John Scott Posted June 4, 2000 Share Posted June 4, 2000 One or both of you migh give me some advice here. Being computerized FI illiterate: Rick, how does your after market FI system work with the supercharged boost? How much freedom do you have with the fuel curves. Lets say driving from 4000 to 13000ft altitude, will it sense the change and adjust accordingly? I'm playing w/ the idea of the Syclone double batch FI system It has the L98 corvette throttle body. Wondering if it could be run from an aftermarket system like yours?? Scott, do you know if the Sy/Ty injection system can be run from aftermarket computer systems? Stock system upgrades for high 18+ psi boosts? Thanks! [This message has been edited by John Scott (edited June 05, 2000).] Quote Link to comment Share on other sites More sharing options...
John Scott Posted June 5, 2000 Author Share Posted June 5, 2000 Scott, found a guy who builds a custom chip for the turbo. Still shy of the 18 psi though. JS Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted June 5, 2000 Share Posted June 5, 2000 John: I'm going to talk about Accel's DFI engine mgmt system cause it's the one I know best. Electromotive, Haltech, et.al., are similiar in configuration and operation, and I'm sure, work well. The DFI sys is both fuel mgmt and ignition control. The sys is very GM compatible and uses the same sensors and elect connecters. Like most newer (86 & newer) computer controled cars, It has a water temp sensor, air temp sensor, throttle position switch (TPS), idle air controler (IAC), O2 sensor, air flow speed/density (Ford is mass flow sensitive), and the all important MAP (manifold absolute pressure)sensor. This sensor is going to answer most of your questions. Starting with the 1st sensor 1) Water temp sensr tells the ECU that the temp of the coolant is below operating temp and to run the injectors richer-it is your electronic choke. 2) Air temp sensor tells ECU that the temp of the ambient air. Depending on the temp, the ECU will tell the inj to lean or richen. Unlike a carb which has no compensation for denser air (more power). 3) The TPS is your electronic accelerator. 4) Your IAC is the idle feature and provides additional air when accessories are on and the engine starts to droop rpm wise at idle. It shuts down under normal driving conditions. 5) The O2 sensor tells the ECU how efficient the engine is running and tells the inj the right amount of fuel to send to meet proper stoichiometric ratio or even a little lean for fuel economy. This is called "closed loop". "Open loop" is when you're accelerating past a set TPS setting, say 70%, then the ECU bypasses the O2 sensor and goes to the performance setting for richer fuel delivery, ign timing, etc. Kinda like the secondarys on a carb setup. 6) The air flow sensor which measures air speed and density tells the ECU "how much" and the ECU tells the inj the right amount of fuel to deliver-closed loop for economy-open loop for performance!! 7) Finally, the MAP sensor. This is a barametric sensor based upon the air pressure sensed in the intake manifold. It senses the air pressure under full load (WOT) down to deceleration and idle. Depending upon this pressure, the ECU tells the inj to decrease fuel or add fuel. Therefore, it automatically adjusts to your elevation-from sea level to 13000 ft. and higher. Unlike a carb which has no compensating feature. Naturally aspirated engines have a 1 bar MAP programmed into the ECU or "chip"; meaning a range covering your lowest vac draw at idle and deceleration to WOT which shows "0" on your vac guage. Supercharged (turbo or belt driven) engines have a 2 bar MAP programmed in the ECU or chip. A 2 bar MAP configures the naturally aspirated mode AND the supercharged mode. Normally, a 2 bar MAP goes from -15 to +15 (-15 to 0 being NA, 0 to +15 being SC). The 0 to +15 mode directly reflects the lbs of boost to 15+ lbs. If one wants to go 18 lbs or higher, say 25 lbs, you would install a 3 bar MAP which reflects -15 to 0, 0 to +15, 16-30+/-. The beauty of a sys like Accel's DFI and other after market setups is that it is lap top programmable!!!!! No chips to mess with and hope and pray that the chip manufacturer has a chip that will run your application. Want to change your cam or change your heads, or bore and stroke?? You can reprogram your fuel and ign curve. Afraid of detonation? you can help that situation by programming the top ign load limit down to a lower advance setting such as 34 deg or maybe 32 deg. An engine mgmt sys such as Accel's DFI and others is a speed freak's, balls to the wall, supercharger's dream!!! And John, one of the western states premier DFI master Techs and installer lives right there in Loveland!! His name is Ron Anderson. HE'S THE MAN!! He installed my DFI setup in 1992 when I had my Mini-Grand Natl setup on a ZX turbo block. In 1995, I expanded the setup to allow me to drop a 383 into the car. Several years ago, he and a client built a Chevy 4X4 truck using the DFI sys for the Pikes Peak hill climb. He would have beat the Chevy sponsored truck if his truck hadn't weighed 800 lbs more!! I will email his address and phone # to you when I find it-I've temporarily lost it. GO FOR IT!!! [This message has been edited by Fast Frog (edited June 05, 2000).] Quote Link to comment Share on other sites More sharing options...
John Scott Posted June 5, 2000 Author Share Posted June 5, 2000 Rick, Thanks for the boat load of info. I like answers like that! I have a lot to learn. We'll be in touch on this one. The Sy/Ty guys have been telling me to get with the program and go computerized FI. I always research way ahead of my bank account, but as with the countless other files of good info I get off this site, it will be put in the "GOTTA HAVE IT" box. Two more questions. 1)Is ther a way to hook up the knock sensor? The few times mine has protested, (years ago when I was tuning) Its been noticible. With more boost, by the time I hear it it could be too late. 2) When you talk about the MAP sensor and ECU, is a 3 bar part of the Accel system? I will definitly be running more than 15 psi boost. JS [This message has been edited by John Scott (edited June 05, 2000).] Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted June 6, 2000 Share Posted June 6, 2000 John Scott-this is your lucky day!! I've got a hold of Ron Anderson's phone # and talked to him for a few minutes this morning!! Got some great news!! You can do a similiar setup to mine without the expensive TPIS type injector manifold and TB ($2500) and the total Accel engine mgmt sys (only need the fuel calibration part-ECU and harness from JEGS is $900+; however, if going with hi boost, you'll also need the ign timing setup in order for the knock sensor to work)!! All you need is a good breathing manifold, a good set of heads, and a good (even salvage)late model throttle body-like off of a GM truck or other vehicle. The TB has all the sensors attached. You'll also need the O2 sensor that taps into your collector just below the headers. Additional cost above a traditional carb setup is $1000-$1200 more. Ron says that this setup is much more efficient and will increase power at least 10% above a similiar carb setup!! And yes, this Accel sys has a knock sensor which detects detonation and electronically retards the ign timing. Also, a 3 bar MAP is available for high boost!!! Ron's # is (970) 667-4239 Email is ronaldsa@earthlink.net He works graveyd shift at HP so 8am in the morning is a good time to catch him. I can tell you're going for it!! Isn't it great have'n titanium balls!!! [This message has been edited by Fast Frog (edited June 06, 2000).] Quote Link to comment Share on other sites More sharing options...
John Scott Posted June 6, 2000 Author Share Posted June 6, 2000 FastFrog Thanks for Rons #s. I'll be in touch with him. Not that familiar with TBI. I hope it allows big #s. JS Quote Link to comment Share on other sites More sharing options...
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