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Assembling a sticky! Who Know's something about K24/K20 Frank Setups??

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87K views 110 replies 53 participants last post by  alexEF  
#1 · (Edited by Moderator)
Note: This is a compilation of information I scoured over K20A.org, I did however forget to take note of which members said what on some of the content. So if you read it, and you go “hey I wrote that!” just PM the link and I’ll add your name in.

I still have alot of needed info, there are questions in red, if you know some info on, I'd like to add your responce in.

Also, if you have any pictures to help display/explain any info below, get them to me, I can host them. Or we can attach them to the thread.

Nice writeup by Chameleon on a k24a4 / k20a2 head.
http://www.k20a.org/forum/showthread.php?t=13887

Block Choices
http://www.k20a.org/upload/Kserieschart.htm
All have 2354cc of displacement and 87mm bore and 99mm stoke

K24A1 (PPA), CRV (LRD)
160hp @ 6000rpm / 162lb-ft @ 3600rpm
Redline: 6500rpm
Compression: 9.6:1

K24A2 (RBB),TSX (CL)
200hp @ 6800rpm / 166lb-ft @ 4500rpm
7100rpm
10.5:1

*K24A3 (RAA), Accord (03+ CM, 5th Gen V6 and Wagon CE)
160hp @ 5500rpm / 161lb-ft @ 4500rpm
6500rpm
9.7:1

*K24A4 (PZD), Element (YH)
160hp @ 5500rpm / 161lb-ft @ 4500rpm
6500rpm
9.7:1

Some info on the Cranks
Code -- Bore -- Stroke - rod length - crank throw - journals - weight
k20a - 86mm - 86mm --- 139mm ---- 43.18mm ---- 20mm --- 38lbs
k24a - 87mm - 99mm --- 152mm ---- 49.53mm ---- 20mm
RDX -- 86mm - 99mm ----- ? --------------------- 20mm
F22c - 87mm - 90.7mm - 149.65mm --------------- 24mm
F20c - 87mm - 84mm --- 153mm ------------------ 24mm
http://www.k20a.org/forum/showthread.php?t=19405

Stock deck height
K20 212mm
K24 231mm?
F20C 224mm

Conbustion Chamber volume
K24 53.5cc
K20A/A2 50.7cc
K20A3 48.0cc - from JE
F20C 53.6cc +/- 0.2cc

Bore
K20 86mm
K24 87mm
F20C 87mm

Stroke
k20 86.0mm
k24 99.0mm
F20C 84.0mm
F22C 90.7mm
H22 90.7mm
F22C 106.0mm (inline pro stroker)

*IPS offers 86mm, 88.5mm, 90.7mm, 93.2mm, 96.5mm, 99mm, 101.6mm stroke options for K24

Rod length
k20 139mm (5.473") (rod/stroke = 1.62)
k24 152mm (5.984") (rod/stroke = 1.54)
F20C 153mm (rod/stroke = 1.82)
F22C 149.65mm
H22 143mm (5.630")

Rod BE Diameter
K/H/F 51mm

Rod Journal width
K20/24 19.8mm (0.780") BE width
H22/F20 23.8mm (0.938") BE width

rod journal diameter
K/H 48mm BE


Will except K20 head (straight bolt on), yes/no and why.
K24A1 (crv) - yes
New Compression Ratio:
K24A2 (tsx) - yes
New Compression Ratio: Around 10.2:1 ?
*K24A3 (element) - no, valve clearance issues
New Compression Ratio: As stock cannot be used, compression depends on choice of aftermarket.
*K24A4 (accord) - no, valve clearance issues
New Compression Ratio: As stock cannot be used, compression depends on choice of aftermarket.

* I have seen some resources say both the accord and element are both A4's, other's say A3/A4, anyone want to pop they're head under they're moms element?

Head Choices
TSX Exhuast cam more aggressive than the k20a/2 ? Cam differences? Valve/Spring Differences?
The k24a2 head has smaller intake port openings than the k20a/2 this allows for higher velocity air speeds entering which helps the low end torque the k24 was built for in the lower rpm range, while the k20a/2 has larger ports to help flow in it’s power band, the higher rpm’s that the k24 doesn’t reach. You can see the smaller ports in this photo.

Image


Discussion is still open on which head is “better”, some prefer 1 over the other. The k24a2 does have more metal to work with, so I would assume it is preferred by porters to work on.

There are differences in the k24 line of heads. As you can see from these pictures (Photo’s courtesy of wsuk20) the TSX head does not have the “reconnecton” of the intake runners. The other k24 heads (crv, element, accord) intake ports all split and then rejoin again.

Speculation as to why…
http://www.k20a.org/forum/showthread.php?t=10028&highlight=head

First is a K24 (non-tsx), Second K20 (used for comparison purposes, k24 is the same in regards to not having the reconnection)
Image
Image


Lagachette - The TSX head's have better air velocity than the Type-S . With the TSX, you will have higher flow rates at low lift but this advantage stops when you pass the 276 CFM line. After that the Type -S will continue to flow until 300 CFM. I think that the TSX has more potential than the Type-S has. If you can make a good porting on the TSX, You can go at 300 CFM with the advantages that the TSX had at low lift. But if you open the TSX head to much by porting it, you will lose the flow at low lift that is for me really important. It is that, that gives the torque. It is not only the maximun CFM that we have to considering in the dyno flow. The most difficult thing to do for a head porter is keep a good flow at low lift and incerasing the top flow at the same time. A lot of head porters think that they are good with impressive top flow numbers but they forget that velocity is also important for performance and torque... By the way, I did a test to compare valves on the stock TSX head with :Manley, Supertech, Skunk2 and stock valves. The Skunk2 are the best, after that, the Supertech are really close, Manley was third. With aftermarket valves, you will have around 7 CFM gain in all the range. But don't forget that if you make a porting, all these results can change. One kind of valve can give a better result with the kind of porting that you did. It is a lot of work to make a good porting and a valve combination. Also, you can tell your porting men that it is better to stay at 3 angles at the intake. I have lost 10 CFM with 5 angles... If you want good informations about that, You can check the 2006 february Sport Compact Car magazine. They did a porting work on a K24a2 head. There is a picture of porting. But for me, i think that they opened the k24a2 head a little to much...

K20A (PRC/RBC), Integra Type-R/Accord Euro-R (Japan)
ITR K20A stock redline is 8600
CTR K20A stock redline is 8400

K20A2 (PRB) RSX Type-S (DC5) ’02-‘04
K20A2 (including Euro CTR) stock redline is 7800

K20Z1 ) RSX Type-S (DC5) ’05 +
7900rpm

K20Z3 Civic Si coupe (FG)
8000rpm

More specifics on which head has best cams for different set-ups, best intake manifolds, throttle body sizes, etc...

Throttle Body
How to get rid of DBW (drive by wire)? DBW come standard on 06+ Si's and TSX's. Any others?

Head Flow – Element (K24a4) vs. Type-S (K20A2)
http://www.k20a.org/forum/showthread.php?t=6235&highlight=flow+chart

K24a1 Head Flow Chart – CRV (K24A1) vs. Prelude (H22)
http://www.k20a.org/forum/showthread.php?t=6575&highlight=flow+chart

Flowbench data k20a2 head
http://www.k20a.org/forum/showthread.php?t=10689&highlight=flowbench

Tranny Options
K24’s tranny’s will not work with any current mounts on the market (12/28/06), a K20 tranny must be used.

To use a k24 tranny you have to custom it. Fastback20 wrote up how he approached it.
http://www.k20a.org/forum/showthread.php?t=22080

Tranny A vs. B Graphs, VERY GOOD
http://www.k20a.org/forum/showthread.php?t=7317

Experiences with either...? Price range...?
LSD Options?
OBX?
Quaffe?
Type-R OEM LSD / 06+ Si OEM LSD – will fit fine, needs shimmed due to tolerances. Will it fit in all trannies fine?

Tranny Specs
http://www.k20a.org/forum/showthread.php?t=6395
5-Speeds vs. 6-speed

ECU Options
K-Pro
These links will take you 3 days to read, it's THAT good. Both are STICKIES in the ECU forum.
http://www.k20a.org/forum/showthread.php?t=2009
http://www.k20a.org/forum/showthread.php?t=117

K-100
AEM-EMS
Stock ECU options?
Comparison on k-pro vs aem ems

Parts Prices
K24a1 (Crv) Motor - Around $1300
K24a2 (TSX) - Around $3000
K24a3/4 (Accord/Element) - Around $1000

The reason for the price difference in the k24a1 vs a3/4 is because the crv can be used with a k20a head with out modification to stock internals.

Where to buy?
www.car-parts.com

k20a.org For Sale Section.
Junk yard.
Any ideas? TSX motors escpecially...

General 1/4mile Times

General Power Made Hp/Tq.
Amazing 231whp /186ft-lbs torque from a TSX stock/k20a r head motor
231 whp at 7600 rpm and 186ft-lbs torque
http://www.k20a.org/forum/showthread.php?t=2771&highlight=flowbench

With a TSX block, k20a2 head, h.c. valves, and kpro, you will have around 207hp 175 TQ on a Mustang Dyno, with k20a2 block, k20a2 head, h.c. valves and k pro, you will have 210hp 155pound. The power from the k20a2 block will be between 6k and 8.5k. With the TSX block, the power will come earlier between 4.5k and 7.5k and sometime 8k.

If you want to have more information about the TSX motor, try to find the magazine :Sport compact car (February 2006) They have put Skunk2 stage1, H.C.valves, Kpro, 45*vtc pulley, bigger throttle body, head porting, with these modifications, on a dyno jet, they have had 238hp, 183pounds with a max RPM of 8.2k.

Driving Styles
Here it is a question of taste. If you like to rev your engine you choice will be the k20 but if you like the torque the TSX block is the best choice (the torque on the TSX start at 1.8k at 150pound!) Personnally, in the street, I prefer torque. If you use the TSX block you will have more compression than the K24a1 block that have 9.6:1. It makes a notable difference in power. Also, the TSX block is a better block than the k24a1 is. The TSX have an oil stream under the piston to keep them at the good temp. The TSX block have better rods and bearings this block is set to rev by the factory at 7.1k and the k24a1 at 6.5k.

Clearances Issues
Crx hood clearance: Hood must be cut. Or after market / custom
http://www.k20a.org/forum/showthread.php?t=7686&highlight=k24+block+k20+head
EG ?
EK ?
After market hoods that will work?

Piston Speeds
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.
http://www.k20a.org/forum/showthread.php?t=11793

How To?
http://www.sportcompactcarweb.com/tech/0406scc_hybrid/
Suprfast - When doing a bolt on Frank Swap an 87mm Head gasket is needed.
ARP head studs for the K20a will fit the K24 engines in a frank.

Oil Pump / Squirters
Don't forget, if you use the K24 block, all of them use counterbalanced oil pump. It is better to replace this heavy pump by the k20a2 oil pump that didn't use balancer. If you do that, don't forget to plug the secondary oil line on the k24 block that is to lubricate the bearing of the k24 pump.

K24a2 meets Type S Oil Pump w/pics(no56k)
http://www.k20a.org/forum/showthread.php?t=12560&highlight=tsx

Oil Squirters
HotWheelz - TSX block is superior, because it's already pre-drilled for squirters and other things if you haven’t noticed other k24 blocks aren't

VTC
TSX set to/maxed at 25? Can CNC to 45? How modify? Supafly can do it.
 
#4 ·
Tell me about it, I am in the same boat, in korea for a year. Cant drive my car so I write articles for K-series.com.

Kevin - for the trannies, what specifically do you need?
Part prices - did you need average price brand new?
 
#7 · (Edited)
EvaUnit01 said:
Tell me about it, I am in the same boat, in korea for a year. Cant drive my car so I write articles for K-series.com.

Kevin - for the trannies, what specifically do you need?
Part prices - did you need average price brand new?
Click to expand...
Basically, i'd like a good non-bias (if possible) of a 5 speed vs. 6 speed, based on different expectiataions, goals etc... confirmation on the oem lsd, and it's compatibility and what's neccessary.

Part prices, I'm trying to get people a general field on used and brand new, so they know what to expect, it will be dated, as we know k-series are generally new and prices are bound to fluctuate depending on what/how many are produced from honda etc... basically general prices people have payed, are willing pay brand new from the dealer as well as used.

I really appreciate any and all help in keeping the forum top notch info, and hopefully i can click the "make sticky" button in the near futrure :up:

ps. suprfast, i'm going to kill you! :p like literally... i'm gonna murder you. pps. oh i didn't forget, i'm formulating a plan mauhaha HAHAHA MUAHAHAHAHAHAH

pppppssssss. it's 5:30 am , i'm drunk, my friend is too, and uh yeah... lets make this forum rock :D !!!!
 
#10 ·
kevinoneill said:
K24A1 (PPA), CRV (LRD)
160hp @ 6000rpm / 162lb-ft @ 3600rpm
Redline: 6500rpm
Compression: 9.6:1

K24A2 (RBB),TSX (CL)
200hp @ 6800rpm / 166lb-ft @ 4500rpm
7100rpm
10.5:1

K24A3 (RAA), Accord (CE)
160hp @ 5500rpm / 161lb-ft @ 4500rpm
6500rpm
9.7:1

K24A4 (PZD), Element
160hp @ 5500rpm / 161lb-ft @ 4500rpm
6500rpm
9.7:1

Will except K20 head (straight bolt on), yes/no and why.
k24a1 (crv) - yes
k24a2 (tsx) - yes
k24a3 (element) - no, valve clearance issues
k24a4 (accord) - no, valve clearance issues
Click to expand...

awesome write up man!!! need to fix accord/element K tho :up:
both are a4...
 
#15 ·
kevinoneill said:
I went to bed at 10a.m. :up: The accord/element codees, i sited from http://www.k20a.org/upload/Kserieschart.htm I have heard that before though, both being A4, I might go back and just site that difference.
Click to expand...
haha ya.. thanks for doing thw rite up :up:

i checked the engine out the engine in the garage and it said k24a4.. also for ur chart u could update and add in k24a8 also just an update for every1 :up:
chart also missing k20z1 dunno if any1 brought that up to u
 
#16 ·
Deak said:
haha ya.. thanks for doing thw rite up :up:

i checked the engine out the engine in the garage and it said k24a4.. also for ur chart u could update and add in k24a8 also just an update for every1 :up:
chart also missing k20z1 dunno if any1 brought that up to u
Click to expand...
What car's in your garage? Never heard of the A8, what's that one from? Euro/Jap Model?

I'll get the Z1 on there, in the next day or 2. Heading to Miami for a Braves Baseball game. :D First baseball game I'll of been to ever.
 
#18 ·
some more information about the tsx:

POWERTRAIN

AT A GLANCE

Engine

2.4-liter, DOHC, i-VTEC 4-cylinder engine that produces 200 horsepower at 6800 rpm and 166 lbs.-ft. of torque at 4500 rpm
i-VTEC "intelligent" valve-control system adds VTC (Variable Timing Control) to VTEC
Drive-by-wire throttle control system
Computer-controlled Programmed Fuel Injection (PGM-FI)
Dual balance shafts for exceptional smoothness
Direct ignition system
Lightweight alloy pistons and high-strength connecting rods
110,000-mile tune-up intervals

---------------------------------------------------------------------

CYLINDER HEAD / VALVETRAIN

The cylinder head is pressure-cast aluminum alloy and features four-valves-per-cylinder driven by dual overhead cams. An automatically adjusted silent-type chain drives the cams; it is maintenance free and runs in an oil bath for maximum durability. The combustion chambers have large "squish" areas to promote faster flame propagation and more complete burning-factors in reduced carbon monoxide (CO) and hydrocarbon (HC) exhaust emissions.

CRANKSHAFT, ENGINE BLOCK AND OIL PAN

The TSX uses a forged-steel crankshaft with a relatively long 99 mm throw. To reduce friction and improve long term durability, the crankshaft journals are micropolished. The die-cast lightweight aluminum block has cast-in iron cylinder liners with 87 mm bores. The liners are made using a spin casting, centrifugal process. To maximize the rigidity and minimize noise and vibration, the block is a 2-piece design that fully supports the five main bearings with a single cast-alloy bed-plate assembly.

NOISE, VIBRATION AND HARSHNESS (NVH) CONTROL

The high output in-line 4-cylinder engine features comprehensive NVH reduction features. The pressure-cast block with its bed-plate type main bearing cap is a highly rigid assembly, helping to resist vibration. A pair of chain-driven balance shafts further smoothes the inherent vibration of a large displacement in-line 4-cylinder layout. A self-adjusting silent-type camshaft chain and a serpentine accessory drive belt also reduce NVH.

110,000-MILE TUNE-UP INTERVALS

With a self-adjusting silent-type cam chain, long wearing platinum-tipped spark plugs and a precision-engineered valve train, the TSX is engineered for low maintenance. Other than routine fluid changes and inspections, the first scheduled engine tune-up is required at 110,000 miles.

6-SPEED MANUAL TRANSMISSION

One of the standard transmissions in the TSX is a close-ratio 6-speed manual gearbox. With exceptionally short 45 mm shift throws (most European sedans have shift throws of about 60-65 mm) and a precise, light shifting action, this transmission perfectly complements the car's sporting character. With six gear ratios instead of the more common 5-ratio arrangement, the TSX has closely spaced gears for superior acceleration, yet still has a top gear that allows for a low and efficient cruising rpm.

To reduce weight, the compact transmission case and bellhousing are cast of a special magnesium alloy-the first use of this lightweight material in the transmission of an Acura product. This complex casting is seven pounds lighter than the comparable aluminum version, and is highly rigid to damp out noise and vibration. Inside, the gearbox has multi-cone synchronizers on all gears (including reverse) to reduce shifting effort.

A lightweight clutch with low-inertial mass allows the engine to rev quickly, the clutch pedal stroke is short and the effort is comfortably low. A broad and progressive engagement band makes the TSX easy to launch smoothly from a stop. The clutch incorporates a wide-angle clutch-torsion mechanism that reduces the gear rattling sound that is common in many manual-transmission designs.
 
#21 ·
oh i got the 04 accord k24a4 in garage hhaha but ya, the k24a8 is 06+ accord which has been stock modified like tsx (intake and exhaust)
06 accord specs
166 horsepower @ 5800 rpm and 160 lb-ft. of torque at 4000 rpm;
new features include DBW throttle control and high performance intake and exhaust valve timing
note: hp and tq # are new SAE rating w/ the old system this coulda been 170-175hp(guestimate)

for comparison, the 06 element stil has the old engine whish is now rated 156hp@5500 160tq@4500 (w/ new SAE)

and 06 crv stil has old engine which is now 156@5900 160tq@3600
so the crv has the same power as the element yet at a sooner rpm ... dont know if the new SAE ratings has anything to do w/ it

the 06 tsx got increased hp/tq (205 hp @ 7000 rpm..164lb-ft @ 4500 rpm..10.5CR ..redline 7100) due to those reason, thats why the 06 tsx has different part # for IM , altho 06 tsx is still k24a2, dont know why accord changed the code yet tsx still remains the same...another thing is that the 06 tsx has a more agressive intake cam than the pre-06

that is all i know for now
 
#23 ·
bossman032 said:
some more information about the tsx:

POWERTRAIN

AT A GLANCE

Engine

2.4-liter, DOHC, i-VTEC 4-cylinder engine that produces 200 horsepower at 6800 rpm and 166 lbs.-ft. of torque at 4500 rpm
i-VTEC "intelligent" valve-control system adds VTC (Variable Timing Control) to VTEC
Drive-by-wire throttle control system
Computer-controlled Programmed Fuel Injection (PGM-FI)
Dual balance shafts for exceptional smoothness
Direct ignition system
Lightweight alloy pistons and high-strength connecting rods
110,000-mile tune-up intervals

---------------------------------------------------------------------

CYLINDER HEAD / VALVETRAIN

The cylinder head is pressure-cast aluminum alloy and features four-valves-per-cylinder driven by dual overhead cams. An automatically adjusted silent-type chain drives the cams; it is maintenance free and runs in an oil bath for maximum durability. The combustion chambers have large "squish" areas to promote faster flame propagation and more complete burning-factors in reduced carbon monoxide (CO) and hydrocarbon (HC) exhaust emissions.

CRANKSHAFT, ENGINE BLOCK AND OIL PAN

The TSX uses a forged-steel crankshaft with a relatively long 99 mm throw. To reduce friction and improve long term durability, the crankshaft journals are micropolished. The die-cast lightweight aluminum block has cast-in iron cylinder liners with 87 mm bores. The liners are made using a spin casting, centrifugal process. To maximize the rigidity and minimize noise and vibration, the block is a 2-piece design that fully supports the five main bearings with a single cast-alloy bed-plate assembly.

NOISE, VIBRATION AND HARSHNESS (NVH) CONTROL

The high output in-line 4-cylinder engine features comprehensive NVH reduction features. The pressure-cast block with its bed-plate type main bearing cap is a highly rigid assembly, helping to resist vibration. A pair of chain-driven balance shafts further smoothes the inherent vibration of a large displacement in-line 4-cylinder layout. A self-adjusting silent-type camshaft chain and a serpentine accessory drive belt also reduce NVH.

110,000-MILE TUNE-UP INTERVALS

With a self-adjusting silent-type cam chain, long wearing platinum-tipped spark plugs and a precision-engineered valve train, the TSX is engineered for low maintenance. Other than routine fluid changes and inspections, the first scheduled engine tune-up is required at 110,000 miles.

6-SPEED MANUAL TRANSMISSION

One of the standard transmissions in the TSX is a close-ratio 6-speed manual gearbox. With exceptionally short 45 mm shift throws (most European sedans have shift throws of about 60-65 mm) and a precise, light shifting action, this transmission perfectly complements the car's sporting character. With six gear ratios instead of the more common 5-ratio arrangement, the TSX has closely spaced gears for superior acceleration, yet still has a top gear that allows for a low and efficient cruising rpm.

To reduce weight, the compact transmission case and bellhousing are cast of a special magnesium alloy-the first use of this lightweight material in the transmission of an Acura product. This complex casting is seven pounds lighter than the comparable aluminum version, and is highly rigid to damp out noise and vibration. Inside, the gearbox has multi-cone synchronizers on all gears (including reverse) to reduce shifting effort.

A lightweight clutch with low-inertial mass allows the engine to rev quickly, the clutch pedal stroke is short and the effort is comfortably low. A broad and progressive engagement band makes the TSX easy to launch smoothly from a stop. The clutch incorporates a wide-angle clutch-torsion mechanism that reduces the gear rattling sound that is common in many manual-transmission designs.
Click to expand...
nice info!!!!!!!!:) , but...............I want info like this on the a1:up:
 
#24 ·
chairwitharmrests said:
nice info!!!!!!!!:) , but...............I want info like this on the a1:up:
Click to expand...
k24a1...?
Engine
The CR-V uses Honda's latest i-VTEC "intelligent" valve-control system. This technology combines VTC (Variable Timing Control) - which continuously adjusts camshaft phase - with Variable Valve Timing and Lift Electronic Control (VTEC) that changes valve lift, timing and duration. First appearing on the Acura RSX, this is the first Honda product in North America to receive the i-VTEC system. The result is impressive horsepower and high torque with outstanding fuel economy and low exhaust emissions. The broad torque range allows the 2002 CR-V to offer smooth and powerful performance in all types of driving conditions ranging from in-city to freeway driving to hilly terrain. In addition, the CR-V's transversely mounted engine block has been rotated 180 degrees. As a result, the exhaust manifold is closer to the catalyst for improved light-off and reduced emissions at startup. The engine rotates clockwise.

The 2.4-liter DOHC i-VTEC 4-cylinder design uses 16 valves, a dual-stage intake manifold, and the i-VTEC system (VTC on intake cam shaft) to deliver 160-horsepower at 6,000 rpm and 162 lb-ft. of torque at 3,600 rpm. The engine also has a dual-stage intake. The i-VTEC system represents a new, highly intelligent valve timing/lift mechanism that combines the VTEC mechanism for switching cams between low- and high-speed ranges, along with VTC, which sequentially controls cam phase based on engine speed and load. Overall, the engine's low to medium power range has improved greatly compared to the previous CR-V's powerplant - resulting in better throttle response at low engine speeds. The 2001 CR-V engine produced 146-horsepower at 6200 rpm and 133-lb.-ft. of torque at 4500 RPM.

i-VTEC VALVE CONTROL SYSTEM
The Formula 1 racing derived Variable Valve Timing and Lift Electronic Control (VTEC) system delivers abundant low-rpm torque, exhilarating high-rpm power and outstanding fuel efficiency. On the all-new 2002 CR-V, Honda unveils the latest version of this remarkable engine system: i-VTEC. The "intelligent" i-VTEC system adds new VTC (Variable Timing Control) to VTEC to provide continuously variable camshaft timing - taking the concept of variable valve timing to new heights. In short, i-VTEC = VTEC + VTC. Not only does i-VTEC provide a substantial performance increase across a broad power band, it boosts fuel economy while also reducing engine emissions.

VTEC (Variable Valve Timing and Lift Electronic Control)
Honda's innovative VTEC system is able to adjust the lift and opening duration of the valves to help the engine produce both abundant low-rpm torque and excellent high-rpm power. At low rpm, VTEC adjusts valve timing and lift for optimum cylinder filling. In addition, the timing of the intake valves is staggered and their lift asymmetric - creating a swirl effect within the combustion chambers. The result is increased burn speed with improved combustion stability. As engine rpm builds, VTEC transitions to a high-lift, long -duration cam profile for improved high-rpm engine output.

The 160-horsepower CR-V employs a new version of VTEC and applies variable timing and lift to the intake valves. The system uses two roller arms per pair of intake valves. During low rpm operation, intake air is drawn almost exclusively through the primary intake valve, thereby creating a very strong swirl effect to maximize combustion. At higher rpm, the secondary rocker arm engages the primary roller causing both intake valves to open for the same lift and duration, substantially increasing airflow into the cylinder and boosting performance. When combined with VTC, a remarkably broad and smooth power band is produced with exceptional torque and horsepower.

VTC (Variable Timing Control)
The new i-VTEC system adds a new camshaft VTC (Variable Timing Control) system to VTEC for continuously variable camshaft phasing across the engine's entire power band. As engine rpm builds, a VTC actuator--controlled by an engine-control unit that monitors cam position, ignition timing, exhaust-gas oxygen content and throttle position--advances or retards the intake cam throughout the 50 degree range, optimizing engine output and reducing emissions.

During typical operation, the intake camshaft timing is almost fully retarded at idle to help provide more stable idling while reducing exhaust emissions, especially NOx. The reduced levels of NOx helps qualify the CR-V in the more stringent LEV-2 category. As rpm increases, the intake camshaft is advanced, opening the intake valve sooner and providing additional valve overlap.

This results in increased fuel economy (by reducing pumping losses) and a further reduction in exhaust emissions (by creating a large, internal exhaust gas re-circulation effect). Also, to generate additional power throughout the rev range, the intake camshaft is continuously varying the amount advance or retard, instantly adjusting to provide additional power.

Cylinder Head/Valvetrain
The CR-V engine uses an aluminum cylinder head and a double overhead cam, four-valve-per-cylinder valvetrain. A generous "squish" area around the combustion chambers yields increased gas turbulence for faster flame propagation and excellent efficiency. The camshafts are operated by a silent-chain drive that helps provide smooth, refined performance while also being maintenance-free.

Engine Block/Crankshaft
The CR-V engine features a compact aluminum block with cast-in iron liners--a design known for its light weight, high rigidity, and excellent durability. The block has a one-piece aluminum crankshaft carrier that has ferrous-carbon inserts in the bearing caps for additional strength. The crankshaft is a highly rigid, forged-steel design that uses a special micro-polished surface finish for reduced friction and increased durability.

Programmed Fuel Injection (PGM-FI)
The CR-V engine is equipped with a Programmed Fuel Injection (PGM-FI) system. The system monitors such variables as throttle position, engine temperature, intake-manifold pressure, atmospheric pressure, exhaust-gas oxygen content, and intake-air temperature. It controls fuel delivery with four newly developed, multi-holed injectors. The ECU also tracks the operation of the engine with position sensors on the crankshaft and both camshafts.

Exhaust System
The CR-V has a newly designed, stainless steel, low heat-mass exhaust system. The system employs a high-density catalytic converter for improved light-off performance and reduced hydrocarbons and NOx. Emissions performance is further improved thanks to the engine's new design, which positions the exhaust manifold on the rear of the engine--which shortens the distance that the exhaust gases must travel to the catalytic converter, resulting in faster light-off and more complete conversion of the exhaust gases. A resonator before the muffler is also used to further reduce engine noise.

Engine Noise Vibration and Harshness Control
In addition to the CR-V's outstanding power and response, the engine has been engineered for class-leading smoothness and refinement. To that end, the 2.4-liter four-cylinder employs such NVH-reducing features as highly rigid, ferrous-carbon inserts in the main bearing caps for added rigidity, a one-piece crankshaft carrier, a silent chain cam drive and a balancer shaft (integrated with the oil pump). Four engine mounts (two liquid-filled) and reinforcements in the engine compartment help further reduce engine noise and vibrations.
 
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