Wideband O2 Tuning
 

I have a Holley Comander 950 MPI Kit. I have been using the narrow band sensor until now. I have just recieved my wideband kit and I am just woundering about the target numbers for marine engines. From past experence with narrow band the engine desired to be a much richer fuel mixture than advised in the book. I can set the target from 10.00 (rich) to 15.00 (lean). I have a 500HP 489 stroker with one of RMbuilders roller cams. Anyone have a good starting point for target numbers? I have 8 different RPM inputs and 8 map inputs from 400 to 4500 RPM.
Thanks,
Jeff

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I nice thing about the ability to measure is you don't have to make the engine overly rich except at higher RPM's to WOT. We expect to finish polishing on our 1150 Dominator's jetting next week. In the boat, we expect to be at about 12-6-12.8 at 5500 RPM to WOT using 3.5 PV's. From 3000 - 5500 RPM (PV's closed) our target is 13.6-13.8. At idle in gear, we should be at 14.5-14.7 by changing the idle air bleeds. We also check the plugs after a 2-5 min mid-range run and then stagger jet until the plug color is equal. With our set up we will be 2-4 jets smaller in the front.
What are others doing? I feeling like we are still wasting fuel in the mid-range.

Find "tunertec" on here. He can help you out.

Thanks, good info:ernaehrung004:

Jeff,
I have a datalog file from my EFI.. It is always a tune in progress, but it should give you an idea of what to sneak up on. The motor is a 565" NA, with 65# injectors..

Have fun!! Tuning is always a great excersize for the brain.

OSO wont let me upload an Xcell file.. send me your email and I can fwd it to you..

Dick

I aimed for 14-1 to 14.7-1 from idle to 2000,from 2000-2800 I aimed for 13.5-1 give or take a little,from 3000-4200 I aimed for12.8-1 to 13-1 then I went to 12-1 anywhere above that when not in boost and 11.4-11.6 under boost,remember you might end up with a tank of gas with a bunch of ethanol in it so don't try to tune as lean as possible you will have no safety margin since you get no exhaust feedback/correction.
My son has been going to local college tech program for ase automotive training and they had a alchohol spectrometer tester,he took samples from every local gas station and there were some as high as 16-18% (speedway/admiral),I'm not sure how strictly they keep the mix at 10% BUT if the samples came up high obviously no one watches it real close,Smitty

Mr. Gadgets,
I your wouldn't mind, i would like to have a copy of your file [email protected].

Smitty,
Are most blown applications richer than NA or are you just being safe?....I have zero experience with blower motors.

Ray (Raylar),
Where do you set your the fuel mixture on your higher HP 496's?

At 12.5+ after a solid run at WOT the plugs are still dark brown...even on 5 & 7 and 6 & 8.

on the 525 upgrade he wants it set 50psi key on engine off

Thanks for the good info on O2. The upgaded program alows you to set a target and alow the PCM to add or subtract fuel. I will see how that works. I empty my tank completly in the fall. I disconect my fuel line from the fuel rail and pump the remaining fuel into a 5 gallon can and put it in the truck. Then I start fresh in the spring. I blew my engine a few years back, it destroyed the tops of all the rod bearings.

I believe I have read where ethanol has properties that prevent (better than straight fuel) detonation. That is if it is fresh and not full of water obviously. I have a place close by where I can get straight gas but I have been a little hesitant due to reading this. The sc engines have been running great on 93 oct ethanol e10..

If you can get pure gas, GET IT!! The E10 is awful for boats. E10 also has less BTU which means less power, a slower boat that uses more fuel.

Thanks, this will be very helpful. I hope to start tuning on the next good weather day. It has been raining all month and the local rivers are getting screwed up. Hopfully things do not start getting flooded.

I was having a problem with the tach signal from the MSD distributor and went to a crank trigger. The rpm that the ECU saw was jumping as much as 120rpm in 50ms.. It was affecting the pulse width, so I ran it rich to not melt things..
After that my pulse width settled down and started to lean it towards the 13.0 mark at the top.. mostly it looks like 12.8-13.0 at the higher rpms..

Pressurized motors need way more fuel to stop meltdown and make power.. Smitty knows how all that works. I am just headed in that direction, if I can get all these darn outdrives done first.. :) :)

Dick

Blowers motors should always be run a little richer.

I agree with what Artic friends says about mix ratio. My only change would be to see what the motor likes at the top end while in boost. 11.4-7 to 1 might be too rich. You must spend alot of time tuning on the water to get it right.


If your motor is not tuned right, it will wash down the cylinders and kill the ring seal--been there done that or too lean and burn a hole in a piston. Been there too....


Best thing is to find a guy who is really good. And one who takes his time.....


Smitty

I have hundreds of hours tuning with narrowband (my own boat). I have gotten pretty good with it. I hope the wideband is better and easier. From what everyone says it was a good investment.

I tune mine for right about 11.7 in 90* air to give room for leaning out a bit when cool air arrives (supercharged).

My engine is not supercharged NA with MPI, I can change my fuel map at any combination of RPM and MAP. So should I be looking for numbers more like MrGadgets is using. He also has a NA engine, but a bigger engine turning more RPM. I am going to prop for 5400 RPM. Also what timing are you guys running? I usually run 34 to 36 total and 12 at Idle with full timing in at 3000RPM. The timing is fully adjustable on the laptop.

My timing is at 40 but we also have a very efficient combustion chamber including flat top pistons that allows 40 degrees timing with no detonation. We also raced offshore with this timing with 93-94 pump gas at 9.3-9.5 CR.
Jeff, I think your settings are good and also safe. Extra timing might make 6-10 HP at 6000 RPM+ vs. 5400 RPM. The best place to test is on the dyno with your exact combination.
I just looked at some old dyno sheets. Our dyno testing at 5400 RPM showed +1 HP at 42 degrees vs. 40 degrees. This was done with race gas to be safe. For 1 HP, we raced at 40 degrees with pump gas. Can't find some the old test, but I remember +2 to 3 HP from 38 to 40.

Thanks, good info. I will leave it at 36, I have 8.9 to 1 compression with flat top pistons. In the past I have used 91 to 93 octain, when gas went to $4 I tried 89 and could tell no diffence.

Fuel suppliers are replacing tolulene and other good additives with ethanol,it gives you no extra tolerance to detonation because the extra octane it adds is taken away from the rest of the mix. What it does do is LEAN out your actual mixture as it has less energy and btu's. If most the local gas your going to run has ethanol in it then you should definately tune with it so your mixture is safe,Smitty

The O2 tuning was mostly a bust this weekend. We did get the timing set and tested the AFR at idle. We changed the idle air bleeds from 51 to 49. That richened the AFR at idle to about 14.5...hard to be very accurate at idle with big cams as the gauge fluctuates a lot.
Now the water test. We couldn't get on plane as we think we may have an issue with one of the new Crane HI-6 ignitions (winter project). It could be an installation error but we didn't find any issues. From 1000-4000 RPM at the dock, everything including the advance curves was just as expected. The throttle response was crisp and everything seemed right. The idle in and out of gear was sweet....no stalling. We went out in the river and never got on plane. The Stb engine backfired and quit at 2000-2500 RPM coming on plane under load...WTF! Tried twice but something was wrong....idled back to the trailer.
Carb and fuel systems seem fine. Checked and rechecked the Crane wiring Port vs. Starboard and didn't see any issues. The fuel pressure was 6.5-7 lbs and the HI-6 boxes worked fine up to 4000 RPM at the dock. As this issue only shows under load,
is it likely the coil? There wasn't enough time to switch components engine to engine.
Today, I found and ordered a new Crane 6000-6462 marine box and LX-92 coil. We will be ready to parts swap in June as needed. Does anybody have any suggestions of where to look for additional ghost on my June trip?

Sounds lean, my boat won't get on plane at those A/F ratios.

14.5 is just at idle at the dock. The AFR is where it is set at13.5-13.6 in the mid-range. It isn't possible that the starboard carb has an issue, but it doesn'ts seem likely. Thanks for the thought, we will swap carbs for one of the test.

Did you happen to check a plug

Backfired out the intake or the exhaust?

Didn't check a plug...backfired on intake (carb)

Here is the current plan pre-launch:
1. Check the Stb plugs (If typical move on)
2. Swap carbs
3. Install new Stb coil
4. Water test
Results:
If no back fire, it was the Stb coil. If the Port backfires it is a lean carb (assumes FP is good). If the Stb still backfires, it is likely the ignition box.
4. Change out the Stb ignition box and retest.

Stb still backfires?....make offers :p

I got the boat on the water yesterday and did a little tuning. I found the boat liked 13.5 at idle all the way up to 3400 RPM. I did not test WOT yet. I will post updates on my other post Roller Cam Upgrade.

Intake backfire = lean most often. Be careful. Check float level for shore.

Blue,
You were possibly right on the lean but it is confusing as the carb is now so far off that we have sent it back to Holley to be tested. We did find out that we made and error in setting up the new Crane ignition boxes. If you don't use the Crane ignition retard feature, you are to directed to cut off the brown wire and set the dial on 1. We cut the wire, but neglected to reset the retard that is pre-set at 8. With a 8 setting, the retard is X 2 = 16 degrees! Woops...
We fought the carb all day Saturday as it got extremely lean above 4000 RPM (testing with AFR meter). Tried new PV's but no change.
I am think that the BIG backfire we incurred in May (with 16 degree retard) may have damaged the carb as we could not get it under control. Will have to wait and see what the Holley Custom Shop says.
We did swap the carb's on Sunday and the problem followed the carb...way lean above 4000 RPM.
Couldn't spend anymore time trying to figure this out as I we want to participate in LEOPA's July Poker Run.

Blue,
You were right, it was lean. Not sure this was the original issue that caused the backfire, but lean was surely the issue on our last trip. Holley found a small piece of debris in a needle and seat that was restricting flow; this carb was off 70 lbs at WOT.
We are back to "Go". We will replace the fuel/water separator filters to make sure they aren't the issue.