Dave, Do you have a digital camera that can take short videos (<30 seconds)? If so, there is a perfect co-pilot -just set the camera up so it can see the speedometer and EGT. And you can share the run with fellow listers too :)
Andy P.S. If you don't have a camera that can do this, here is the perfect excuse! On 7/10/05, Dave M. <[EMAIL PROTECTED]> wrote: > Andrew, > > I don't have any data on the rate of increase, as it's simply too hard > to capture. All I can do is note the start and end temps on a > zero-to-whatever WOT run, either time or distance. If I had a second > person who could watch the gauge and write down data during the run > that might work, but I don't have the free time at the moment. At > ~100mph it's up to approx 1300F with the fuel delivery increased 0.5 > turns. > > About peak temps, you should read my post here: > http://buymbparts.com/forum/showthread.php?t=395 > > What I'd add to that is I would be comfortable running up to 1300F but > I would probably back off at 1350F, and I'd prefer under 1300F for > extended periods. Even without WI or IC, I almost never see anything > close to these numbers in normal driving. > > About the boost controller, I think that may be overengineering things > a little. There's no advantage to extra boost with a cooler engine, > etc. I make the same power with 12psi that I make with 17psi and so > far I can't see ANY advantage to running higher boost pressure than is > needed to make peak power. It would just increase backpressure > pre-turbo and subsequently increase EGT's. Now if we're talking about > replacing the stock turbo with something different, that's another > story (and much more complicated.) > > What I *would* be interested in some type of thermocouple safety > switch, that would kill the ALDA signal line if EGT's exceeded 1400F > or so. That would be nice for a little peace of mind on a 'tweaked' > motor. On a side note, it's my current belief/theory that Mercedes > installed the overboost circuit NOT because the pump can deliver more > fuel than needed for factory power specs (it can't), but because if > the wastegate jams closed and boost goes to 18+psi, the EGT's could > get beyond safe levels and cause damage. I'm not sure Marshall would > agree, and I don't have any proof at the moment, but it's something to > kick around in the ol' noggin. Note that later (1990+?) OM60x engines > deleted this circuit but I think they simply had other computer > controls doing the same thing, just in a different way. > > :-) > > Best regards, > > Dave M. > Boise, ID > > > ---------------------------------------------------------------------- > > Date: Fri, 8 Jul 2005 20:38:28 -0400 > > From: Andrew Cunningham <[EMAIL PROTECTED]> > > Subject: Re: [MBZ] Turned up fuel on OM603, sans IC or WI > > > > Dave, > > > > I was looking for the rate of increase during the run not just the end > > points. Within a typical (current config no WI) 0-100mph run how many > > seconds does it take to get to 900, 1000, 1100, 1200 ack 1300? > > > > The other thing that I was wondering was how long (seconds/minutes?) > > would you be confortable running at 1200F? If you could run WOT for a > > minute, what would you consider your max temp? > > > > The reason why I am asking is I am designing a boost controller with > > an EGT Type-K feedback. This would allow more useable boost (maybe > > 16psi+) earlier when the engine is cooler and slowly reduce (down to > > maybe 10-11 as needed) the boost to prevent EGTs from going too high. > > You keep the pedal to the metal, as temps increase the boost drops > > which also reduces exhaust back pressure. I have a few complete > > designs that I am considering. > > > > I am at the beginning design stage of an injection pump controller > > that adjusts the pressure signal to the ALDA. The basic concept is to > > adjust the fuel delivery based on the intake temperature and pressure. > > I don't have all the pieces or figured out how it will all connect > > yet, but I am learning how to program a microcontroller to handle the > > adjustment. > > > > Charge density should be proportional to the absolute pressure / > > absolute temperature. Typical charge density is around 0.05 psia / K > > with no turbo and maybe up to 0.10 psia / K with an intercooler. > > NOTE: the EGR must be disabled for this to calculation to determine > > how much air you have to burn. > > > > At a given charge density, there should be an ALDA pressure that > > corresponds to a near perfect match for the fuel. This way, when you > > floor it you will have exactly the fuel you can use based on how much > > air you have to burn. The trick will be to use a 10 point calibration > > curve from no turbo all the way up to full boost. > > > > One thing that I haven't confirmed yet is: > > On a given 617 injection pump, the pump squirt/rev is independant on > > the actual rpm. i.e. if the throttle position and ALDA pressure is > > the same at 1000 rpm as 4000 rpm, will each rev of the engine will > > inject the same amount of fuel? > > > > Anyone know if that is the case? > > > > Thanks, > > Andy > > _______________________________________ > For used parts email [EMAIL PROTECTED] > For new parts see www.buymbparts.com > For repairs see www.oldworldauto.com > > To Unsubscribe or change delivery options go to: > http://striplin.net/mailman/listinfo/mercedes_striplin.net >
