Hey everybody, the only mod I have now is the pilo intake but even before that, there has always been something peculiar about the powerband of the engine. If you are going WOT and get to 3k RPM, the engine sounds like the a/f mixture gets very rich, you could tell by the way it sounds, like it's just a lot more gas it's trying to process. This condition stays like this all the way till mid 4k RPM. In the 3k RPM it's the most noticeable because it feels like it should be making a lot more power than it really is, so it lags and you have that 'deep' rich sound coming from the intake. This engine overall though with just an intake, is pretty intense, on cool days especially. The top-end is just magnificient, but it sounds like the power is being dictated purely by the ECU settings because you feel the same difference in pull after about 4.8k RPM's almost everytime. It is kind of like my parents E320 MB, that feels like the power is limited purposely at distinct points as well. For those who have the latest and greatest ECU upgrades, is there a change noticeable from specifically, 3k RPM and above? I am just wondering if it truly is just an excessively rich mixture that attributes to that sound and power output in the mid-range, or is it simply the naturaly tendency of a supercharged engine?? I would love to hear a bit of info on this, the more I learn the more fun this car gets :smile:

 

I can't speak specifically to the engine in the MCS, but in general, forced induction cars come from the factory tuned to run on the rich side. The risk in running too lean is high EGT's which leads to high warranty $ for the manufacturer.

 

I don't believe anyone other than Smokey Yunick could tell how rich an engine is running by the sound of it.

The MCS starts out rich and gets richer all the way to the top rpm range.

 

>>I don't believe anyone other than Smokey Yunick could tell how rich an engine is running by the sound of it.
>>
>>The MCS starts out rich and gets richer all the way to the top rpm range.

Why only him? I was very into racing 1/10 nitro sedans for a few years and now it's just seldomly and tuning those engines needed to be precise, so listening to the exhaust output helped let you know how find the mixture is running. Granted, those were 2-strokes with carb's, 4-strokes are different but the sound behavior of them can still transfer over.

 

>>>>I don't believe anyone other than Smokey Yunick could tell how rich an engine is running by the sound of it.
>>>>
>>>>The MCS starts out rich and gets richer all the way to the top rpm range.
>>
>>Why only him? I was very into racing 1/10 nitro sedans for a few years and now it's just seldomly and tuning those engines needed to be precise, so listening to the exhaust output helped let you know how find the mixture is running. Granted, those were 2-strokes with carb's, 4-strokes are different but the sound behavior of them can still transfer over.

I used the temp to check if the engine was running rich, like with a temp gun or one of those on-board temp gauges. sound isn't a very good gauge of fuel intermix as it can vary greatly from pipe to pipe. (you are running an O.S. CV aren't you? CVEC pipe or robinsons or Picco?)

 

I trust my wideband air/fuel meter even more than Smokey.

 

>>I used the temp to check if the engine was running rich, like with a temp gun or one of those on-board temp gauges. sound isn't a very good gauge of fuel intermix as it can vary greatly from pipe to pipe. (you are running an O.S. CV aren't you? CVEC pipe or robinsons or Picco?)

I use a iR temp gauge as well now, helps a lot but it's not the ultimate, it's just an aid b/c it doesn't reveal how well the entire low to high end performs specifically. It's a PiccoP12 with the Paris turbo ring pipe.

 

I for one am very interested in understanding what you listen for to distinguish the differences, if you can even explain online without audio samples.

Jim

 

Here's what I logged on my '03 MCS, totally stock and with the 15% pulley.

 

Hey Andy, Why does this thing run so dam-n rich?

I mean air:fuel ratio of ELEVEN at 4500 RPM????

 

Siemens does not seem to have the same engine management skills that Bosch does. 8.5:1 CR, not THAT much boost, and ludicrously rich mixtures. That just doesn't make sense. I'm tempted to try an adjustable fuel pressure regulator to see how leaning out the mixture affects power and timing.

 

>>Siemens does not seem to have the same engine management skills that Bosch does. 8.5:1 CR, not THAT much boost, and ludicrously rich mixtures. That just doesn't make sense. I'm tempted to try an adjustable fuel pressure regulator to see how leaning out the mixture affects power and timing.

You could be feeling the fuel pressure regulator kicking the pressure up as the boost starts to build around 3,000 rpm. Do you have a stock or reduction pulley? I used to get a little flutter as it kicked in.

Andy: Run your curves without the regulator. You won't need the 'puter to feel it running (safely) leaner. I'd be very interested to see how the WOT A/F curves then compare with the stock AND the EVO ECU A/F map.

 

BlueMCS wrote:
No way. Not unless you have a spare engine I can use.

 

John does :smile:

The A/F meter running of the existing O2 sensor is still 1/3 into the rich range. WOT with the regulator is maxed out at 2/3 into the range. Part throttle A/F indications seem unchanged as they should be.

I have water injection so I am not worried but I don't think (it doesn't FEEL like) its running too lean.

 

>>BlueMCS wrote:
>>>>
>>No way. Not unless you have a spare engine I can use.

OOOPS!!!

Sorry, forgot that you're EVO'd. You don't want to do it (not that you would) as you would be too lean.

 

I don't have an Evo chip.

 

>>I don't have an Evo chip.

Ahhhh, that's right. Andy w/no chip=jlm w/chip.

Can't keep it straight without a program.

Go4it