Modded C32 Ignition Timing Question
 

To all modded C32's (and frankly, other M112K cars as well):

For any of you who datalog to keep an eye on your ignition timing - what is a "normal" range to expect?

My car seems to be retarding timing quite a bit, but I don't have a baseline for comparison, since I didn't have my Carchip when my C32 was stock... :smash:

I'm pretty sure there's a way to post up graphs from Carchip's software - I'll have to look and see.

Any comments/insights are welcome, TIA! :y

P.S. Mod list is LET ECU tune, LET 181mm pulley kit, LET headers, LET phenolic spacers, LET HE, CM30 pump, and K&N filters. I log IAT's as well, which is typically 120F or less - occasionally as high as 140ish, which usually then drops pretty quickly into the 120's. Also, not sure if it matters, but I run 93 octane.

Figured out how to save images from Carchip's software... here's what I'm seeing (three trips - IAT, Intake Manifold Pressure, and Timing Advance)

First example:
http://i276.photobucket.com/albums/k.../Trip12IAT.jpg
http://i276.photobucket.com/albums/k.../Trip12PSI.jpg
http://i276.photobucket.com/albums/k...ip12TIMING.jpg

Second example:
http://i276.photobucket.com/albums/k.../Trip14IAT.jpg
http://i276.photobucket.com/albums/k.../Trip14PSI.jpg
http://i276.photobucket.com/albums/k...ip14TIMING.jpg

Third example:
http://i276.photobucket.com/albums/k...r/Trip3IAT.jpg
http://i276.photobucket.com/albums/k...r/Trip3PSI.jpg
http://i276.photobucket.com/albums/k...rip3TIMING.jpg

I have quite a few datalogging trips so far. IAT's tend to hover around 120F, and timing seems to average -15 to -20 degrees. To date, the most advance has been +18 degrees, most retardation has been -35.5 degrees. Highest Intake Manifold Pressure has been 30.0 psi, highest IAT was a brief spike to 147.2F.

Excellent post. Incidentally, you’ve appropriately earned Super Member status. :y

Your data is pretty much par for the course with its modifications. It’s readily apparent that the upgraded heat exchanger circuit is working properly. Relative intake manifold pressure is in keeping with expectations, as its high-flow exhaust manifold’s tend to reduce restrictions (and commensurate boost) within the airflow tract. Our spark retard under load is far greater than I’d expected, but perhaps that is due to AMG’s conservative settings to help preclude vaporizing pistons or ventilating the crankcase. Can’t hardly fault them for that, as they’ve a warranty period with which to contend.

Even while consuming Sunoco 260 GT 100 fuel, my spark timing and overall performance remained essentially the same. Perhaps revisiting our tuning parameters is in order.

When the boost is over 25PSI under hard acceleration, is this a boost spike during shifting or regular boost with the 181mm Pulley?

Thanks.

Thank you splinter - knew I could count on you for some useful and insightful information. :y

One clarification (bolded above, my emphasis). I'm running an LET Motorsports ECU tune that's been paired with my exact mod list... not the stock AMG parameters, to my knowledge.

One follow-up question - see in the trips above (esp. 12 & 14). The long stretches where the manifold pressure is relatively low, and the timing appears to be -22 degrees (give or take) - these are light load, highway cruising stretches. Would this still fit with your "our spark retard under load" comment?

Thanks again... have a safe and enjoyable holiday weekend, my friend. :zoom:

Any PSI reading you get you have to subtract 14.50326 (a bar) to get your
manifold pressure. Also the reading you get is every 5 seconds, so in order
to see your true reading you're gonna have to hit your final gear for a good
5 seconds which can range anywhere from 100-150 with his mods which I
don't recommend. But I do suggest to get a boost gauge.

Thanks.

:popcorn:

Thanks neihouma :y

Have a dyno appt in about two weeks... same dynojet dyno I used for my baseline earlier in the year - I plan on having my Carchip plugged in for those runs, which I hope will yield some good (i.e. useful) data, as well as give me the rwhp and rwtq increases over stock.

Slightly off-topic from what you posted - but I recall you use Carchip's software as well. Does it record advance as negative and retard as positive? :nix: That seems counterintuitive to me, but I was advised that may be the case by a helpful, knowledgeable forum member :y

You're welcome!

You're welcome too!

Yes. The timing is simotanously (sp?) I can't access to any PDF files I have
(I'm at work right now) but when I went from Power**** to EVOtech's ECU
I saw a big change in timing advance not being pulled. I should be able to
pull some PDFI files tonight when I get out of work.

It's very helpful to the tuner, I wil say I have the following settings for my
carchip:

1) MPH
2) IAT
3) Intake Manifold Pressure
4) Coolant Temp
5) Timing +/-

================================================== ===

PS: I don't think my car is running 34.5psi no? :smash:

https://mbworld.org/forums/c32-amg-c55-amg-w203/224886-18-5psi-40deg-f-20psi.html

Attached is my Carchip datalog in table format.

The ignition timing point is retarded by the ME-SFI control unit in line with the intake air temperature and "load" (engine speed and air mass).

The ignition timing point is retarded only if the engine is operating at a high load and begins from an intake air temperature of approx. +35 °C and reaches its maximum at approx. +65 °C.

Example for full load:
35 °C --> (retarded 3.5°crank angle)
45 °C --> (retarded 6.3°crank angle)
65 °C --> (retarded 9.5°crank angle)

The following information is processed in the ME-SFI control unit:

Intake air temperature
Engine speed/crankshaft position/ignition circuit detection
Throttle valve position
Air mass (boost pressure in supercharged engines).

Your IAT's really need to be under 100° F during normal driving and under 120° F during a run.

Excellent data... thanks Jerry! :y

In skimming your attachment, I noticed many cases where your intake manifold psi was pretty low (less than 10 psi), your IAT was under 100 deg. F, and your ignition timing was -28.00 deg, -28.5 deg, etc. This is what I was seeing as well - good to see it's normal; thanks again.

Question (regarding comment bolded above) - ambient temps here have been up to 100 deg. F this summer, and pretty consistently high 80's/low 90's during the day (plus hot sun, and moderate to high humidity). Consequently, I'm not sure sub-100 deg. F IAT's are attainable for me until fall without major modifications, since I already have HE, CM30, and phenolic spacers. However, any ideas to help a little bit more? Saw a thread over in the w211 forum about thermal-wrapping the intake tubes... would that help? Also, I'm still running stock plugs, would going to a colder plug help?

Thanks, talk to you soon.

Hello Jerry,

thanks for the data:y

in Germany we can run 100 octane. Does this help to avoid the ECU from retard timing ? I also run the LET-HE and CM30...

Thanks.

No, the heat is generated after the blower, when the air is compressed.

A few ways to combat high IAT's would be to:

1. Get a larger more efficient Heat Exchanger
2. Seperate the IC circuit and use a larger fluid reservoir
3. Upgrade the Intercooler
4. Run lower boost

I have done all of the above except #3, which hopefully will come soon.

As you can see, my IAT's are very low and that is because of my boost level (15 PSI) and my water tank in the trunk.

http://www.letmotorsports.com/tank.jpg

http://www.letmotorsports.com/tank2.jpg

If your car is tuned for 100 Octane, then yes. My car isn't uned for 100 oct, but I do run it every now and then. 100 oct helps with engine detonation, which shouldn't happen until 185F+, unless the map is set for too much timing and not enough fuel.

BTW - This is my normal drive to work.


http://www.letmotorsports.com/iat.jpg

And this was before the tank in the trunk. Same drive to work.

http://www.letmotorsports.com/iat2.jpg

Hey, question everyone:

I have a Carchip E/X, which I actually won back at CES 2007 because the our company's exhibition booth was right next to Davis and I got in one of their races and won this unit. My question is, I used the thing on my 2006 yukon xl denali and it worked fine. I want to use it on my E320 but noticed something interesting on the web site about cars excluded. It said that cars with tiptronic transmissions may experience stuttering if a carchip is used. Any of you guys have a problem with this? Are Benzes considered "tiptronic" because they are not like Audi's or BMW's in the design and functionality?

Been doing some rather substantial data acquisition in anticipation of my next tune.

Without disclosing any proprietary intellectual property, of course, have you been able to document any significant spark timing and mixture strength differences - when compared with your previous ECU modifications - to account for its most recent version’s drivability and performance enhancements?

TIA.
-John