A/F ratio
 

Is there a way to calibrate the A/F ratio without having the engine on a dyno? If so how do I do it and what do I need?

Sure, what exhaust do you have? Have a bung in welded in your exhaust and use a wideband O2 sensor to monitor. You could use a gage or a handheld monitor. There are a bunch of kits out there.
I have a Holley MPI kit and I can adjust mine with the laptop.

I'm running K/E headers, I'm going to have the tails modified so I'll have them add a bung in the tail pipe.

Do you have EFI or carb? You can install a wideband O2 as jeffswav said to measure the A/F ratio. Here is where you can get one at. http://www.innovatemotorsports.com/products/lm2.php

I'm running a carb.

Just be sure they will not get wet...

Not to hijack the thread but I am also looking to monitor A/F ratio and the product shown looks interesting. Can you just "monitor" the A/F ratio or can you change it? I have an adjustable fuel regulator so I know I can change fuel pressure but if I do not have the correct A/F ratio do I need to have my ECM re-programed...??? (Running a Procharger @ 5lbs on a 454 Mag MPI))

You can check it with the monitor, if it is off have one of the guys here reprogram it for you.
Mine is cool because I can do it myself and I can set target A/F ratios and let the PCM tweak it out.

You can use you fuel press to offset the fuel curve but it won't change the shape of it.

Jeff

Just trying to wrap my head around this......so if I find I have the A/F ratio a little "lean" at say 12 or 13, I can find this out with this kit but would have to send the ECM in to be re-programed? Or at those numbers, (I was told about 11.5 is what I should be running) can I richen it up a little with higher fuel pressure???

Jeffswav, what do you mean by letting the PCM "tweak" it out..? Thanks.

If you have a nice consistent fuel curve already and it it's a little lean or rich, you can use the fuel pressure adjustment to fix the condition.

The a/f meter will tell you if there are "spots" that are different etc.

You would really only need to program if you find a range or speed that for no apparent reason becomes much leaner or richer when running the boat.

Better to put the bung in the forward most part of the riser or elbow. You'll need a pretty talented welder to install in so it won't leak, etc.

Thanks for that, on the dyno my numbers were a little lean but I was told the numbers would come down with the engine in the boat with the wet exhaust. My numbers on the dyno were 13.56 @ 3000rpm and dropped to 11.56 @ 4700rpm so hopefully if I am still a little lean when I use the A/F scan tool I can adjust the fuel regulator......:confused:

I also agree about a "good" welder.....:coolcowboy:

Again, you need to check the af's while running the boat in the water on plane. Adjust the fuel curve according to the engine builder's recommendation (not what someone on a forum tells you).

Matter of fact, I'd have them make sure your tuning is acceptable by their standards.

No reason for you to be responsible for fuel trim if you're buying/building a new engine.

Kind of a different situation here.....I had the engine "built" by a very good local shop but they build stock and sprint car motors and very few marine MPI motors that have a Procharger.....they did an awesome job on the build but we needed advice from various sources, see attached thread.

http://www.offshoreonly.com/forums/g...she-lives.html

Long story short, I have ordered the A/F ratio scan tool and will run the boat with that and the lap top and see what umbers I get and go from there....as soon as it stops snowing..!!!:traurig001:

Wideband 02 with data logger and RPM works the best. You can't fix rich and lean spots with the regulator, it makes changes across the board.

This is what I ordered, I can change settings without sending the ECM out???

http://www.innovatemotorsports.com/products/lm2.php

I may be wrong but, I believe that's a data logger, you would need tuning software and a laptop to make changes to the ECU.

The Innovate LM2will only monitor the A/F. If you have MPI/EFI you can somewhat adjust the mixture if it is close to what it should be, but as hallj stated you can't change the shape or curve of the mixture.
Jeffswav has the Holley EFI setup so he can change the setup using his laptop, but with the stock MEFI1,2,3,4 you would better off to pay someone to reprogram it for you and several builders on the forum can do that for you.

There is no way to change fuel curve in the box without someone flashing it.

The link you put up is for the tool to "measure" what's going on.

You can use the fuel pressure regulator to change it up or down as long as there are no trouble areas. The meter will tell you if there are.

Otherwise, if you have spots in the rpm range that are rich or too lean in the curve you will have to reprogram it.

You really ought to have this done for you by a professional based on what you're saying. If you built a nice engine with someone and they are leaving it up to you to finish it... I don't know... And you are playing with one aspect that will kill your motor if you are not sure of what you're doing.

Having "car guys" build boat engines never seems to smell right.

Just be careful and don't lean it out for very long.

If the reprogram is necessary and if you send it out, you'll need to keep testing until you know what you have.

I hear what you are saying, problem is, there are no marine engine builders around here......closest I would trust is Alex Haxby who is in Vancouver and it is major time and money to get the boat over there. I am happy with the build and happy where things stand right now but when the weather permits and I can get some water test time under my belt it will be nice to monitor the engine and make sure we got it right, if not, we can make changes based on the info we get.

I had my ECM re-flashed by Mark Boos but perhaps I did not supply him with all the info he needed, on the dyno it seemed to run a little lean, but until we run it on the water under load I don't know if we got it right.

The A/F reader I ordered comes with software and a laptop connection so I assume certain things can be changed.......as far as getting a "professional" up here to set it up for me, it ain't gonna happen unless I fly somebody in......the other half would shoot me.....:eek:


Thanks for all the feedback boys......:coolcowboy:

[QUOTE=FogduckerIII;3334267]
The A/F reader I ordered comes with software and a laptop connection so I assume certain things can be changed.

Once again I may be wrong, but I think that just lets you set up the data logger.

The LM2 will help you tons to see where you are at. I am no pro at A/F, but maybe someone on here can help once you have good numbers based on RPM's, A/F and boost levels. Details would be needed, but based on your statement of "My numbers on the dyno were 13.56 @ 3000rpm and dropped to 11.56 @ 4700rpm" depending on the numbers in between, that may not be far off. You are at 11.5 in boost and that is where your builder said you needed to be at.

endeavour32, once you get the Innovate setup and see where you are, you will be able to adjust by changing your jets in the carburetor. Now what A/F should you be at? Too many variables for to me to help on a boat motor, but cars shoot for around 14.7 to get fuel milage.
FYI, that car is at cruising rpms of 2000 which is totally different in a boat.

I apologize, I did end up hijacking the thread....my bad......

14.7 in a boat might just pop the head gaskets, 11.5 at top end might wash the cylinders. 13.5 cruise 12.0 wot works for me, may not for you, timing, air temp, octane and boost change things.

With the aftermarket systems the fuel map is adjusted on the laptop. After you get the fuel map set, you set it to closed loop. The computer will add or subtract fuel to get it to your target O2. I set the correction limit to -5 / +15. You can also adjust things like accelaration enrichment (map & TPS), cold start, timing curve, and anything else you can think of. This took me a lot of hours of tuning to figure it out. You must be a patiant person and like to work on things untill you get it right.
Again, this is not the case for the Merc systems. You can monitor the O2 then get that info to somone that can reprogram it for you. There are a bunch of guys on here that can do it for you.

THIS THREAD HAS OFFICIALLY BEEN HYJACKED :lolhit:

+ 1:lolhit:

As mentioned, you first must start with a wideband O2 sensor of some sort. To get that into the motor, you need to have a bung welded through the water jacket, and into the exhaust stream. Depending on what motor/manifolds you have, you may be able to buy something like this, which goes between the manifold and riser: http://cgi.ebay.com/ebaymotors/OXYGE...ssoriesQ5fGear

Many header manufacturers will include or add bungs to their systems...CMI, Lightning, Dana Marine, etc. Dana Marine will also install a bung in the 496mag/ho risers on an exchange basis for $115...just send your stock riser back as a core. (Ask for Don).

Once you have a safe place to put the sensor, you need something you like. There are quite a few systems on the market. The Dynojet WideBand 2 is one option. http://www.dynojetwb2.com You can connect a gauge or, for more data, you can connect the LCD display. With the LCD, you can record to an internal SD card (up to 1gb) all the parameters it records. It will read A/F ratio, and can be connected to RPM and a single analog 0-5v input (handy to use MAP if you're going to tune). With that, you'll have the data as to what to do.

Tuning is another thing though. I think the OP was carb'd, so he can just jet it. Not many end-user options for EFI applications, but I know of one that will be hitting the market in the next month. ;)

Fogducker don't even worry about the a/f numbers from the dyno. Check it out in the boat when it warms up and see where you're at. An engine running in a cold dyno cell with headers is worlds apart from an engine enclosed in a small hot humid engine compartment with wet exhaust. Also a dyno sweep test doesn't load your engine the same as the boat. You'll be in completely different parts of your fuel map on the water. It'll be all good :drink:

Fixx
 

Jeremy,the lm2 will only do OBD II Cars on the scanner portion of it,,you will be able to scan your ford truck and that's it..the merc efi system in your boat is based on a OBD 1 style system and you will need special software to get into it..the lm2 will need a bung welded into the riser in order for it to give you the AFR readings..if you cant seem to get it rite you will need to fly someone in like eddie young,i dont think mark will go to you but for the rite price eddie probably might..

Dyno numbers are just for a starting baseline. Load water testing is really the only way to get your A/F close. On an EFI blower engine with no boost 13-13.8 is optimum for cruising. Caution should observed if you load the engine and climb quickly in boost.
Unless you have a system that has boost reference variable corrections you can find yourself in a detonation situation. As boost climbs, your A/F should drop to fight detonation (pump gas of course). Aluminum heads are little more forgiving to fight of detonation. Regardless 11.9 - 12 is optimum under boost. Total boost cautiously to 7lbs. Fuel pressure should remain constant per the injectors particular recommendation. Changing fuel pressure other than for boost reference is not a wise idea. Programming changes A/F by adjusting time injector fires compared to MAP.

:DThanks Alex, point(s) taken......:coolcowboy:

I have to come over and at least check out your shop in the very near future......

Awesome info, thank you. As well as yourself, others are telling me to wait and see the numbers I get IN the boat. I have ordered the LM-2 Innovate unit and even if it just gives me a real world base line, I am ahead of the game, thank you again gentlemen.

PS. Fix, is the ex tired of you yet?:grinser010:

Fixx
 

))))



Nope,,still pumping her full of fluids:grinser010:

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Amen to that brotha!!!! car guy here just fried his fresh 7.4 rebuild that was "upgraded" with more cam, ported heads and bigger valves.... motor ran lean (suspected detonation)and now I have rod knock! I wish this thread would have been here about a month ago! I have an innovate LM-1 that I have used very successfully to tune carbs and make jetting changes in cars. I am not sure how to tap into the exhaust stream on my OSCO manifolds but I see that tuning the engine in the boat with water manifolds is the best and most accurate way to tune your engine............. I guess learning things the hard way is better than not learning at all????? TBF

I blew mine up 3 times before I figured everything out. If you want to do your own programing you will have to go aftermarket. There are very few dealers that can program the factory comp.

See my post (#29) in this thread for some options. Depending on what motor/risers you have, one of those may work.

That won't be the case for long. :party-smiley-004: Check out booth #214 at the LA Boat Show in a few weeks. ;)

I have been using the Innovate LM-1 for a few years now with very good results. The best way to tune carb or efi is with a wide band O2 sensor. As far as a solution to getting a sensor in the cast manifolds, check the classifieds.

http://www.offshoreonly.com/classifi...o38189-en.html


Jeff

That's a good looking part. Problem is; they don't make that for dry joint. Many of us still have to do the expensive welding etc.