Where to get started on tuning FiTech?
 

I am running FiTech on both cars. I'm looking for some advice on tuning these units. They do a great job learning, and run great, but I wanted to know how to tune them for optimum.

With a carb: I've always tuned for best manifold vacuum at idle. Can I adjust the efi idle afr to achieve the same thing? Or is there some other gold standard?

Tuning WOT: I guess having butt-tons of runs at the strip is great, but how do I know what "numerical" afr target is ideal for my heads and cam? O2 sensors and electronics also have variances that allow "optimal" to fall within a significant range.

Are there any good resources out there on the web that do a good job of "nailing it"?

Thanks!

Have you considered going to a chassis dyno? Easiest way to see the results of timing and fuel ratio changes.

In said it before and i’ll say it again. One look through the FiTech “tuning forum “ confirms exactly what I suspected. Same crap as the powerjection and the retrotek before that. Bad IAC’s, bad TPS. Wont be long before they disappear from the forum, close it and rename their company something else. Sure hope im wrong for your sake.
Good luck but to the point. Fitech has a tunners forum. Check it out. Might find some help.
Oh, I stopped by their booth at SEMA last week. Pretty familiar looking faces. Hmmm....

I strongly disagree I have been running the fi tech 1200 with a boosted turbo motor on E 85 and it runs great , idles perfect , starts up instantly ..I set my idle at 950 and it stays right there , air fuel is perfect at all rpms . It is way better than any carb I have had for sure , not to mention that it has a datalogger so you know exactly what’s going on with your tune at real time . It a winner in my book .. the only downside for me is that on e85 I am limited to 850 hp instead of 1200 ...

I just tuned my air fuel for idle mid and wide open under boost which is 11.5 to 11.8 at wot and I have my timing locked out at 24 degrees..

Not exactly sure what you “stongly’disagree with” ? Quik pop into forum shows some folks looking for part numbers already for IAC and TPS that have gone bad. Very limited company participation in forum( which in case of retrotek and powerjection became none then forums eventually closed when folks could no longer get help). Company changed from Retrotek to Powerjection not honoring warranty then closed again. Now magically along comes another “New company” and from what I have seen, and now believe I have confirmed with my stop at SEMA is not only the uncanny resemblance of the products between the three companies but also some of the names and faces in the booth, hmm...
So then I gave the website of the forum and said “good luck” So what part do you strongly disagree with?
I know I have said it before on this site and been rebuked by several folks that have had excellent results. Not saying it doesn’t work,as my powerjection runs fine. (no thanks to them). Still runs crappy cold and suffers from amnesia requiring me to always have my old laptop in the car. (Oh yeah, windows 98 version). What I am saying is help, parts and software no longer available and instead of continuing to develop a product, there seems to be a pattern of release, log the flaws, implement improvements by closing, changing names and moving on leaving users in the learch. So they won’t ever get another dollar from me and their unit is slated for the trash.
I could still be wrong but you’re not fooling me twice. Saving my pennies for the direct port from Edelbrock.
Good luck

Well all I know is mine and lots of others it works as advertised , I think a lot of issues that people are having are not related to the fitech but other mechanical problems with there engine , like vacuum leaks , bad wiring , and just no experience in setting up crucial parameters and understanding terminology , it Is a nice unit for the price point $1,300 and it has has performed awesome for me , I had more $ invested in a boosted carb that could not do what the fitech has done and the best part is the only tool I need is a finger to input data .... if you want to spend a lot more $ on the edelbroke than have at ... good luck

Lots of people had excellent results from thalidomide...
I’m glad yours works. Your a very astute consumer and I stand and applaud you. I myself am a poor consumer apparently and as such had bad experience with a company that created a product with big problems then instead of fixing them changed names for the second time. As I am sure the “three strikes “ rule applies in the world of astute consumerism, you will be fine.
Enjoy

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.

It’s not that I got screwed JL. Just merely trying to let others know that not everyone is a “casual fan” of the fitech, but rather has a vested interest using this forum as a cover. and IF I’m correct, and I say that to avoid the comments about slander but If I’m correct its the same guys selling their latest version. They may have worked the bugs out and thats great, but people cry all day about getting bad repro parts but give this kind of behavior a pass and a BUNCH of people got screwed, not just me. The only good thing was they used off the shelf **** components that could be replaced to make functional.
End of rant. Say hi to Bryce for me JL.

I'm enjoying my FiTech so far. But dude... quit wiping your ass with my thread. I was looking for tuning advice, not a product review. People don't go into business to fail. But most successful business people have several failures for every success until they get it right. We'll see, but there's other threads to discuss that in.

I have looked at the FiTech forum, and the info is light so far. I appreciate the suggestion.

Yes, Ken was behind retrotek, which was sold to Professional Products and rebranded as Powerjection. We've been through all that before. I know you've had issues with your Powerjection system and feel slighted by it's lack of support. Since it's not a retrotek, that issue falls on Profession Products who purchased the company and rights to that intellectual property. In truth I haven't heard much good about that system.

That said, I think that FiTech at this point has proven itself pretty well. In this thread alone there are 5 well functioning units. I know Squidward has two, er455 has one and I have two. I can't speak to the others, but my Go EFI 4 has been in service for over 3 years now and has about 15000 miles on it. I also have a Go Street on my Wife's Chevelle that has been in operation about 3/4's of a year and about 2000 miles. I've had only a single issue crop up on mine that was related to the product itself. I detailed that in the street section for all to view if they are inclined. It was a connector failure for which the early units were prone to before they switched the connector. It cost me 40 bucks and about an hour of work, so I didn't lose sleep over it.

Like it or not, the FiTech disrupted the market in a positive way. It spawned price matched clones from Holley and Summit (which is just a rebranded FiTech). For the hobbyist that wants to drive their car and doesn't want to deal with the ever increasing issue of modern fuel and carburetors, it's put EFI within reach. Until FiTech, you were looking at 3-5K and a significant learning curve to make the swap.

My apologies Squid. You have always been a source of helpful information. Sorry for the hi jack

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.

Thanks. Respect to you, brother. Moving forward.

What cam are you running in the car? For what it's worth, my idle AFR is set at 14.1 and I run my WOT fueling closer to 13:1.

General rule of thumb is leaner will produce more power. Based on what you're saying here, it sounds like you may currently be at optimal spark advance. Might focus instead on fueling.

Have you run any logs of your runs? Running logs for the pass and comparing specifically intake air temp and the resulting cylinder temp can help equalize runs where you may be losing power simply to added heat if you're hot-lapping.

One more thought here. If you replaced a poorly tuned carb with the FiTech, it's possible that you may be increasing combustion efficiency by way of proper fueling and better spark control. It's not out of the question, that reducing timing may increase power as a result.

I downloaded my data logs, and did some charting. Attached below are a couple of runs, back to back, with some of the dead time truncated. The composite of rpm, afr, etc. is the first one. The next ones scale back the size by eliminating the rpm and fuel flow rate to focus on the smaller numerical data streams (afr, afr target, inject duty cycle).

One thing I was worried about was fuel flow up around 5k, and if I had any unexpected lean condition. Power has always nosed over above 5k, and I wondered if there was a fuel delivery issue from the pump/regulator. This doesn't show any evidence of fuel starvation, since the system was able to maintain afr of 12.5 to 11.9 against a target of 12.1 throughout the WOT condition. I suspect the variation was due to shifting gears, and the engine loading change.

Looking at the injector duty cycle, it never got over 30-something percent. I guess that means I have a lot of headroom for a bigger engine, huh?:o

The only 2 things of concern I could see were highlighted in yellow.

1. At the start of the run (launch), It went momentarily a little lean, and then over-corrected. It started out with idle afr target of 13.45. Then I launched off the foot brake and mashed the pedal to WOT. AFR went up to 14.0, then corrected down to 11.9 until coming back to the targeted 12.1. I'm thinking maybe I give it some more "pump shot" fuel to smooth out that lean jump? I also wondered if I can speed up the response gain to minimize the overshoot below afr target (when it went to 11.9).

2. Letting off the pedal at the end of the track caused my AFR to jump lean to 20.6. Is this normal, or something to be concerned with? At this time it was just coasting and braking. Maybe an adjustment to the decel fuel cutout? It seems odd to me that the computer would be targeting 14.2-14.3, yet readback was at 20.6.

Thoughts welcome!

I tried richer because it was safer. I picked up a little bit of mph with the changes, so I thought I might be going in the right direction.

My carb was pretty good. It was a Quick Fuel 780 vac secondary. I simply wanted efi as the next phase of the relationship. I never got a chance to completely tune the jets for WOT, or tune the rate at which the secondaries opened up.

Cam is a Voodoo 702, 219/227 on a 112 LSA.

I see what you are saying about intake air temp. The 2nd of the 2 logged runs was a tenth slower, and I compared intake air temp at 3k rpm in first gear. 2nd run was 4 degrees warmer.

The lean tip-in oscillation is the FiTech's biggest weak point. The problem stems from the fact that it has a lot of adjustment in it's fueling between the VE table, learn and trim. So fast transient moments like that can cause a reducing oscillation where it over-corrects, then corrects back and it does that until it gets back to target. What you want to increase here likely isn't the accel fuel total, but the dTPS gain. Accel Pump in the system works off of map and is mostly concerned with on-throttle responses like, going heavy to pass a car on the freeway. dTPS Gain is TPS based and is designed for fast transients like going WOT from a stop. So go up on the dTPS gain first before adding more accel fuel.

That oscillation will always be there somewhat unless you start modifying the VE table cells and look to either reducing the amount of learn the system can do, or turning it off completely. The people that have this sorted out have spent the time tuning the VE table itself based on what their engine likes and needs. They are then able to turn fuel learn off and limit the trim for more consistent fueling. It takes time to get there though.

What you're seeing on your shut down at the end of the run is your DFCO coming on and over-riding commanded AFR. I believe the later software revisions modified the basic parameters for Fuel cut and return, but on my system the factory defaults cut fuel at 28Kpa MAP and return fuel at 30Kpa MAP. What you're seeing at 20.6 is the system's upper limit for reading and displaying AFR values. That's what it's saying, but there's zero fuel being provided at that time. You can change these parameters if needed, but I typically advise against completely disabling this system, it's there for more than just fuel economy.

Power nosing over can be any number of things. But, I would check to make sure through your throttle linkage that you are opening the butterflies completely on the throttle body itself. the TPS only looks at the front butterflies, so if there's an adjustment issue where the front's are open completely, but the rear butterflies are not, that won't show up in the logs. It will affect airflow however.

You should also check and set your vrAdvance 4000 to make sure you're compensating for any drift in your mechanical advance at higher RPM's. You may find you need to add a degree or two of advance up there.

If you're gaining mph, you're going in the right direction. ET's can very a lot based on traction, but if you're in it through the entire run, the MPH should be pretty consistent. So changes there can tell you if you're going in the right direction.

In regards to power falling off, did it do so before with the carb as well? If so, there's always a possibility that's not tune or fueling related. It could be something like valve float occurring.

I'm assuming this is on your car that has the 350/#62 combo? That cam should be pretty healthy in that setup.