Quote:
Originally Posted by JLMounce
lfdsteve. We get it, you got screwed on your Powerjection and you're holding a grudge. That's your choice, but you're not helping in this thread at all. If you take a look at the Holley Sniper forums, you'll find the exact same issues, as you will with the Edelbrock offerings. Kindly contribute meaningfully, or butt-out.
Squid, if you're trying to optimize, you do need to hit the dyno. Every car is different, so what your particular combination needs will be slightly different.
For idle tuning, you do exactly as you stated, set your afr/spark targets to achieve maximum vacuum. That's still going to be your engine's happy spot off load. Don't forget to listen to your nose as well. Stinky tail pipes will tell you a lot.
I've mentioned this before, but I don't like the "self learning" nomenclature that these companies are using. The system doesn't learn what your engine needs, it just learns how to produce the results that you command from it. If what you're commanding from it isn't optimal for your combination, it won't run optimally.
You've had your FiTech's running on your cars for a while now so any kinks in setup etc. should be sorted. Now is a good time to get it on a dyno for a couple hours which can help you tune your WOT operation. This is how I'd go about that.
Make three pulls based on where the car sits right now and average the power and torque
Then, just like you would when setting up a distributor manually, start adding or subtracting timing in 2* increments. Watch for power increases or decreases as well as detonation. Chase the increasing power with spark until you start going the wrong way, then back up to the previous advance settings.
From there, do the same thing with your fueling. Does it pick up power going fat or lean? Move in that direction until power starts to drop off, then move back to the previous setting. This will produce the happy spot for your engine in WOT operation.
From there, you can road tune your cruise operation over time by seat of the pants feel as well as what the car is getting for mileage. Work on one aspect at a time, either timing changes or fuel changes and chase max efficiency. The best way to do this the quickest, is to pick a route that you can duplicate that's maybe 50 or so miles and starts/stops at a fuel station. Include some city and highway driving in that. Make a change, fill your tank and start your journey, then fill up at the end and measure fuel consumption. Repeat this process with each change you make, noting if consumption increases or decreases.
Make some mental notes about how the car is driving. Minor amounts of fuel consumption increase may not be worth dealing with things like bucking, or increasing coolant temp etc.
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I will check around with local chassis dyno shops. There are a few in my area. That seems like a better time/money investment than piles of trips to the strip. Thanks to you and others for the suggestion. I like what you provided about the methodical approach. I tried the idle afr adjustment. I got slight changes in vacuum, but it was pretty much ranging from 13-14" even as I adjusted idle afr target from 13.5 to 13.1, to 13.8. I finally settled on 13.4.
I was at the strip Sunday. I got 4 passes in before I called it good enough. I didn't want to break my car when I had a 25+ mile drive back home. I got data logs, too.
My street timing has 16*/36* timing, with 15* vac advance. I started my first run at 16/36, and put in a
[email protected].
Next run I bumped timing by 2* to 18/38, which has almost always been good for a tenth and a mph or so. Instead, I got
[email protected] (wrong direction)
3rd run I pulled the 2* back out, and changed WOT afr's from 12.2 to 12.1. I got a
[email protected]. Half track mph was up 76.01 vs 73.66 from previous run. All of these runs were pretty much hot lapped, first run at 1051 am, and the last at 1110 am. All runs were 10 minutes apart.
My 4th run had no changes because I had to choose a dial-in for the trophy bracket race. I ran a
[email protected]. I got knocked out by a guy who is waaay better at racing than I am. He competes in NHRA class racing, with a 301 turbo car that runs 12's. He had a lot of room to toy with me, much like a cat with a mouse. He cut a better light by .3, and I was slower vs. index by .2. So I made it real easy for him to tap the brakes just before crossing the finish line.