Discussion regarding power limitations of the MS3

[Realgib3]

Originally Posted by Lex ^^ Now we're thinking. Top post mentions all of these. This is why it's not magic. We would SEE if any of these parameters went into limp mode or did anything crazy regardless of what anyone claims.

OK OK so now I'm a little excited...

Ok so for arguments sake, lets say timing is the issue...
and for arguments sake...lets say CP-e has NOT unlocked injector timing...

So what can be changed...right now???

Just a thought, but if we now have more fuel(yay!), and the timing of the injection process is a constant...but we need to get fuel in earlier in the ignition process...
Can't we change the timing of said ignition???
Everyone has been trying to up the timing up top to combat the loss of power...but isn't that just making it HARDER to get more fuel in before ignition???

So if we RETARD the timing up top shouldn't that give us MORE time to inject fuel prior to ignition????????

[kore2000]

You just have to think systematically and if you break everything down in sections. You remove the blocks one by one until there isn't any blocks left. The community and vendors have been doing this one by one for the last 3 years. Remember when we were all complaining about the damn throttle plate..lol

We have to be systematic.

EDIT: Well, in Jan. I get my fuel pump, and I'll have my GT35. If we don't figure it out by then, I'll get some logs at redline for you guys. I don't have an AP, and will either have CPE's flashs or Versa tune, but I'm down to help if I can.

[cld12pk2go]

FYI, I do not believe that we have any airflow limitations due to the ECU.

If we did, we would see the MAF g/s fall off. This obviously doesn't happen now that the throttle blade is held open.

Obviously, spark isn't the issue either.

So it is quite simply a fuel related phenomenon.

Based upon the Cobalt's recent break through, our path forward is quite apparent.

There might be a few new twists involved in rectifying our situation due to specifics in our ECU and fuel rail hardware, but it will be resolved in the near future.

[djuosnteisn]

Here's to 2010!

[fjames]

Just babbling some generalities, and yeah, I know you can't compare dyno numbers, but I'm going to anyway. Like I said, general observations ...

12pk and RR make the same peak tq.

12pk and RR hold peak tq for the same time (~1000 rpm)

12pk and RR are above 300 tq for the same time (~2000 rpm although if you squint, maybe 12pk holds a little longer)

12pk holds above 250 tq for significantly longer than RR - about 750 rpm longer.

12pk and me log the same loads but he makes way more tq presumably.

I understand that the RR solution to turning the speed into a drag car is a good one and I'm not criticizing them, I just think the comparison (similarities) to a stock turbo screaming for mercy is interesting.

[cld12pk2go]

Originally Posted by fjames Just babbling some generalities, and yeah, I know you can't compare dyno numbers, but I'm going to anyway. Like I said, general observations ... 12pk and RR make the same peak tq. 12pk and RR hold peak tq for the same time (~1000 rpm) 12pk and RR are above 300 tq for the same time (~2000 rpm although if you squint, maybe 12pk holds a little longer) 12pk holds above 250 tq for significantly longer than RR - about 750 rpm longer. 12pk and me log the same loads but he makes way more tq presumably. I understand that the RR solution to turning the speed into a drag car is a good one and I'm not criticizing them, I just think the comparison (similarities) to a stock turbo screaming for mercy is interesting.

I don't think the calculated loads are very accurate. I make over 2.0 loads when temps are below 30F, with lower MAF g/s than when I am at ~1.8 load when it is around 60F.

IIRC my recent logs showed about 4.5v on MAF compared to 4.6v ish when warmer and my WGDC was going to 0%.

[Lex]

Temperatures have an effect on calculated load as it should but there's more to it than just oxygen mass. I would like to know what formula is used to derive the load parameter.

[cld12pk2go]

My highly inaccurate butt-o-meter indicates that the higher load does not equate to faster go in the above two situations.

I would also like to know how it is calculated...

[djuosnteisn]

I read on a post on a bmw forum by a bosch guy.

He stated that load is not just air, but rather the amount of fueling needed for the air that entered.

So it may shed a lil light on your observations 12pk.


Here's the quote:

Motronic needs exactly three things to calculate LOAD. 1) A signal from the air meter, normalized to "Q" airflow in kg/hr 2) A measure of current engine rpm "n" 3) A programmed injector size constant "Ki" (K sub eye) LOAD aka Tl (Tee sub ell) is calculated as: Tl = Q / (n * Ki) LOAD is not just a representation of cylinder filling, but the theoretical Injector Time Open (Ti, Tee sub eye) needed to reach stoich (Lambda= 1) with the current injector setup assuming that the motor is "perfect". Which it isn't, hence there are fueling tables which are used as multiplicative corrections to LOAD to reach the actual Ti. Hope this clarifies. Jim Conforti.

[cld12pk2go]

I have been thinking of the load as

Tl = Q/n

Which should pretty much represent torque production.

I am not sure I understand why an injector constant would need to be added...

[djuosnteisn]

I'm pretty sure the constant is just used to "scale" the equation. Basically adjust the slope of the line for a given injector characteristic.

[MS3Zoom24]

im really interested in this too,

pre maf cal, i was hitting loads around 180 at 3k (21psi) tappering to 155 at 6k (17.x psi)

now post maf cal, im hitting 20X at 3k (18.X psi) tappering to 16X at 6k (14-16psi)

its really a huge difference and I feel its really high load for a stg1 mscai 105 (i also have tmic, bpv,aem)

Well hopefully there will be some enlightenment in the near future

[djuosnteisn]

How much did your afr's & LTFT's change from pre to post maf cal? Would be best if you could give numbers like LTFT went from +12 to -1 or something like that.

[fjames]

That sounds like cold weather. I gain about .12 in the cold here (20-30F vs. 75 when calibrated.) I target 1.84 and hit about 1.96, and that carries through most of the range. In normal weather I'm spot on.

[11cruzito11]

Originally Posted by superskaterxes i will say that during my last dyno i did a couple logs and for some insane reason i saw 20 deg of timing on one of my runs near redline. lemmie see if i can dig that up.

where in the PID datalogging in the AP do you find Timing? I am interested in knowing how much timing my car is running at WOT.

[jahman]

Originally Posted by 11cruzito11 where in the PID datalogging in the AP do you find Timing? I am interested in knowing how much timing my car is running at WOT.

I think they call it spark advance

[JMEngineer]

Originally Posted by djuosnteisn I read on a post on a bmw forum by a bosch guy. He stated that load is not just air, but rather the amount of fueling needed for the air that entered. So it may shed a lil light on your observations 12pk. Here's the quote:

Were they discussing a direct injection system? I'm pretty sure injector size (as opposed to fuel pressure) is less important on a DI car than on port injected cars.

If the system can handle significantly increased pressure, we should be able to get a lot more fuel before ignition without changing the injection start time.

[rigor]

ON OTHER DISI MTRS WHAT PSI ARE THEY RUNNING TO GET THE LETS SAY 500 HP. AND IS IT GOING TO BE REASONABLE TO GET OUR DI FUEL SYSTEM UP TO THIS PRESSURE AND FLOW RATE, OR BE CHEAPER TO AD THE AUXILIARY FUEL SYSTEM. BECAUSE IN MY SIMPLE MIND WE NEED THE FUEL SHOT IN BEFORE THE SQUEEZE ON THE FUEL. AND WHAT KIND OF INJECTOR IS THAT GOING TO TAKE IF THEY EVEN MAKE THEM JUST MY .02 I HOPE ITS PROGRAMING BUT I DOUBT IT

[JMEngineer]

Our stock injectors should be able to inject a lot more fuel if we increase the pressure and stay with DI. If we add port injection we should be able to use just about any injectors we want since it will have to be a custom setup anyway - it shouldn't take very big injectors since we'll still have the stock ones too.

[11cruzito11]

Originally Posted by jahman I think they call it spark advance

what is considered a safe range for "spark advance" or timing?

[cld12pk2go]

Originally Posted by 11cruzito11 what is considered a safe range for "spark advance" or timing?

A good question, which I haven't found much info on.

I can vouch that my timing curve is safe for my mod combination. It is actually in all likelihood conservative.

I am not looking to trailblaze; however, and would like to know what others have done successfully prior to tweaking.

[djuosnteisn]

IMO it's best to tune spark advance on a dyno, where you can get immediate feed back on each incremental change, not just butt dyno. Safe range is determined by detonation and EGT's. Typically you want to shoot for minimum advance for maximum torque.

I'm all talk though, cause i've yet to actually tune my timing on a dyno, still waiting for my hardware to be finalized.

Also, on a dyno, as you advance the timing, you'll eventually see a point where torque starts to fall off with increased timing, and egt's will go up quite a bit. This means you've gone too far.

[spnkr21]

well, so far, I believe people have tried to advance timing but didn't really see any results. Of course things are changing around here pretty quickly so we will see.

[SilverDemon]

I picked up 10 HP per degree in timing advance. With no detonation and EGT's were still well within check. The problem I ran into, was once we tried to go past 3 degrees, the car threw a multiple misfire code.

[cld12pk2go]

Originally Posted by SilverDemon I picked up 10 HP per degree in timing advance. With no detonation and EGT's were still well within check. The problem I ran into, was once we tried to go past 3 degrees, the car threw a multiple misfire code.

Can you post your initial/final Ign maps and your mods....

Tks

[2007speed3]

Please post it up, i would like to see where you uped it.

Now i know the ATR that we use is somewhat limited in how we can adjust timing. what timing changes does the professional ATR allow that we cannot?

[Fobio]

the new 500hp 911 Turbo's with DI uses 2000PSI fuel pumps...

[rigor]

so do they have better flowing injectors cause you would think if the Cly is in the intake stroke i shouldn't take a lot of pressure to over come Cly pressure if the injector open's up to let it flow. but on DJ,s post on injector pulse with i just looked to me it would just stay open longer the higher the revs? i assume the pressure was still good so that would tell me the injector is not able to flow the fuel in the short amount of time just my .02 btw you guys kick ass

[SilverDemon]

I use the SB, so this will not help you guys that run the AP very much. The day of this tuning session the ECU was running around 10* advanced at WOT. This same tune is also running a solid 11.8 AFR and about 1300* on the EGT (probe is in the DP) I looked through the Dash hawk logs I did a few days after this tune, and the highest recorded knock at WOT was .7 for less than a few tenths of a second.

[spnkr21]

that's crazy. I was pulling so much timing before my build to get rid of knock

[cld12pk2go]

Originally Posted by SilverDemon I use the SB, so this will not help you guys that run the AP very much. The day of this tuning session the ECU was running around 10* advanced at WOT. This same tune is also running a solid 11.8 AFR and about 1300* on the EGT (probe is in the DP) I looked through the Dash hawk logs I did a few days after this tune, and the highest recorded knock at WOT was .7 for less than a few tenths of a second.

So 3° above the stock map everywhere above 3.8v on the MAF.

That would mean that you were running ~4-7° more than me in the 4500-5500 RPM range and about the same from 6000-7000 RPM.

Very interesting.

So you are saying you picked up ~30hp with the 3° increase? Got any dyno plots?

[Lex]

I believe that in order to avoid codes with the SB, you have to incrementally advance timing such that the ECU does not see a sudden jump in crank speed. In other words you have to ramp up the timing, only 3 deg difference from cell to cell or less.

[SilverDemon]

I just have the final dyno, I am sorry I completely forgot to ask for the baseline graph, but the car pulled 290hp and 285lbft on the first pull of the day, all the charts at zero.

EDIT: I have already posted the dyno chart in another thread.......let me dig up the other thread and I will post a link



LINK: http://www.mazdaspeedforums.org/foru...eed-3-a-34435/
POST 16

Originally Posted by Lex I believe that in order to avoid codes with the SB, you have to incrementally advance timing such that the ECU does not see a sudden jump in crank speed. In other words you have to ramp up the timing, only 3 deg difference from cell to cell or less.

Double merge post FTL!! As you can see from the chart, we took the timing up incrementally, moving one degree of timing per cell. Once we got to 3* is when the car thew the code.

[djuosnteisn]

Wonder if you were pushing the spark advance into the fueling event, and that caused the misfires.

[SilverDemon]

No audible misfire, the car did not stumble or nothing funny happened, it just threw the CEL.

[djuosnteisn]

Wonder if the ecu would interpret a spark during fueling as a misfire, even if ignition was still successful. I mean even with a piggy back the ecu would still know if it were spraying during a spark event. Just an idea.

[SpeedSixxx]

HKS twin spark...

[SilverDemon]

The HKS will not, at this point, cure the random misfire code, since it really is not a misfire. I think (and correct me if I am wrong) the ECU interprets how many spark events happen in a cam rotation, and advancing the timing to a point where the spark event happens outside of that window throws the CEL.

[Lex]

Misfires are determined by examining the rate at which each tooth of the crank sensor is accelerated during the power stroke. The SB retards timing by delaying the crank pulse. The ECU senses this discrepancy and throws a misfire code. The SB might also be doing this a little crudely - not sure how fast their processor is.

[SilverDemon]

Ahhh, it is the crank position, not the cam position that makes the determination. Thanks for clearing that up for me.