General Info about 03 cl7

Discussion in '7th Generation (2003-2008) [Acura TSX]' started by hsyasin, Wednesday 8th Oct, 2014.

  1. hsyasin Valued Contributor ★ ★ ★ ☆ ☆

    United Kingdom Hammad Bury St. Edmunds
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    Hey guys, is this true for our uk based Accords, i found on wiki
    K20A6
    • Found in:
      • 2003-2006 Honda Accord (European)
        • Displacement: 1,998 cc (121.9 cu in)
        • Compression: 9.8:1
        • Bore x Stroke: 86 mm x 86 mm
        • Torque: 190 Nm @ 4500 rpm
        • Power: 155hp @ 6000 rpm
        • Redline: 6800 rpm
        • i-VTEC: 2500 rpm
    I thought i read somewhere that i-VTEC gets engaged around 5500rpm :Unknown:and also, why is the redline limited to 6800rpm where we've RPM meter going upto 8000
     
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  2. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    I think i-VTEC is always engaging but I believe with my K24 engine the main VTEC engagement is at 6,000rpm.
     
    Last edited: Wednesday 8th Oct, 2014
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  3. DeviateDefiant Co-Founder Staff Team

    United Kingdom Leo Northants
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    Yes that's correct for the Pre-Facelift 2.0. The dash is shared between all the petrol variants (with two different colour schemes for each Pre/Facelift), the K24A3 revs to 7200rpm stock, the K20A Euro-R to 8600rpm.

    VTEC engages when VTEC engages not all the time :Smile: i-VTEC has an adjustable VTC gear to retard/advance the intake camshaft as opposed to the original VTEC implementation which just swapped between two cam profiles.

    EDIT: VTEC is 6800rpm on the K24A3/CL9 btw.
     
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  4. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    You'll need to update wiki then! lol
     
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  5. DeviateDefiant Co-Founder Staff Team

    United Kingdom Leo Northants
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    Well, I wasn't sure how to interpret your post. i-VTEC is always utilised as its just part of the way the engine operates, same could be said for the original VTEC system, but when the high cam comes in is still what people refer to as the "VTEC" point itself.
     
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  6. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Sorry, was confusing the RPM for max. torque. It's showing as being 6,000rpm but although the i-VTEC is always working something definitely happens at 6,000rpm as I'm sure the dyno graphs reflect this plus you can hear the difference and feel it.

    Check out this graph, you can see the power start to level off but then at 6,000rpm it starts increasing again.

    19407ACC_K24A_BMENCIG_SENICA_21042004.


    Here's a link to the thread: Dyno test of My Honda Accord 2.4 '04 - 190PS - AcuraZine Community

    Also from Wiki:

    K24A3[edit]
    Found in:
    2003-2007 Honda Accord (Europe) and Japan (JDM) and 2003-2007 Honda Accord Euro CL9 (Australia, New Zealand)
    • Displacement: 2,354 cc (143.6 cu in)
    • Bore and Stroke: 87 mm x 99 mm (3.43 x 3.90 inches)
    • Compression: 10.5:1
    • Power: 189 hp (140 kW) @ 6800 rpm
    • Torque: 164.5 lb·ft (223;N·m) @ 4500 rpm
    • VTEC Engagement: 6000 rpm
    • Redline: 7200 rpm

    But it did always confuse me how there could be a main VTEC engagement with i-VTEC?
     
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  7. DeviateDefiant Co-Founder Staff Team

    United Kingdom Leo Northants
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    Deleted my previous post. I think you're misinterpreting what I'm saying. VTEC comes in at 6800rpm, there's VTC/cam advance control all the time, the power dip you see is from the stock map (I've covered that in more detail on my project log).
     
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  8. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    So with i-VTEC is there still a point where the high cam comes in?
     
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  9. DeviateDefiant Co-Founder Staff Team

    United Kingdom Leo Northants
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    Yes the VTEC engagement point. I'm writing on a tablet at the moment while munching, I'll try explain it better at the PC later :Smile:
     
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  10. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Cool, I think it's terminology that's confusing things here lol
     
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  11. hsyasin Valued Contributor ★ ★ ★ ☆ ☆

    United Kingdom Hammad Bury St. Edmunds
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    nice conversation here :GoodJob:
     
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  12. DeviateDefiant Co-Founder Staff Team

    United Kingdom Leo Northants
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    Sorry I was shattered earlier and reading it back I didn't pick my words very well :Laughing:

    VTEC effectively engages a high-lift cam profile (what people tend to refer to as the "high cam") at a set point, otherwise it runs on the "low cam" which the car idles, and drives at lower RPM with. The high cam is about making power, the low cam about smooth idle, good fuel economy and fairly balanced torque to keep the low-end smooth. When the high cam comes in tends to be called the VTEC "crossover", "point" or "engagement". On the earlier VTEC engines, the D/B/F/H-Series this quick swap between cam shaft profiles at the "crossover" lead to a pretty big torque surge, with a change in the engine tone to match.

    VTC is an actuator/cam pulley that sits at the end of the intake camshaft, it continually retards/advances the camshaft to optimise the engine output and emissions. At low RPM it's almost fully retarded to allow for a smoother idle, as you move throughout the rev range the camshaft is advanced further which opens the intake valve sooner increasing valve overlap, that improves fuel economy by reducing losses from the injectors, and kinda recreating an internal EGR effect also improving emissions. Effectively, more fuel gets combusted and less injected down the exhaust ports. VTC is always in operation, as you drive along the retard/advance is optimised on the fly for the throttle position by the ECU (to set values from the map/tune).

    i-VTEC is a combination of VTEC and VTC.

    Both VTEC and i-VTEC still have a set point where the high cam comes in, the only difference is that the VTC adjusts the valve overlap at all RPM. i-VTEC isn't engaged all the time, VTC is always adjusting, the "VTEC" part of the system is still as it was before. The CL9 and CL7 Euro-R have this set-up, K24A3 and K20A, the latter is also found on the DC5R and FD2.

    Just to make things more confusing there's also VTEC-E, which basically just works on leaving 4 valves disabled and only activated at a set RPM.

    Some i-VTEC systems are actually just VTC + VTEC-E whereby there's no "VTEC crossover" or high camshaft profile whatsoever, just the valve "activation". Some call it i-VTEC-E and that's what where we find ourselves with the K20A6, "VTEC" is at 2500rpm however there's no high cam profile, it just re-activates 4 valves which were left redundant (12 valves below 2500rpm). The K20Z2 on the Facelift is likely the same though I haven't read up on it.

    To answer the original question:

    The reason the rev counter goes to 8600rpm on @hsyasin's K20A6 CL7 is that the K20A CL7 Euro-R revs to 8600rpm and shares the same dials.

    The reason the K20A6 only revs to 6800rpm is the lower compression ratio of 9.8:1, compared to the K24A3 at 10.5:1 and the K20A 11.5:1. ​

    If I have anything wrong or someone knows better, please feel free to chime in.
     
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  13. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    Sounds a pretty good explainantion to me mate
     
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  14. hsyasin Valued Contributor ★ ★ ★ ☆ ☆

    United Kingdom Hammad Bury St. Edmunds
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    Explained very nicely :GoodJob:
     
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  15. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Nice one, great explanation cheers!

    So what do diesels use?
     
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  16. DeviateDefiant Co-Founder Staff Team

    United Kingdom Leo Northants
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    Their engine be from a 'ractor.
     
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  17. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Aye but we get cool James Bond features like the "oil slick" and "soot cloud" for the dispersing of pesky high revving wasps buzzing behind us :BooYeah:
     
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  18. Nels Moderator Staff Team

    @DeviateDefiant IMHO, the explanation above need to be in the Technical Articles section so that we and others can find it in the future. :vtec:
     
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  19. DeviateDefiant Co-Founder Staff Team

    United Kingdom Leo Northants
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    I think that's a good shout mate, but I'd end up rewriting it a bit so it's not tailored so much to the Accord :Smile:
     
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