Well, I was at the track yesterday and chatting with Gerry from PRM about my next steps for what I'm doing to the car this winter. We got to speaking about boring the TB and then he started on about removing the VRIS plates completely, knife edging their pathways and all that.
If I remove the VRIS plates, plug the pin holes, knife edge and machine the pathways, what do I have to do with the VRIS sensors and electronics of it all? Do I have to do anything, and if so, what is it that has to be done?
Just keep the solenoids plugged in if you don't want to get codes 41, 42 i think. The only time your engine will benefit from this is 4000-6000 rpm, you'll get some more power, but you will loose it under 4000rpm
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Yeah, Gerry was telling me I'd lose power under 4000, but under WOT race situations I wouldn't really be under 4k anyways. So are you telling me I could leave all electronics in tact, and simply remove both plates, knife edge the ports and plug the pin holes?
oh.....alright. Thanks Sting, I appreciate the words of wisdom. I'll be sure to post how the whole thing went when I get around to doing it.
Is it true that you could port the IM too much??? I heard that there's a point where there's too much airflow, is that true?
Do not do it ... unless you are spraying or are under extreme performance mods, and the engines resonance induction is altered from that of the factory ...
mazda spent a great deal of time, depicting the air way travel through that IM, and if the engine's pistons creating the vacumm hasnt been altered enough, to a different point of resonancy than you will be hurting yourself ... So many people Do not understand the VRIS system ... at all ...
you have to understand what resonancy or resonant frequency is to understand ...
for example a tuning fork a 1khz, when placed in front of a speaker .. if that speaker is playing a 900hz tone, the fork wont do anything , but as soon as the speaker starts playing a 1khz tone, the fork will go nuts ...
another example is you can take a tube, with one end open ... and another end that is adjustable, making the tube adjustable in its length parameter...smack a tuning fork and place it next to the open end of the tube, then start adjusting the end, varying the length of the tube, and you will finally find a resonant spot, at which the audible tone of the fork will double in output decibels .. that is the resonant frequency of that tube, in that length ... what happens is that the soundwaves bounce back off the back of the tube, and head back towards the tuning fork, when you hit resonant frequency, the waves heading back, overlap perfectly with the waves heading in ... thus doubling the output of the tone ...
Im an audio guru, so I make alot of audio relations ... but air travel, Ie, air being drawn in as a vacumm, will have similar charcteristics, so by removings the Vris Plates, you will be changing the resonancy of the IM, and as the motor climbs in RPM's, the resonancy wont change as the plates open and close, and you WILL have Dead Spots ...
the best thing for you to do, is the make a vris controller, (Jeff Jeske has a system for this, he can tell you how,), and then dyno tune your car, while altering the open and close points ... you will have much better results ... but you wouldnt want to do this untill your done modding ...
Thanks Steve. It all makes sense except what I was told about porting in order to allow a better volume of air to pass through the IM. In boring the TB to 65mm (which is my next mod) don't you change the size of the frequency? Doesn't that throw the original Mazda calculations off? Is it more about frequency, or volume? In boring the TB, doesn't that improve airflow significantly by allowing more air, more quickly, and more efficiently?
I'm not disagreeing with your thoughts, I believe them to be quite accurate and I vaguely understand the theories behind audio frequencies, all to which you are very knowledgeable. But is the idea behind the intake system to allow a more effective air FLOW, or to provide the ultimate FREQUENCY of air?
I am definitely hesitant on the idea of removing VRIS plates at this point, but what about the idea of boring the TB to 65mm?
Originally posted by Diggler Thanks Steve. It all makes sense except what I was told about porting in order to allow a better volume of air to pass through the IM. In boring the TB to 65mm (which is my next mod) don't you change the size of the frequency? Doesn't that throw the original Mazda calculations off? Is it more about frequency, or volume? In boring the TB, doesn't that improve airflow significantly by allowing more air, more quickly, and more efficiently?
I'm not disagreeing with your thoughts, I believe them to be quite accurate and I vaguely understand the theories behind audio frequencies, all to which you are very knowledgeable. But is the idea behind the intake system to allow a more effective air FLOW, or to provide the ultimate FREQUENCY of air?
I am definitely hesitant on the idea of removing VRIS plates at this point, but what about the idea of boring the TB to 65mm?
close, but its not the systems design to just let more air flow, if it was about more air flow, then they butterfly would have never made it in there, its about air velocity and turbulence, as the engine climbs in RPM's, its going to alter the turbelence and velocity of the air entering the IM, while boring the TB, will change the velocity of air entering the IM, it will NOT change it so much that you would need a complete removal of the butterfly's, and the VRIS system, thats why designing a VRIS controller be optimum, I also believe it to be, that boring the TB, not effect it much at all, because its not really in the IM design ... while slightly more air will enter the TB, and The IM, its still going to be restricted to the passage ways that the IM has. now you were to get the IM ported, and/or extrued Honed that would be a different story ...
while your on the kick of getting more air into the engine, You should consider porting your heads, I noticed quite a nice gain, when doing this, and when you think about it, what point of redundancy to you get when trying to cram more air, into the IM/TB, when only so much can pass through the heads anyway ... ive spent a great deal of time thinking this concept over, and I believe the only way to achieve decent gains from mods of this sort, is to have them all done, one mod compliments another tremendously ...
in your case, Id try to snag a ZE IM, port it, port heads (exhaust and intake), build vris controller, open TB, exhaust, Test pipe, and of course CAI .... all of those combined, will have a good effect, and will transfer air in and out of the heads, allowing for decent gains of the motor ... But keep your VRIS system in tact, because nothing short of extreme motor work, is going to want it to be removed ....
Read some things that Mike94PGt has posted about VRIS, he has a much better understanding about it than I do, (he has a much better understanding of everything than I do... ) there was a good thread about a week ago, where me, him and Jeff Jeske was talking about VRIS ... Also Im gonna try and dig up a good post on PT, where someone explains Air turbulence, and velocity whithin an exhaust system ... same principal applies for an Intake ...
I found the thread on PT, Ill cut and paste the article here, originally posted by Adrag10 on PT ... its about exhaust but similar principals apply about air velocity, ect.
Quote:
There seems to be this misconception floating around that backpressure helps create low end power or torque. This is generally based on personal experience or word of mouth how ever it is completely false. Backpressure is always bad for performance. It will always hurt power and never give you any extra torque. The reason that bottom end power is lost when switching to large exhaust piping is because of lower exhaust velocity. Here's how it works.
The exhaust flowing from the exhaust ports is moving very fast,
at the speed of sound actually. It slows down some as it cools and starts to become turbulent. It is still moving at a very high rate of speed though. When the exhaust valve closes, the exhaust doesn't just stop, it's moving too fast for that. Because it keeps moving, it temporarily creates a small vacuum between the exhaust gas and the valve. When the exhaust valve opens again, this vacuum helps to draw out the spent gasses from the combustion chamber. It also helps to pull in a fresh charge because the intake valve is open at the same time. This causes a torque gain. So, as a general rule, you want to keep exhaust velocity as high as possible.
One way to keep velocity high is to make the exhaust piping small. The smaller the pipe, the higher the exhaust velocity. If you don’t believe me, look at the nozzle on your garden hose. It has a small opening and the water leaves with a high velocity. Take the nozzle off and the water flows much slower. The problem with small piping is that it is more restrictive that larger piping. It causes a higher backpressure at higher flow rates(ie higher rpms). So while the motor will make nice power at lower rpms, it starts to choke off the motor at higher rpms. Now you can switch to larger piping and gain some high rpm power, however, the larger piping means lower gas speeds, and therefore a loss of bottom end power.
Backpressure is always bad. Why does exhaust gas flow? It flows because it is going from high pressure(the combustion chamber) to lower pressure(your exhaust). The higher the difference in these pressures, the faster your exhaust will flow. When you increase backpressure, the exhaust will flow at a slower speed because you've decreased the pressure difference. Remember, lower velociy is bad. Backpressure also makes your engine less efficient because it requires the engine to work to pump the exhaust out. There are many sources of backpressure. The fiction in the piping wall and the turbulence in the muffler are the biggest contributors. There are other sources of turbulence. Turbulence is also caused by sharp bends, sharp transitions of pipe diameters and anything protruding into the stream such as O2 sensores and poorly designed muffler baffles(read cherrybomb mufflers). The higher the turbulence, the higher the backpressure. Anything you can do to reduce turbulence/backpressure will pay off with a more efficient exhaust and motor.
So as you can see it's a trade-off. Like a cam or intake, you have to decide if you want power on top, middle or down low. Ideally we want an exhaust with very high velocity but no backpressure. Unfortunately, physics just won’t let us do that. The best we can do is to pick the correct diameter for the rpm range you will most likely be running in. Then its a matter of making the exhaust as efficient as possible by reducing backpressure causing turbulence. Of course none of this velocity stuff applies to turbocharged engines. And everything stated above is on top of any resonance tuning that may be done to the motor.
Do not do it ... unless you are spraying or are under extreme performance mods, and the engines resonance induction is altered from that of the factory ...
In that case would it be more beneficial for me to remove the VRIS from my ZE IM before I install it? If you read my sig you can see all I have done.
Also, my car is going away for the winter in a couple weeks. I was planning on doing some headwork (ie. P&P, and valve job). My ZE IM will also be gettig a P&P and bored TB. Will this have any ill effects due to the N20?
In that case would it be more beneficial for me to remove the VRIS from my ZE IM before I install it? If you read my sig you can see all I have done.
Also, my car is going away for the winter in a couple weeks. I was planning on doing some headwork (ie. P&P, and valve job). My ZE IM will also be gettig a P&P and bored TB. Will this have any ill effects due to the N20?
I would like to refer that to jeff jeske, he is the one who sprays, and who removed his VRIS, because he found it to be detremental ... I couldnt say within any certaincy of accuracy ...
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