MaxEffort  TM digital programmable fuel management  TUNING TIPS

When racing you only need to think about 3 things, and the sequence in which they occur:

1.  0-4000 Power Enrichment

When staged under boost at the line or when at 1/3 throttle or more
  and under 4000 rpm, the ECM is in the Power Enrichment mode of the
 MaxEffort chip.
Position 3 allows one to modify the amount of fuel being delivered from 0-4000 rpm in order to:

     A.  Adjust the fuel to obtain optimum boost at launch and quick
  spooling initially.

  B.  Compensate for additional air flow created by "air leaks"
  deliberately created between the MAF and the turbo.

          C.  Allow one to run with lower fuel pressure but compensate for it
  at this point.

      An adjustment of four numbers in this position is the equivalent of
  changing the fuel pressure by approximately 1.5 psi.

2.  Spool Up Curve

When the engine passes 4000 rpm for the FIRST time, the MaxEffort
 switches to the spool up mode between 4000 rpm and 4800 rpm. This allows one to select a fuel curve that angles the fuel up as the boost angles up. It allows one to launch with a leaner fuel curve for the better part of
 first gear when the engine can tolerate a leaner mixture due to the lighter
 load imposed by first gear.

Usually the default spool up curve works well during this phase.

3.  Wide Open Throttle Fuel Curve

After one passes 4800 rpm for the FIRST time, the fuel curve used
 will be the one selected by the Thumbwheel Setting.  These settings are
 approximately 4% apart at full throttle.
It is best to start with the richest (highest number) setting initially and then dial down until the EGT is satisfactory and no detonation is occuring.

         It is much more desirable to use EGT and/or knock retard as a
 tuning guideline than to rely upon stock O2 sensors which are extremely
 non-linear.  For racing purposes, O2 values are a very poor criteria unless
 one is using the broad band, five wire sensor used by the Speed Pro unit.

Setting Idle fuel

1.   Start car and let it warm up. When temp reaches 160, note the quality of the idle, and also the richness.

2.   Shut off engine and place TW on position 0, idle fuel, and start by removing a few numbers. Restart car and note Idle fuel again. Sometimes, if too lean, you will notice a stumble when you drop it in gear. The tighter the converter the more noticeable it will be. As a rule, put just enough numbers in to make it idle well and not stumble, then add 1 or 2 more and forget it. If you have to add 8 or 10 or more, there may be a problem
as usually the default is pretty close. Also, when you start the engine, if it revs unusually high and then slowly recovers, you may have an air leak in the intake somewhere.

3.   Adjusting throttle plate/ IAC /TPS. Units equipped with scanmaster logic will not show IAC (idle air control motor) counts unless you have DirectScan. I try to keep these counts down around 0 and let most of
your idle air come in through the butterfly. If IAC motor is too far out and the throttle plate is closed off too much, you may notice an idle that oscillates by going up and down signaling the operator that the engine is too dependant on the IAC motor for air. First thing to do is reset TPS to .38 to get that out of the way for a while. Then, keep opening throttle with screw until you notice idle picking up and then correcting back down. Shut off engine every time you do this so IAC resets. Eventually, if you keep doing this the IAC motor will close off and the idle speed will not recover back down. It is at this point you know the IAC is closed off and all of your
idle air is coming in through the butterfly. Now, back off on the butterfly a little until the speed comes down to the prescribed 900 or so and then reset your tps to .46 at idle and you have it. Sometimes, after you run it a bit on the road the idle will go back to hovering high so you know you are on the edge a little too close. Simply back the throttle plate off a little and you should have it. When making throttle plate adjustments, NEVER let the TPS go over .48 with the car running. If so, it messes up the anti - stall and a throttle follower will start backing out the IAC motor. Shoot for .46 TPS with the motor running and anything over 4.20 at WOT is good.

0 - 4000 RPM power enrichment fuel

Usually you wont have to mess with this. It hits this mode when you crank down on the accelerator about 1/3 throttle or more, and your RPM's are less than 4000. This can basically be used to correct for artificial air leaks induced by the operator between the turbo and mass air to eliminate any
restriction from the MAF. A good example would be if a person has a 4' inlet turbo. Coming off the turbo with 4" ducting, put the taper down
to 3" adapter right at the MAF. Install 1/2" holes for 360 degrees all the way around the taper point. You now have a partial MAF bypass that can be covered with scotchbrite and oiled for an air cleaner. It might not be the best air cleaner, but it will filter somewhat. Before drilling the bypass holes, power brake the car up when up to temp and note the 02 reading. After installing the holes repeat this and keep adding 0 - 4000 fuel until the 02 comes back to the same point or close. Record your values, you are done with 0 - 4000 fuel.

Cruising Fuel

Normally the car is in the cruise fuel range at about LV8 64 to LV8 115 or so. (LV8 is the load) When cruising down the road at a STEADY speed you may notice the 02 voltage go from rich to lean and back and forth depending on your LV8 and TPS position. What you are seeing is the computer jumping in and out of the cruise fuel mode. At a steady speed, lets say 65 mph, I just give my cars enough cruise fuel so that there is no occasional slight "buck" to the car signaling a too lean condition. I work in 4 to 6 number increments. when I reach the point where it is cruising well, I may look at 02 and notice it still reads 0v. I run my cars at cruise like that but it probably would be wise for you to give it enough cruise fuel so that the 02 at least reads something. Sometimes, especially on the 55 or bigger injectors, you will notice a slight flat spot when you slightly depress the accelerator when cruising. This is signaling you that you still may have an injector or 2 too lean at cruise. The bigger the injector, the more erratic at
low pulse width. It may be best to give it more cruise fuel to eliminate this condition, but there is another way to do it if you are a little bit bold. On an 8 position MaxEffort this adjustment is fixed due to lack of extra positions for all the adjustments, but on a 16 you can set the TPS/cruise fuel adjustment to kick you out of cruise fuel mode via an operator programmable TPS threshold setting, thus eliminating the flat spot when you give it slight throttle. The way to do this is to go down the road at a steady speed and adjust the cruise fuel until the car is happy. Flip up to position B on the TW and note tps in "engineering units" ( It does not matter what position you are on when cruising, all positions run the same until you get on it) Still maintaining a steady speed, you can take this
number, add a few numbers to it in your head, and plug the new number into position 8, "cruise fuel vs tps kick out point." From this point forward, when you cross this TPS threshold, you will be kicking out of cruise fuel mode thus eliminating the "flat spot." Different size throttle bodies will require different numbers. It takes more TPS to maintain 60mph with a stock TB than it does, lets say, with a 70mm.

Cold start

With the coolant temp showing cold, one can put numbers here to eliminate stalling problems when first started. Disables at about 140 degrees or warmer coolant temp. Some 8 position models have this function eliminated due to lack of importance. Other functions such as "fuel out" or
"offset" may take priority over this depending on the setup and injector size.

Fuel Out

Some versions set up for alcohol injection such as my white car have a function known as "fuel out."  This allows the operator to install oversize methanol and water/alcohol jets and trim back the gasoline farther than the leanest TW position will take it. Once the car hits 4800 rpm's for the FIRST time, it will be assumed by the computer that the alcohol is going by then, and the computer will then look at the "fuel out" programmed number and subtract it from your fuel curve. I have alcohol jets large enough on my white car to require 40 numbers here, which, at 8 numbers per TW position would be like running on TW -5 (negative 5) with my TW position already on the leanest (full throttle fuel) position 1. So therefore, I virtually shut my 83's down to about half the pulse width of a stock car with stock injectors, and the car is switched over to mostly alcohol for the rest of the quarter mile.


V 6. X   16 Position Alcohol solenoid enable

vs. knock retard

You have capability here of triggering an alcohol nozzle when knock retard meets or exceeds an operator programmable amount. Alcohol/pump gas cars should have this capability providing they do not have problems with false knock. ALWAYS keep an EVEN number here for normal operation because an extra capability was squeezed in, and that is; if you put an ODD number here, the extra alcohol solenoid will now also turn on during the "Spool Up" mode, 4000 to 4800 RPM's, to assist the injectors for one of the following reasons:

A.    To compensate for extremely good air or lower fuel pressure without messing  with the Spool UP fuel curve.

B.   To replace gasoline with methanol.

C.  To check for false knock in first gear by enabling this and monitoring knock retard.

 This function reads out, and is programmed in engineering units, so keep in mind you must divide your number by 2.56 to know actual spark advance.


Fuel Limiter when MAF reads less than 255

After 4000 rpms the fuel starts to get into some pretty big numbers. If you part throttle your car up on boost a little, and the rpm's exceed 4000, this function will allow the car to maintain a reasonable F/A ratio. Have problems with part throttle knock? Try taking this up 16. Problems with over rich fluttering during part throttle acceloration? Go back down.The default is on the lean side.

Accelerator pump (Tip in) / Throttle body size

Much like a carburetor, we also have an instantaneous shot of fuel that
is delivered when the throttle plate is moved decisively. Keep this on the lean side, and sometimes you have to work back and forth between the TB size and Accelerator pump to get it right, or as close to right as you can get it. On 55's on up, it is not advisable to mess with the TB size at all. On any other injector, you may have to go down on the TB number 1 or 2 but no more. You would do this ONLY if you just cannot seem to work a slight no load hesitation out. For the most part, just concentrate on position #1,  accelerator pump. 1 or 2 numbers here at the most. Default number of 0 usually works the best. Like idle fuel, keep this on the lean side.  Do not attempt to cure flat spots in acceleration, for this is instantaneous. Accelerator pump is always position 1 and TB size is generally position #6.

Knock retard vs mph

Some motors that have forged pistons that slap and set off the knock sensor or have dreaded camshafts that generate noise (valve train noise is the same frequency of knock) require that the knock sensor be programmed out vs Mph. Also, some people have trouble with false KR the first time the rpm's fly up when they nail it. There is a hidden function here that disables the knock sensor---irregardless of speed---until the first
time the the car spools up to 4800 RPM's. This is accomplished by putting an "odd" number in  "Knock retard vs MPH."

Spool up

With the MaxEffort you have the option to "spool up", or come off the line leaner than you will be for the rest of the run. The idea here is to taper the fuel up at approximately the same angle that the boost tapers up. Normally the default spool up value is good. There are 4 curves to choose from; 3, 4, 5 and 6 and you would plug 1 of these 4 numbers into position 7.

MAF Lock - On at 255

This is operator programmable such that if an aftermarket MAF should happen to read low, you can adjust this number to "Lock On" the MAF at 255 when this many GM/sec of air is achieved.

Other thoughts on tuning and reliability

Knock will bump your fuel curve a little which will make a difference on racing fuel if you are just pinging slightly, but may not make a difference with pump gas. I use EGT and Knock sensor to dial in my car that runs racing fuel, and strictly go by KR on my pump/gas and alcohol car. Unless
you have a Speed Pro, using 02 is about useless for tuning on our cars because a 1 wire readout varies a bunch vs EGT. Many people notice the 02 coming down toward the end of the run......because the EGT is going up. Unreliable.  However, some guys have success with 02 because it establishes a "pattern" and they recognize that pattern and can associate it with the way the car runs.

Unless you have an odd size bore or need a lighter piston to spin the motor higher, stay with the stock tight fitting pistons. They were designed along the lines of diesel piston's, specifically designed for our application of abuse. The top ring sits in cast iron and have shown to be superior in reliability to a common forged in dyno detonation/failure tests. Also, to eliminate valve train noise possibilities, stay with the stock cam with 82.5 pounds(factory specs) of valve seat pressure. It is much better to be overturboed and undercammed. It is fairly easy to be able to run High 10's with the stock cam. Besides that, after market cams have a tendency to go flat. If you are not happy with high 10's  and put a larger cam in, you may experience false knock and you will have to program the kr sensor out and be prone to failure due to knock so you must, or should, run racing fuel. 

Another problem you will run into is the reliability of the block. You can take it to the "edge" with a stock cam, so why go bigger if you want something that is going to be reliable. Lately I have observed 2 motors with the webbing blown out, with steel caps on the mains. Based on this observation, I have formed the opinion that it is better to put a girdle over the steel caps, if you already have them, or the stock caps, like I did and possibly avoid having to line bore the motor. The idea here is to build a motor that will go 100,000 miles rather than an after market short block that might go 20,000 miles. Spend a few more dollars up front and save a bundle down the road. Buick specs for clearances are fairly tight. My motor runs 1.5 on the mains and rods, and like Ruggles told me, it is critical to keep it tight and maintain oil pressure from the stock pump. He has several reasons why not to use the hi volume pump.

Heads are another concern. The stock torque-to-yield head bolts were specifically designed for our application. I would never consider using studs, or anything else with iron heads. Lawrence Conley once said, when "Black" was just into the 10's that stock head bolts with 1 steel shim 85 gasket coated with clear Permatex RTV silicone gave him reliability. The gasket is much thinner than stock. The fatter the gasket, the easier it is to push it out. I followed Lawrence Conley's advice and have not had a head gasket problem since on my black car.. The factory head bolts are not designed to be used over, so always use new ones. The heads really are not "lifting", but rather the combustion surface is flexing up into the water jacket due to lack of webbing on the back side. This is when it tries to push the gasket out. You may have observed that the gasket likes to come out under the intake or on the exhaust side. This is where the deck support webbing is the least. Staking the heads by putting pins in to hold the combustion surface from flexing, may be a partial solution to the problem. Champion Heads is the only company I know that does it.

One of the neatest things about the cars shown in the picture section is the the fact that they repeat from run to run, from week to week. Once these cars were dialed in, we didn't have to touch any of the parameters again. That's one of the keys to being able to have more fun and reliability, in the sense that you don't have to waste a bunch of runs dialing it in. Everybody knows that every time you jump on one of these motors, the fuse gets a little shorter. The key to it is following the rules, and the rules are keep everything the same. Keep the boost fixed, and keep the same gas in it all the time. Jeff hasn't had to touch anything concerning the engine or thumbwheel position going on 4 years now on his 10.01 car. For that matter, the transmission is going on its 4th year now as well. The white car can sit for a month, and I can jump in it, and it will have 26 pounds of boost and never miss a beat. When you set a car up to repeat, you can anticipate a map sensor pretty easily. The manufacturers have been doing that with their toys for years.

As far as the block learn is concerned, there are a bunch of "cells"that the 02 sensor teaches on a typical car. These cells provide a fuel air ratio correction for various loads on the motor. The larger the injector, the tougher it is for an 02 to deal with an increasingly erratic fuel curve. Basically it gets pretty tough to take a single chip and do it all in any car using closed loop. When I say that, I mean cars with large injectors and cams and what not, and expect them to provide a peak fuel curve with drivability and idle quality. It can be done, but its just a lot more messing around than I care to do, not to mention continuosly fouling out the 02 with lead. The MaxEffort allows you to program the cells up yourself and forget it. The timing is fixed for a reason, and the reason is: You can pretty much dial your boost accordingly, and a lot of times end up with the same results as going up and down with the timing.

I have observed that a lot of people are bound and determined to run these things on pump gas. Well, years of experience has taught me that after X amount of cylinder pressure, combined with X amount of cylinder temperature, is going to cause detonation. I would never consider jumping on my black car without straight C16 in it, and in my pump gas car I would never consider jumping on it without lots of alcohol, and keeping it dialed back from the edge a little. That's how I got 120,000 miles on that thing without pulling a valve cover, and it has had a John Craig TA63 turbo on it for quite some time now.





8 Position

16 position

Tuning Tips








Site designed
Joe Tripodi