PDA

View Full Version : MEFI BURN and Ecm Tuning


DRRICK
08-09-2012, 02:05 PM
Title says it all. Anyone use this product on their Mastercraft?

As noted, I have recently upgraded to roller rockers at 1:6 ratio, from 1:5, and I need to recal. my ECM to increase the fuel pulse to match the increase in breathing.

If no one has used it, I will probably get the system, use it on my boat and make it available to people here. I figure if the system costs $600, and I rent it out for $50-$100 bucks, I just might be able to get my investment back.

If there is anybody in Oregon that can tune the engine for me, please stand up and be counted.
Thanks

mckevin
08-11-2012, 06:32 AM
I have been looking at the MEFI Burn stuff too. I am running MEFI 5. I don't think what works for yours will work on mine. That blows. Let me know if you like it. I will probably order one for mine too.

DRRICK
08-15-2012, 06:17 PM
I have come to the conclusion that I am not going to spend the money to re-cal my ECM. I have an Email to the tech. dept at Indmar-they might be able to help.

Otherwise I will just send the ECM to Bob at OBD2 to have him upload a new calibration that he knows will work for my engine.

To do it my self is gonna cost around $700, and many hours of work, including Drilling throught the water jackets on the riser and installing an O2 sensor, that I would remove after the tuning.

Andyg
08-15-2012, 07:04 PM
What engine and year are you modifying? I added 1.6 roller rockers to my 2003 MCX and recalled my ECM with what Indamr recommended. It caused idle and surging problems. I went back to the stock program and never had a problem after that.

Andyg

DRRICK
08-15-2012, 09:56 PM
What engine and year are you modifying? I added 1.6 roller rockers to my 2003 MCX and recalled my ECM with what Indamr recommended. It caused idle and surging problems. I went back to the stock program and never had a problem after that.

Andyg

After I wrote the above, I went to a local guy who actually knew what I was talking about. I went home and pulled every other spark plug. They look pretty good. They certainly do not look TOO lean (def not rich, though). So I am showing them to other folks to get a read.
I am unable to upload right now, but I will up load spark plug photos tomorrow.

I did a write up of the upgrade with photos. Did you change your push rods?

1994 prostar LT-1 http://www.mastercraft.com/teamtalk/showthread.php?t=45951

DRRICK
08-16-2012, 11:28 AM
Here are the plugs.

COmments??

Too lean? (certainly not too rich)?
Just right?? approx 3hours on the plugs.

DRRICK
08-16-2012, 12:03 PM
Local engine guy says too lean. But not causing damage YET. Avoid WOT. Get new calibration ASAP. No skiing or boarding. Or Hole shots.

DRRICK
07-31-2014, 02:21 PM
Local guy wrong. 120 hours on rebuild Plugs look the same.

TRBenj
07-31-2014, 03:01 PM
Can't tell much from the photos... Fuel burns pretty clean these days. Certainly not overly rich but not silvery in color either (indicative) of pistons melting) which is a good thing. If you really want to know how your jetting is, you'll need to chop the plugs and look at the width of the soot ring on the base of the insulator. You'll want to be at wot when you shut it down and remove the plugs, obviously- else you're only looking at how rich/lean you are at idle.

Where did you end up getting the tune from?

CantRepeat
07-31-2014, 03:19 PM
The only real way to tell is data logging with an O2 sensor and mapping the VE table to get an AFR of 14.7.

Once you adjust the VE table then you need to data log the BLMs and adjust for rich or lean conditions.

In my highly unprofessional opinion, those plugs look lean and dry.

Trying to adjust VE while doing just WOT is not a good plan. In fact, at WOT most ECMs ignore the VE table so unless all you plan on doing in your boat is WOT you will need to data log.

DRRICK
07-31-2014, 04:36 PM
I hear you loud and clear. I spent a lot of time with this. After 120 hours, If there had been a problem it would have shown up. Setting up for the testing you outline is not impossible, just a PITA for a boat this old.

I did not get a re-tune, since the factory settings for those LT-1's are already too rich. The mapping was changed in later years, as they added O2 sensors.

CantRepeat
07-31-2014, 06:26 PM
What makes you think they are too rich? I would think Indmar spent many hours on the dyno dialing in the tunes.

I don't know if the mapping was changed in later years. The Indmar CAL files are encrypted so unless you work at Indmar it would be pretty hard to say what has changed. I have every CAL file from ECM 1 through 2011 but the way Indmar and Rinda have it setup you can't "author" a CAL file unless you get the ok from Indmar so it is unlikely that anyone has Indmar's mapping/VE tables. I'm sure they did this to keep competitors from learning from their dyno work.

1redTA
07-31-2014, 06:57 PM
the small amount of lift and duration added should be in the computer's ability to compensate I would think. The plugs should be grey or tan.

CantRepeat
07-31-2014, 07:03 PM
the small amount of lift and duration added should be in the computer's ability to compensate I would think. The plugs should be grey or tan.

I wouldn't bet my pistons on it. I know you know that BLMs only have so much learning they can do and that learning wont exceed fuel psi or flow. It can't.

Rossterman
07-31-2014, 08:18 PM
Looks somewhat lean to me as well but not off by too much. I'd probably do the mefi burn recal for $200 and call it a day. As an alternative, I know some folks ( in the auto world supercharging world) address this by raising the pressure in the fuel rail slightly to provide a equal increase in fuel across the range. 5% increase in pressure = more fuel per pulse. Can't remember if the fuel pressure regulator is adjustable on your boat but some are.

TRBenj
08-01-2014, 08:40 AM
I'm curious how anyone can tell whether the engine is lean based on that pic... Not enough information to tell by looking at the tip alone. Width of the soot ring at the base is the only really way to tell beyond gross guesstimating. Black or wet is rich, gray or silver is lean (pistons are fragging) and tan or white is TBD until you chop the plug.

Getting afr data throughout he rpm band would be ideal but you can find out a lot by plug chopping.

I would not necessarily expect even a minor head, cam or lift change to be accommodated by the ECM, especially if the engine doesn't have o2 sensors to know how much to adjust.

Rossterman
08-01-2014, 08:48 AM
I'm curious how anyone can tell whether the engine is lean based on that pic... Not enough information to tell by looking at the tip alone. Width of the soot ring at the base is the only really way to tell beyond gross guesstimating. Black or wet is rich, gray or silver is lean (pistons are fragging) and tan or white is TBD until you chop the plug.

Getting afr data throughout he rpm band would be ideal but you can find out a lot by plug chopping.

I would not necessarily expect even a minor head, cam or lift change to be accommodated by the ECM, especially if the engine doesn't have o2 sensors to know how much to adjust.

Agree- the only way to tell for sure is with an A/F sensor.

Also as you point out, without an O2 sensor in the system, there is ZERO MEFI adjustment being made. The cal file just reads the parameters (temp, vacuum, throttle, etc) and determines which pulse width to use from the table.

jprcrprv2
08-01-2014, 09:30 AM
I'm curious how anyone can tell whether the engine is lean based on that pic... Not enough information to tell by looking at the tip alone. Width of the soot ring at the base is the only really way to tell beyond gross guesstimating. Black or wet is rich, gray or silver is lean (pistons are fragging) and tan or white is TBD until you chop the plug.

Getting afr data throughout he rpm band would be ideal but you can find out a lot by plug chopping.

I would not necessarily expect even a minor head, cam or lift change to be accommodated by the ECM, especially if the engine doesn't have o2 sensors to know how much to adjust.

What he said. Cut the plugs and look at the soot ring. Theses motor are calibrated to operate in a very wide margin of atmospheric conditions. But in no what can they adjust to a higher rocker arm ration which is effectively the same as going with a camshaft with more duration and lift.

IMHO just give yourself peace of mind and have the ecm reflashed to meet the new parameters your engine has with the new rocker arms.

eficalibrator
08-01-2014, 09:42 AM
Agree- the only way to tell for sure is with an A/F sensor.

Also as you point out, without an O2 sensor in the system, there is ZERO MEFI adjustment being made. The cal file just reads the parameters (temp, vacuum, throttle, etc) and determines which pulse width to use from the table.

Finally, a correct response... ;) The correct way to log and reflash would include recording delivered AFR with a wideband (UEGO), comparing it to the commanded AFR from the ECU, and adjusting the ECU tables (probably the VE surface) to bring these two into alignment.

JimN
08-01-2014, 09:44 AM
What makes you think they are too rich? I would think Indmar spent many hours on the dyno dialing in the tunes.

I don't know if the mapping was changed in later years. The Indmar CAL files are encrypted so unless you work at Indmar it would be pretty hard to say what has changed. I have every CAL file from ECM 1 through 2011 but the way Indmar and Rinda have it setup you can't "author" a CAL file unless you get the ok from Indmar so it is unlikely that anyone has Indmar's mapping/VE tables. I'm sure they did this to keep competitors from learning from their dyno work.

With only MAP, TPS and ECT, it's not as accurate as it would be with O2, IAT and a Catalytic converter. It is rich, because they don't want people burning up their engines, but not so much that a plume of black smoke follows them.

JimN
08-01-2014, 09:47 AM
Looks somewhat lean to me as well but not off by too much. I'd probably do the mefi burn recal for $200 and call it a day. As an alternative, I know some folks ( in the auto world supercharging world) address this by raising the pressure in the fuel rail slightly to provide a equal increase in fuel across the range. 5% increase in pressure = more fuel per pulse. Can't remember if the fuel pressure regulator is adjustable on your boat but some are.

The correct way to increase fuel delivery is by increasing the pulse width. The pressure ensures proper atomization and changing that isn't an accurate way to adjust delivery.

Even people in the supercharging world will adjust the pulse width if they can. With a carb, A/F ratio is a crap shoot, at best.

JimN
08-01-2014, 09:54 AM
What he said. Cut the plugs and look at the soot ring. Theses motor are calibrated to operate in a very wide margin of atmospheric conditions. But in no what can they adjust to a higher rocker arm ration which is effectively the same as going with a camshaft with more duration and lift.

IMHO just give yourself peace of mind and have the ecm reflashed to meet the new parameters your engine has with the new rocker arms.

"Theses motor are calibrated to operate in a very wide margin of atmospheric conditions." and by using the MAP sensor, it makes adjustment for extreme high or low readings. Valves opening more increases vacuum, causing the ECM to "think" the throttle plate is open less than it is. The TPS tells it that this isn't true, but above idle, the MAP sensor runs the show. This is why a recal is important but hauling off and making a change based on a guess isn't the right way to do it. When they find the correct A/F ratio, they monitor the exhaust gas temperature, exhaust components, power and other parameters. This engine is likely running lean, but if it's not run hard for long periods, it probably won't burn the valves, seats and pistons.

Unless the heads are on a flow bench and through data acquisition, found to cause a situation where changes to the fuel delivery are needed, running it hard is a gamble.

CantRepeat
08-01-2014, 09:59 AM
With only MAP, TPS and ECT, it's not as accurate as it would be with O2, IAT and a Catalytic converter. It is rich, because they don't want people burning up their engines, but not so much that a plume of black smoke follows them.

I'm well aware of all of that.

But without me doing some logging I wouldn't know if it was a rich tune or not.

JimN
08-01-2014, 10:06 AM
I'm well aware of all of that.

But without me doing some logging I wouldn't know if it was a rich tune or not.

Sorry, I think I replied to the wrong post. I wanted to comment on Rossterman's post "Also as you point out, without an O2 sensor in the system, there is ZERO MEFI adjustment being made. The cal file just reads the parameters (temp, vacuum, throttle, etc) and determines which pulse width to use from the table.".

Rossterman
08-01-2014, 11:29 AM
The correct way to increase fuel delivery is by increasing the pulse width. The pressure ensures proper atomization and changing that isn't an accurate way to adjust delivery.

Even people in the supercharging world will adjust the pulse width if they can. With a carb, A/F ratio is a crap shoot, at best.

Sorry I wasn't clear. I wasn't suggesting this was the best way but just one option. If it was me, would go for the reflash as I stated if the plug checks confirm it is running too lean. That being said. The vortech supercharger kit I installed on my 1993 f-150 used this approach and it worked fine for the 5 years I had the truck before I sold it. My guess is they used this approach as a alternative to larger injectors because the OEM stuff was flow rate limited at max pulse width...

CantRepeat
08-01-2014, 12:26 PM
Sorry I wasn't clear. I wasn't suggesting this was the best way but just one option. If it was me, would go for the reflash as I stated if the plug checks confirm it is running too lean. That being said. The vortech supercharger kit I installed on my 1993 f-150 used this approach and it worked fine for the 5 years I had the truck before I sold it. My guess is they used this approach as a alternative to larger injectors because the OEM stuff was flow rate limited at max pulse width...

The increase in pressure is needed so the injectors are not over working. IE if your VE table needs a lot of high 95ish numbers to reach the 14.7 you increase the pressure so you can lower numbers. Instead of pulsing they would just be sparing all the time in order to reach the correct AFR. This way the injectors don't burn up from over working.

You want your VE table to range from 25ish to 95ish and smooth consistent map from cell to cell. Increasing the pressure without logging and refining the VE table isn't the best way to tune.

I would also think that adding any type of forced induction system would need a lot of work on the spark table as well.

I use one of the Innovative wide band O2 sensors to tune with.

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

1redTA
08-01-2014, 04:48 PM
I think y'all are giving a rocker swap to much credit the lift and duration is minimal, most of the gains come from overcoming friction

CantRepeat
08-01-2014, 05:04 PM
I think y'all are giving a rocker swap to much credit the lift and duration is minimal, most of the gains come from overcoming friction

I dunno, without knowing the lift on the stock cam there really isn't anyway of figuring out how much the lift change is. The reduced friction is also a nice boost for longevity in the rockers.

1redTA
08-01-2014, 07:15 PM
a hot cam with 1.5 rockers has .492 lift, with 1.6 .525 I dunno the duration difference but the lift is only .033

CantRepeat
08-01-2014, 07:38 PM
a hot cam with 1.5 rockers has .492 lift, with 1.6 .525 I dunno the duration difference but the lift is only .033

OK, I gotta do it. What is a "hot" cam? Is that one of those half race, 3/4 race or full race cams from the 80s? :D:D

mikeg205
08-01-2014, 08:30 PM
can you guys speak MC-English please ;)

1redTA
08-01-2014, 09:27 PM
a HotCam is from the LT series engines, it is an offering from GM for a LT1 engine, it was used in the LT4 performance variant in 96 M6 corvettes and Camaros with the leftover 4 bolt block tuned by SLP. I had one in the TA pictured in my profile pic for about a year. The kit contains the following

http://www.jegs.com/p/Chevrolet-Performance/Chevrolet-Performance-LT1-LT4-Hot-Cam-Kit/753463/10002/-1

it was a good kit with an awesome lope but lack luster performance compared to some specialty LT1 offerings estimated to increase horse power by about 40ish HP with a tune

CantRepeat
08-01-2014, 10:14 PM
a HotCam is from the LT series engines, it is an offering from GM for a LT1 engine, it was used in the LT4 performance variant in 96 M6 corvettes and Camaros with the leftover 4 bolt block tuned by SLP. I had one in the TA pictured in my profile pic for about a year. The kit contains the following

http://www.jegs.com/p/Chevrolet-Performance/Chevrolet-Performance-LT1-LT4-Hot-Cam-Kit/753463/10002/-1

it was a good kit with an awesome lope but lack luster performance compared to some specialty LT1 offerings estimated to increase horse power by about 40ish HP with a tune


But none of that tells us anything about the Indmar grind.

1redTA
08-01-2014, 10:28 PM
that's top secret apparently, I was mistaken the 96 M6 vettes had the LT4 cam. which is between the LT1 and HotCam

1redTA
08-01-2014, 10:28 PM
edit from Makers Mark :-)

1redTA
08-01-2014, 10:30 PM
But none of that tells us anything about the Indmar grind.

I doubt the indmar grind has the lift, the Hot Cam specs were for comparison

JimN
08-01-2014, 10:39 PM
But none of that tells us anything about the Indmar grind.

It's not "Indmar grind", it's GM grind- they take the engines from the assembly line and put the marine parts on, just like Mercruiser, PCM, Volvo-Penta, etc.

CantRepeat
08-02-2014, 12:09 AM
It's not "Indmar grind", it's GM grind- they take the engines from the assembly line and put the marine parts on, just like Mercruiser, PCM, Volvo-Penta, etc.

Well, I don't know what Indmar does to the engines. I'm not enginenut and I don't work for Indmar so I don't have any idea what they do to the engines or the cams.

bret
08-22-2014, 06:15 PM
Allan Tehan was the early guru for these engines, TBI and LT1, who set up the engine "builds" per MC directives, then test, then Indmar.

I think WAAY to much credit is being given the AFR of 14.7 in this discussion, in theory a stoichiometric mixture has just enough air to completely burn the available fuel, which is great at idle, but even at cruise speeds, 1/2 throttle say, you'd want at least 13.5-14.1 IMHO. For those that understand WBO2 and data logging, you know the numbers can change quickly and it doesn't take much to change those numbers once you get the 75% throttle, where most ECM - DME - EMS - all go to WOT maps and open loop(O2 sensor is there but not feeding data for fuel), not closed loop with O2 sensor( input to the ECM with regards to MAP, TPS, IAT for injector pulse width or how much the pintle reacts to put fuel in your cylinder); unless you have a SMT6 or Mafterburner or some other piggyback computer off your harness, you have what you have unless you send out to be "tweaked or re-calibrated".

At the end of the day, an engine is a big air pump, with a certain design to produce this much hp. Give it more air, it needs more fuel in relation to the change to stay "healthy". This is why in the Porsche world of turbochargers and manual boost controllers with external wastegates, we call the manual boost knob the wheel of fortune: Turn it to far without proper tuning, it will cost you a fortune.

I personally like 11.7 to 12.1 AFR when stomping the gas or WOT, this helps with Torque as the air comes, then lean out to 12.3 - 12.5 or 6(for top HP) but no more at WOT. After that, it gets lean quick and head gaskets go or worse. But with the cooler temps our engines run compared to the automotive world, maybe a proper data log would show otherwise. But honestly, how many of us run the MC's at WOT a lot? If someone did have a datalog of any of these motors, I would love to see it.