JohnBradley

iTrader: (30)

Sounds completely unrelated to MIVEC. I can take a look if you want to send the tune over.

sales@englishracing.net

MIVEC is a closed loop system so whatever the map says it tries to do with the available range it has. Doesnt matter if its a 4G63 or 4G64 block.

eric06ix

iTrader: (3)

Would changing my MIVEC maps to match the JDM setup hurt anything on a stock tune? My only mods are a Taipan turbo back with the high flow cat. I used to have a custom tune with a MBC, but driveability was not all that great, so I removed those.

Raptord

iTrader: (10)

No it won't hurt anything.

211Ratsbud

iTrader: (1)

Why the significant overlap at high rpm? I've been reading about the s2's and what my mivec table should do and this sticks out pretty good
I've been thinking I had too much overlap causing knock but you have a lot, where as most others taper aggressively after 5k and try to zero out after 6k

Skylineracer

iTrader: (21)

This map has quelled alot of my knock under wot condition still need to mess down lower on my timing

211Ratsbud

iTrader: (1)

Which map?

Jb are you taking into account the 11 degree diff between 0 on an 8 and 0 on a 9? Looks like it but I don't see where everyone else is targeting 0 relative.. Hrmm

JohnBradley

iTrader: (30)

It's actually 19* between 0 on an 8 & 9.

It has been taken into account, modified, spit out, retested, and still something like the screenshot presented. That one is actually even an old version, but was my S2 map for quite awhile. The MIVEC map like many things with our cars has not sat but has evolved over the years. There are 3 basic forms of it now, Stock cams-S2s, R2s, and S3s. None of them share the same advance as that map past 3750.

211Ratsbud

iTrader: (1)

Gotcha. I appreciate the info and I'm going to start there and re create my sd rom. This s2 setup is kicking my rear, I'm ending up with like 460 load on a hta71 30 psi and my resolution is what I'm thinking is beating me up. Gonna get things more inline.

I've studied the avcs map from my Subaru that a tuner did and it's crazy smooth looking.

Skylineracer

iTrader: (21)

I was talking about that old map ER had posted. And +1 accounting for the s2s in the tune has been a pita.

211Ratsbud

iTrader: (1)

Ditto on the map helping. Now it appears I have a good startin point

fireroasted

iTrader: (3)

I have read this thread a few times and I needed to screen capture many of the maps so that I could look at them side by side by side to learn. Most of my learning came from understanding the flow of air through the cylinder and the movement of the valves. The discussions on the overlap and advancing the Mivec value making the intake valves open earlier (and close earlier) was key. I decided to post a collection of the maps in the thread so far, to make it easier for anyone to see most of the maps at once. I found it helpful. Remember that these are all for different setups so its just a comparison to see the style, possibility, and get comfortable.

The actual posts provide details on why folks did what they did, so reading the whole thing is still the best choice, but I thought this was interesting to review.

Stock


JDM RS Stock


NJ1266 Combo (snappy)


NJ1266 Combo idlefix


JB EDM Stock


JJ JDM RS


John Bradley S2


Evo9 GT Stock


EvoIppo


Fil78


IanEvoMR9


IanEvoMR9_old

fireroasted

iTrader: (3)

yup more

JordanS4


KillerP21


Lemmonhead


MarcoEvo9


MrFred


Nonschlont


NonSchlont_old


Raasfaas


Recompile


Recompile 2


RMutt


SWOLN


ThatsMR2u


TurboRacer


VMRevo9

mrfred

iTrader: (50)

Nice post. My current 2 cents on MIVEC intake in the high power part of the map is that the appropriate amount of MIVEC intake advance depends on the ratio of intake pressure to exhaust gas pressure. When the exhaust gas pressure starts exceeding the intake pressure, reversion is a certainty, and the least amount of overlap is best. I think people have understood this for a while, but perhaps what people haven't recognized is how high the exhaust gas pressure can get.

Check out the attached plot of exhaust manifold pressure (EMP) vs boost pressure for my BBK pushed to the limit on E85. The ratio of boost to EMP is 2:1 at 3500 rpm, but EMP rises very rapidly and matches boost pressure by 5500 rpm. By 7500 rpm, the ratio is ~1:2 (very unfavorable and a bad place to be for extended periods of time). In my estimation, overlap should be minimal by 5500 rpm (MIVEC set to zero). My current MIVEC map is also attached, and apparently, I'm not quite listening to my own assessment because I still have some advance at 5500 rpm. But I'm pretty close, and next time I'm on the dyno, I plan to investigate this a little more. Also, notice that lower load range of the MIVEC map, I begin to add back MIVEC on the assumption that the ratio of boost to EMP starts to become favorable. I haven't done any low boost pulls to verify the ratio though. Its another thing I need to investigate........

Most people wrapping out a stock turbo or any of the stock frame turbos on E85 and max boost are probably in the same boat, and I suggest experimenting with zeroing out MIVEC after about 5500 rpm for best power. Comments are welcome (and inevitable).

mrfred's recent datalog


mrfred's current MIVEC map

vmrevo9

iTrader: (33)

Good info guys.

I have since Added some changes to my Mivec map after reading what Mr Fred had just posted. Last month I have been playing with the idle cells and I also tapered the advance in the high load areas starting with the addition of adding 3250 rpm cell. I did that to help with spool and throttle response. I had experimented with starting the taper at 3000. Although it felt more snappy and responsive I was worried about to much stress to the bottom end.

I also lowered the advance at the 5500 cell in efforts to combat some knock that I was seeing.
Unforunately I haven't been able to test it since the latest change due to leaving on a short notice trip.

When I get a chance I'll try and load up the new map so you guys can see.

I was looking at one of my logs and I have noticed that timing seems to come in 250 rpms sooner than what is on the map. For example let say at 5000 rpm load cell 280 I see 4 degrees and towards It's transition to the next rpm range same call it will advance the timing 250 rpm sooner than what's on the map.

Is Mivec the same?

jimib

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