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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
Have any of you guys tried that FAST EZ-EFI 2.0 fuel injection system? I'm considering it as an option for my 89 IROC LS1 swap. It's self tuning which would save money and is super easy to install, according to FAST.
My only concern is will my A/C still function without signal from the ECM?
I talked to a rep yesterday and he said they offer a harness which provides power and a relay for the fuel pump. So that's an easy plug and go set up. Plus it's compatible with nitrous and forced induction as it comes with its own wideband and fuel pressure sensor. Seems like a good deal for the money, considering having Hawks build me a harness will cost a grand then another $300.00 for a computer tune.
AC can be ran independent like carbs had it. Self tuning computers arent as precise as properly tuned computers so dont consider that a fix-all
Most aftermarket controls systems are designed for racecars so many creature comforts and other aux controls are not supported. AC, electronic automatic transmissions etc
The self tuning features are more for minor changes like temp/humidity/altitude so a racer can spend more time banging gears and not poking a laptop. The racrer would still need to spend most of the prior T&T session dialing in the combo
Don't listen to fast. I had the fast .2.0 and it was a great quality system. It can be used for nitrous which is great. Can NOT be used for forced induction. You don't want self tuning when you have boost, esp when it can come in at any rpm and load. Fast tech told me this a few months ago when I was going forced induction, I was pissed and had to take a huge loss on selling my system. Now I have OEM LS ECM. But I was looking at the Holley HP system, but as soon as I said boost and meth they said dominator setup which is 2k just for the ECM lol
I have Holley HP so I had to work out a solution too. There is no single answer to your question because there are a lot of ways to make the AC work. I think I came up with 8 different ideas for my own car.
The AC head unit supplies +12V when the AC or defrost is selected (light green wire in my case). In its most basic form, that signal should be run through the Low and High pressure switch and operate the AC compressor, and turn on the radiator fan for extra cooling. You'll need a relay to turn on the fan when +12V is applied to the AC compressor circuit. Stock Thirdgens also put the power steering pressure switch in-line with the AC compressor. This helps idle stability by cutting power to the AC compressor if steering goes full lock at idle. My 4th gen power steering lines don't have a pressure switch so I eliminated the switch. The only difference between earlier Thirdgens and later Thirdgens is the engine ECM took over more functions associated with AC, and that allows more control of radiator fans and engine idle speed.
You can add extra levels of features if your engine ECM can support it. For example, you could let the ECM see the +12V signal from AC head unit and program the ECM to turn on radiator fans and bump up idle speed with AC on. If you want to be a little fancier you could have the ECM control the AC compressor so that you can cut AC at full throttle. This is what I did. My circuits are shown below for reference. I don't know what the FAST EFI will support.
10-07-2015, 07:39 AM
