Tuning

HOW TO TUNE AN ENGINE THE RIGHT WAY...  by Jeff Schaefer

#1  Proper Break-In.   Refer to break-in article HERE.

#2  What do I need to tune a car effectively?    Good question Jeff, glad you asked that!  lol.  Here is a list of what you need:
-A Dyno of any kind, preferably DynoJet or Dynapack.  There are positives to both, but I am going to have to give the nod to the dynapack for a few reasons.  The primary reason is that it is much easier to tune a car for light, normal driving on it, and much more precise.  For full throttle, they are both equal.  Sure, the Dynapack is a few times more accurate, but when your talking 1/10 of 1 HP, who cares.  So if you have a dynapack in your area, use that, you will get better drivability daily out of tuning from that. 
-Second thing your going to need to tune a car is a second person.  This person is your go-to guy, so to speak.  He stays outside the car and takes orders from the guy inside the car with the laptop.  He is also an observer, and can spot any potential problems, like a loose timing belt, that the guy in the car has no clue about.  He is also useful to adjust timing on the car, while the tuner inside the car with the laptop gets the car to idle properly.  He can also adjust fuel pressure to the desired level the tuner inside the car wishes.  He can spot fuel leaks the tuner cannot see.  In other words, its a 2 man effort to do it completely perfect.  Otherwise, your running in and out of the car all the time.  One thing the 2nd person should not do is relay information about the graph to the tuner.  The tuner should look at the graph, in person to determine the next changes to be made. 
-The third thing you will need is a Wideband 02 sensor hooked up to the car, either deep into the tailpipe, or screwed into an 02 bung BEFORE the cat.  You want to make sure its screwed in right before the cat, and not say, 6 inches out of the head in the primary header part.  At that point, it is only reading 1 cylinder, not a combination of all 4, which is what we desire. 
-You may also need a clip board, with a blank piece of paper to take notes on.  I will talk about this later.
-Bring an extra set of spark plugs, a gapper, and a tool to remove and install spark plugs with you.
-Always bring 1-2 extra quarts of oil.
-Bring ear protection in most cases for cars with no cat, or muffler.
You are now ready to tune a car.  lets get started.

I am going to be speaking to you all in regards to a Hondata unit, but no matter what unit you use, its all similar.

Step 1:  Put the Wideband on the car, before you start it.    Do that, then hook up your laptop and start up the car.  Immediately look at the air/fuel ratio the car is warming up at.  When the car is warming up, it will tend to be a little rich, like in the 13's:1 air fuel ratio.  When the car gets past a certain temperature, like when the temp gauge starts to move past the first line, the car should have an air/fuel ratio of 14.7:1.  This is a number you need to memorize.  14.7:1.  During idle, and all normal driving under 50% throttle, you want 14.7:1 air fuel ratio.  What does under 50% throttle mean?  People ask me that.  It means that in the tables your ECU is programmed with, your half way up the table, so if the table has 10 columns, your in column 5.  Look at this illustration below.  Notice I have it showing a row for vacuum, and above that the rows 1-10, 1 being no throttle, to 10 being full throttle.  Your car will idle in 1-2.  or it should.

See that blue highlighted area on the upper left of the matrix, that's when I am datalogging it is showing me exactly where in the matrix I am at while driving.  At this case, its bouncing back and forth between columns 1 and 2, at idle, at around 750-800 RPM.  Notice that the proper air/fuel ratio up to 50% throttle is 14.7.  This is going to get you maximum fuel economy.  Now you are NOT going to change the numbers in the matrix to change the air/fuel ratio to get the car to idle at 14.7.  Not yet.  First your going to rev the car up and down to like 3k, with slight throttle to see if the numbers are consistent.  Say, your idling at 14.7 then you give it a little throttle and your at 12:1, thats not normal and going to need attention.  If your satisfied the numbers are consistent then go ahead and adjust the INJECTOR MULTIPLIER until your near 14.7, and when you rev up and down a little, the numbers are consistent around what your shooting for.  Otherwise, your just going to need massive changes all over your matrix, and your making more work for yourself.  Most often, then not, on most motors, when your idling at 14.7, the rest of the matrix up to 50% throttle won't be horribly off.  It could be 13.xx, or 16.xx but that's ok, we can fix that later. I am talking about going from 14.7 to like 11:1, or 19:1... So now we have the car idling at around 800 RPM, and its got an air/fuel ratio of 14.7:1.  Now you call on your boy out there standing over the motor to check the timing.  You want to set the timing at stock, which is 16 degrees, at 800 RPM.  Make sure the cam gear that controls the timing, like on a B series motors its the intake cam gear, is set at 0.  Now adjust your distributor until your at 16 degrees.  Great, now check in your Hondata to make sure its BASE timing in the settings is 16 degrees, here is how to do that:

File-->Settings-->Vehicle tab---> Make sure its 16, and then hit OK.  This is critical.  You see, don't make the mistake of a rookie tuner by having the number in the Hondata different than the number on the distributor.  Talk about confusing.  Don't even think about starting without 16, and 16, I don't care who tells you otherwise.  turbo, NOS, whatever, your doing it that way!  DO IT!  Because what these rookies didn't think of is that 99% of the time your driving around in less than 50% throttle and the reduction in timing due to the NOS, or Turbo, or Blower are not going to be needed until columns 6-10, for when your giving it alot of throttle.  If you make the timing anything different than 16 in the Hondata, or on your distributor, your effectively throwing off your entire matrix of numbers.  We want the numbers to stand for exactly what they came from the factory, at Honda, and go from there. 

Ok, now we have the air/fuel ratio at 14.7:1 at idle, and we have the timing at 16 degrees.  That's excellent.  Remember when i told you to rev it up and down a little before going to check the timing was at 16 degrees?  Well now our work has paid off, and we are going to start to drive the car...Put the car in first gear and ease into it at a very low RPM, like 1500 or 2000.  Drive it slowly up to like 3500 RPM and take note of the air/fuel ratio at light throttle up to 3500 RPM, if you did the first exercise right with the injector multiplier, your probably in the ballpark.  Drive the car in say, 3rd gear, from like 1800 RPM to like 3500 RPM and try to hit all the columns between 2 and 6.  This is your fuel economy area and attention must be paid to this area.  If you are on a Dynapack, your going to have an easy time at this.  Because you can lock in the computer at say 1750 RPM, and then you can give it throttle up to column 5 or so and it will stay at that RPM the entire way.  So you just do it slowly, and deliberate, and make changes so your air/fuel is 14.7 up to column 5.  Columns 6 will be 13.5:1 so just hit that column and stop there....making that last column 13.5:1.
then you do the same for 2000 RPM
then you do the same for 2250 RPM
then you do the same for 2500 RPM
then you do the same for 2700 RPM
then you do the same for 3000 RPM, you get the idea...you look at the Hondata program, and see what exact RPM, it has numbers you can change.  And you tune to that exact RPM.  Every other RPM in between is extrapolated from the last RPM and the current...so you want to be as accurate as possible and tune for the exact RPM's the unit you have displays. 

Well pretty soon, your engine is loving it and your sitting pretty at 14.7 all the way up to column 5 at any cruising RPM.  Say before 6k.  Now take note of the cars responsiveness under these light throttle activities.  When you give it a little gas, does the car feel responsive?  If it does not you may require slightly more timing in these areas.  Try adding like 2 degrees in areas you feel like it was not responsive, and see if it makes a difference.  If it makes no difference, go back to the lower timing.  If you put the timing up to high, and have a blower, or a turbo, and say its very hot outside, you might start detonating at light throttle under harsh conditions. so be conservative.

Notice that the entire procedure so far, is pretty much what I stated in the break-in article?  The previous steps of setting idle, timing and narrow throttle tuning SHOULD BE DONE before you drive that car 100 feet!  After you do all that, you can drive it around if you want to before you tune for full throttle.  Or you can do like us, and just go for it that very day with like only 20-40 miles on the motor.  After taking apart alot of motors broken in like this, with the pistons looking brand new and so good you could almost put them back in the box and re-sell them, we are sticking to it.  Some famous motorsycle guys do it this way too, as do professional racing teams. 

before we move on, its important to look at the matrix your working with to make sure its pretty linear.  Meaning it is consistent and not jagged, or you have any numbers in column 2, say, higher in value than column 3!  Look at this example, see how each column 1-10 is right below the others in unison?  And that its fairly flat across the band not all jagged?

If it was all jagged, with the 2nd line from the bottom (which is column 2) touching column 3, or even column 1, this will be an area your ride is probably not smooth, or it hesitates.  hesitation is usually the result of going from an area too lean/rich to an area of too rich/lean.  Your motor wants a smooth transition. 

We now set VTEC.  In the Rom Editor, you should be on tab "Ignition & Fuel Tables" as shown in the picture above.  You might be looking at the matrix view of the graph, because the picture above is looking at the 2D graph.  Anyway, click on the tab to the right of the tab your on, called "VTEC".  Click "FIXED VTEC POINT" and make sure that box is checked, then go into that area and type in a number you think is lower than where VTEC might be.  Like say, with JUN cams, VTEC might end up near 6000 RPM, like Toda cams, which are even higher than that.  But we are going to take out the guesswork by using a shortcut to find VTEC in a hurry.  We are going to set VTEC like at 5000 RPM and get ready for the test pass...

Time for a test pass! 
*Turbo/NOS/Blower your going to want to gradually lower the timing from column 7 on to into boost.  Hondata tables are already reduced in timing, but reduce them some more for safety sake, and then when your tuning bring them back up slowly.
**REMEMBER THE AIR INTAKE TEMPERATURE MUST BE EXACTLY THE SAME EVERY SINGLE PASS.  Keep the water temperature consistent also.  That affects fuel at a certain point...so if your dynoing at 180 degrees water, and 100 degrees air, try and keep that every pass.  Whatever the car is comfortable with.  If you find yourself waiting 10 minutes between each pass, your not dynoing at the cars normal temperature and doing it wrong.  The wait should be a few minutes at most, unless its very hot outside.  And you must start at the same exact RPM each time, when you floor it.  Consistency is key in tuning.  Ok, now your ready to give it a little throttle.  Go to like 2000 RPM and floor it...keep your eye right on the lambda meter, and keep your ears open for detonation.  At full throttle, we are searching for around 13.5:1 air/fuel ratio for a naturally aspirated engine.  Turbo, we are seeking from 12.0-12.5.  Supercharger, you would want it around 12.0 on the richer side of the spectrum because it generates so much heat.   Anyway, 13.5 or so for all motor, so you give it gas at 2000 and see the indicator that's datalogging jump up to column 9-10 pretty fast, and you notice your at 15:1 air/fuel ratio as soon as you floored it to when you let off at about 3000 RPM.  You let OFF if your outside of say 13.9:1 or higher, or say your richer than 11.0:1, you let off right away.  Then, instead of making adjustments to that one area from 2k-3k, its pretty reasonable to assume your going to be lean (15:1) across much of the band, so go ahead and add fuel in the last column all the way to your rev limiter. 
If you make a change to column 10, always change column 9 the same amount!  So if you adjust 5% richer across 10, do it to 9 also.  The reason is, you might not be exactly the vacuum of column 10, just barely into it, and the computer is using the numbers from 9 AND 10 and extrapolating.  So change both, and you don't have to worry. 
Don't forget to switch the tables to VTEC table, which is the number 2 on the fuel icon.  In the picture above, the number 1 fuel icon is indented...showing you your on the non-vtec lobe.  Pay attention to where your making changes, you want to be making changes in the right table!  VTEC or Non-Vtec.  1 or 2.  so now you made a pas up to about say, 6500 RPM, and your letting off every time you go outside your parameters.  So if your up at 7000 RPM your motor should be tuned for air/fuel ratio pretty damn good up to that point.  When you get up around a point where your in VTEC and have gone a little past VTEC, you will get a graph like this:

You had put your VTEC at 5000 RPM, and when you hit VTEC it was too soon, as noted from that dip from 5k-5800 you see there.  So then that should turn a light bulb on your your head to think "well, it would be nice if I couldn't even feel the VTEC transition, and it was just a straight line"  Well exactly.  So now, you look at the point where your curve below 5k would hit the line in VTEC above, if it carried on its current trajectory upward, and forward.  Take into account its going to not be straight, it will probably round down slightly.  Take a good guestimate in your head and then place VTEC where you might think its going to be a good transition.  In this case, VTEC will probably come in at 5700-5800 RPM  and the graph will clean up nicely.   This is a shortcut method, so you don't spend 7 passes trying to find the proper VTEC point.  We also don't want to focus on tuning that much above VTEC until our permanent VTEC point is discovered because changes in your VTEc point will have an effect on fueling after VTEC.  Now your graph should look like this:

Also, note in the above picture I might be able to bring the VTEC down like 100 RPM to make it more of a perfect straight line?  You could do this, but if you do, you won't feel when VTEC comes in and it will be just a noise.  I have a philosophy on this subject and I believe the Honda experience should be fun to drive.  So what I do is set the VTEC 100, or even 200 higher than its "straight line" position, so that when the customer hits VTEC, the torque jumps up like 10 LBS and the HP climbs steeply up and he gets thrown back in his seat a little bit.  It makes the car feel "quick" in that area, and makes it more fun to drive.  On 2 liter motors especially, I like to make it steep after it hits VTEC so the customer can chirp the tires just hitting VTEC.  Like this graph for example...

See the area I circled?  I could have easily set the VTEC 200 RPM lower so that the graph went up less steeply after VTEC, but I wanted the customer to feel the VTEC power when it kicked in.  See the torque immediately jump up 10-15 lbs in an instant?  The guy gets a little chirp out of it, and gets him excited about driving his car.  The job of the tuner is not only to make the air/fuel ratio great and the car safe to race, but to make the car FUN TO DRIVE.  BTW, you can mess with VTEC points like this all day long and it does not make the car any slower in a race, because only a beginner would be at that low of an RPM on a VTEC motor racing anywhere.

HIGHER RPM's  Your motor will want fuel up to a certain RPM, and then it will want a little bit taken away, or the fuel curve will flatten out.  Look at the graph here, below.  See how from like 6500 RPM to like 9000 RPM the fuel is pretty similar?  That is how most engines are.  And if you went past 9000 RPM, the fuel might be a little less, you can see at a certain point it peaks, then the fuel backs off slightly.  Remember this when your tuning, so make sure the graph is smooth, and not all bumpy.

Ok, we have come a long way already, and we need to finish up.  Well what about columns 6-8?  We never really talked about that much.  You could have taken care of those in 2 ways.  You could have done them after you did 1-6 in the narrow throttle and tuned them before you started the full throttle, or you can do what I do which is effective also. 
Columns 6-9 are all 13.5:1 Air fuel ratio on most vehicles, except boosted ones, where on them column 9 would be like 12.5:1 perhaps or 12:1.  Also of note, its pretty difficult and hard on your engine to sit there on a dyno at 8,000 RPM and tune for columns 6-8.  Its hard to do it even at 3,000 RPM sometimes.  Because what happens is your letting on and off the throttle and thats junk, because your injectors are going nutz on and off.  So do this.  Take your mouse and highlight from column 6 to column 9, and then go to the menu under edit, and do:  "Interpolate Selection" or ALT-E, this will average between column 9 and 6 everywhere in between and give you a nice smooth transition to full throttle.  But notice it won't change the number on column 6 or 9.  Remember, you can do this step before you start the full throttle exercise but its more difficult also if you don't know your precise VTEC point.  Then go and test the air/fuel ratio in a few area's in your matrix to see how good the interpolate was.  then make minor adjustments from there.  I have datalogged probably 3 thousand miles in various cars before and I have not even once, cruised in columns 7-8 ever.  I am either giving it gas to get on an onramp in like columns 4-5, or I have given it almost full throttle and I am in column 9.  Columns 7-8 are really just transitional areas to full throttle, and rarely used daily. 

Now I have 13.3-13.6 or so, Air fuel Ratio all the way across, what now?  Before we tune the timing curve, we are going to play with the cam gears, or IVTEC, etc.  Start with the timing cam gear first (the one on the other end of the distributor).  When you move this cam gear, it will affect timing, so get your timing gun out and put the timing back to exactly 16 degrees after you move the cam gear.  We do one cam gear at a time, starting with the timing one first.  Do a pass, notice the graph move up or down, start with a modest adjustment like +1.  If it likes it, go more, until your engine builder says its unsafe.  If it likes +1, then it likes +2 even more, you can count on it thats its going to hate -1, or more...heck motors might like +6, if you have that much clearance in your piston/valve & valve/valve.  Now that the distributor/timing cam gear is done, move to the other one.  Adjust that one...this one doesn't affect the timing, so it goes pretty fast.
TIPS:  If you advance the intake cam gear and retard the exhaust, you bring the valves closer together.  So with big cams, you probably don't want to advance the intake cam gear too much, because that will bring the valves closer to hitting the pistons, and if you left the exhaust gear at 0, its bringing it closer to that valve too.  So as a rule of thumb with motors with tight tolerances, your going to want to leave the intake cam gear around 0, or +1, and ADVANCE the exhaust cam gear to like minimum +2.   You advance your exhaust cam gear, you move the valves farther away from each other, and reduce overlap! 

Now its time to fine tune the timing curve.  Now we got the cam gears to where the motor is breathing nicely, and it likes it... Start out with a nice blanket of say 2 degrees advanced across the entire wide throttle 9-10 area, in both non-vtec and VTEC.  see if it likes that.  If it likes it up to say, 7000 RPM, add maybe 1/2 a degree more before there and then go back and lower it after 7k, slowly.  You don't want to go from say 34, to say 30 right away, you want a smooth transition like 33, 32, 31, etc.  The higher RPM you go, the lower timing it will probably like in most cases.  So you might have a peak timing of say 33 on the matrix at 8000 RPM, and then at 9k your timing is 31, then at 9500 your at 29.  At this point your tuning for maximum upper range horsepower, since your lower range is probably lines over lines at this point.  So you do 1/2 a degree at a time in the upper areas until you get the power to carry on as long as possible.  Now that you have the timing perfect, or as good as you can get it all up there, you take a step back to fuel...

Back to Fuel...  This is a short step and may only take 2 passes.  Changing the timing/cam gears could slightly alter the air/fuel ratio, but if your only adjusting a couple degrees, probably not noticeably.  But anyway, for maximum power, now we are going to blanket change the power band to see how the motor likes it.  We highlight from say 7k-9500 and add 1% fuel across that area, and do a pass.  Did it like it?  Did it run .2 richer?  If it liked it, do another 1/2 a percent until it reaches maximum.  Do the same for leaning it out 1% if the first pass of Richer was not good. 
**REMEMBER THE AIR INTAKE TEMPERATURE MUST BE EXACTLY THE SAME EVERY SINGLE PASS.  You also want the water temp to be consistent too, because that affects fuel too at a certain point.  And you must start at the same exact RPM each time, when you floor it.  Consistency is key in tuning.

So now we have hit the cam gears, the timing curve, we have hit the fuel curve 2x, and we are pretty much done.  Now is the time to experiment with other mufflers, or whatever, intakes, to see how it affects your ride.  You should have tuned your car exactly the same as your going to race it.  Don't show up at the dyno with a cat on your car, if you race with no cat.  That won't work at all. 

Here are the mistakes people make when they go and tune:
-They changed the exhaust/header.  Get your exhaust BEFORE you tune. or Go fine tune again.
-They put on a High-Flow cat.  Time to re-tune, now your running lean.
-They changed the cams...DO NOT DO THAT!
-They took off the cat to go race, now your probably melting pistons, your way too lean.
-They put in a different thermostat, and the car runs at a different water temperature than when tuned.  This will change the air/fuel ratio, don't do that.
-They thought they were smart and tried to mess with the timing, or fuel pressure.  When your done tuning, notice what your timing and fuel pressure were, and MARK THEM.  Do not change them.  Even if you go up or down in elevation, it is only going to run slightly leaner or richer, not crazy off.
-With a turbo, never change any aspect of your setup, if you do, go back to tune.  Wastegate, manifold, turbo, piping, intercooler, anything, or your asking for trouble.

What is ok to change after I go tune?
-Most intakes are ok, unless your talking about going from stock, to cold air, thats no good. 
-Spark Plugs are ok.
-valve adjustment is ok.
-Oil change. LOL
-Air Filter is ok

As a general rule of thumb, something that affects airflow a great deal should not be changed after the tuning.  Unless you want to put it back up for a few runs to adjust.

So in review we have a few basic steps here.
-Go to a dyno
-Get a buddy to assist you.
-You have to have a Wideband 02 sensor
-Set Idle at 14.7
-Set distributor/Timing at stock 16 degrees
-Make sure Hondata/Unit is set to 16 degrees
-Make sure your air intake temp is the same before each pass, and your water temp is full warm and the same before each pass.
-Tune for 14.7 from column 1-5, and 6 for 13.6 up to VTEC or 6k or so.
-Do VTEC shortcut to find VTEC, remember, make the car fun to drive.
-Tune fuel for upper RPM's in VTEC
-Play with Cam gears
-Fine tune the timing, using blanket adjustments
-Go back to fuel, again, and use Blanket adjustments for fine tuning.
-Do not change anything on your motor after tuning that can affect air flow greatly, unless you re-tune.

Now I would say your machine is pretty fine tuned.  Pretty dang good.  The approach is systematic, its deliberate, and your not on there long at all.  You memorize the above, you know what your doing, and you will be consistent in your tuning.  The approach also makes it very hard to hurt a motor because you have your observer there, and your going up the RPM's tuning it slowly, 1 pass to a new RPM each time until your perfect all the way up. 

If you follow this approach, you will be successful at tuning cars.  One thing I did beyond what the above states is that I had my wideband directly wired into my laptop, so that the air/fuel numbers showed right on my screen, like this:

Those numbers are the air/fuel ratio the motor is in at that particular RPM, and throttle %.  So you can see, when I have these numbers, it makes it really systematic.  Most tuners do not have this like the above and simply look at the air/fuel ratio on the dyno machine and make the changes manually.  This is an OK method, but that takes more time for sure and is less accurate.
So guys, if you have the Hondata dealer package, and you don't have your lambda wired directly into your laptop, make it happen!!  Its wonderful.  I would only say its not really necessary on a dynapack, because of the accuracy of the loading at each RPM.  But it would be better nonetheless to have it like the above. 

There are other options on the Hondata worth discussing, but they really don't affect how to tune a car.  Like for example, you can remove the knock sensor on Hondata, any ECU, and for example, you can disable the 02 heater so you can run your car just fine with no 02 sensors even plugged in.  You can even mess with the idle speed if your idle has a slight lope, you can fix that.  You can have your Hondata switch off your A/C after a certain throttle position. You can set the boost cut at any amount you want, lmited by the map sensor you have plugged in, and you can also set the rev limit anywhere you want.  It also has a NOS controller on board to change your timing curves and fuel curves for when your on the unit. 

Pretty smart little box this Hondata is.  I recommend supporting Hondata by buying from them, or their dealers.  One of the better business's in our realm.