megasquirt - Page 2 - PeachParts Mercedes-Benz Forum

300EVIL · #16 03-09-2007, 10:07 PM

Quote:

Originally Posted by AustinsCE

I'm pretty curious about that myself. Take a 350 chevy stock does 180, but play with it and you're over 375+. I want to see someone play with a 100 engine.

The scientific property your inquiring about is Volumetric Efficiency, AKA, VE. How can a 500 cubic inch Pro Stock engine make 1200 HP?..... Volumetric Efficiency!

VE is the percentage of air moved compared to the engines actual displacement. So, lets say you have a 4 liter engine with a VE of 50%. That engine is only moving half of it's displacement which would be 2 liters of air every 720 degrees of crankshaft rotation.
My guess is that the 6.3 liter M100 engine has a VE somewhere around 75%. The new AMG 6.3 liter (I don't know the engine number) has a VE somewhere around 100%!That's where your big difference in power output comes from.

Now, how’s it done???? Cam profiles, head design, exhaust manifold, intake manifold, compression ratio, valves, ect.... That's how you move a stock Chevy engine from 180 HP to 375+.

Also, it is possible to achieve over 100% VE. A pro stock engine has a VE of over 115%! It actually flows so good that it forces more air than the displacement into the combustion chamber. Kind of a naturally aspired forced induction....

300EVIL · #17 03-09-2007, 10:36 PM

Quote:

Originally Posted by AustinsCE

300Evil- what are your thoughts on a different 3rd party ignition unit, like MSD, or you think integrating everything in the one MSII unit is better?

MSD is better for 2 reasons.
First let's look at the stock Megasquirt ignition driver. It's basically a transisitor that takes a 5 volt signal and turns it into a 12V signal to the ignition coils primary winding thus producing 25-35KV @ a couple microamps to the distributor and ending up at the spark plug...... little spark

Now, the MSD does this better by amplifying this 5 volt or so signal to 575 volts with about 15 or so amps behind it. With this amount of power going to the coils primary, the secondary output of the coil is about 45-55KV @ a couple of milliamps! OUTCH! BIG SPARK!!!

What this effectively does is ignite the fuel in the combustion chamber faster when it fires. It's like starting a pile of wood on fire with a blowtorch versus a match.

An engine will make a little more power, precicely if you are able to produce a large flame front in the combustion chamber. The MSD ignition system does exactly that. Just don't expect to make a great difference. We're talking like a 2-5% power increase. This is why some engines have 2 spark plugs per cylinder. They can produce two flame fronts at once thus a quicker burn.

The second reason is in the name. MSD (Multi Spark Discharge) The idea is that a number of sparks happen in the cylinder per power cycle thus the turbulent mixture ignites in many places during the event. In effect this is like starting a bonfire at four locations around the pit versus just one. There is some controversy around this theory but it does make sense.

300EVIL · #18 03-09-2007, 11:04 PM

Quote:

Originally Posted by wbain5280

To add to what Mr. Evil

wrote, the old 6.3 V8 is a cast iron block with aluminum heads and Bosch mechanical FI. It produced gobs of torque.

The new 6.3 is a low friction engine all aluminum engine producing lots of HP with a modern FI system.

Yes, low friction does help..

300EVIL · #19 03-09-2007, 11:37 PM

Quote:

Originally Posted by squarebush

I know what you are trying to say, I meant replacing the distributor with an electronic ignition firing box it is actually under the megaspark project. anyways I am also not just talking about a little switch but a little software cue that feeds a different set a values. I guess what I am really going to do is borrow one of the small handhelds laying around the house and use them to talk to the system.

Ah, Megaspark. Just a pre-megasquirt II bandaid. don't give it a second thought. What you want is distributorless ignition. Go to a junkyard and get a Ford EDIS8 system, $30-$40 and your all set. The software is already avalable and is fully adjustable for advance/retard.

As for using a handheld to load map settings, software is only avalable for MS I the only handheld software avalable for MS II is a data logger. You can get an MS I and load different maps as you describe but you will be happier with an MS II and a small/cheap laptop.

Quote:

Originally Posted by squarebush

I am still learning the subtle facts about cars but I am open minded and ready to listen

Admitting it is the first step!

In all seriousness, I'm still learning myself. If I knew everything, a lot of pro tuners in drag racing would be out of a job. I'm glad your willing to learn though. Many passers by think they know something because of their best friends brothers uncle told them so. The willingness to learn and understanding is the key to moving foward in the performance world.

squarebush · #20 03-10-2007, 12:45 PM

Quote:

Originally Posted by 300EVIL

Ah, Megaspark. Just a pre-megasquirt II bandaid. don't give it a second thought. What you want is distributorless ignition. Go to a junkyard and get a Ford EDIS8 system, $30-$40 and your all set. The software is already avalable and is fully adjustable for advance/retard.

As for using a handheld to load map settings, software is only avalable for MS I the only handheld software avalable for MS II is a data logger. You can get an MS I and load different maps as you describe but you will be happier with an MS II and a small/cheap laptop.

Admitting it is the first step!

In all seriousness, I'm still learning myself. If I knew everything, a lot of pro tuners in drag racing would be out of a job. I'm glad your willing to learn though. Many passers by think they know something because of their best friends brothers uncle told them so. The willingness to learn and understanding is the key to moving foward in the performance world.

I am planning to go into mechanical engineering with an automotive focus. I am trying to make the transition between pedal powered mountain bikes to internal combustion engines. I've got the fundamentals for the most part, but somethings I have taken for granted... thus why I sometimes say dumb things or reach bazaar conclusions. usually I don't think how dumb something is until some one points it out and then I can't believe I ever came up with that.
Honestly though, I say something wrong and some one corrects me, that is the end of that, I am not set in my ideas, I am just trying to learn

squarebush · #21 03-10-2007, 12:48 PM

oh and on that note, I am having a little problem with the relay board. . . I need 3 relays, I don't know much about relays. I know how they work and what they are made of and the principles, I don't know the ratings at all.

Megasquirt gives a part number but it doesn't match the digi-key catalog... so I have no real starting place. Any idea what sort of rating or markings I should look for? I have a lot of parts in my room so I need to know if I can use what I have or go out and get something different.

squarebush · #22 03-10-2007, 12:50 PM

oh and the ones I need are http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1Z312JAVT21A0RI7YS&year=1972&make=MB&model=280-SE-002&category=P&part=Fuel+Pump+Relay
$83!!!!
what do I need instead?

300EVIL · #23 03-10-2007, 07:21 PM

There's no dumb questions, only dumb answers.

Here's the type of relays your looking for. http://www.partsexpress.com/pe/pshowdetl.cfm?Partnumber=330-073&raid=55&rak=330-073 These are 12V 30 amp relays and will be able to handle any vehicle switching needs except for the starter.

squarebush · #24 03-11-2007, 09:31 AM

awesome that was what I wanted to know, 30 amps, I suppose if I had looked at the fuse I could have figured it out.
$1.39 hmmm that is alot better then $83.03 haha

pentoman · #25 03-13-2007, 09:05 AM

I'm sure I saw an S-class put on aftermarket management, in fact it was in a magazine (but online) and it was a whole article about doing it. I think it was a pre-W126 model, which ever that is? But I could be wrong.

might be useful, sorry I can't be more specific. Oh yes I'm reasonably confident it was done in Australia.

squarebush · #26 03-13-2007, 09:37 AM

Quote:

Originally Posted by pentoman

I'm sure I saw an S-class put on aftermarket management, in fact it was in a magazine (but online) and it was a whole article about doing it. I think it was a pre-W126 model, which ever that is? But I could be wrong.

might be useful, sorry I can't be more specific. Oh yes I'm reasonably confident it was done in Australia.

oh, like a w116, original s-class? The people next to my girlfriend have one sitting in their drive way, it hasn't moved for at least a year. . . I so want it, I might ask them about it. My parents would kill me if I got it, well actually maybe not. . . we do need a second daily driver for the winter since my Florida 280se lives in the garage

I found an older model 250c left for dead and asked the people about it, they said their friend was going to have it restored, and the Lincoln continental I've had my eye on for two years finally disappeared, I love dreaming about all of the old forgotten cars you see around you, I might start doing a photo documentary on them.

New engine management isn't hard, if you know about cars, it is jumping in the deepend hoping to learn about cars by completely re-engineering one is where it gets hard.

I just scored a major cache of supplies and I am really on track now, I've sorted all of the wiring through the fuse box and fire wall and I think I have just about every circuit figured out, accept I may have forgotten which wire goes on which side of the coil. . .

I think I wrote it down though

I am not that bad.

oh yeah, look for that artical, I think I would like to take a look!

300EVIL · #27 03-13-2007, 10:27 AM

Here's the article:
http://www.autospeed.com/A_0001/cms/article.html

AustinsCE · #28 03-13-2007, 01:00 PM

Quote:

Originally Posted by 300EVIL

MSD is better for 2 reasons.
First let's look at the stock Megasquirt ignition driver. It's basically a transisitor that takes a 5 volt signal and turns it into a 12V signal to the ignition coils primary winding thus producing 25-35KV ...

Thats what I figured, didn't know exactly what the MS did, thanks for the input.

Matt L · #29 03-13-2007, 01:52 PM

I think this is mostly MSD Kool-Ade.

A "normal" system sends an AC spark impulse to the plug. There isn't just one spike of DC current. I do believe that MSD produces a stronger spark than a points system, but I don't believe that they have much on a stock electronic system.

Also, a hotter single spark is NOT AT ALL similar to having two plugs. Two independent flame fronts change things enough that you have to retard the spark several degrees for best performance. A stronger single plug will resist fouling better. I am extremely leery of any claims of increased power in the absence of misfiring on the stock system.

alabbasi · #30 03-13-2007, 04:20 PM

Quote:

Originally Posted by Matt L

I remember from my SAAB days that the D-jet MAP sensor is quite expensive. What does it cost for a M-B?

I make sure that I pick one up every time I was past a w108 at a junk yard. I had horrible issues with my 4.5 for the longest time. It turned out to be a duff computer. I now pick those up at every opportunity.

Since I replaced the MAF and the computer, the car runs like a train.