Matching an ECU with injectors is no longer enough.

[tryingbe]

First, let’s go over the basic overview of how ECU controls an engine. In the simplest term, an ECU reads from the sensors (MAP/MAF, TPS, Crank, CAM, CLT, IAT, etc), do some calculations, then output fuel and spark. Injection of fuel does not need to be precise while it is critical for the spark timing to be very precise.

ECU might also turn on fan, shut a/c compressor off, control the idler, turn fuel pump on, boost control, alternator control, and so on, but we are only focusing on fuel right now.

The fuel amount is calculated based on a static but critical pump efficiency or volume efficiency tables on a MAP (speed density) based calibration. What’s pump / volume efficiency? It simply means how well your engine can breath/pump air at a given RPM, see ShelGame's post below for detail explanation on the difference of the two. MPtuner uses pump efficiency table while Megasquirt uses volume efficiency table.

Let’s compare some pump efficiency of the stock calibrations and my custom calibration in MPtuner.

You can find MP tuner here
http://www.turbo-mopar.com/forums/sh...l=1#post593977
Calibration files here.
http://www.turbo-mopar.com/forums/fo...ost&order=desc

Navy blue is from 89 2.5L MTX/ATX

Red is from a 89 2.2L ATX Chrysler TC by Maserati

Pink purple is from a 87 2.2L MTX/ATX

Green is a 89 2.2L TII MTX

Light blue is my 2.2L with a ported cylinder head and big valves and other modifications.



You can easily see how using 89 2.2 TII calibration on a 89 2.5 will make the engine run rich at higher RPM, even though both 2.2TII and 2.5TI uses the same injectors.

You can also see how using my calibration on a stock 89 2.2 TII will make it run rich.

Every ones uses different parts to modify their engine, which resulting in every modified engine has a different pump / volume efficiency. Tuners often have to make an educated decision (best guess) of the pump / volume efficiency since most tune are done remotely. Sometimes the tuner gets lucky, other times the calibration is way off. Personally, I learn my lesson and I refuse to tune an engine if I can't touch the engine physically.


Do you need to re-tune after changing one part?

Here is another example.

Navy blue is my ported head with big valves on my 2.2L.

Light blue is a stock 782 head with back-cut valves on the same 2.2L block, same turbo, same injectors, same everything as Navy Blue.

Light green is a stock 89 2.2 TII for comparison purpose.



One part can make a major difference in the Pump /Volume Efficiency!


My advice for tuning?

At minimal, buy a wideband and prepare to work with your tuner to keep trial and error until you get a tune that works for your engine.

The better options would be buy or make a socketed ECU, buy Moates Ostrich, buy wideband, learn to tune your own car, then tune your own car.

You would also want to check your tune every time you changed a part and re-turn if needed.


As always, I'm not prefect, if I miss something or wrong, please kindly point it out and I will edit this post.


Edit after Shelgame's explanation regarding to pump \ volume efficiency.

[bgbmxer]

A very educated post but also put into terms anyone can understand. People learning need more of this. Myself included. Thanks sir

[wheming]

Well done Harry!
You point out specific examples and is written so everyone can understand.
I would only offer one other suggestion for those reading (and I am no expert tuner).
But in order to successfully tune your engine you need the proper tools. Harry mentions a wideband O2 meter, I would suggest reliable and accurate instruments.
In keeping with the reliable and accurate instrumentation, in order to properly adjust your tune you must be able to log certain values and analyze them later for changes.
Using a Turbonator based cal, you are able to use the WB2NB function (for somes ECU's) and it allows you to log your WBo2 value directly.
For those not using that feature or on ecu's that don't support it, you could use a new device called MPSciLink, that accepts up to 4 analog inputs and they will be logged right along with any ecu parameters you select.

I would submit for consideration that a flashable ecu is clearly the best option for tuning. It is easier to reflash than have to remove, wipe, and burn chips. It is as easy as connecting a cable to your Ostrich and reflashing, however with the MPSciLink you can flash your flashable ecu with your Android device over bluetooth! And you can use the bin editor to make tuning changes in the palm of your hand and then reflash.

I didn't mean for my response to be a sales pitch. But the point is the same as Harry's. In order to have a safe and successfully optimized cal in your car, the customer must become his own tuner. In order to do that, you must have the tools to analyze the data, and be able to make those changes yourself.

For anyone that would like to learn more about MPSciLink, or any of the MPSuite line of tuning aids, there are threads in the EFI Tuning section.

[contraption22]

All good points.

[ShelGame]

Sorry got to put my engineer hat on here - Just semantics, really. But, our table is NOT a volumetric efficiency table, strictly speaking.

Ve is defined as the volume of the cylinder at TDC compared to the volume the air in the cylinder would occupy at atmospheric conditions (temperature and pressure). Clearly, by this definition and with a turbo, our volumetric efficiency would be dependant on boost; and would easily exceed 100% when in boost.

It's called 'pumping' efficiency as it's actually a slightly different calculation than Ve. The Pe is the comparison of the volume of the cylinder @ TDC compared to the volume the air in the cylinder would occupy at MANIFOLD conditions. This takes boost out of the efficiency calculation.

[Reaper1]

Rob, not to buffer up this thread, but using your description of how PE compares to VE, would that mean that using a PE calculation on an N/A engine would be the same as the VE calculation given that the condition in the manifold is equivalent to atmosphere?

[88C/S]

Thanks for sharing, just what I needed.

[ShelGame]

Rob, not to buffer up this thread, but using your description of how PE compares to VE, would that mean that using a PE calculation on an N/A engine would be the same as the VE calculation given that the condition in the manifold is equivalent to atmosphere?

Yes, on an NA engine they should be equivalent.

[GLHS60]

Can someone explain this to me please??

Old age hasn't been kind!!

Thanks
Randy

""You can easily see how using 89 2.2 TII calibration on a 89 2.5 will make the engine run rich at higher RPM, even though both 2.2TII and 2.5TI uses the same injectors.""

[tryingbe]

Can someone explain this to me please??

Old age hasn't been kind!!

Thanks
Randy

""You can easily see how using 89 2.2 TII calibration on a 89 2.5 will make the engine run rich at higher RPM, even though both 2.2TII and 2.5TI uses the same injectors.""

Can you see the graphs ok? X axle is RPM and Y axle is % of engine efficiency.

If not, click this. http://thelostartof.net/tryingbe/dodge/VEcompare.jpg

[GLHS60]

Hi Harry:

I appreciate your reply and I'm not disputing your postings.

I'm calibration illiterate but like to follow along calibration posts hoping to learn something!!

I can't seen to grasp the T-II cal makes the 2.5 T-I run rich at higher RPM.

I've never tried this but have heard of others experiencing Engine damage running a T-II cal on a 2.5 T

Can you elaborate on why this is so in grade 1 terms please !!

As you mentioned they share the same injectors and are essentially identical other than displacement.

I always thought the T-II cal shortened the injector pulse width to utilize the "larger" injectors.

Any input is appreciated!!

Thanks
Randy

[88C/S]

Thought I knew what the PE graph represents, but now? So, what changes the graph from stock, injectors, cam, turbo? and how. If there is a link to info here on some forum, please post a link so that I may study it. It will be awhile before I can make use of a dyno.

[tryingbe]

I'm calibration illiterate but like to follow along calibration posts hoping to learn something!!

Download and install MPtuner and open all the calibrations to look around. They are all free to use, start getting familiar!

MPtuner
http://www.turbo-mopar.com/forums/sh...?45009-MPTuner

Turbonator calibrations
http://www.turbo-mopar.com/forums/fo...ost&order=desc

I can't seen to grasp the T-II cal makes the 2.5 T-I run rich at higher RPM.

Can you elaborate on why this is so in grade 1 terms please !!

Calibration is inherently complex but I'll have it a try.

I'm going to ignore every other tables in the calibration and focus only on the pump efficiency table.

Here is the pump efficiency table of a TI 2.5 (green) vs TII 2.2 (blue)

At 6018RPM, the green line is at about 68% efficiency.
At 6018RPM, the blue line is at about 80% efficiency.

(80-68) / 68 = 17.6% so, do you see that blue line require 17.6% of fuel and air than green line at 6018rpm.

As you mentioned they share the same injectors and are essentially identical other than displacement.

I always thought the T-II cal shortened the injector pulse width to utilize the "larger" injectors.

I'm lost? There is no "larger" injectors in production vehicles as production 2.5TI, 2.2TII, 2.2TIII, 2.2TIV all uses the same injectors size.

Injectors are simple devices, ON of OFF is all you get, so ECU control when the injectors are ON as OFF is the default state of the injectors.

I've never tried this but have heard of others experiencing Engine damage running a T-II cal on a 2.5 T

There are several ignition timing tables, on the main RPM vs Spark TI 2.5 (green) vs TII 2.2 (blue), 2.5L have less ignition timing in the timing table in the calibration. According to the calibration, most of the time, 2.2L would have more ignition timing than 2.5L.




Did that help, or not at all??

[chromguy]

Great job Tryingbe,

Randy, in other words
Re pump efficiency above.
Since this 2.2 TII is more efficient at pumping air at higher RPM the calibration must add more fuel. When this cal is in a 2.5Ti the cal/ECU does not know what engine is attached so it provides the same amount of fuel vs RPM but the 2.5 T1 cannot pump as much air. Same amount of fuel but less air = rich..... approx 18% more in Tryingbe's example above.

[tryingbe]

Thought I knew what the PE graph represents, but now? So, what changes the graph from stock, injectors, cam, turbo? and how. If there is a link to info here on some forum, please post a link so that I may study it. It will be awhile before I can make use of a dyno.

I'm not sure what you're asking?

Are you asking what parts make the engine flows more air? Or are you asking what parts changes the PE/VE of the engine?

[88C/S]

What parts change the PE/VE of the engine.
For instance, say you go with a Super 60 cam instead of an 88 TBI. What, if any, change would you have. Or, you go with the BMF intake instead of a 1-piece or 2-piece. Thanks.

[chromguy]

What parts change the PE/VE of the engine.
For instance, say you go with a Super 60 cam instead of an 88 TBI. What, if any, change would you have. Or, you go with the BMF intake instead of a 1-piece or 2-piece. Thanks.

Anything and everything in the flow path between the air intake to the tip of the exhaust pipe will affect the PE. Air filter, intake tube(rough or smooth,large ID,small ID), intercooler, throttle body,intake plenum, intake runners,intake ports, bowls, valves, valve seats,exhaust ports,exhaust manifold, Turbo, Swingvalve,Exhaust pipe, Cat, Mufflers, tail pipe. I am sure I missed a few as well
Think of anything that could cause a restriction in your flow.
Stick a tennis ball in your intake tube or potato in your tail pipe and your PE will drop.
I hope that helps and it is a reason that you can't buy a perfect tune for your ECU off the shelf because everyone has something different.

[tryingbe]

What parts change the PE/VE of the engine.

As chromguy says, everything, well, except maybe the injectors and bov. Even bore/stroke ratio, bore size, stroke size will affect the PE/VE.

For instance, say you go with a Super 60 cam instead of an 88 TBI. What, if any, change would you have. Or, you go with the BMF intake instead of a 1-piece or 2-piece

Difficult question to answer as you almost never see a TM person do a back to back dyno on just one part. Most of the time, theory and guess is all you have to go by. I know my ported head made my engine breath between 5000-7000rpm as I swapped a stock head on my setup and had to re-tune the pump efficiency table, so I have two pump efficiency tables to compare.

Engine Master did a pretty good job on the V8 engines for back to back dyno, https://www.youtube.com/playlist?lis...t5dIHutSOu7srE you may want to check them out.

Navy Blue stock TII

Green, stock cylinder head on my setup.

Light Blue, FM ported head on my setup.

My setup is continually changing (for the better I hope), http://www.turbo-mopar.com/forums/sh...=1#post1103213

[88C/S]

Thanks, everyone.
Since I have on my 2.5 the BMF with a 52 mm TB, 44 mm intake and 37 mm exhaust valves in a mildly ported head, TU cast header, gt35 clone turbo, super 60 like cam, 3" v-band downpipe, and exhaust, I can assume there will be more efficiency somewhere around 3600-4200 in the PE curve. Haven't been able to find out, due to the AFR being at 10 when I try to get into boost. So once that is taken care of, I will see what adjustments I really need to make. For now, I lowered the PE a little at the beginning to reduce wasted fuel in the exhaust, as well as making adjustments to the part throttle fuel curve. That helped once the engine got warm. The AFR went from 10.3 to 11.2 or better. I'm using the AEM UEGO 30-4100 for wideband to narrowband.
I changed the wideband O2 sensor a couple of weeks ago, it's been in the car from around 2011.

[tryingbe]

Thanks, everyone.
Since I have on my 2.5 the BMF with a 52 mm TB, 44 mm intake and 37 mm exhaust valves in a mildly ported head, TU cast header, gt35 clone turbo, super 60 like cam, 3" v-band downpipe, and exhaust, I can assume there will be more efficiency somewhere around 3600-4200 in the PE curve. Haven't been able to find out, due to the AFR being at 10 when I try to get into boost. So once that is taken care of, I will see what adjustments I really need to make. For now, I lowered the PE a little at the beginning to reduce wasted fuel in the exhaust, as well as making adjustments to the part throttle fuel curve. That helped once the engine got warm. The AFR went from 10.3 to 11.2 or better. I'm using the AEM UEGO 30-4100 for wideband to narrowband.
I changed the wideband O2 sensor a couple of weeks ago, it's been in the car from around 2011.

How are you tuning? MPtuner? If so, get the car to warm idle with 14-15 a/f ratio, adjust part throttle so you can drive it around in vacuum. Set the boost level to 7-9psi, then adjust the WOT fuel table so when you WOT, it's at 11.5 AFR, then run the engine thru the entire RPM range to Redline while monitoring and takes notes of the RPM and AFR. Adjust AFR until the entire run is 11.5 AFR, after you're done, you have your pump efficiency set.