VRIS



  • On my K8 at 2/3 rds throttle about 4500 rpm you could feel the vris cut in and the engine would pull more, even the exhaust note changed slightly.

    Since i have installed the KLZE i have tried to replicate this but it doesnt seem to cut in. I have checked the pipes for splits, and the valves are not seized, i can even rev the car from under the bonnet and watch them open and shut.

    Is there another way to test other than a dyno day? Or is the power curve on the KLZE softer at peak revs?

    Please help i am now concerned i am not getting full potential :lol:



  • it is on the ecu
    witch one you running
    the kl36 has the beter vris points



  • I have the JDM KL31. :shock:



  • i think thats the way they are
    kl36 for beter vris points
    kl31 for longer power curv



  • Thank you for ya speedy answers, i have to admit the power curve does feel nice and long and smooth.

    LOL my girlfriend just re read my post and i noticed how the end sounds.

    :lol: :lol: :lol: :lol: :lol:



  • lol yeh
    you have a difrent dizzy to me so there must be 3 types
    as i have 2 difrent types



  • Ya must admit that power spike is unreal in the #K8. Seriously going to go for the KL36 to replicate that feeling, as said in a previous post,

    'It's like a 50 shot of NOS'

    So true. But what excatly are the VRIS points and their function. Are they pressure regulators for the fuel injection line? if so why is their two of them???

    But Mechanic Marco was telling me that for the straight neck KLZE you would need the KL36 to match VRIS points as the 'Chipped Probinator K* ECU only matches the mellina curved neck manifold KLZE.



  • Originally Posted by Mike94PGT
    Imagine a turning fork and a speaker, side by side. Connect the speaker to a audio signal generator that sweeps from 20Hz to 20000Hz. Turn on the generator and crank the volume up, pointing the speaker at the tuning fork. Slowly wind the generator from 20Hz up…

    When the frequency of the signal generator gets close to the frequency written on the side of the fork, it will start to vibrate. When the frequency of the generator matches that of the fork, it will vibrate alot and the system is said to be in "resonance". As the frequency moves on past the resonance frequency, the fork will stop vibrating again.

    Now consider a flute: a hollow tube of specific length with holes placed strategically along it's side. If you blow across the end, you hear a note. If you change which holes are covered, you change the note that's played. What's happening is that the effective length of the flute is being altered by covering/uncovering the holes. This changes the natural frequency of the flute and thus the note you hear.

    In the engine's intake manifold, you've got a similar setup. The engine changing speed is equvalent to the change in frequency in the speaker example. The pulses of the speaker are similar to the pulses produced by the action of each cylinder's intake valves (and chamber pressures when the valve open etc...) The tuning fork might be considered to by the medium - the air in the runners in this case. As the engine runs through the RPM range, the intake valves open and close faster and faster as engine RPM increases, just like the speaker pulses faster and faster as the frequency dial is turned. The length of the runners, their volume, manifold pressure and temperature etc all determine at what frequency the air in the runners & surge tanks will resonate -- that is, vibrate just like that tuning fork.

    During times of resonance, the vibrating columns of air (which, though moving, still can support a standing wave) can actually help charge the cylinders. A vibrating column of air has dense sections and rarefied (low pressure) sections. If the standing wave is just right, a dense section of air meets the valve just as it opens. The denser air pours into the port, moreso than if resonance (and thus this standing wave) wasn't happening. The effect is a very mild "supercharging".

    But the engine RPM is always changing. If there was only one runner length, there would only be one resonance point. Mazda makes the manifold like a flute that can resonate at several wavelengths by making the runners have variable effective lengths. They do this by using butterfly valves in the manifold to direct air a "long way" or a "short way" (#2 is primarly responsible for this). Closed, the path is "long" and the primary resonance frequency is low. Open, the path is short and the primary resonance frequency is higher. By further changing the frequency in each surge tank (by opening or closing #1 valve, which exposes the each bank to the others' intake pulses, effectively doubling the frequency each surge tank sees), they manage to get several points at which good standing waves are set-up through the RPM band.

    In the KL03, the VRIS (variable resonance intake system) plates are controlled by the PCM, which is looking at engine RPM and loading (throttle angle) to know when to open the valves. #1 opens at 3250, which doubles each surge-tanks' frequency. #2 opens at 4250 which then shortens the average path length by 1/2. At 6250, both valves close.

    This 6250 point is a bit of a let down. The natural tendency would be to further shorten the path length but the realities of aluminum casting (driven by packaging and cost concerns) rears its head: there's no provision to make things even shorter. The only recourse they have is to revert to the longer path and lower frequency and rely on the 2nd-harmonic to provide a reduced-but-still-effective ram effect. It's a compromise and one of the things I dislike about the KL03 manifold.

    The North American I4 does not have this system, just the V6.

    BTW, people who get a KLZE but who don't upgrade their PCMs are getting hosed: the KLZE, with it's markedly different manifold, has different resonance points than the KL03. The PCM doesn't know this and switches the valves thinking it's an '03. Meanwhile, the ZE manifold never really has a chance to do its resonance thing properly because the PCM is stupidly flipping the valves at the wrong times.

    Also, people who remove or "tie" their VRIS are also hosing themselves. By disabling this feature, they're removing resonance points from the RPM band. Engine torque will suffer in the affected RPM areas and peak power will not climb. (Well, if someone completely removes the #2 valves & shaft, I suppose a bit might be gained from the removal of the restriction in the 4250-6250 range, but it won't be a huge gain and output will suffer everywhere else...)



  • Well…..... Thats it then lol. Leaving cert physics came rushing back. Very well explaned though.



  • Remember on a ZE the VRIS are supposed to open all the time, not just at full thottle, as in the DE engines.

    Another point, if you get a big kick on a DE engine at 4500, it's sometimes due to VRIS 1 being duff and only VRIS 2 working, there should be a slight increase, but a BIG one is usually due to the first solenoid not operating.



  • with one is first and second the litle one on the side and big one in the middle witch opens first ?
    and do they open if revs are slowly taken up when operateing it by the throtle body so you can see them ?



  • @add0206bb4=james:

    with one is first and second the litle one on the side and big one in the middle witch opens first ?
    and do they open if revs are slowly taken up when operateing it by the throtle body so you can see them ?

    Looking at the engine from the front of the car, 1 is left and 2 is right.

    I wouldnt do it using the TB.

    Put a bit of paper in the 'end stop' (closed position) and go for a drive, if the paper is still there, they didnt open.



  • kl31 and kl36 have the same affect on the klze - they have the incorrect vris points… the best option is to get a chip from probinator to modify a k8 ecu - this is the best option hands down.

    also what intake are you using? stock k8 or curved neck?



  • Mooneggs dont think thats right. the KLZE comes with 3 diff type of intake manifolds.

    1. The Millina circular manifold (with the V6 24 Valve sticked)with the cuved neck to the trottle body. Thats works well with the chipped MX3 K8 ECU. VRIS points match up.

    2. The MX6 Flat manifold with the curved neck to the Trottle body.
      Thats works well with the chipped MX3 K8 ECU. VRIS points match up.

    3. The MX6 Flat manifold(with the V6 24 Valve sticked) with the straight neck works best with the KL36or KL31 ECU(jap ECU only). THe VRIS points match up here.

    It's so so so important you know what type of engine u have. If you dont match the right engine to the right ECU your not going to get VRIS points, so no semi supercharging, no 200BHP



  • Using the KL31 ECU, with the JDM KLZE… this is the inlet i have think its the MX6 one.



  • ya thats the manifold im after too. getting it soon, very soon.

    does the KL31 ecu match the VRIS points?
    I thought the only diff between the kl36 and kl31 ecu from the import mx3 was that kl31 only did manual transmittions and the kl36 did both manual and automatic?



  • @a4c7f81ae2=MDM_MX3:

    does the KL31 ecu match the VRIS points?

    I think so, doesn't feel as much as a kick as the K8 did when the VRIS comes in but feels alot longer and smoother power band. Got to get it on a riolling road really to see.



  • stupid question here what is vris???



  • Na man not stupid at all.

    Mazda mad a manifold with an idea in mind. this idea was to use the different lengths of runners(the part of the intake going into a particual section of the engine) as a way to resenate the air to produce high pressure, dense pockets or waves(occilations) of air to flow into the cyclinder producing a mild supercharging effect at certain RPM ranges.
    The long discription that mechanic posted explaines it very well.

    The natural physics behind it is that every object including living ibjects have a natural fequency. when this certain fequency is produced by a speaker or source it causes the atoms(that make up that particular object) to vibrate. this is called resonance.

    now in physics if you can vibrate air, (resonate air), you cause a build up of pressure as these atoms are bouncing around like made trying to vibrate more and more. as they do this in an enclosed area(the runners of the intake manifold) pressure builds up and hense causes the same affect as a supper charger of a car.

    Higher intake air pressure into the cyclinder= more fuel required to burn all air = more power.

    the flute effect explained in the previous page is discribing how two actuators open different ports in the intake manifold causing a difference in fequency. go ahead if u have the V6 MX3 and pull the trottle cable whild the engine in running. you'll see one actuator open first then the second at the higher rpm.

    Its just to keep this effect when doing an engine chance you need the right computer(ECU) to tell the actuator to open on the right RPM as different length of intake manifoldhave different harmonics.

    And Hormonics are for a different day lol.

    Long peice…....i need money to pay more attention to my car lol.

    Hope it helps



  • would that explain the flat spot at 4300 rpm??? oh and ya can have those bumpers mate!


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