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Thread: The Facts - Vectra 'c' mods

  
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    johno johnson's Avatar
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    The Facts - Vectra 'c' mods

    having read many debates regarding the Vectra 'c' mods i would like to pass on some facts surrounding this modification, after talking to a family friend who has worked for Vauxhall technical for 18 years.
    Vauxhall spend millions on each vehicle they develop and were one of the first manufacturers to actually fit the air inlet pipes to the front of vehicles to ensure cold air feed. no matter how big the air scoop is, the AFM/ECU and cubic capacity of the engine will determine how much air is used and for ideal combustion this will be 14.7 parts(by weight) of air to 1 part fuel. The stock pipework is made such that it allows good linear/smooth airflow with good cold air feed from the front of the car to enter the inlet manifold quickly and without disruption. derestricting the airbox for more power is a myth and only serves to louden the induction noise and actually reduce the RAM effect that was there in the first place, it also upsets linear flow. The main thing is to have a cold dense air flow feeding the inlet manifold with as least disruption as possible. Which is exactly what Vauxhall have done with the stock tubing. So original airbox and pipework with a decent panel filter... job done and hard earned pennies stiil in your pocket.

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    KevT.'s Avatar
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    but when people are using bigger pipe work and different air box's then this is a worth while mod and for the £13 it costs its got to be a bargin!

    AOC top 15 car at PVS 2009 & 2010
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    The thing is though mate is that most people don't do the veccy c mod to increase the power of their cars but to increase throttle response and it does seem to make a bit of a difference on mine.

    Interesting facts though and I'm sure more will be along soon to add their own thoughts!
    Europa Blue cabriolet turbo...now with VXR turbo, collins dump valve and a large number of Courtenay hoses

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    So why did they put on the same diameter intake pipe on the 1.4 N/A engined astras as the 2.0 Turbo???? surely that needs access to more air

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    Cos making lots of different sizes costs money...
    1.9 cdti (120) black ASH
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    Cheers, but I have to reply ....

    Vauxhall make and develop their cars and engines to fit a general demographic of a mass market - FACT
    Vauxhall do NOT develop their cars specifically for the minority of modifiers (such as AOC etc) - FACT

    So, if changing the airflow characteristics by de-restricting makes it 'noisy' then of course vauxhall will not do it as standard, BUT doing this modification DOES improve throttle response. I know, I have driven before and after within minutes of the mod, and noticed the change.

    Ask your mate about the inlet flow after the air exits the airbox..... and ask why it's so long and complicated - answer is to restrict power so that classes of engines fit into the proper sales bracket / and other reasons.

    There are many compromises made by vauxhall, although it's only us that want power and performance that see them as compromises.....
    Just be thankful that they are there, so that we can have fun changing them to suit !

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    Quote Originally Posted by johno johnson View Post
    derestricting the airbox for more power is a myth
    Correct - I don't think that anyone with an ounce of understand of how engines work would dispute that fact. Can't speak for those that don't tho

    De-restricting the air box along with the Vectra C inlet is purely done to ease the passage of air into the engine. You even state the benefit yourself...
    Quote Originally Posted by johno johnson View Post
    The main thing is to have a cold dense air flow feeding the inlet manifold with as least disruption as possible.
    That's what desrestricting the air box and Vectra pipe actually do

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    this is correct Ffoeg, but why change the flared inlet pipe for the Vectra 'c' pipe when it the same length as the stock Astra part and has no more or less restriction in it than the Vectra 'c' inlet pipe and they both connect to the same size elbow pipe that feeds to the base of the airbox. No matter how much air you think you may squeeze in, they both reach the same restriction at this elbow. I stated that the main need is to feed dense cold air to the air box and where as i am sure the Veccie 'c' pipe does this, so does the original pipe and equally as well if not better due to it's flared mouth. Just look at throttle boddies etc, they all have flared mouths to help draw air and create a funnelled RAM effect, something the Veccie pipe does not have. I am not judging this Modification, good or bad but merely passing on info that was given to me as there has been much debate here about it and from some of the latest threads i have been reading a few people are reversing this Mod and finding that their cars are actually responding better to the stock system. it is all down to personal taste.

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    if u dont like it then dont fit it - simple

    thousands of Vauxhall owners across the globe have fitted larger intake pipes and have proven gains (not to be mistaken for power gains) and are therefore happy with this improvement

    You can argue as much as you wish but the fact so many ppl have noticed an improvement is enough in most peoples minds to warrant such a modification.

    So have you tried this yourself or is all this "info" based on your "friend" ?


    I couldnt care less either way as I dont have a standard or Vectra intake or mine - I have in the past and noticed a definite improvement, just wondering what your genuine intention of this thread is?

    I hope this is just a one-off and not an ongoing argument ala fdrightup and his similar posts

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    I noticed the airbox mod made a difference to throttle response minutes after doing the mod. However when I fitted the Veccy C pipe a week later, i felt that some of the responsiveness was lost. I also had a K&N panel in at this point. Earlier this morning I switched back to the original intake and the punch is back! :P

    but, everyone to their own, whatever works best - works.
    EUROPA BLUE COUPE

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