Anybody remove their MAF screen? Did you see any gains?
I did that in 1987 when I had a Corvette. Saw no gains and a freshly oiled K&N set of the MIL light. Did the same in 1998 when I had an Audi, same thing, no gain and had to "lightly" oil the K&N. There was a chance that removing the screen may let the nichrome wire get dammaged if debris hits it. Not expensive in a 'vette or Audi, but I won't chance it for a "plecebo" HP gain in my 355 JD
There is also a chance you will screw up the metering efficiency of your MAF. The screen isn't there to 'catch debris". It's a silly/sad form of flow straightener, and as silly/sad as it might be, the characteristic curve of that MAF was calculated/measured with it. Remove it and "all bets are off". In short, don't! Jim Conforti
I cant believe the screens are really that important. Never spent a lot of time learning about fluid dynamics, but how disproportional can the air flow really be? Just for my own entertainment Ill plot MAF curves with and without the screens. Having looked all over the net and finding so many conflicting opinions, I think that its time for some empirical data. Jeff, I still cant get any good info on those Denso cops.
I was bored one day and removed mine to see what happend . It semmed to drive fine for awhile then it would die at stoplights .Put it back and all was good .
Don't think there's a good secification comparison / p.n guide for all the Denso Coil-on-plugs out there. Each motorcycle manufacturer has their own specs and see's if Denso has an OEM application. When I did my conversion, I just looked for the appropriate length and made sure the primary and secondary resistences of the coil sticks would work with the DIS4. I have no clue what the output voltages are, but that since they run in highly stressed Sport Bike applications, they should be OK with the 355. I also saw them being used in a Nissan GTP race car at the Historics last time at Road Atlanta when the car had its engine cover off in the paddocks. JD
Thanks Jeff. Well, before I went any more crazy, I did some reading and have come to the conclusion that the screens do serve a useful purpose and their air flow resistence is inherent part of the design. Crap. Maybe back to the two MAF idea ala 360?
DON'T REMOVE the screen, on many cars it is there to smooth out the flow into the meter, reduce turbulence. If you remove it you may get incorrect air-flow readings.
Mark, they are. Feel free to google my name If you want to increase the airflow, you can change the MAF to a (physically) larger unit that is electrically compatible, and then: 1) Redesign your intake system to use it properly 2) Reprogram the Motronic ECU(s) to handle the new transfer function You could also go to 2 MAFs, but that would require an offboard CPU to "combine" the signals to provide one unified MAF signal unless you are very very handy at writing code for the Intel 87C196KN processor in your M5.2 Motronic and also had the tools to program the Bosch CC460 memory chip in said Motronic. Jim Conforti PS: Plotting the transfer function of a MAF is a very difficult thing to do unless you have some pretty PITA equipment.. a MAF flowbench is about 15' in length to "do it right". Your MAF maxes out at 1038 kg/hr of air, the transfer curve is programmed into the DME as a table of 256 16 bit words. I can send it to you if you want.
Jim, where have you been hiding? My 355 currently uses a single Bosch 0 280 217 800 MAF. The MAF also has these other numbers on it: 1 702 078 and 769 01 1 A. The later being a hot stamp. The present induction system has two air filter boxes that lead into a Y tube which leads to the single MAF. The system then splits at a second Y that feeds the two intake plenums. My plan is to re-plumb the system without the Y fittings into two parallel systems . Im thinking about using 2 MAFs with their signals processed into a single signal that looks, to the 5.2 ECU, as if it was the original MAF. Getting real data on these, and any other MAF, seems to be like asking for the secret of life. If you can send me the plot for my MAF it would save me a ton of time. I was going to wire a data logger to the car and drive around to get it. ;-) I would use the RPM, estimate of 88% VE, and, temperature to guess the mass of the flow. At this point you might be asking youre self, why? Well, Im thinking that I can see an improvement in VE. Im not looking for an overall improvement in HP. Im more concerned with the slew rate.
these stupid sensors pretty much control your whole Ferrari experience, whether you will love the car or curse it . Don't even get them wet when you wash the car...I had mine rebuilt and it totally changed the drivability of the car...there are so many electrical bugaboos and gremlins with the 348, you really don't want to mess with the MAF...they give the ECU's key info that can make your life hell, if they are off.
Doing all the low voltage wiring at my new home under construction... (tele, data, sat, alarm, home automation, cctv, etc) You're welcome to join me That's the same meter as the V8 (540) BMW's.. easy to find. Jim
Jim, if you lived closer, I would. Do you have a plot for that MAF? I am curious as to how it works at low flow rates. If I implement a split feed and effectively halve the flow, will I still be in a good place on its curve? I do not what to pull you away from all the fun you are having, so if you can recommend a source for this kind of stuff, please let me know. By the way, you sound like my kind of idiot. I insist on doing most of my own work. I would rather spend money on specialty equipment that I may never use again, buy and install the equipment myself, sweating, cursing and sometime bleeding, than just hiring someone else to do it. Anyway, back to the MAF. All the books I have bought so far have been worthless. No good data, either they talk at a very high level or they are more of a repair manual. Personal Vent: Ive always considered high level to be an oxymoron.
Unfortunately there IS no "good source". There is no proper information on Bosch ECU's outside of Bosch. Jim
Looks like its time for me to actually do some work. My plan is to get 2 MAFs (3) in addition to the large one (4) currently on my car. Ill insert the other two MAFs into the induction system after the Y connector and just before the plenums. Ill log the signals from the three MAFs and create a map. Ill post my progress through this little journey. PLEASE, if Im doing something that could end very badly, speak up!
