DIY_EFI Digest Saturday, October 9 1999 Volume 04 : Number 569 In this issue: injectors Re: DIY_EFI Digest V4 #568 Message from CSH, HQ Re: How completcated does Efi HAVE to be? Date: Sat, 9 Oct 1999 14:12:14 +1000 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 8 Oct 1999 15:51:58 -0400 (EDT) From: justin w ivan und stnt Subject: injectors Can anyone point me to a good source of Porsche injectors. I am looking for a stock set from a 944 turbo? They do not have to be new as I would send them out to get cleaned anyway but I am looking for an inexpensive source. The best price I have found is $68 a piece but if you can get mustang injectors for $125 for a set of 8 I think you should be able to get the 944 injectors cheaper. Also can anyone tell me the correctr way to size intercooler piping for a turbo car? Should it be the same size as the turbo outlet, Throttle body or the endcaps on the intercoolers. Anyhelp would be appreciated. Justin ------------------------------ Date: Fri, 8 Oct 1999 17:23:30 -0700 From: rpettibo@xxx.com Subject: Re: DIY_EFI Digest V4 #568 This conversation is very interesting to me because I rely on a wide array of sensors on my project and find that each one is necessary. I hope people do not try to invest in fuel injection with the tought of keeping it simple will keep it cheap and then I can aford to upgrade. I think this is the wrong approach to fuel injection. My experience is it cost MONEY to do it and do it correctly. The question is not so much how complicated does EFI have to be but how sophisticated. None of these sensors or triggering devices for fuel or spark management is that complicated. The value of them is in the ECM's ability to read them and through precise programming, by you or the computer defaults, modifying the fuel and spark events for best power and torque. If you truly want it simple, put on a 3310 Holley. If you want the benefits of injection spend the money and the time to install all relevant sensors, have the ability to monitor and record them, spend the time understanding what they are telling you and utilize this data to dial in the system. This is the area you will spend the most time and effort in and it will be worth it. Be sure you also invest in systems which allow you to directly interface and change programming in the computer. Based on your sensor data, RPM, LOAD (VAC), THROTTLE POSITION, O2 READING, H2O TEMP AND INLET AIR, you will be able to dial in your system at that point of engine operation. To dial in a fuel injection system you may have to dial in as many as 256 fuel and spark map points for proper operation. As a side note the most valuable tool I invested into my EFI project (515 hp, 535 lb-ft sb Chevy) is an EGT system from Autometer. I monitor at least two cylinders at all times and record all peaks. The differences between being 10% lean or rich and on the money are definitely worth the price of admission. Invest the money and time to do it right.!!!! ------------------------------ Date: Fri, 8 Oct 1999 17:12:43 -0500 From: nacelp@xxx.com (CSH-HQ) Subject: Message from CSH, HQ Well CSH, HQ is back on line. Got one very good lung, (verified by X-Ray, by me). Amazing capacacity. Surgery was really tough, heart kept stopping, so got one of 2 possible lungs. Was so bad they turned anthesia was down, and I remember parts of it, that is something to be avoided, test me, on what a open heart messauge feels like. Have drop foot but down to using a cane for that, hopefully will finish clearing that out, soon. All in all, no pain. Or given enough medicicne to numb it, best part is 2 days after surgery, taken off O2, so no more pushing green bottles aroung Staff (of 7), here and eating out alll the time is getting expensive, so we bee making every effort to get back to acrcanum real soon ------------------------------ Date: Fri, 08 Oct 1999 18:22:49 -0700 From: Will McGonegal Subject: Re: How completcated does Efi HAVE to be? > > >sensor, which means you need the flywheel, transfer case and the actual > > >sensor. > > > > Surely it doesn't have to be *that* accurate? Why not use the coil? 2 per > > Rev should be enough, you only need speed not accurate position? > > No, it does. You have to have a very good accuracy (I think the minimum > is 6 "steps" per revolution) because otherwise the system will get > confused when the engine changes speed quickly. I did some calculations to check into what kind of errors you'd get on your speed under constant acceleration if you used a single pulse per revolution Speed [rpm]=> V1 = 60.0 / (T1 - T0) Case 1: Engine accelerates from 600 to 6000 rpm in 0.5 seconds (no load?!) The first revolution takes 0.063597837 seconds. The speed change is 600 to 1287 rpm. With that time period you'd calculate the speed to be 943 rpm. A 27%, or 344 rpm error. After 27 revolutions (0.494977295 s) the engine turns at 5946 rpm. One more revolution (0.010000405 s) later the engine is at 6054 rpm. We calculate that speed to be 6000 rpm (1 %, or 54 rpm error) Case 2: Engine accelerates from 600 to 6000 rpm in 5 seconds (0 -60 mph?) The first revolution takes 0.092327988 seconds. The speed change is 600 to 700 rpm. With that time period you'd calculate the speed to be 650 rpm. A 7%, or 50 rpm error. After 27 revolutions (4.989990984 s) the engine turns at 5989 rpm. One more revolution (0.010009016 s) later the engine is at 6000 rpm. We calculate that speed to be 5995 rpm (0.09 %, or 5 rpm error). Since case 1 is probably not normal operation, the error there is probably acceptable. If the case 2 error is still too high for a DIYer, then one could also calculate the rate of acceleration (from two (or more) time periods) and factor that into the speed calculation to get a value that is closer to the actual speed. I tried a simple acceleration calculation which reduced the error of the 1st revolution in Case 2 to 3 rpm. More pulses per revolution will increase accuracy but do all applications need it? I think you could do it with a pulse every second revolution and have it run better then a carburetor. Will McGonegal ------------------------------ Date: Sat, 9 Oct 1999 14:12:14 +1000 From: "Warwick Anderson" Subject: Date: Sat, 9 Oct 1999 14:12:14 +1000 hi all im new to the list and need some help iv got a jap import motor, a toyota 1ggze with out the supercharger(2 litre 24V DOHC) when thay remove these, thay just cut all around the motor till it comes out so the harness gets the chop. i cant get a new harness. i cant seem to get hold of a wiring diagram for this motor. i can get the ECU for it but this is not much good to me as i cant wire it up i was thinking about the efi332 project or using a GM unit mabe as i can get the wiring for GM stuff (used to work for em ) i would have to some how reprogram the GM unit as the toyota motor is only 2 litre. any body help please!! nothing worse than having a new toy that ya cant use ------------------------------ End of DIY_EFI Digest V4 #569 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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