Megasquirt on 1995 C36 AMG. - Page 5 - PeachParts Mercedes-Benz Forum

nick.ged · #61 10-01-2009, 10:04 AM

forgive me if im wrong but on a non boosted engine afr doesnot have to be so rich, max power on gasolen is made at 14.7 to 1

any extra fuel above 14.7 1 is only to cool the engine down

i run my boosted 103 (max boost at present 15psi) at an afr in the target table of ms1 v3 extra is as follows

below 4000 rpm, upto 95 kpa afr is 14:1 from 95 kpa to 110 kpa afr is 13.5:1

above 4000 rpm upto 95 kpa afr is 13.5:1 from 95 kpa to 110 kpa afr is 13:1

and this is a boosted engine, my pipe work and gearing ect makes it so that when ever i press the loud pedal it goes into boost imediatly. so needs more cooling around the 100kpa mark than a N/A motor because it will often be at 85-99 kpa after being much higher so more heat is present. i am gonna fit another oil cooler and a charge cooler to reduce heat soak as much as possible.
.

my egt and coolant temp are fine, no pinging ect, the leaner the engine runs the better the power, as long as it aint getting hot or pinging.

i read an article was discussing N/A tune, and the guy was saying that in his experience, when he tuned n/a engines, he would look at the power curve and the timing curve, and ignore the afr, and tune for max power, (obviously the engine is not allowed to ping) and almost always, when he looked at the afr's after achiving max power in these tunes, it was 14.5:1 and higher to about 15.5:1, he said for a street application where ware rate ect was an issue he would probbably richen by 0.5 afr for safety.( ie 14.1 to 15.1)

the fact is that N/A engines dont need extra fuel thrown down the bores to cool the pistons and valves!

fit a bigger rad and oil cooler and use high quality oil if you want engine protection. that will dissapate heat, the bugatti veyron has 11 rads!

when i first ran my boosted engine i thought be rich to be safe, and had 12's and 11's from 95 kpa and the power was way down .

i have extra code so could tune spark, and advanced the spark untill it started to ping, retarded it by 3 deg and then leaned out the fuel again til it pinged, and the added 3 points to the map. the difference is amazing, and fuel consumption is lower too!

with n/a you dont need to richen it up, tune for power not numbers, then add a bit of fuel for safety.

jhodg5ck · #62 10-01-2009, 05:07 PM

With spending time dyno'ing M117 5.6 SOHC, 6L DOHC, and M119 5 & 6L E's they very much like to be rich, ie down in the middle 12's for max power.

Just look @ the early vs late M119's, early w/ their 320 odd HP all had WOT enrichment. 94 and later did not, peak power fell about 15hp.

FI cars vary in Just how much fuel they want....Porsche 930's being the Most demanding w/ peak power #'s coming in @ a fuel soak 10.X-1....!

Jonathan

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Joreto · #63 10-02-2009, 05:28 AM

Quote:

Originally Posted by nick.ged

forgive me if im wrong but on a non boosted engine afr doesnot have to be so rich, max power on gasolen is made at 14.7 to 1

any extra fuel above 14.7 1 is only to cool the engine down

no this is wrong, 14.7:1 is the stoichiometric (all the air and fuel are burned) mixture for gasoline engines, the mixture for max power depends on the given engine but commonly it's between 13:1 - 12.5:1 . Turbo engines run on the rich side for two purposes, one as you said is the cool the combustion chamber and avoid detonation (help to same extent but there is a limit) the second is a precaution, bad gasoline or say an injector gets dirty and doesn't squirt well or a fuel filter gets clogged up and so on. I always like to run on the rich side (i.e. ~ 11.5:1 - 12:1) when in boost since it's better to be on the safe side even if I lose 10-15 hp .

Quote:

Originally Posted by nick.ged

with n/a you dont need to richen it up, tune for power not numbers, then add a bit of fuel for safety.

this is also true for FI, tune for max power but usually tuners then back off the ignition for safety (say different grades of gasoline ).

JayRash · #64 10-02-2009, 06:44 AM

Quote:

Originally Posted by Joreto

no this is wrong, 14.7:1 is the stoichiometric (all the air and fuel are burned) mixture for gasoline engines, the mixture for max power depends on the given engine but commonly it's between 13:1 - 12.5:1 . Turbo engines run on the rich side for two purposes, one as you said is the cool the combustion chamber and avoid detonation (help to same extent but there is a limit) the second is a precaution, bad gasoline or say an injector gets dirty and doesn't squirt well or a fuel filter gets clogged up and so on. I always like to run on the rich side (i.e. ~ 11.5:1 - 12:1) when in boost since it's better to be on the safe side even if I lose 10-15 hp .

this is also true for FI, tune for max power but usually tuners then back off the ignition for safety (say different grades of gasoline ).

True, ideally one would aim for 13 AFR for best power.

nick.ged · #65 10-02-2009, 03:02 PM

http://www.bristoldyno.com/tech/airfuel.htm

stoich meand all petrol is burnes, how can extra petrol make more POWER.

n/a engine should be set to stoich, then either add a bit of fuel, or loose a bit of timing for road engines to make them last a while.

jhodg5ck · #66 10-02-2009, 04:14 PM

Well aware of what stoichometric means & that under Ideal conditions that's what Should be.
However, in the real world where things are not Ideal I've spent the Hours of time on the dyno, even chatting w/ Hartmut they found the Same thing back @ AMG.. Mercedes like to be on the Rich side of things for max power...

I've demonstrated as much to my self Many times on the dyno and have no plans on sending my cars out running 14.X-1 @ WOT!

Jonathan

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JayRash · #67 10-02-2009, 05:00 PM

Quote:

Originally Posted by jhodg5ck

Well aware of what stoichometric means & that under Ideal conditions that's what Should be.
However, in the real world where things are not Ideal I've spent the Hours of time on the dyno, even chatting w/ Hartmut they found the Same thing back @ AMG.. Mercedes like to be on the Rich side of things for max power...

I've demonstrated as much to my self Many times on the dyno and have no plans on sending my cars out running 14.X-1 @ WOT!

Jonathan

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From hearsay, the W202 C36 is set by amg at 13 to 13.1 on WOT. Can u confirm?

i know my M103 300e Runs at 12.5 almost at WOT

jhodg5ck · #68 10-02-2009, 05:54 PM

I'll have to hook up my wideband w/f meter and play around.. I need to do motor mounts so I'll likely add the extra bung @ the same time.
Once I have some #'s I'll post em up!

Jonathan

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RBYCC · #69 10-02-2009, 10:28 PM

I'm running 11.7:1 AFR on boost for max power.
MAPS were entered while on a dyno with input from a wide band O2 sensor.

jfilipcic · #70 11-24-2009, 04:51 PM

any updates?

JayRash · #71 11-25-2009, 01:31 AM

Quote:

Originally Posted by jfilipcic

any updates?

From my end (C36AMG) nothing really, as i am tight on time and funds :S
so my MS plan will have to wait,

400Eric · #72 11-25-2009, 03:59 AM

I still think that you ought to be able to make decent power with the Bosch Motronic that is already in the car. There are people making good power with that system. Can't somebody here help Jay with that?
Regards, Eric

Joreto · #73 11-25-2009, 05:31 AM

Quote:

Originally Posted by 400Eric

I still think that you ought to be able to make decent power with the Bosch Motronic that is already in the car. There are people making good power with that system. Can't somebody here help Jay with that?
Regards, Eric

In my opinion if Jay can find someone who can program/tune the Bosch Motronic that'll be the best route to go.

JayRash · #74 11-25-2009, 06:20 AM

Quote:

Originally Posted by Joreto

In my opinion if Jay can find someone who can program/tune the Bosch Motronic that'll be the best route to go.

I have someone who can reflash the ECU, all i need is either a modified map, or some software i can use and ill tune the car my self.

Between my friend and i we have gr8 knowhow on how to tune cars, all i need is some software by which i can open up the read map from the ECU and change the map values for fuel and timing.

I can use the on road live data of the DAS to fine tune for knock. and i already have a wide band to tune the AFRs.

@Eric,
Its knock control on this system that is really limited, its only half a step up from that on the KE M104s!!!!! the old one listened to knock and pulled a max of 6 deg across the range, i believe the ECU used same tricks you and i know abt the reference R16/1 and cutting the CTS line going to the EZL.

As for the HFM well it pulls a max of 9 point in case of knock for the Cyl knocking. and although 9 point should be enough to kill any knock going on it did nothing to save my HG.
So i now believe my knock sens are deaf, thou they haven't thrown a fault in any of the scans i have done.

AMGc36 · #75 10-18-2010, 02:56 PM

well i am thinking of turbo charging my 1996 c36 and i dont know what to do about the resonance flab and the variable valve timing so if u finished ur project maybe u can help me