What is it about say the 200hp K20 in the rsx type s and the newer civic si, or the 195hp B18 in the last US incarnation of the ITR that allows them to make so much top end without sacrificing drivability?
Take the 2.2 eco in the cav for example: it beats both of the above by at least ten percent in displacement, and has a healthy-breathing DOHC valvetrain. So why does it fall 60 hp behind? Is it cam profile, or head design, or is it all about VVT and tuning, or a combination of all?
Take a more "fair" comparison - the LE5 2.4 VVT eco. Something like 170hp with twenty percent more displacement vs the K20.
Basically, I'm wondering what honda does that GM is not with their DOHC style engines. By rights, the LE5 should easily put out 200-220hp n/a. (Hell honda's K24 puts out 200hp IIRC)
good question i would like to know as well
It is the cam profiles and timing mixed with higher revving engines. They are designed to run high hp at high RPMS with very low torque. Where as our ecotec motors have cam profiles and timing that dont sacrafice TQ for HP.
I prefer to have the torque.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
So you would say its strictly cam profile? What about head/TB/intake manifold combinations?
It makes sense what your saying, because I know ITR cams were like the "secret cam" swap of the B series...
Well the other thing that is different is that Honda uses a log style intake manifold. That also moves the powerband to the higher rpms. Where as our cars use a equal length runner manifold. That gets you to your power band quicker and is less peaky.
That is another reason why the 2.4 guys swap to the old 2.3 manifold (it was a log style).
So if you were looking to get your ecotec to run like an N/A honda you could. It would cost more in the long run then it would to just turbo your car.
List of mods you would need to put about 200 to the wheels N/A:
Head: P&P, stage 3 street cam, dual valve springs, SS valves, Ti retainers, bronze guides...(fully built head)
Intake manifold: Log style from GM w/ 75mm TB or log style from Hahn racecraft or swap to the 2.4 ecotec intake manifold (it is runner style just better flowing)
Fuel: Fuel pump, injectors (450cc), FPR
Spark: MSD Dis 2
Then to make it all work and to tune it you would need to go with a stand alone. So Mega Squirt or something more expensive. HP Tuners will only let you go up to about 8000rpm. With a stand alone and MSD dis2 you can make it rev to about 9500rpm before the bottom end pops.
Or buy just the Hahn stage 2 turbo kit and get the same power and call it a day.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
umm did you guys forget these engines have very high compression and thats a big part of the equation
basically this is how it goes
high compression + high revs + aggressive cams = high hp
vtec is manly there to help with driveability and fuel efficiency
Yes I did forget about that.
He is correct they also have high compression. Hondas are usually 11.0:1.
This can be achieved in the ecotec in two ways. 1. Ask Cometic to make you a mls gasket that is thinner than stock. 2. Go oldschool and have the head shaved by a machine shop.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
It's never a good idea to use a thinner than stock head gasket on a performance engine. To safely raise compression, it's my opinion that a domed style piston should be used. If you're going to build a performance engine, at least build one that is reliable.
The largest difference between a normal 4 cylinder and a B-series or K20A, is VTEC.
The Vtec camshafts use 3 lobes per cylinder. Each camshaft serves as having two completely different cams in one engine. The two outer lobes are a mild profile used for normal driving, and the middle camshaft profile is essentially a "race only" cam profile (much higher lift than anyone here uses). At a certain rpm, a solenoid is switched that uses oil pressure to lock this bar that no longer allows the smaller lobes to open the valves, and the engine runs purely on the "race cam" profile. That is why Hondas can make some of the highest NA 4 cyl horsepower and rev to the skys while still remaining streetable. If other manufacturers were allowed to adopt this technology, a Honda wouldn't be anything special...But Honda has a patent on this, so only they can use it.
Darryn DiSanto wrote:Yes I did forget about that.
He is correct they also have high compression. Hondas are usually 11.0:1.
This can be achieved in the ecotec in two ways. 1. Ask Cometic to make you a mls gasket that is thinner than stock. 2. Go oldschool and have the head shaved by a machine shop.
Darryn
The correct way to raise compression in a OHC engine is by changing the piston shape. Otherwise, you will lead to problems with skipping timing. On an OHV engine it's fine because all of the timing components are below the head.
EDIT: And VTEC isn't VVT. VVT involves changin the timing of the cams. VVT usually retards the cams through oil pressure to allow more top end horsepower. However, I believe the new i-VTEC motors do both VTEC and VVT.
Edited 2 time(s). Last edited Thursday, December 06, 2007 9:15 AM
-
"Youth in Asia"...I don't see anything wrong with that.
^ also true.
Point being... TURBO your ecotec and F honda.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
Darryn DiSanto wrote:Yes I did forget about that.
He is correct they also have high compression. Hondas are usually 11.0:1.
This can be achieved in the ecotec in two ways. 1. Ask Cometic to make you a mls gasket that is thinner than stock. 2. Go oldschool and have the head shaved by a machine shop.
Darryn
The LE5 already has 10.5:1
CHM wrote:Darryn DiSanto wrote:Yes I did forget about that.
He is correct they also have high compression. Hondas are usually 11.0:1.
This can be achieved in the ecotec in two ways. 1. Ask Cometic to make you a mls gasket that is thinner than stock. 2. Go oldschool and have the head shaved by a machine shop.
Darryn
The LE5 already has 10.5:1
You beat me too it. I figured it had to be a combination of things, not just compression or just VVT. Maybe GM's most aggressive profile is still pretty wimpy?
Wouldnt going thinner than stock HG net only a very small increase in CR? I mean, you can see the difference between say a 9:1 piston vs a 12:1 piston for a given engine. I would think you would have to go with thinner HG and shave the head significantly to get any appriciable gain in CR.
Quote:
VTEC
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For the education institution, see Virginia Tech.
VTEC (Variable Valve Timing and Lift Electronic Control) is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. This system uses two camshaft profiles and electronically selects between the profiles. This was the first system of its kind. Different types of variable valve timing and lift control systems have also been produced by other manufacturers (MIVEC from Mitsubishi, VVTL-i from Toyota, VarioCam Plus from Porsche, VVL from Nissan, etc). It was invented by Honda R&D engineer Ikuo Kajitani.[1] It can be said that VTEC, the original Honda variable valve control system, originated from REV (Revolution-modulated valve control) introduced on the CBR400 in 1983 known as HYPER VTEC.[2].
http://en.wikipedia.org/wiki/VTEC
here is a history lesson...
http://en.wikipedia.org/wiki/VVT
Quote:
VVT
History
Fiat was the first auto manufacturer to patent a functional variable valve timing system which included variable lift. Developed by Giovanni Torazza in the late 1960s, the system used hydraulic pressure to vary the fulcrum of the cam followers (US Patent 3,641,988). The hydraulic pressure changed according to engine speed and intake pressure. The typical opening variation was 37%.
In September 1975, General Motors patented a system intended to vary valve lift. GM was interested in throttling the intake valves in order to reduce emissions. This was done by minimizing the amount of lift at low load to keep the intake velocity higher, thereby atomizing the intake charge. GM encountered problems running at very low lift, and abandoned the project.
Alfa Romeo was the first manufacturer to use a variable valve timing system in production cars (US Patent 4,231,330). The 1980 Alfa Romeo Spider 2.0 L had a mechanical VVT system in SPICA fuel injected cars sold in the USA. Later this was also used in the 1983 Alfetta 2.0 Quadrifoglio Oro models as well as other cars.
Honda's REV motorcycle engine employed on the Japanese market-only Honda CBR400F in 1983 provided a technology base for VTEC.
In 1986, Nissan developed their own form of VVT with the VG30DE(TT) engine for their Mid-4 Concept. Nissan chose to focus their NVCS (Nissan Valve-Timing Control System) mainly at low and medium speed torque production because the vast majority of the time, engine RPMs will not be at extremely high speeds. The NVCS system can produce both a smooth idle, and high amounts of low and medium speed torque. Although it can help a little at the top-end also, the main focus of the system is low and medium range torque production. The VG30DE engine was first used in the 300ZX (Z31) 300ZR model in 1987, this was the first production car to use electronically controlled VVT technology.
The next step was taken in 1989 by Honda with the VTEC system. Honda had started production of a system that gives an engine the ability to operate on two completely different cam profiles, eliminating a major compromise in engine design. One profile designed to operate the valves at low engine speeds provides good road manners, low fuel consumption and low emissions output. The second is a high lift, long duration profile and comes into operation at high engine speeds to provide an increase in power output. The VTEC system was also further developed to provide other functions in engines designed primarily for low fuel consumption. The first VTEC engine Honda produced was the B16A which was installed in the Integra, CRX, and Civic hatchback available in Japan and Europe. In 1991 the Acura/Honda NSX powered by the C30A became the first VTEC equipped vehicle available in the US. VTEC can be considered the first "cam switching" system and is also one of only a few currently in production.
In 1991, Clemson University researchers patented the Clemson Camshaft which was designed to provide continuously variable valve timing independently for both the intake and exhaust valves on a single camshaft assembly. This ability makes it suitable for both pushrod and overhead cam engine applications.[1]
In 1992 BMW introduced the VANOS system. Like the Nissan NVCS system it could provide timing variation for the intake cam in steps (or phases), the VANOS system differed in that it could provide one additional step for a total of three. Then in 1998 the Double Vanos system was introduced which significantly enhances emission management, increases output and torque, and offers better idling quality and fuel economy. Double Vanos was the first system which could provide electronically controlled, continuous timing variation for both the intake and exhaust valves. In 2001 BMW introduced the Valvetronic system. The Valvetronic system is unique in that it can continuously vary intake valve lift, in addition to timing for both the intake and exhaust valves. The precise control the system has over the intake valves allows for the intake charge to be controlled entirely by the intake valves, eliminating the need for a throttle valve and greatly reducing pumping loss. The reduction of pumping loss accounts for more than a 10% increase in power output and fuel economy.
Ford became the first manufacturer to use variable valve timing in a pickup-truck, with the top-selling Ford F-series in the 2004 model year. The engine used was the 5.4L 3-valve Triton.
In 2005 General Motors offered the first Variable Valve timing system for I-head V6 engines, LZE and LZ4.
In 2007 DaimlerChrysler became the first manufacturer to produce a cam-in-block engine with independent control of exhaust cam timing relative to the intake. The 2008 Dodge Viper uses Mechadyne's concentric camshaft assembly to help boost power output to 600 Bhp.
enjoy.
1997 RedR - ZedR
oldskool wrote:CHM wrote:Darryn DiSanto wrote:Yes I did forget about that.
He is correct they also have high compression. Hondas are usually 11.0:1.
This can be achieved in the ecotec in two ways. 1. Ask Cometic to make you a mls gasket that is thinner than stock. 2. Go oldschool and have the head shaved by a machine shop.
Darryn
The LE5 already has 10.5:1
You beat me too it. I figured it had to be a combination of things, not just compression or just VVT. Maybe GM's most aggressive profile is still pretty wimpy?
Wouldnt going thinner than stock HG net only a very small increase in CR? I mean, you can see the difference between say a 9:1 piston vs a 12:1 piston for a given engine. I would think you would have to go with thinner HG and shave the head significantly to get any appriciable gain in CR.
Reread what I wrote...
Brian Whalen wrote:The largest difference between a normal 4 cylinder and a B-series or K20A, is VTEC.
The Vtec camshafts use 3 lobes per cylinder. Each camshaft serves as having two completely different cams in one engine. The two outer lobes are a mild profile used for normal driving, and the middle camshaft profile is essentially a "race only" cam profile (much higher lift than anyone here uses). At a certain rpm, a solenoid is switched that uses oil pressure to lock this bar that no longer allows the smaller lobes to open the valves, and the engine runs purely on the "race cam" profile. That is why Hondas can make some of the highest NA 4 cyl horsepower and rev to the skys while still remaining streetable. If other manufacturers were allowed to adopt this technology, a Honda wouldn't be anything special...But Honda has a patent on this, so only they can use it.
Darryn DiSanto wrote:Yes I did forget about that.
He is correct they also have high compression. Hondas are usually 11.0:1.
This can be achieved in the ecotec in two ways. 1. Ask Cometic to make you a mls gasket that is thinner than stock. 2. Go oldschool and have the head shaved by a machine shop.
Darryn
The correct way to raise compression in a OHC engine is by changing the piston shape. Otherwise, you will lead to problems with skipping timing. On an OHV engine it's fine because all of the timing components are below the head.
EDIT: And VTEC isn't VVT. VVT involves changin the timing of the cams. VVT usually retards the cams through oil pressure to allow more top end horsepower. However, I believe the new i-VTEC motors do both VTEC and VVT.
-
"Youth in Asia"...I don't see anything wrong with that.
Vtec is over rated, Vanos FTW
Like Brian said, the reason VTEC engines can make so much more top end power is because they quite literally change from a tame, street friendly, emissions legal cam profile to a high performance racing cam at a set RPM point. The VVT in the LE5 only changes the cam timing, it does not change the actual lift and duration of the cam like VTEC does.
To put it simply... A stock ecotec makes 140 hp. Say with a set of Comp Cams Stage 3's, it makes 180 (just pulling this figure out of my ass, don't put any actual stock in it). If the eco had VTEC, it would be like having the magical horsepower genie swap the cams from stock to the Stage 3's at say 4500 rpm.
The reason they can get away with this is that 99% of emissions laws only govern emissions from idle to 3000 ish rpm, because thats where the average engine owned by the average person spends most of its time. This is how the Honda engines can maintain Ultra Low Emission Vehicle standards and still out-horsepower pretty much every NA 4 cylinder out there, they use the wimpy ass emissions and economy friendly profile below 5000 rpm, and switchover to the aggressive cams at WOT at 4500-5500 rpm. Its really an ingenius system, especially when you consider that its been around since GM was just starting to introduce overhead cam 4 cylinders to the mass market (and no, before someone says it, the cosworth vega does not count).
Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said
lots not forget though...
vtec generally increase the PEAK hp. if you look at the power curves, an engine equiped with vtec is a gutless wonder until that cam swap is ingaged, and alot of times still remains a gutless wonder after.
1997 RedR - ZedR
Vtec is the best when you use Hondata's reflash and lower it to 5kRPM so you use it more often
Proud member of Jbody of Kentucky ... Click on sig to go!
JoeyDaBomb wrote:Vtec is the best when you use Hondata's reflash and lower it to 5kRPM so you use it more often
thats generally because you have done other modifications to it already, like making it breath better. without modifications like thay, it wont see as much of a benefit by lowering it that 1000 rpm.
1997 RedR - ZedR
whitegoose( RedR-ZedR) wrote:JoeyDaBomb wrote:Vtec is the best when you use Hondata's reflash and lower it to 5kRPM so you use it more often
thats generally because you have done other modifications to it already, like making it breath better. without modifications like thay, it wont see as much of a benefit by lowering it that 1000 rpm.
You see the power faster, it's not about adding power as much as it is moving your powerband down to a better range where you will see it quicker and more often.
Proud member of Jbody of Kentucky ... Click on sig to go!
