DIY_EFI Digest Saturday, June 26 1999 Volume 04 : Number 380 In this issue: DIY Silicone hoses... DIY_EFI Digest FMU, rising rate regulators and other non linear fuel devices on MAF based systems GM '89 Bosch MAF - was RE: MAF & base fuel tables See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sat, 26 Jun 1999 14:11:43 +0200 From: =?iso-8859-1?Q?J=F6rgen_Karlsson?= Subject: DIY Silicone hoses... Hi guys! Does anyone know how to make custom shaped silicone hoses? It is a bit of topic but most turbo guys probably need one sooner or later. Jörgen Karlsson jurg@xxx.se jurg@xxx.net http://come.to/jurg http://quattro.tsx.org ------------------------------ Date: Sat, 26 Jun 1999 09:09:43 -0500 From: Jason Haines Subject: DIY_EFI Digest I somehow got switched to the digest list - anybody know why this would have happened? Jason ------------------------------ Date: Sat, 26 Jun 1999 09:40:07 -0500 From: Jason Haines Subject: FMU, rising rate regulators and other non linear fuel devices on MAF based systems I was wondering if anyone has had any experience with using FMU's, rising rate regulators and other devices that change the effective fuel injector delivery in mass air flow (MAF) based systems that have had an aftermarket supercharger or turbocharger installed. It would seem to me that the FMU or similar device would compound the ECU's calculated fuel delivery unless you were at the maximum duty cycle of the injectors (and the ECU couldn't command anymore pulse width). With the ECU not knowing how large the injectors really are (with the rising fuel pressure and unless the ECU has a fuel line pressure look up table similar to some of the MAP based injector flow look up tables), the ECU will provide too much fuel unless it can't command anymore. Does this make sense? In a non MAF based system such as a speed density system where the ECU does not recognize positive manifold pressure so it cannot compensate for the added cylinder filling, I can see how a FMU or similar device could work reasonably well but I see a problem in MAF based systems. It would also seem that you would only want the FMU or rising rate regulator to come into effect when the ECU no longer looked at the O2 sensors for fuel trims so that you don't have very large fuel trims from the changed fuel flow. Jason - --------------------------------------------------------------------- Jason R. Haines jhaines@xxx.com Lingenfelter Performance Engineering 219-724-2552 / FAX 219-724-8761 1557 Winchester Road, Decatur, IN 46733 USA http://www.lingenfelter.com catalog, shop talk and more sales@xxx.com sales and tech questions - --------------------------------------------------------------------- ------------------------------ Date: Sat, 26 Jun 1999 12:26:33 -0500 From: Jason Haines Subject: GM '89 Bosch MAF - was RE: MAF & base fuel tables Does anyone know of a mass air flow sensor (MAF) that has higher flow than the 1989 GM Corvette Bosch MAF that also gives a 0 to 5 volt output like the Bosch sensor does? Something that gives higher than 255 g/s at 5.0 volts (double would be nice). Some European car has to use a Bosch sensor and make over roughly 350 hp with just one sensor (I see a lot of the newer high output cars are using two sensors). I have been trying to use a frequency type with a frequency to voltage converter but it is not working very well and I would rather just put another voltage based MAF in and figure out the airflow versus voltage table for the new sensor. I have even tried using a "drop" in Ford MAF from Best Products that is supposed to replace the GM Bosch sensor but that has not been working very well either so far. Thanks, Jason ------------------------------ End of DIY_EFI Digest V4 #380 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".