VTC is one of the main reasons why the K is a superior engine.
[QUOTE=tilegend;1893533]J30 > B17
its even more rare to see… cause if you think about it… an engine must be for bragging rights and looks rather than performance.[/QUOTE]
ok? did i say it was about looks? no so what are you getting all sarcastic for? i just said gsr is more rare then k20 because its like 16 years old
This is a super long read, but it will help people understand the differences that the K offers. While it is not as practical to K swap a DA as it is to swap an EG or the like, I’m doing it and I would like to help others, so no haters on this post please.
Here are the best Information about K motors
#1 Basic codes/Information about K motors.
Thank you…
The i-VTEC system found in the Honda K20Z3.The Honda K series engine is a four-cylinder otto cycle engine. It is available in 2.0 L and 2.4 L naturally-aspirated variants, and a 2.3 L turbocharged model.
The K series engines are all equipped with DOHC valvetrains with Honda’s i-VTEC variable valve timing control.
Honda made this engine a big improvement over its older 4-cylinder engines by including friction-reducing technologies to reduce parasitic loss.
The K-series uses a DOHC valvetrain, which utilizes roller rockers to reduce friction. The VTEC system on engines like the K20A3 is only on the intake cam, and at low RPM when not engaged, allows the engine to function as a 12-valve engine, opening only one intake valve so that the air swirls for better combustion. This VTEC system was designed with fuel economy in mind. In engines like the K20A2 found in the RSX Type-S, The VTEC system always allows the motor to run as a 16 valve engine, and when VTEC engages, its on both the intake and exhaust rockers, and opens all 4 valves even more at high RPM
The K-series motors all use DI, or distributorless ignition. It uses a coil on plug system, in which each spark plug has its own coil atop it. This allows the ECU to send the spark exactly when it wants it, and removes the need for spark plug wires.
A wide variety of aftermarket parts are available for the K engines, and tuners are finding that 240 and more bhp are available with routine modifications.
K Series
K20
K20A
Found in:
2001-2005 Honda Civic Type-R (EP3)
Displacement: 1998 cc
Compression: 11.5:1
Power: 212 hp (215 PS, 158 kW) @ 8000 rpm
Torque: 149 ft·lbf (202 N·m) @ 7000 rpm
Redline: 8400 rpm
2001-2006 Honda Integra Type-R (DC5)
Displacement: 1998 cc
Compression: 11.5:1
Power: 217 hp (220 PS, 162 kW) @ 8000 rpm
Torque: 152 ft·lbf (206 N·m) @ 7000 rpm
Redline: 8500 rpm
2002-2006 Honda Accord Euro-R
Displacement: 1998 cc
Compression: 11.5:1
Power: 217 hp (220 PS, 162 kW) @ 8000 rpm
Torque: 152 ft·lbf (206 N·m) @ 7000 rpm
Redline: 8500 rpm
K20A2
Found in:
2002-2004 Acura RSX Type-S and 2002-2005 Honda Civic Type R (EP, European)
Displacement: 1998 cc
Compression: 11.0:1
Power: 200 hp (147 kW) @ 7400 rpm
Torque: 142 ft·lbf (193 N·m) @ 6000 rpm
Redline: 8200 rpm
K20A3
Found in:
2002-2005 Honda Civic Si
Displacement: 1998 cc
Compression: 9.8:1
Power: 155 hp* (119 kW) @ 6500 rpm
Torque: 139
2002-2006 Acura RSX
Displacement: 1998 cc
Compression: 9.8:1
Power: 155 hp* (119 kW) @ 6500 rpm
Torque: 139 ft·lbf* (191 N·m) @ 4000 rpm
Redline: 6800 rpm
(* Horsepower and torque calculations reflect new SAE J1349 procedures revised August 2004)
K20Z1
Found in:
2005-2006 Acura RSX-S
Displacement: 1998 cc
Compression: 11.0:1
Power: 201 hp (150 kW) @ 7800 rpm (sae NET Rev 8/04)
Torque: 140 ft·lbf (194 N·m) @ 7000 rpm (sae NET Rev 8/04)
Redline: 8200 rpm
K20Z2
Found in:
2006- Acura CSX (Canada)
Displacement: 1998 cc
Compression: 9.6:1
Power: 155 hp (114 kW) @ 6000 rpm (sae NET Rev 8/04)
Torque: 139 ft·lbf (188 N·m) @ 4500 rpm / 188 N·m @ 4200 rpm (Singapore)
Redline: 6800 rpm
2006- Honda Civic (JDM)
Displacement: 1998 cc
Compression: 9.6:1
Power: 155 hp (114 kW) @ 6000 rpm
Torque: 139 ft·lbf (188 N·m) @ 4500 rpm
Redline: 6800 rpm
2006- Honda Accord Sport(Europe)
Displacement: 1998 cc
Compression: 9.6:1
Power: 155 hp (114 kW) @ 6000 rpm
Torque: 139 ft·lbf (188 N·m) @ 4500 rpm
Redline: 6800 rpm
K20Z3
This inline-4 cylinder internal combustion engine is found in the redesigned Honda Civic Si. It has an aluminum block with aluminum heads, and a bore and stroke of 86 mm*86 mm, resulting in a 2.0 Liter displacement.
Found in:
2006+ Honda Civic Si
2007 Acura CSX Type-S
Displacement : 1998 cc
Compression : 11.0:1
Power: 197 bhp (147 kW) @ 7800 rpm (sae NET Rev 8/04)
Torque: 139 lb·ft (189 N·m) @ 6200 rpm (sae NET Rev 8/04)
Redline: 8000 rpm
K23
K23A1
Turbocharged
Found in:
2007 Acura RDX
Displacement: 2300 cc (acura.com)
Compression: 8.8:1 (acura.com)
Power: 240 hp @ 6000 rpm (SAE net)
Torque: 260 ft·lbf @ 4500 rpm (SAE net)
Redline: 6800 (acura.com)
Bore: 86 mm
Stroke: 99 mm
K24
K24A1
Found in:
2002-2006 Honda CR-V
Displacement: 2354 cc
Bore and Stroke: 87 mm x 99 mm (3.43x3.90 inches)
Compression: 9.6:1
Power: 160 hp (119 kW) @ 6000 rpm
Torque: 162 ft·lbf (220 N·m) @ 3600 rpm
Redline: 6500 rpm
K24A2
Found in:
2004-2006 Acura TSX
Displacement: 2354 cc
Bore and Stroke: 87 mm x 99 mm (3.43x3.90 inches)
Compression: 10.5:1
Power: 205 hp (149 kW) @ 6800 rpm
Torque: 166 ft·lbf (225 N·m) @ 4500 rpm
Redline: 7100 rpm
K24A3
Found in:
2003-2006 Honda Accord (Europe, Japan, and Australia)
Displacement: 2354 cc
Bore and Stroke: 87 mm x 99 mm (3.43x3.90 inches)
Compression: 10.5:1
Power: 189 hp (140 kW) @ 6800 rpm
Torque: 164.5 ft·lbf (223 N·m) @ 4500 rpm
Redline: 7000 rpm
K24A4
Found in:
2003-2005 Honda Accord, 2003-2006 Honda Element
Displacement: 2354 cc
Bore and Stroke: 87 mm x 99 mm (3.43x3.90 inches)
Compression: 9.7:1
Power: 160 hp (119 kW) @ 5500 rpm
Torque: 161 ft·lbf (218 N·m) @ 4500 rpm
Redline: 6500 rpm
K24A8
Found in:
2006/2007 Honda Accord
Displacement: 2354 cc
Bore and Stroke: 87 mm x 99 mm (3.43x3.90 inches)
Compression: 9.7:1
Power: 166 hp (124 kW) @ 6000 RPM
Torque: 160 ft·lbf @ 4000 rpm
Redline: 6500 rpm
More Information on the K-series engines THIS IS A MUST MUST READ
ALL IN THE FAMILY
By Keith Buglewicz
A sense of nervousness has seeped into the Honda performance community. It comes not from new anti-racing laws, or emissions regulations that will weld the hoods of new cars shut. No, this nervousness comes directly from Honda itself.
K. It’s just a letter, but in the coming years its significance to Honda enthusiasts will achieve the status that “B” has now. With the introduction of the Acura RSX, the new Honda Civic Si and CRV, Honda chucked more than 12 years of engine experience and aftermarket support out the window for a clean sheet of paper design. The new engine family is the K series, and on paper, it makes even the highest performance VTEC B series engine look like yesterday’s blue plate special.
Look at the specs. The K20A2 in the RSX Type-S churns out a solid 200 hp from its 2.0- liters. That’s 100 hp per liter, and you can thank i-VTEC for this specific output. The “VTEC” part of that acronym is already familiar to Honda enthusiasts. When the engine reaches a certain speed, rocker arms are locked together, linking them to a higher-lift cam, and allowing more fuel and air into the engine. In the world of variable valves, this is known as cam shifting right now, only Honda, Toyota, BMW and Porsche sell cam-shifting systems in the United States.
However, that little “i” means a lot. It means the K series engines are also equipped with VTC, or Variable Timing Control. This cam phasing system uses a spool gear, oil pressure and some fancy electronics to change the angle of the intake cam by plus or minus 30 degrees of timing.
The result is an engine with excellent power and especially torque, but one that still manages better fuel efficiency and lower emissions than its predecessor.
Now, this is all fine and good, but what does this mean for an aftermarket that has been centered on the B series engines? What can be done with it? Can it be turbocharged? Can it be swapped? Does it respond to the simplest bolt on mods? These are the questions on the minds of Honda enthusiasts, and we intend to answer as many as we can. First, let’s take a close-up look at the engines as they come from the factory.
THE ENGINES
The K series currently consists of four power plants. The K20A3 is found under the hood of the standard RSX. With 160 hp at 6500 rpm and 141 Ib-ft of torque at 4000 rpm, it churns out the same power as the B16A, 10 hp less than the B38C1, but much more torque than either one of them, all at a lower engine speed. The i-VTEC system works only on the intake cam on this engine, and it has a composite two-stage intake manifold.
Similar to the K20A3 is the K20A found under the hood of the new Civic Si. K20A-what? Well, we’re not sure. The cars we’ve seen have all been pre-production vehicles, without the requisite engine code stamp on the block. The best information we have so far is that it’s a K20A3, same as the RSX. But that sounds a little off to us. While it has the same i-VTEC system as the RSX, it boasts the fixed, single-stage aluminum intake manifold of the K20A2 under the hood of the RSX Type-S instead of the dual-stage manifold of the base RSX. Whatever the final engine code works out to being (we’ll just call it a K20A for now), this manifold swap actually works against the Si, reducing its torque. It weighs in with the same 160 hp, but with only 132 Ib-ft of torque at a higher 5000 rpm than its K20A3 sibling.
Following the logic of Honda’s engine codes, the K24A1 is a 2.4-liter version of the K series. Following a philosophy similar to the B20 found in the previous CR-V, it’s tuned to be a torque monster with a long, 99 mm stroke. That’s a full 13 mm (0.51-in.) longer than any of the K20 engines. The extreme stroke works. With 162 lb-ft available at a low 3600 rpm, the CR-V is a veritable stump puller among small four-cylinder SUVs. At the top of the enthusiast heap is the K20A2 that powers the RSX Type-S. With a lofty 7900-rpm redline, 200 hp and 142 lb-ft of torque, this engine really is as good as its hype. With the exception of the stroked K24, the engines are all very similar structurally. AII three of the 2.0-liter versions share the same 86 mm x 86 mm bore and stroke. This is known as a square design. An oversquare engine has a longer stroke than bore, like the K24. This generally results in more torque, but at the expense of peak power. Conversely an undersquare design (such as the S2000’s engine) has a bore larger than stroke, and generally produces more high-end horsepower at the expense of torque. Not surprisingly, a square design like the K20 is a compromise between these two extremes, offering good torque and good horsepower without sacrificing or optimizing either. Aside from the manifold change on the Si’s version of the K20, the main difference between these engines is the way they manipulate their valves.
VALVE DANCING
The K20A2 in the Type-S works the way you expect VTEC to work. The two camshafts are equipped with three cam lobes and rocker arms for each cylinder’s pair of intake and exhaust valves. At 5800 rpm, oil pressure activates pins that lock the outer rocker arms to the center arm. This forces both valves to use the higher lift, longer duration center camshaft profile. However, this is augmented by VTC on the intake side, which manipulates the timing of the cam itself. This can be used to augment torque, reduce emissions or a variety of different things depending on what the computer thinks is best at the time. The RSX’s K20A3, the Si’s K20A and the CR-V’s K24A1 use i-VTEC differently. First, it only operates on the intake valves. But even then, the philosophy is changed. Until the VTEC threshold is reached, the lesser K engines essentiality only use one intake valve per cylinder. The other is opened just a crack, enough to keep fuel from pooling behind the valve, but that’s about it. In addition, the VTC is tuned primarily to keep emissions as low as possible. All this weirdness results in excellent swirl inside the combustion chamber and very efficient combustion. It’s great for fuel efficiency and low emissions. However, it isn’t so great for driving fun, as the engine inhales less deeply and revs lower.
FRANKENSTEIN RETURNS?
The K24A is more closely related to the K20A3 and K20A. While it uses the same i-VTEC tuning as those engines, it’s the long stroke design that’s intriguing. The difference is in the block. The K24’s deck height is roughly 19 mm higher than its smaller siblings. It’s also slightly bored, with 1 mm larger cylinders. The compression ratio is also down slightly from the non-Type-S engines, 9.6.1 vs. 9.8:1. So what? Well, the natural temptation is to throw the K20A2’s efficient head onto the K24A1 block, raise the redline and have a torquey, ultra-powerful i-VTEC stroker Frankenstein monster engine.
The actual bolting on part wouldn’t be too difficult, as the heads should mount right up. However, you do run into an issue with piston speed. At its 7900-rpm redline, the K20A2 in the Type-S has a piston speed of 4464 feet per minute (fpm). Thanks to its long stroke, the K24A1 comes close to that, running at 4225 fpm at its much lower redline of 6500 rpm. By the time you’ve spun your K24 up to just 6900 rpm, you’re already at 4485 fpm, and at the 7900 rpm redline of the K20A2, you’re at a crazy 5135 fpm. For comparison, even the hyperkinetic S2000 with its 9000 rpm redline doesn’t exceed 5000 fpm (it maxes out at 49% fpm). And the Integra’s B18C1 only reached 4573 fpm. Translation: If you’re going to plunk a K20A2 head on a K24A1 block and redline the concoction to 7900 rpm without seriously building up the bottom end… duck.
If you scan the chart on page 85, you’ll see that we’ve covered most of the cars there. The Integra is just for comparison, of course, and we’ve hit the RSX and CR-V engines. So what’s the S2000 doing there? That is the true wild-card in all this. It seems as though despite the different engine code (F20C1) and north-south orientation, the S2000’s engine block is a kissing cousin of the K series. In fact, according to engine developer Paulus Lee at Advanced Engine Breathing Systems in San Diego, the head gaskets are the same. This means the S2000’s standard VTEC head could, in theory, be put on the K series block.
HEAD GAMES
The head design of the different Ks are intriguing, beyond just valve manipulation. The K20A2 found in the Type-S is a wonderful design, according to just about everybody; Honda nailed it, putting even the very effective B series engines to shame. The valves are huge, noticeably bigger than the B series valves even without the use of a caliper. But measure them and the difference is that much more apparent. The intake valves on the K are 2 mm bigger than the B series intake valves, and the same goes for the exhaust valves. The intake port angle is also excellent, with a straighter shot into the combustion chamber than the B series. On the other side of the head, the improvements continue. While the B series heads force the exhaust gases through a strange humped path through the head, the K sends it straight out to the manifold.
There are other improvements. The K uses roller rocker arms. This not only reduces friction in the valvetrain, making more power possible it also frees up the aftermarket to offer durable billet cams for the Ks. Slipper followers like those in the B series put too much pressure on billet cams, wearing them down prematurely. Forged camshafts are better, but expensive to produce in small numbers. Note the difficulty Crane has gone to in creating roller followers for its new billet B series cams. But with roller followers built in, we expect to see some radical profiles for these engines in coming months.
The other K head is not quite as efficient. While the Type-S head boasts big, smooth, unobstructed ports, the regular head features a strange groove cut into the wall between the intake valves. Undoubtedly there to help improve the single-valve operation of the VTEG system these engines use, any head porter can tell you this kind of weirdness plays havoc with airflow into the engine. The result is pretty clear. The Type-S K20A2 is the engine to have. While the other two K20s are OK in their fuel-miserly, non-polluting way - and the K24 is the undisputed torque champ - they are less ambitious, and offer less potential for improvement compared with the mighty K20A2.
THE BOTTOM OF IT
Under the head is an all-new block. Made of aluminum alloy, it’s a beefy unit, heavily ribbed and gusseted for extra strength. However, it’s also an open deck design. An open deck means that at the top of the block (the deck), the water jackets around the cylinders are open to the head, and rely on the head gasket for sealing. This limits the amount of boost that an engine block can withstand, because the individual cylinders can actually wobble slightly under high pressures. This is why drag racers will seal the deck on their B series engines before pumping the pressure up to bone-crushing levels.
But for a naturally aspirated engine, this is pretty darn strong. Flip the engine over and you’re greeted with a bearing girdle that actually makes up the lower quarter of the block. Known as a split case, this design is much stronger than the internal bearing girdle used in the B engines. About the only drawback to this design is that it only uses two bolt mains, rather than the four bolt mains preferred by racers. No matter, considering the overwhelming beefiness of the design, this is still quite acceptable. Remove the lower part of the case, and you’ll see there’s a lot of room inside the block. This means that one could go pretty crazy with rod length before the block itself needed modification.
The crank is Honda’s typical overbuilt forged unit. The Type-S crank is, again, the better of the two, being fully counterweighted. The rods are similar in both designs, although the Type-S rods are stronger to cope with the higher piston speeds encountered in the engine. The pistons are another matter, however. The Type-S pistons are about what one would expect, and are in fact quite similar in design to the high domed structure that one finds in the B series engines. The piston itself accounts for the higher compression in this engine, as the bore and stroke are identical. On the other hand, the lower end K series piston looks, well, weird. Off center on the top of the piston is an odd, round dish that for all the world looks like a bellybutton. We can only speculate that this is another way the non-Type-S engines achieve good fuel economy and low emissions.
WHAT ABOUT SWAPS?
It goes without saying that the various K’s should swap into the RSX, Civic Si and CR-V engine bays without a problem. In fact, one of the first swaps we’re likely to see is the anemic K20A in the Si being ditched in favor of the more powerful K20A2. This is a drop-in replacement. In fact, the same hatchback is sold in Europe with the K20A2 and called the Civic Type R, and there’s some speculation that we’ll see this exact car in the United States sometime in the 2003 model year.
But the real question is will it fit in the standard, non-Si EM-chassis 2001-2002 Civic? Well, after analyzing the size of the engine bays and the way the engines bolt in, we’ll say that it’s possible, but it won’t be the drop-in replacement we’ve become accustomed to with the EJ Civics and the B series engines.
The EM Civic, the Civic Si, RSX and CR-V are all cousins under the skin. However, that EM Civic is the redheaded stepchild of the group. In an effort to save some RBD bucks, Honda opted to further revise the venerable D series engine which powered Civics since the late '80s, rather than plunk the new K engines in them. At 1.7- liters and 127 hp (in the EX), it runs well enough, and is still a solid economy car engine. Of course, EM Civic owners want more.
One major obstacle is the D series engine spins the wrong way. For a very long time, Honda engines all spun counterclockwise, backwards from almost every other engine on the market. Why? Well, it put the engine on the left side of the engine bay, which is the passenger side in Japan. This made the steering mechanism easier to route. But with Honda being an international company for several decades, it mainly was a case of corporate culture sticking around for no good reason.
The K series engines spin clockwise, like most other engines, and as a result they sit on the right side of the engine bay. In order to make one basic engine bay that would fit both a left-side and a right-side engine, Honda had to do a little bit of clever engineering. The transmission side of the engine in each car attaches directly to the frame using a beefy engine mount, which bolts to the tranny case. The pulley-side mount bolts to a “box” that is welded to the frame. The problem is that the “box” is on the right side of the engine bay in the RSX, Type-S, Si and CR-V, and on the left side in the EM Civics. Dimensionally, there isn’t much of a problem. The K engines should fit into the Civic engine bay just fine without any clearance issues. Getting it to bolt in place, however, will require some tricky mounts. To top it all off, you’ll have to drop in the K20 transmission and driveshafts as well. Even if the engine mount situation is solved, the cost of this engine swap (at least until K20A2 engines become more readily available) will be so much that one might as well just buy an RSX Type-S.
Of course, this doesn’t mean that somebody won’t try it. As for earlier EJ Civics or earlier Integras, we’d just leave that whole can of worms unopened until K20A2-powered EM Civics are commonplace.
WHAT DO TUNERS THINK?
The reaction to the Type-S engine has been overwhelmingly positive. Despite a few reservations about VTC, the engine has been greeted with open, loving arms. Many tuners have delved deep into the guts of the K engines, and are coming back with some interesting findings. The non-Type-S engine has received a more lukewarm response. Although it is a decent engine, it isn’t really the best choice for an enthusiast. We can expect to see intake and exhaust systems for this engine, maybe supercharger kits later down the road. But this is not like the B18A “LS” engine, which is a pretty good powerplant by itself. It’s best left alone.
You’re probably wondering what tuners have discovered about the engines, though. For example, how easy is it to turbocharge the K series’? What kind of internal mods have they made? Can you really put an S2000 head on a K block? The answers to these and other questions will be found in Part 2, in the next issue of HT.
Don’t you just love cliffhangers’?
Part2: The Tuners’ Perspective
In the April/May issue of Honda Tuning, we took an up-close look at Honda’s new K series engine, the motivational power behind the RSX, new Civic Si and CR-V sport utility. We compared it to the B series powerplants, far and away the mainstay of the Honda tuning market, and discovered Honda really did its homework on this engine. With robust construction, bigger ports, extremely trick valvetrain, and a number of other goodies, we were positively giddy with excitement.
However, we’re just a bunch of magazine schlubs, so we talked to some of the top tuners to discover what they thought of the K, what they have planned, and what obstacles they’ve had to overcome to achieve their goals. Although we wanted to give the tuners a little more time to develop their various K series projects.
RECAP
The K20A2 found under the hood of the RSX Type-S obviously king of the hill. While the A3 in the standard RSX and new Civic Si, and the A1 in the CRV, have been tuned with an eye toward fuel efficiency and low emissions, the A2 has been tuned for power.
The big difference between the A2 and the other K series engines is how the cam-switching part of iVTEC works. The A2 uses a cam-switching technique familiar to the most Honda fans. Extra rocker arms are slaved to one of two cams, increasing lift and duration at higher revs for better high-end power. The other engines use a version tuned for fuel efficiency. One intake valve is essentially closed when “off-cam,” and when the switch happens, the closed valve is just slaved to the same cam the opening one does. No higher lift or duration, but some pretty good fuel economy and emissions figures.
The K20A2 is a gem of a powerplant, and is already making serious power in the Type R versions of the Integra (Yes, it’s still called that in Japan.) and Civic. It’s clear it has plenty of potential for performance, but how will it react to intake and exhaust modifications? What about nitrous oxide and forced induction? Can the engine be turbocharged or supercharged with all that cam-phasing wackiness?
BASIC TUNING
If you’re looking for basic, bolt-on power you’re in luck. The K20A2 responds beautifully to intake systems, some systems making a solid 10 hp at the wheels. Manufactures, such as AEM and Injen, are coming up with short ram and cold-air systems. Short ram systems bold right in, while the location of the windshield washer bottle requires a bit more work form cold-air systems. The bottle must be relocated or removed, and a small portion of the fender liner needs to be trimmed, as well.
For the skinny on exhaust systems, we turned to DC Sports of Corona, Calif. These guys have been in the Honda exhaust market longer then just about anyone in the United States and are the first to have both an effective cat-back system and header for the Type-S.
The engineer in charge of the K series engines, Jehan Tetangco, told us the RSX proved to be a tricky customer. Naturally, DC fell back on its prior knowledge of Honda engines, fitting a 2.25-inch B-pipe to the car. It promptly lost power. A 2-3/8-inch pipe lost even more power. After going backwards and fitting a 2-inch pipe, which pushed power back up to just less then stock levels, he finally reached for the B series power handbook and threw it away. Clearly, this K was a completely different animal.
After much experimentation, Tetangco finally discovered a combination that worked. According to DC Sports, its Twin Canister System axle-back system and a 2.5-inch B-pipe resulted in a solid 6 hp gain and an average 3 hp gain from 3000 rpm to redline.
Headers are even more difficult proposition. The good news is the catalytic converter is still separate form the exhaust manifold. However, it is shoved so close to the head that there is very little room for long exhaust runners. In fact, Tetangco discovered Honda’s engineers did such a good job on runner size that he, instead, focused attention on the collector. After trying numerous designs, he discovered one that worked, again adding a nice 6 hp and 3 hp, average. Together, the header and cat back are good for 8.6 hp, according to DC Sports. However, add DC’s cold-air intake system and the power gain shoots up to over 22 horses, with almost a 10 hp average from 3000 to redline. Clearly, intake, not exhaust, is the K20A2’s biggest shortcoming from the factory.
NITROUS OXIDE AND FORCED INDUCTION
Traditionally, one of the quickest and easiest ways to get power form an engine is a shot of good ol’ nitrous oxide. With more power just the push of a button (and a few hundred dollars) away, many vehicles fine themselves with nitrous bottles in the trunk for a little added oomph. Simple, single-fogger systems are commonplace, but multiple fogger systems with ports drilled directly into the intake manifold are not unusual.
W spoke to Eric Vargas of Advanced Engine Management in Torrance, Calif. Eric is the brain behind AEM’s burgundy, nitrous-charged RSX you might have seen in our sister publication, “Sport Compact Car.” The car has been through a lot, including a blown engine caused by an unforeseen problem with the fuel delivery system.
The Integra (and previous Hondas) used a fairly conventional fuel and ignition system. The fuel routed to the rail where a regulator controlled pressure, and excess fuel was returned to the fuel tank. Even in the high-tech Integra, a mechanically activated distributor controlled the ignition.
The K series has a “headerless” fuel system, meaning the regulator and return line are actually in the tank. There is no fuel return from under the hood. This gives Honda the advantage of building the pump, regulator, return and fuel level sensor all in one unit. It also helps reduce evaporative emissions.
Vargas tells us the down side to this type of system is it becomes very difficult to build extra fuel pressure. It used to be that adding a fuel pressure regulator would build enough additional pressure from the stock pump to make forced induction or big nitrous applications relatively simple. The way the K series’ fuel is supplied make building adequate pressure much more difficult.
Unfortunately, there is no simple workaround for this problem. The stock fuel pump is capable of about 55 lbs of pressure, adequate for low-horsepower (40 hp or so) nitrous system or very low-pressure turbo or supercharger. Any higher and the system will run very lean-a dangerous condition that could result in a blown engine.
For higher horsepower application, a return line will have to be run, meaning the single-piece fuel pump/regulator/return/level sender assembly in the tank will have to be separated into individual components. This is an expensive and time-consuming process that would make a bolt-in kit a more diffcult proposition. Of course, that hasn’t kept HKS, Greddy and Jackson Racing from continuing to develop kits. Racing applications that need more than just a few pounds of boost are still in the future.
The ignition system is also very different. The B and H series engine use distributors, despite all the high-tech valve gizmos. The K uses a computer-controlled ignition without a distributor. While this is great for precisely retarding and advancing spark to meet different conditions, it makes it very difficult to alter the spark curve using external devices. Simply put, the engine freaks out and switches into limp mode until the computer itself is allowed to manipulate spark again.
ENGINE COMPUTER
It’s easy to see the K’s computer is the dominant force in the engine, and nobody knows Honda computers better than Doug Macmillan of Hondata in Torrance, Calif. After digging into the stock computer, his excavations have unearthed some surprising-and hopeful-answers.
First, the programming is extensive. The fuel maps alone take up more memory then all of the programming for the B series put together. Macmillan told us there are six non-VTEC and six high-lift cam tables. There are also another 24 that, as of press time, he was still working on. He also discovered the ignition tables and the tables governing VTC cam advance.
Additionally, he discovered something tuners are going to love about the stock ECU: Flash programmability. Unlike the previous car, this would make reprogramming of the computer far simpler. And with the hurdles surrounding ignition and cam timing for forced-induction engines, being able to directly manipulate these factors is crucial.
Macmillan also told us a possible trouble spot doesn’t seem to affect the engine’s performance potential. The RSX’s compute is multi-plexed, meaning it sends multiple signals to different systems down the same line. This would have the potential to play havoc with aftermarket tuning but it seems the multi-plexing is confined to systems outside the engine compartment.
FRANKENSTEINS AND SWAPS
One of the greatest performance features of the B series engines is the interchangeability of the parts. With some modification, you can put a VTEC head with a Type R intake manifold on a B20 block and make yourself a monster of an engine.
Is the same true for the K? Skunk2 thinks so. It’s in the process of building a naturally aspirated race engine based on the Frankenstein concept. With the K20A2’s high-powered VTEC head mated to the CR-V’s long-stoke K24A1, Michael Choi of Skunk2 told us he hopes to create a high-revving, high-power, high-torque monster that will rip the wheels off the shop’s racecar. The biggest obstacle will be the lack of off-the-shelf, high-performance parts. Anybody wishing to build up the internals of their K engine will simply have to wait for those parts to fill the pipeline.
Engine swaps are a different story. We spoke to Brian Gillespie of Hasport, based in Phoenix, Ariz. Known throughout the tuning industry for its engine mount kits, Hasport has already been working on stuffing the K into its chassis mates.
The easy part is swapping the K series engines between car that were originally equipped with them. So, if you want more bang out of your Civic Si, it’s relatively simple to drop in an RSX Type-S engine and be on your way. The only snag might be with swapping a K24 engine into the RSX or Civic, owing to its slightly taller block.
The non-Si Civics are a different matter. The current-model EM Civics are built on the same basic chassis as the RSX and CR-V. This means that, theoretically, the K series engines should fit in the Civic chassis. However, the engines mount differently in their respective bays-the D series engines used in the Civics on the driver’s side, the K on the passenger side. This is a more complicated proposition for potential swappers.
According to Gillespie, the trick is using the RSX subframe. This subframe simply bolts in place of the standard Civic subframe, and ahs the rear engine and transmission mount in the proper place for the K series engine. After that, it’s a matter of developing the proper engine mount on the sides of the engine. Gillespie is confident the swap will be complete soon, and that before long he’ll have a K20A2-powered Civic coupe up and running. This is great news for owners of current-model Civics who have been stymied by the D17’s lack of tuning options.
FINAL WORD
The future is bright for the K series but, compared to what the aftermarket is use to, the K series is a whole new ball game. From the most basic tuning to the most advanced, it’s going to take time for the RSX and its counterparts to get up to speed. But it will. Whether you like it or not, Honda is not making the B anymore. Smart tuners are going to get cracking on the new K as soon as they can. Those that don’t, will undoubtedly be left behind.
K20A VTEC breakdown
The K20A3 does not have a standard DOHC VTEC valvetrain as we know it from the B-series engines - the K20A3 should actually be called a “DOHC i-VTEC-E” engine, because it uses a VTEC-E cam setup. The K20A2 is the “real” DOHC i-VTEC engine, utilizing the standard DOHC VTEC cam setup we’re all familiar with. To help you understand the differences between the K20A2 and K20A3 engines, I’ve included the following information from a post I made elsewhere:
Allow me to evaluate. Let’s start out by defining some terms:
VTEC - Variable valve Timing and lift Electronic Control. At low RPM, a VTEC engine uses a normal cam profile to retain a smooth idle, good fuel economy, and good low-end power delivery. The VTEC mechanism engages a high-lift, long-duration “race” cam profile at a set RPM value (i.e., ~5500RPM on the B16A) to increase high-end power delivery.
VTEC-E - Variable valve Timing and lift Electronic Control for Efficiency. This system isn’t really VTEC as we know it. At low RPM, the VTEC-E mechanism effectively forces the engine to operate as a 12-valve engine - one of the intake valves does not open fully, thus decreasing fuel consumption. At a set RPM value (i.e., ~2500RPM in the D16Y5), the VTEC-E mechanism engages the 2nd intake valve, effectively resuming operation as a normal 16-valve engine. Note: in a VTEC-E engine, there are no high-RPM performance cam profiles; this engine is supposed to be tuned for fuel economy, right?
VTC - Variable Timing Control. This is a mechanism attached to the end of the intake camshaft only which acts as a continuously variable cam gear - it automatically adjusts the overlap between the intake and exhaust cams, effectively allowing the engine to have the most ideal amount of valve overlap in all RPM ranges. VTC is active at all RPMs.
i-VTEC - intelligent Variable valve Timing and lift Electronic Control. This is a combination of both the VTEC and the VTC technologies - in other words, i-VTEC = VTEC + VTC. Currently, the only engines that use the i-VTEC system are the DOHC K-series engines.
Now this is where things get tricky - Honda uses the term “DOHC i-VTEC” for two different systems: The first system is used in the K20A2 engine of the RSX Type-S. The second system is used in the K20A3 engine of the Civic Si.
The First System (K20A2):
This system is pretty close to the older DOHC VTEC engines. At low RPM, the K20A2 uses a normal cam profile to retain a smooth idle, good fuel economy, and good low-end power delivery. At 5800RPM, its VTEC mechanism engages a high-lift, long-duration “race” cam profile to increase high-end power delivery. The only difference between this i-VTEC engine and the older VTEC engines is the addition of the VTC system. The intake camshaft has the automatic self-adjusting cam gear which continuously optimizes valve overlap for all RPM ranges.
Here we see an image of the intake cam lobes of the K20A2. Notice there are 3 lobes; the two side lobes are the low-RPM profiles, and the center lobe is the high-lift, long-duration profile which engages at 5800RPM. Basically the same setup as the old VTEC engines we are familiar with.
Now here we see the VTC mechanism - the gear on the end of the intake cam that adjusts valve timing (overlap) automatically on the fly.
This system is used in engines powering the JDM Honda Integra Type-R, Civic Type-R, Accord Euro-R, and the USDM Acura RSX Type-S and TSX.
The Second System (K20A3):
This system does not really conform to the “DOHC i-VTEC” nomenclature, as Honda would like us to believe. As I mentioned in my previous post, it actually should be called “i-VTEC-E,” because it uses a VTEC-E mechanism rather than a standard VTEC mechanism. At low RPM, the VTEC-E system effectively forces the engine to operate as a 12-valve engine - one of the intake valves does not open fully, thus decreasing fuel consumption. At 2200RPM, the VTEC-E system engages the 2nd intake valve, effectively resuming operation as a normal 16-valve engine. There are no high-RPM performance cam profiles; this engine is tuned to balance fuel economy and power, rather than provide pure performance. On the intake cam, there is the VTC mechanism which basically is an automatic self-adjusting cam gear used to continuously optimize the valve overlap for all RPM ranges. This being a VTEC-E system - and not a true DOHC VTEC system - is the reason the K20A3 redlines at a measly 6800RPM, while the K20A2 is able to rev all the way to 7900RPM.
Here we see an image of the intake cam lobes of the K20A3. Notice there are only 2 lobes - there is a nearly round one used only for the low-RPM disabled intake valve, and then there is the regular lobe used by the other valve at low-RPM and by both valves at high-RPM:
This system is used in engines powering the USDM Acura RSX base, Honda Civic Si, Accord 4-cylinder, CRV, and Element.
Special note: The K20A3 engine used in the Acura RSX base has a slightly different intake manifold design from the K20A3 engine used in the Civic Si. The RSX engine uses a dual-stage manifold, similar in concept to the manifold of the B18C1 in the old Integra GSR. It uses long intake runners at low-RPM to retain low end power, and switches at 4700RPM to a set of shorter intake runners to enhance high-end torque. This accounts for the extra 9 ft-lb of torque in the RSX (141 ft-lb, vs. 132 ft-lb in the Civic Si).
Here is an image showing just how this dual-stage manifold works. On the top, you can see the low-RPM (long) runners are in use, and on the bottom, you can see the high-RPM (short) runners in use.
Myths:
- The i-VTEC engine engages VTEC gradually, and not suddenly like in the old VTEC engines.
Wrong. The i-VTEC engine “engages VTEC” at a single set RPM, like always. Whoever started this rumor is a ****tard. Read the definitions above.
- VTC engages at a set RPM.
Wrong. VTC is always activated. Read under “VTC” above.
- The K20A3 engages VTEC at 5000+ RPM.
Wrong. Technically, there is no “VTEC” (as we think of it) in the K20A3 engine - it uses a VTEC-E technology, which engages at 2200RPM. Read under “The Second Sytem” above.
-Borrowed from Team Pacman
no but you’re saying you want a motor because its rare… rather than what it can do for you, you’d rather have something that will give you bragging rights…
so in your situation I recommend the J-series motor.
[QUOTE=tilegend;1948595]no but you’re saying you want a motor because its rare… rather than what it can do for you, you’d rather have something that will give you bragging rights…
so in your situation I recommend the J-series motor.[/QUOTE]
sorry i wasent trying to imply that at all, the b17 would be alot cheaper to get, alot more easier to swap and more worth it than a k20 in these cars (DA) not saying you shouldent do it, but hey thats your choice and your money, i dont look at motors for bragging rights in anyway, because i dont care about looks i care about performance, and for these cars, i dont care who says what. in my opinion its not worth it to do a k series swap, when you can problly find a rsx for a little more money and build it to be twice as fast as the DA. so sorry if you misunderstood.
exactly what im doing… i bought the car like this and was like “this setup isnt gonna fly for me”
i have a couple points to make…
its funny you are comparing a b17 to a k20 and saying a b17 is a better choice in your opinion because you care more about performance then bragging rights. if you really cared about performance then you would agree that the k20 is a better choice over ANY b-series. thats just a statement of fact.
and i would also think that getting a b17 to outperform a k20 is more about bragging rights then just swapping a k20 and doing a few bolt ons.
unless u find crack head deals on an RSX, and want to GUT a car that you’re financing and paying full coverage insurance on, this statement is just blatantly false.
i understand these are your opinions. i replied with mine. discuss if you want to.
^
that depends on how the person perceives “better”
I agree that the K-series is everything the B-series was, and is taking it 30 steps ahead of that “second letter” series.
when it comes to a DA, SOME people like the “drop in” factor of the B-series.
When $$$ and time is not a factor, then who in their right mind WOULDN’T go K?
my two copper lincolns.
[QUOTE=imcnblu;1950907]^
that depends on how the person perceives “better”[/QUOTE]
the person who i was responding to seemed to think that performance was most important.
10-4, holmes 
i like how the redline is 8500 for the k20z1 and 8300for the k20z3.
Wow, this thread back again.
Could also argue that when $$$ and time not a factor, convert to RWD and F20C. Or any other number of expensive and difficult modifications.
I hope everyone goes ape shit for k series so the prices of b series plummets and I can afford a decent build. :burnout:
already happened.
Needs to drop a liiiiiittle more. Hahah.
I like just the drop in aspect. K is smokin’, but I haven’t planted my money tree yet.
[QUOTE=2Door;1980365]Needs to drop a liiiiiittle more. Hahah.
I like just the drop in aspect. K is smokin’, but I haven’t planted my money tree yet.[/QUOTE]
a buddy of mine is selling a GSR long block for like $1200 because he can’t get anyone to buy it. nobody wants B-Series anymore.
I’m glad that’s happening 
I sold my full GS-R swap for 1000 with a GS-R YS-1 cable tranny
hey bud,
the cock suckers on this fourm hate me way more than the one on that other fourm were on