west_minist

lol I have my own

Either, this was a very good post.

9sec9

iTrader: (2)

I know that many of you have continued to test and tune on the mivec maps, But I have a question that may be answered somewhere , but I haven't read it yet. It seems that I read somewhere that the mivec value of 10 was possibly the same as straight up 0 Crank. If that is true, wouldn't that make anything less than 10 the same as retarding the cam up to 5 degrees (10 crank) and anything above 10 and up to 30, the same as advancing it 10 degrees (20 crank)? And if all of that is true, then each cell would be whatever it's value is - 10 and divided by 2 giving the camshaft advance or retard? Please, straighten me out if this hasn't been shown to be true. Thanks in advance. tom

DynoFlash

iTrader: (91)

Actually TOM in the ecu hex value 80 is zero advance - I only work in hex. The table goes from 0 - 255 in hex - with 80 being dead center - or no correction.

9sec9

iTrader: (2)

Thanks Al. I've been reading the posted mivec maps with 0 to 30 and I've just been trying to get on Page 1 of understanding the changes and results that have been posted. By looking only at these graphs and tables, It's easy to see that a value of 30 in low rpm range (can't tell load values) up until 4500 was an improvement over the JDM map, but falling back to a value between 0 and 10 above 4500 showed slight improvements. That would stand to reason that the '10' in the cell could indicate a 0 on the cam. Even after studying several of the maps used with good results by others, they are curiously hanging around that 9.6 to 10 value also above 4500. This could indicate what I was suggesting earlier that the cell value of 10 would possibly be 0 on the cam. I understand hex values, I use hex and octal dumps at times, but just trying to understand the values and results in these maps. Thanks again Al for the great job on both of our cars.

9sec9

iTrader: (2)

If the map goes to a hex 255, then 80 would be fairly close to the 10 value (approx 33 % of each respective scale.).

JohnBradley

iTrader: (30)

Actually the 0-30* table is timing (IVO BTDC) according to normal cam engineering specs. If I understand your reference to older threads that was in part information presented by me by other sources. Its not directly accurate however and was covered in the other MIVEC thread. For reference a stock cammed VIII will have IVO events at 19* BTDC. Running 10* on the MIVEC map would therefore be equivalent to running a stock cam -5* (retarded relative to a stock VIII).

EFIxMR

iTrader: (10)

Performance camshafts in the past have suffered from a number of compromises. Some cams provided great top end at the expense of low end torque, and some cams provided increased low end grunt at the expense of top end hp. Additionally, aggressive camshafts suffered from poor idle quality known as loping and had equally poor emissions.

The MIVEC system equiped in the revised 4G63 cylinder head in essence has mitigated many of these compromises by creating a variable phase intake camshaft mechanism. The intake camshaft is controlled via a sophisticated hydraulic actuator using electronics with PID feedback control. This allows the intake camshaft to be "advanced" or "retarded" depending on engine load conditions with fine precision. Essentially this is an adjustable cam gear like you can purchase for an EVO8, except it does not have a static setting.
Since the introduction of user programmble reflashing, it has become possible to change these camshaft settings inside the ECU. The MIVEC 4G63 has a very powerful camshaft inside from the factory, the only problem is it must be tuned to unlock its potential.

For the past number of months, our company has been researching and conducting tests on our two in house EVO 9's, and our efforts have been passed down to our many customers who have had their cars custom tuned by us. Now that we have our own AWD dyno, we can devote more resources to explain our processes and the cause and effect of tuning.

Our test vehicle is an 06' EVO 9 5 speed with approximately 6000 miles. It is currently equipped with an HKS hi power exhaust as its one and only modification. The goal of today's testing is to show the gains which can be achieved with pure tuning only demonstrating the benefits of the MIVEC system. No added boost, no added parts.




The above chart is an overlay of the camshaft held at a fixed angle under WOT operation. Each color is a different cam angle, and as you can see some fixed angles work better at different rpm ranges than others. The goal of MIVEC tuning is to create a single composite profile of camshaft angles that maximizes engine tq and hp. This ultimately is what creates the best of both worlds, a camshaft that has low end grunt and top end hp.



The effect of the optimized composite profile can be see above in the vehicles boost curve compared to the stock camshaft phasing. The turbo spool is greatly enhanced reducing turbo lag significantly.



The blue line is the car's highest baseline and the red line is our new tuned power curve using our optimized camshaft phasing with the accompaning fuel and timing modifications. The maximum boost is untouched.
With our current tune we are not only making more power but we are also doing it higher safety. Even with the factory tuning it is not uncommon for the car to pull timing from knock, as these cars were programmed with 93 octane in mind, and not our California 91 fuel.

In later test we will explore more modifications like an upgraded down pipe, rally cat, ect... and more boost. Stay tuned!

EVOINVASION

iTrader: (1)

nice

iTune

iTrader: (3)

You guys seem to be on the right track with variable cam phasing. You could learn a lot from the Honda i-VTEC engines. Honda was one of the first to employ this technology and has had great success with VTC. If any of you are familiar with the K20(A) (A2) (Z1) engines and K24 varients, you will know what i'm reffering to. Even though these engines come naturally aspirated from the factory, the technology has proved to be a great advantage on turbocharged and supercharged Honda k-series engines.

We have been tuning and testing these engines since 2001 and thus have a lot of experience with cam overlap and how that relates to power with just about every set-up and variation known to the Honda world.

There is a company called Hondata(i have worked for them on many projects currently and in the past) that makes the top selling fully tunable ECU's for these and other Honda engines. Some of the nomenclature and details are different from the DSM version(mivec) and the Honda version, but the science is the same.

With the Honda VTC(Variable Timing Control) the cam phasing is 0-50deg(+/- 25 crank *) 0* being less overlap and 50* being the most overlap. Honda's version is a bit more complex due to the VTEC system(low speed cam and high speed cam). The mivec system does not have or need this, so thus it's more simple to understand(although still complicated to the novice).

From my understanding, the mivec vvt is 0-30*(-10*/+20 crank*)?? If someone could verify this, it would be helpful to all involved.

We found that in most cases, a aftermaket cam gear for the rear camshaft will allow for even more control of cam overlap, and thus allow for even greater gains. This, as with everything else, can be said for any engine using a variable cam phasing system on the intake cam.

Also, I own a EVO VIII(just recently purchased), but my other cars are all Honda's, including a 650WHP RSX-S. I was a boost pioneer in the Honda k-series world and helped make the k20A2 and other varients the powerhouse it is today(with the help from many great people and companies such as Hondata).

I'm interested in seeing how this pans out for everybody. If my knowledge and experience can prove helpful, i will help out all i can.

CJ

kouzman

iTrader: (6)

what confuses me is the fact that some people, see gains with 0 advance in the higher rpm and some people see gains with some advance in the higher rpm...Does it make sense?

The Mivec adjusts the intake cam on a given exhaust cam timing. If we alter this timing...e.g. advancing or retarding the exhaust cam and then playing with the Mivec, would it result in higher gains, or it would just more the power curve forward or backward as a whole?

Anyone tried it?

dan l

iTrader: (3)

And my "hack street mivec tuning method" netted:



Same mods but you've got a downpipe over this evo 9. The tach pickup wasn't working so no torque sorry.

EDIT:

Also DLL was only 3 hp off from the dyno.

mrfred

iTrader: (50)

Nice job on the MIVEC experimental analysis. The impression I get is that after 4500 there's no obvious point to having more than 0 deg of advance. Before 4500 rpm, set the cells to 30.

lemmonhead

thats strange because my stock map has a "not used, future mivec map" and they got 38.4 and 36 in it?? wonder if this is suppose to be the the EVO X !!!!!

JohnBradley

iTrader: (30)

From what I can tell the numbers dont correlate to actual values. I believe they are there for either the X as you mention or the V6 and V8 dual MIVEC motors. The Subaru maps have independent AVCS adjustment per bank (not sure why) which doesnt mean that Mitsu did the same thing, but possibly. I need to find a 4G eclipse and download the ROM and see.