amak87

iTrader: (1)

Yes, I have extensively been tuning Mivec, I believe my new mivec map for the cosworth cams, I can control fuggin boost w/ mivec and the mivec map he was using had an afr spike, decreased boost, and lowered power(load).

What do you mean hardly? Whats your evidence? I have done many many mivec test on the road and I will be doing them on the dyno. The differences in one mivec map to another can affect EVERYTHING! AFR, BOOST, and ofcourse EGTS.

I have tested that map he is using, and saw the same thing. For some reason, whoever made that map he is using, made the cells go from 28.8 to 24.0, then back to 28.8 in the 4000rpm cell area. (i believe, maybe 4500rpms)

I did logs, and saw in each log, the afr spike and become very unsteady, then the load started decreasing, as soon as the 24.0 changed back to a 28.8, then power(load) started building again, and the afr's calmed down.

I will be releasing a very steady/strong Mivec map for a stock cammed evo and a cossie cammed evo. And I will be showing comparisons w/ the JDM rs map and the "ninja" map. My Mivec map, produces more power, and holds better boost (without using ECU boost), and a very stable AFR..

I will post results when I am finished developing the maps..

RazorLab

iTrader: (8)

Post the data then.

I've never seen such a large spike, however my mivec maps don't usually look like a richter scale, however maybe you have, so post the data.

As far as boost and mivec relation. What I have seen is more mivec down low = more boost for the same WGDC because of higher cylinder pressure, etc. Up top, more mivec = less boost for the same WGDC. This is easily seen by halfing your mivec down low. Or adding a ton of mivec up top.

TakaseEVOIXSE

iTrader: (20)

To the OP (im not trying to hijack your thread... just thought lean spool was my prblem)

anyways.. replying to the above quote.. You mean you've seen my Flash? i dont think i've posted it before.. . but here is my Mivec map. Could you be more specific as to what you think is wrong w/ it?

RazorLab

iTrader: (8)

I personally have never seen a "spike" of .7 AFR from a small Mivec change like 28 to 24. I don't even see that from 14.0 to 0. In fact I have never seen a spike at all from a ton of Mivec testing I did last year. I've run 9's with 0 mivec, maxed out mivec (28.8) and everything inbetween.

However that is what I have personally experienced. Again, if amak87 has data showing this, then please present it.

I personally believe something else is going on but I've been known to be wrong before.

Amak, when you see the different load from 28 to 24, what do those corresponding fuel cells show?

lemmonhead

correct me if Im wrong but from what I understand is
MIVEC is nothing but "WHEN" the intake valve starts to open after the combustion takes place and left over crap escapes through the exhaust valve right? having overlap creates a scavenging affect which helps the crap escape faster because the incoming air helps push it out.
So reason why you get more torque doen low by adding MIVEC is because at low RPM's the intake air is not moving as fast and has less pressure then at higher RPM's. So by making it possible for the air to get in sooner, you make power.
in Higher RPM's the air has a lot more pressure and moves faster so you decrease MIVEC because opening up the intake valve to soon cause a lot of the air to just escape right out the exhuast. this equates to running rich.

SO im pretty sure its impossible for MIVEC to create such a lean condition. adding 0.7 AFR??????????

amak87

iTrader: (1)

i said i will post the data when I am through tuning.

have you actually done tests? or have you just read info?

and maybe for a stock cam evo, more mivec timing=less boost. But not for a cossie cammed evo. I hold 21 psi by redline using a specific mivec map, designed to hold more top end power.. and if you really think about it. Mivec retards the intake cam, w/ higher rpm, more air will be allowed in the cylinders, thus producing a larger combustion, in turn producing more boost. (w/ cams)

Im not saying that the Mivec map can affect AFR 100% percent, but it is the center of why it did spike. It spiked and also caused other problems..

amak87

iTrader: (1)

sure. I will explain.

you see on your mivec map, at 4500rpms, your timing is at 24*, then your timing cuts down to 14.4* at 5000rpms. You stated that your AFR spike occurs from about 5400-6500rpms...

Before I even get into explaining this any further, and taking up alot of my time,(lol) just change your Mivec timing, and keep it at a constant 24* till 7000rpms. Do some logs, you will most likely need to alter your fuel map, and if you can, log boost. just do a before and after run, and post the results. You will see a more stable AFR, and you should see more boost. (maybe not more boost, I have only been testing a cammed IX, so your results may be different)

My cars AFR problem was helped out by correctly tuning the Mivec map, then slightly adjusting the fuel map. I didnt just change the Mivec map, and miracles started happening. Everything must be tuned after Mivec.

amak87

iTrader: (1)

read up on it. But Mivec retards the intake cam, thus letting more air/fuel into the combustion chamber before the explosion, producing a larger combustion=more/faster turbo spool=more boost=more power. This isnt just a guess. I have proven it, and shown others how to hold more boost, using this method. I have shown 3 other people, and each person has seen more boost and more power, in 2 different cars.

I havent done thouroug testing on Mivec down low, but I will be doing that shortly. My hypothesis, is that less mivec timing down low, will help out with a smoother throttle response, better mpg, and perhaps a faster spool up. Thats just my guess, I will start tuning low-end Mivec later next week.

Mivec can greatly affect AFR, and can cause the car to knock less/more. I have done extensive testing w/ different Mivec maps, but using the same timing and fuel maps. All I did between pulls was change the Mivec Map.

I hit higher boost with more Mivec timing. end of story

amak87

iTrader: (1)

I will present the data when I have time to finish my testing, and properly write it all up. I will present the info w/ dyno charts. Using 4 different Evos. (hopefully)

And the fuel was the same. Mivec affects AFR. I have seen almost a full point.

Are you using cosworth cams? Im not really talking about stock cammed evos.. But w/ more mivec, you should see higher boost levels.

RazorLab

iTrader: (8)

I was about to jump on this, but I think you might need to explain this a little bit more because I think something is getting lost over the internetz.

More mivec advance at spool and lower RPM = quicker spool and more torque, advancement increases cylinder pressure at lower RPM:



Yes, many.

Please do.

Again I think you need to explain this a little bit more because I am hoping something is getting lost over the internetz here.

Stock cams, cosworth M1, cosworth M2, Brian Crower, GSC, HKS, Greddy, with exhaust gears, without exhaust gears, etc etc

Asmodeus6

iTrader: (7)

Wow Bryan, you're being awfully nice about this one...

I run lean spool disabled or it fights with Pro. (on my car) Previous to that I have tuned both with it off, and on. And it makes life easier with it disabled. IMO.

mrfred

iTrader: (50)

If he tunes the ROM in your ECU (rather than start with a base ROM of his own), and he doesn't touch any boost tables you'll be fine. Just tell him to ignore the boost tables no matter how strange they may look to him.

mrfred

iTrader: (50)

Wow, AFCII? Definitely try disabling lean spool. Don't know if it would make much difference, but I suggest keeping the overall trend in the MIVEC map (decrease advance as RPMs increase past 4000 rpm), but get rid of the steps in the MAP (e.g. don't have large steps from say 24 down to 14 and then down to 4.8. Don't hold 24 deg out to 7000 rpm. If you want to see a cool mivec test, check out this thread:

https://www.evolutionm.net/forums/sh...d.php?t=240441

amak87

iTrader: (1)

about the dyno chart, which evo is that? I was only talking about the lower Mivec map area, like the cruising zone. Not really the spool up. But I will be doing more test later on in the week.

As for what I stated, Mivec retards the intake cam, letting more air in the combustion chamber before combustion occurs. Basically, the Mivec assembly rotates the intake cam in the opposite direction of its normal operation. Thats why retarding it (for my setup), has given me more boost up top, and less knock (for my fuel/timing maps). Thats my understanding of how it works. Please fill me in if Im wrong or missing something. But I did hit higher boost, in the same gear, same road, 5 min later, letting the motor cool while driving. And The car held more power, and it stabilized my fuel slightly, again, I then tuned it afterwards to get it where I wanted it.

RazorLab

iTrader: (8)

It's a Evo 9.

So are you saying the higher the number in the Mivec table, the more retarded the camshaft is?