Calibrating the 2.4 running stock electronics

[ShelGame]

OK, here's my first stab at this.

I translated the SRT4 Stg2 timing maps from the KC into our 2D tables as best I could. If you need some explanation of what I did, just ask. It's kind of complicated. The timing looks really radical to me, but it does translate to the same final timing (roughly) as the SRT4 Stg 2 data that's been posted.

The knock table I copied over directly from the Neon R/T FCC cal. It may not be 100% right, but should be a good starting point.

The fuel I scaled by 45% for 72pph injectors, and becuase the base cal was a 2.5 T1 cal (34/72 * (2.4/2.5)).

The Pumping Efficiency table I copied from the Masi cal, and then scaled up a bit. Again, probably not 100% right but should be close.

This is based on the 2.5 T1 MP MTX 3-bar cal that's posted in the repository. Sorry, my template data for the SBEC is (still, sadly) not ready for prime-time. I'll work on that.

It does have the CE Flash enabled, for reference. And, switchable boost is in there, too. Though, I didn't touch the boost tables at all. Overboost is disabled, though.

[Aries_Turbo]

why the stage 2 timing vs the stage 3?

the timing table looks to not change after ~14psi as well. there is no change to the 2.4L stuff after 14psi?

Brian

[ShelGame]

Doh, I forgot. Originally, I was (acidentally) building the timing in a 2-bar cal. When I transferred it over, I forgot to add the extra timing point at 28psi. Gimme a few...

[ShelGame]

OK, it's fixed. I also included my very rudimentary spreadsheet for looking at the timing in 3D. I really need to add the effects of the MAP vs. RPM multiplier in there. It really gives a 3D shape to the 2D tables used in the SMEC and T1/IV SBEC. Maybe I'll do that later tonight.

If you look at the cal, you'll see I changed the shape of the 'AdvanceFromRPM1' table. This is the MAP multiplier table. When the advance from MAP is negative, it gets multiplied by this table. If you look at the actual Stg2 WOT timing, and my approx, you'll see that I have mor timing in boost at low RPM. I'm using the MAP Mult table to compensate and bring the timing down in this area. I really need to add that calculation in so we can see the 'true' 3D shape of the T1 tables.

In the T1 cals, the MAP Mult is only used with WOT timing.

Oh, and I used the Stg2 timing becuase that's what Sean asked for...

[Aries_Turbo]

ok that looks better.

yeah that timing does look crazy.

i remember looking at the timing a bit ago and noticing that it looked a bit aggressive but i think the piston design allows some of that.

NOTE.... this timing will not work on a dished piston 2.4L

Brian

[ShelGame]

Timing seems really low in boost - at least comared to the T3. But, then, it has a ton of timing from RPM...

[1FastCSX289]

Rob, THANKS!!! I appreciate your time.....and ill be sending your pizza and beer money shortly! You guys are speaking a bit of a foreign language here as my D-cal skills are pretty limited right now......but thats why im friends with Bucar. Well, that....and I need SOMEONE to pick on at SDAC meetings.

Ive got a little ways to go on the motor install. Im short on cash right now, so my intake manifold is still not bought. But, ive got to get that, install it and make up the intercooler piping. Should be ready to go in a month. So, we'll have to wait a little on the tweaking of this cal, but I do thank you for helping me out......we'll be in touch.

[wowzer]

.... my D-cal skills are pretty limited right now......

i know a solution to that

[Darkapollo]

ok that looks better.

yeah that timing does look crazy.

i remember looking at the timing a bit ago and noticing that it looked a bit aggressive but i think the piston design allows some of that.

NOTE.... this timing will not work on a dished piston 2.4L

Brian

Can we get a modified cal that will work with dished (T2) pistons?

[Aries_Turbo]

take ~8 deg of timing out in boost.

brian

[1FastCSX289]

BTW, I just ebay'd up an intake mani, so I should be able to install it and get the IC piping done this week. Shooting to try out the cal within the next week or two.

[1FastCSX289]

Ok.....car is pretty much done......with the exception of the cal. Woo hoo! I havent written it to the chip yet. Hopefully I can get to do that tomorrow afternoon. I did try to start it on the old calibration (the old 2.2 cal). I dont have any spark. There shouldn't be any cal-related reason to not have any spark with the new set up, would there? I cant think of any reason why this thing wont fire. I have to go through and trouble shoot it, but I figured i would ask around about this before I get the chance to get my nose into it.

[Aries_Turbo]

you using the distributor adapter? did you re-index the trigger wheel?

Brian

[1FastCSX289]

you using the distributor adapter? did you re-index the trigger wheel?

Brian

I bought it from Rich Bryant. It looks like the wheel had been removed and re-installed so I would assume its correct.

I looked into it briefly......it seems like the computer kicks the ASD relay on when the key is on then it shuts off once its cranking. Seems to me like its not receiving a dist reference. I checked the rotor and it is turning. Im thinking it has something to do with the distributor but I cant see how I could have screwed it up. Maybe the HEP is crap or something.

[turbovanman²]

take ~8 deg of timing out in boost.

brian

Wouldn't you add 8 deg? if the SRT pistons are domed so to speak and your using dished pistons, wouldn't you add timing?

[Aries_Turbo]

Wouldn't you add 8 deg? if the SRT pistons are domed so to speak and your using dished pistons, wouldn't you add timing?

no. the crazy quench characteristics of the stock SRT domed piston make it more timing friendly.

you drop the piston dish down in the bore, and not squish the mixture into certain parts of the combustion chamber, and it becomes more timing sensitive.

Brian

[Speedeuphoria]

correct you can get away with lots more timing on srt pistons

[turbovanman²]

Very interesting, thanks.

Ok, so on that note, why aren't the aftermarket pistons domed?

[Aries_Turbo]

i dunno. probably cause the SRT slug came out later and they already had an off the shelf piston for years for a regular 2.4L.

brian

[cordes]

ill datalog the knock volts with a scanner and make sean ride the brakes really hard so we get a good sample of voltage and RPM points. ill also use external knock listening means to make sure we dont have actual knock at that time.


Brian

This is the way I would do it. Does anyone else remember the tech session at 18 mentioning something about just cruising with no load on the motor, record the knock volts, add 10% to those values and call it a day? It seemed as though they were describing that process as independent of motor type?