 pot and staying with a smaller 4 cylinder engine.  The obvious reasons were the weight savings and the increased headroom for higher piston speeds, and after only two weeks (fourteen days!) a prototype engine was built which we’ve come to know as the S14; named after the 14 (once again, only 14!) days it took to create the inline-4 engine.  So what did fourteen days give us?  An existing 2.0 liter 4 pot which was bored and stroked to just over 2.3 liters to match the displacement of their 6-cylinders.

     In addition to that, while spitting out around 195 ponies (5 lost due to the catalyst converter), the 4 cylinder could reach up to 143 mph while maintaining up to 30 miles per gallon.  Not bad.  But that wasn’t all.  M wanted to push the envelope even further by turbocharging it, but unfortunately, due to homologation purposes (the main purpose of development of the road-going M3) the M3 had to be kept atleast a little bit ”civil” to sell the 5,000 required units.  (The homogolation rules required that a car that was entered into the European Touring Car Championship or World Touring Car Championship had to have sold atleast 5,000 models to the public within 12 months.  This rule was put in place to keep companies from building one-off race cars just for the ETCC.)

     But if ”civil” was weighing about 1200 kilos (or around 2650 pounds) to give the car a 6.15 kg per hp ratio which would stand up to today’s sports car standards, then make some more “civil” cars!  Fortunately for BMW, keeping the engine naturally aspirated didn’t matter one bit (I believe it was better that the S14 was kept naturally aspirated) as the E30 M3 sold around 18,000 units over the course of its lifetime of 6 years (’86 to ’92).  So popular was the original model, that BMW decided to offer quite a few variants to the dedicated enthusiasts, starting with the Evo 1, continuing with the Evo 2, finally culminating with the Evo Sport, which sported around 235 horsepower and featured both an adjustable front spoiler and an adjustable rear wing.  By the end of the production cycle for the E30 M3, BMW had gained a new cult following and gained itself a new flagship sports car for years to come.  And the legacy it left behind?  How about the most winningest car model in history (true for the touring car circuit, but I’ll have to check up on that).  I think that pretty much says it all.  History has spoken.

     Next, I’ll detail both the engine and chassis in more detail, giving alot more numbers (yay) and specifics.  Stay tuned.

     M.  The pride and poster boy (or girl if you’d like) of the BMW GmbH.  And according to them, it is also the most powerful letter in the world (catchy marketing).  It’s no coincidence then that the BMW M3 is one of the most renowned performance oriented models in the world.  Known for its racing heritage, BMW seems to have perfected the merging of a track car with one that can be driven from home to work without removing the German luxury expected from BMW.  Many enthusiasts view the BMW M3 series as the “best” sports car in the world; not the “fastest”, “coolest”, or “best bargain”, but just the “best” that every new performance car will eventually be compared against.

     The E30 M3 was the beginning of the the M3 legacy back in 1985 when it was first shown to the public.  It went on the sale the following year in 1986, making the M3 over 20 years old.  BMW is currently on their 4th M3 model (the E92 chassis), and yet the model that started it all is what I’m focusing on right now.  Not that the later generations are worse than the E30, but the E30 is the most “raw” than the rest due to less stringent emission/crash laws back then, and the fact that the only aim of the model was reach 5,000 sales due to homologation rules.  There were no expectations of a certain amount of comfort or performance, nor were there any sales expectations from the higher ups.  Unbound by expectations and rules, the E30 was as close and raw as you could get to a race car.  This is why it is loved by so many; that untamed  feeling and unbound limitations are felt in the engineering, unlike so many cars today.

     Here are a few pics courtesy of a Xbox 360 and a copy of Forza 3:

     and a few more artistic pics of the M3:

     For those a bit less invested in the world of auto technology, I’ll explain the valvetrain for you a bit.  The valvetrain is what controls what goes in and out of the cylinder (intake and exhust).  It consists of the camshaft, the rocker arms, and of course the valves.  The camshaft is a long rod rotating along with the engine running along the length of the engine.  It has a few protrusions (the cam profile) coming out of it which are intended to push a set of rocker arms which then push open the valves.  The valves are the “doors” that let the air and exhaust enter and exit the cylinder during  the four-stroke combustion cycle.

     For a small history lesson; Honda brought the VTEC system to the masses in Japan in 1989 with their Intergra and CRX SiR models.  The U.S. was introduced to it in 1991 with the arrival of their everyday supercar NSX which produced 290 horses with only 3.0 liters of displacement.  Honda then installed their new tech into the Type R versions of their B16 and B18 engines for an easy 100 plus hp per liter.  The B16B built specifically for the Civic Type R boasted an impressive 115.8 hp per liter in a relatively affordable car.  The VTEC system culminates in the S2000, which is the only car to use their infamous F20c engine.  It produces 240 horsepower with “only” 2.0 liters of displacement and no forced induction.  Introduced in 1999 to celebrate the new millenium, the S2000′s F20c still has the highest specific output for a naturally aspirated 2.0 liter car under $100,000.

     Let’s get down to the tech side here.  V-T-E-C stands for Variable valve Timing and lift Electronic Control.  In english, VTEC (and all other variable valve technology) modulates the valves of each cylinder with a computer (just like everything else in this world).  VTEC doesn’t modify the valves directly, but rather the camshafts that the valves are connected to.  As the engine turns, the camshafts turn in relation and they push the valves open for the cylinder.  What VTEC does is change both the duration and lift of the valves as engine speeds change by using different cam profiles.  For example, for maximum performance at high RPMs, both valve lift and duration should be relatively longer.  But for drivability, comfort, fuel consumption, and emissions, valve duration and lift should be relatively minimal.  So for a minivan, larger cam profile is not needed, but for a performance-oriented car that is driven both in traffic on the road and on the track, the best of both worlds are needed.  If you want shorter duration and lift, you want your profiles to be smaller, since they won’t push open the valves as far and for as long.  If you want longer duration and lift, you obviously want a larger profile.  How do we get both smaller AND larger profiles onto one camshaft?  For our example, let’s imagine two cam profiles pushing two rocker arms to open two valves.  Here’s a simple diagram:

“3_a1.gif.” Image. Honda Motor Co. “The VTEC Breakthrough: Solving a Century Old Dilemma.” Honda Worldwide. N.p., 2009. Web. 3 Dec. 2009. <http://world.honda.com/
automobile-technology/VTEC/>.

     What Honda decided to do was to build a camshaft with two cam profiles and the ability to switch between them.  When the time comes to switch from low-RPM comfort mode to high-RPM performance mode, the camshaft makes a small change and switches to its longer duration and lift cam profile.  And then the car slows back down to lower-RPM driving, the camshaft profile switches back.  So how does Honda change the cam profiles on the fly?  Quite simple actually.

     What VTEC does is install another rocker arm (let’s call it the VTEC rocker) between the two rocker arms, and a larger cam profile to operate this larger rocker arm.  This larger cam profile would obviously push the valves open for a longer duration and lift.  The larger cam profile and rocker doesn’t push anything open as there aren’t any valves underneath it, but are just situated between the smaller rockers.  Like here:

“3_a1.gif.” Image. Honda Motor Co. “The VTEC Breakthrough: Solving a Century Old Dilemma.” Honda Worldwide. N.p., 2009. Web. 3 Dec. 2009. <http://world.honda.com/
automobile-technology/VTEC/>.

     During low-RPM operation, the valvetrain works normally; ie. the smaller profiles push the smaller rocker arms which then push open the valves.  But when the engine enters its higher-RPM range, a hydraulic system pushes a pin that connects the VTEC rocker with the two rockers beside it.  When that happens, the larger VTEC cam profile pushes all three rockers even further due to the fact that the VTEC rocker arm is now connected to two non-VTEC rocker arms.  When the larger cam profile isn’t needed anymore, the pin disengages and unconnects the three rocker arms, reverting back to the smaller cam profile.  An animation for your entertainment:

“cam_a07.swf.” Animation. Honda Motor Co. “The VTEC Breakthrough: Solving a Century Old Dilemma.” Honda Worldwide. N.p., 2009. Web. 3 Dec. 2009. <http://world.honda.com/
automobile-technology/VTEC/>.

     It’s quite a simple mechanism actually, just a simple trigger (a certain RPM), a hydraulic system, and an extra set of cam profiles and rockers.  The problem with VTEC is that it is an “on/off” switch, where the cam profiles are either small or large.  The next step is to continuously modulate the cam profile for any and every driving condition.  BMW introduced its “Valvetronic” system in 2001, which Toyota followed with its “Valvematic” system and Nissann with its VVEL (Variable Valve Event and Lift) system.

     Well, that’s basically how the VTEC system (and most variable valve systems) work.  Leave a comment if you’d like.

     //Drive on.

     As a society, we find assurance in math due to their binary nature.  It’s either right or wrong.  There is no “I prefer”, or “I believe” within math, and that makes it so much easier (to a certain extent).  Everything can be reduced to math (mostly).  And math (to me) makes everything easier to understand.  It gives us a certain way to relate, compare, and think.  When you look at a car on the road, I doubt the first thing that pops into your mind is “MATH”, or “I wonder what the exact numbers are behind it”.  But if you want to understand how something works, using math is one of the best ways to go about it.  Just like how being able to teach a subject means you truly understand it, its the same for math and physics/engineering/worldly dynamics.  We might be able to explain “why” a part works using words, but to understand it using math is completely different.  From the chassis to the engine to the suspension, every part is designed using math.  And if we can figure out how each of these parts was designed with math, we can pick it apart and eventually understand it better.  In a world of ebb and flow, of constant change and infinite unknowns, the basics of math keep us grounded in reality and truth. 

     This is why I ultimately delve into the math behind cars: to critically define, compare, and ultimately, understand them.  Because in a way, to understand something is to enjoy it.

     //Drive on.

     When we  change parts to make our car faster, we usually use horsepower to determine whether it was successful/useful/worth the money or not.  We say that we’ve “gained” or “added” 10 horsepower to our engine/car, but that’s not always correct.  What we measure when we dyno our cars to find the horsepower is the power that’s conveyed to the wheels.  So from releasing the energy from fuel via combustion to sending them to the wheels to increase our velocity, there’s a bunch of stuff in between.  What the dyno measures is just the end product (the energy sent to the wheels).  We know there are various ways to make our car “faster” or “quicker” (there is a difference), but sometimes the only way we measure that is through horsepower.  Let me explain.

     One of the easiest ways to make our car faster is to decrease the weight of our wheels, since unsprung weight (or mass) has a larger effect on acceleration than sprung weight (or mass).  It takes more energy to rotate a mass than to push it linearly.  So if we’ve installed lighter aftermarket wheels and take it to a dyno to measure the effects, let’s say that we see an increase in 2 horsepower.  Now that’s not alot, but it’s still measurable through the dynometer, and thus we can make comparisons.  Lighter wheels = more power, right?  Not exactly.  Nothing has changed in both the input and output of the engine whatsoever.  Your engine still produces the same amount of power it did before you replaced your wheels. 

     But how does that make sense if our dyno clearly shows an increase in horsepower?  And an exact 2 hp at that?  An increase in brake horsepower doesn’t always equal an increase in engine horsepower.  And the engine is the only place to produce horsepower, not the wheels.  This is a direct example of that.  We can’t always convert our brake horsepower to flywheel horsepower just to fluff our power numbers.  Reducing the weight of our wheels does NOT make our engine produce more power.  The same amount of air is fed into the cylinder and the same amount of fuel is burned through combustion.  There is no change within the engine, nor is there any change from the input and the output of the engine.  The flywheel horsepower stays the same, but what has changed is the rotational losses of when the energy of the fuel is being sent from  the engine to the pavement (the brake horsepower).  And this is what seperates flywheels horsepower from brake horsepower.  Brake horsepower measures the power being put to the ground, while flywheels horsepower measures the power the engine produces.

     So while our dyno says there’s an increase in horsepower the engine doesn’t see any change.  Thus, while we haven’t “gained” any power, we’ve “freed” or “unlocked” some power through weight reduction.  A quick example of rotational losses would be the driveshaft, clutch, flywheel, brakes, tires, wheels, etc, anything that the engine has to turn while transmitting the power to the ground.  Reducing the weight of any of those parts will reduce the amount of power sapped before the engine power reaches the ground, no matter how small or large the weight decrease.

     So the next time you dyno your car, take care when converting your brake horsepower into flywheel horsepower.  The best thing is to just leave your brake horsepower as is, and to not convert it.

     //Drive on.