Hi,

Im building a vintage rally car with m104 and 717.400 trans
WITH CARBS (3 dcoe webers) and megajolt timing

My first timing attempt was this


at 3200 feet alttitude and 91 pumg gas

the sounds of the carbs is awesome

the torque was great

7200 rpm without problem but I dont feel more power than 6500rpm

I tried more timing but knock sensor reads more noise and temp begins to raise.

I need to make 2 more timing setups, 1 for sea level and other for about 2000 feet altitude

advance cam is at 1900 and retards at 4000rpm

the engine never drops of 4200 rpm

All the time I'm from 4200 to 6000 rpm
load is from 60 to 80
33, 35 37 is the most timing that I saw

let me know your opinion

the car is quick, the engine is flexible, the rear end and trans ratio was the best

I dont want and I dont need an screamer, I need to use the torque of this great amg engine, I need reliability for endurance race

thanks

If you're using 40 DCOE's on a 3.6L engine, the above is probably due to the fact that you're flowing about as much air as those lil' 40's can at 6500, or you're running out of cam. But jayrash turns his 7 without issue, so I'd guess you're running out of air.

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1993 190E 2.6 Sportline

If Im correct I believe that jayrash engine is supercharged ? or is the one with bmw body throttle ?

my first attempt was at 3200 feet of altitude and 91 pump gas

40 dcoe originally came with 28mm chokes, I replaced with max size of 36mm, 36mm x 6 = 216mm, I dont know the conversion rate but is more air than original 70mm body throttle ( I don remember the exact size)

I believe that I have a lot of room for improvement, but fisrt time was great, of course with cold box, 100 octane fuel , and more timing I will achieve better results, but rules says pump gas.

I believe that my timing curve is conservative, but engine runs cool and Im happy

lambda gauge say that I'm a little rich but spark plugs looks great
at this moment I use 50, 200, 110 f11 weber setup

at this 7 days rally exist diferent stage, every day exist a speed stage, but this stage max speed range is from about 70mph or less with a lot of curves, then I need all the torque. from 4000 to 6000 rpm

mag58 ( I cant did it without your help, thanks)

My AMG is bone stock. No BMW intake or throttle and no sc. It has good power up to 6800 but it does feel it starts maxing the cam by 6600. So 7 is abt the max the engine in its state can rev. Any way if u calculate piston speed u will find 7200 is over any acceptable limit to have the engine running at for any period of time.

__________________
Jay,
-----------------
-1995 Blue W202 C36 AMG (M) SOLD ;(
-1995 Black W140 S500 (Lady)
-1992 Black W124 E300 (Dima) (Ex-Mosselman
Twin turbo Kit).
-1988 Black W124 300 E 4-Matic.(Nadeen)
-1983 Brown W126 500SEL.(Old Lady)(Sold)
-1981 Gold W123 280CE.(Dareen)(Sold)
http://www.youtube.com/user/jayrasheed

Thanks a lot for your answer

then Im in the correct way, 6500 rpm I will set the limiter to 6900 rpm

Do you use megasquirt ?, if yes, let me know your opinion about the timing chart

I already made 3 of them

sea level

about 2000 feet

3200 feet


I will test the effect with octane booster aditive

great about megajolt is that I can change the timing charts with a toggle switch

That is just way to much timing for a m104. Max timing at 100 % load should not really be more than 21-24 degrees. Put it on a dyno to verify. I am supercharged but regardless I see absolutely no gains in power past 16-17 degrees of timing. And very little past 15 degrees. Factory timing is about 18-19 degrees. When I first started tuning I saw major detonation at anything up in the 26-28 degree range at full load. That was n/a. Also the Mercedes knock sensors do not read the same as an aftermarket. It takes a significant amount of knock to trigger a signal on aftermarket ecus. I finally gave up on the Mercedes knock sensors.
Bottom line is I would really recommend pulling a lot of timing and putting it on a dyno to see what the motor likes. Most 4 valve center spark plugs do not need a lot of timing.

Nice car, nice project !

is 80 at WOT at 6000 rpm ? If yes then your carbs are restricting. If not, measure load at WOT at max rpm. If you're close to 100 % then your carbs are fine.

You should read advance at max load (ie readings at 100%). In my experience more advance is not always more power. I often hear that best advance is right before pinging. In my case max power is way before pinging. Dyno will tell you.

100% correct. Eduardocastrejon, have you verified your timing with a timing gun (very important on a megasquirt setup) ?

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190E 3.0-24v (M104 980) turbo @ 0.8 bar
1/4 mile: 2.483 / 13.540 / 175.17 km/h (street tires)