DangerousDan

iTrader: (8)

Oh, so documentation from Mitsu about the 4g69 engine and it's systems wouldn't be enough? The sound the engine makes can change due to lot's of factors. The resonance frequency of the air in the intake chamber, for instance, will create a much louder sound than the lower part of the RPM range. Drive slowly in a parking lot in first gear starting at 3000 RPMs. gently accelerate up to 3700 or so and you will hear the valve lift change. You find an explanation for the sound that the valves make changing at 3500 +/- 100 RPM's that is logical and scientific like the example I provided for your "mivec intake sound."

You don't have to believe me. It won't change the way your car operates either way. the mivec will kick in wherever it's going to, regardless of what you or I say.

It's controlled by oil pressure. RPM dictates oil pressure. If you were running out of oil your oil pressure would suffer, maybe you should check your oil?

DangerousDan

iTrader: (8)

the sound change at or around 4000 (depending on mods) is because the power output of the engine is so much greater than it is below 4000. the mivec switchover is at a point in the RPM range where the torque curve from the lower lift cams drops off and the one from the higher lift cams pick up. That is probably why it is smoother than vtec. Mitsu put the switchover at the "optimum" point, not the "biggest power gain" point, which is another reason why the engine tone doesn't change precisely at the switchover.

the tune I run on my car, combined with my SRI, creates a sucking sound that goes completely away at 3500 RPM and doesn't audibly return until over 4500 or so. It turns into a roar at 3500 RPM and drowns out the sucking sound altogether. This is where the engine really starts sucking air in, hence the roar from the engine. the increase in airflow as the engine revs higher lets the sucking sound get loud enough to be heard over the engine, so it's there the whole time.

If I were you, and my car pulled real hard at 4500 RPM's, I would see about some tuning. unless you are turbo you shouldn't have that much lag; especially after about 3000 to 3300 RPMs, and should have a pretty much constant pull after 4000 or so.

ralliart329

iTrader: (6)

i need a tune then.... and a wideband, and $$.

MITVRX

Well my car has been tuned, and I pull quite well at 4000 rpm. According to my dyno chart 3500-4500rpm is when the torque kicks in most and the rest of the curves are smoothed out.

qlitv

iTrader: (1)

I don't even feel it or hear it on my RA it sucks I’m starting to think that I’m running with out MIVEC

ixhavexfaithx

yeah i have the same thing with mine. the SRI stops around 3500 and picks up around 4000+/- for me as well. the lower rev range sounds like i have a window barely cracked though

ralliart329

iTrader: (6)

went out and tested this also. it seems like my power kicks in at 3800 or so. it gets really stable and is all out power from about 4200 up.

MITVRX

I think with tuning mivec is "drowned out" or blended of some sort.

I went yesterday for a spin and 3500rpm, there isn't an 'obvious' changeover, just a little louder roar from the engine, sucking of the CAI and then 4000-45000rpm, it picks up!

TalonTuner4G63

Correct me if I'm wrong, but isn't the MIVEC system used on the Evolution different than that used on the 4G Eclipse? Basicly, I thought MIVEC on an Evolution was simply a module on the intake cam gear, which advances timing based on different values sent by the ECU. Whereas, the MIVEC used on new Galants/Eclipses ect use a system similar to what Honda employs on it's VTEC setup, which is basicly and extra lobe on the cams which engage based upon throttle position/RPM.

If thats the case, how the **** do you "hear" your MIVEC come on on your Evo? Isnt that basicly like saying "I hear my timing advancing?"

ralliart329

iTrader: (6)

this is not evos but its based off our oil pressure kind of like vtec is off throttle position. if you do a search their have been extremely detailed explanations given.

egk-69

Well I dont know, I will put a led on the Mivec signal cable (if someone knows what color or anything, I dont have time even to open the hood for now) But i will put the stupid led to finaly see where is the ECU activating the mivec (at least on my car)

I dont know about you, but what I hear on my car, I bet everything I have it is the mivec, because it isnt a difference in sound, of a gradually change in sound or gradually pull, NO, it is a total change in sound in less than 0050 RPM (no matter what intake I have),

Another thing is that I have the stock exhaust (just the Injen CAI), maybe some of you guys cant hear it cause the exhaust sound is too loud (on modified ex)

BTW: Yes I know my Ralliart is not a HONDA, But my Civic h22, and my civic d16, and my friends Hondas (b16,b18, etc) the VTEC change over, its like what my Ralliart is doing

BUT WHO KNOWS

show time

If you read your owners manual it states that mivec will not engage unless motor is at normal running temp. Not sure why or why not but it states this in black and white in the owners manual. So if ur testing for performance or just to see when its kicking in make sure u have driven around for a few to warm the motor up properly. Mine seem to kickn in around 3500 but were are u guys dropping off?4800 -5200 rpm?

DangerousDan

iTrader: (8)

mitsu knows let us know what you find out. there is a thread somewhere that will tell you where the mivec sensor(it's an oil pressure sensor) is located, just search.

I don't bet unless it's a sure thing, everything you have you say? I'm all in baby.

engine sound≠mivec=oil pressure

DangerousDan

iTrader: (8)

dropping off at around 6k, pickup at about 3200 or so with a little more pull at 3800, smooth otherwise. Logging and tuning daily

Arithmetic

iTrader: (9)

It's @ 3500rpms



What your hearing at 4500rpms is just the increase of power and torque traveling through the exahust and intake.