two part question/post..

I keep bouncing around the idea of convering my '71 camaro to EFI. It has a 406, zz430 heads, solid roller cam (240/248 @0.050, 294/302 advertised, 0.543/0.561 lift, 110* LSA), 10.2:1, and all the hardware you'd expect to support it. I'd use a stealthram and a '730 or '727. The motor isn't ultra radical, but it's certainly no caddy either....

part 1 (the easy part): I'm curious if there are any articles/documents online about the physical part of retrofitting an ECM and a bundle of wires to old metal. tips, tricks, innovative/neat/clean etc ways of doing the work. from an electrical standpoint i understand what has to be done. just looking for professional, neat, clean ways and ideas..

part 2. I've read and re-read the NBO2 & WBO2 vs. big cam posts and it seems like there just isn't a concensus on what works. some guys post that they can get into closed loop and generate NBO2 crosscounts, but that the exhaust burns their eyes (running rich). others post that the car runs great with an indicated WBO2 that is quite lean. It seems to me like these tools just aren't as helpful(?) when you toss a big cam into the mix specifically because you can't rely upon them or trust the measured results.

So, my assumption is that it's best to toss these tools out, run fulltime open loop, and tune via plug reading, performance measurements, seat of the pants, etc.

My question arises - Where do you start? The motor is a total unknown. I can handle the initial timing map, cylinder size, injector constant, etc., but the VE tables leave me with a big question mark. Should I make something up / best guess? Check out .BIN's and VE tables that have been posted publically, and try to come up with something that makes sense? I fully understand that I can't just use someone else's calibration and that I need to do this myself. I'm just trying to figure out where to start, without burning a piston or flushing fuel down the cylinder walls. I'm pretty sure a stock VE table for TPI style motor just isn't going to cut it to even start out with..

So, I'm looking for some hints and tips to get into the same "city" as what the engine needs (nevermind as close as "in the ballpark"). Someone who's done this before and can share some ideas on how to pick values to rough in the initial VE table attempt without being severly off.

If any of my assumptions are incorrect, that's worth discussing too - especially about the WB. It would be so tremendously useful to have an accurate WB to help rough in the tune (i have a DIY-WB), but the various reports in this forum don't seem to bode well for the accuracy/reliability of the values on a motor with a good amount of overlap. (not a slam of the DIY - WB, I built one and think it's awesome.. just an acknowledgment that my overlap and 110* LSA is going to send oxygen and raw fuel out the exhaust valve and apparently these types of sensors don't care for that)

also - having not used an emulator yet...is this the type of tuning that an emulator would be really useful for? it seems like you could dial in the idle VE pretty by observed idle quality / vacuum / exhaust smell, to at least get started.

 

You still need a wideband to get the VE dialed in. Do whatever you want (oops, I mean what the motor wants) with idle. Seat of the pants will simply take too long, and won't end up very good and is dangerous for the motor (carbs are more fool proof, you could say). WB works fine off of idle. I'd also probably go open loop with that cam, as you're planning.

You can get a TPI harness from Painless for a small chunk of change, but it's probably worth it, rather than spending the time and energy converting an original harness. There's also a few <$20 books about swapping in TPIs. I have them, and I can guess that you won't really need them if you buy the Painless harness - they aren't really that helpful.

Emulation makes life easier too. So does a dyno. If you're close to San Luis Obispo later this summer (August probably), I can cut you a deal on our dyno. I'll probably be here in China until July, though. 2 hours on a dyno can get pretty much everything (about warm engine operation) tuned well enough.

 

You could check out my EFI guide. It's written to do exactly what you're talking about. Go to my website and click on EFI Swappers Guide.

 

To me at least, the fuel system is the biggest pitb.
Apparently a 3rd gen sender will fit a second gen tank.
Still need a sump imop.
I grabbed a harness & ecm from a 7730 corsica.
Grabbed a second injector harness from another 4 cyl car.
Just need a few as yet to be determined sensor connector swaps. Got the harness/ecm for $25ea at pick a part. Should only need to lengthen a few wires to reach under the seat.
Then it's all tuning.
I'm running a 243/251 @110 solid cam.