General Pre-Tuning Checklist

Everything you need to know before dyno tuning your car.

Electrical Issues

Electrical issues can be a complete nightmare, and more so while trying to dyno tune your race car!  We have seen most everything over the last 15+ years of tuning, and put together some of the more common issues that you should be aware of while completing your race project. 

Wiring and Connectors: 

  1. No exposed wires on engine harness.  This can lead to a short to ground and cause melted wires or fire!

  2. Solder or crimp all connections.  Never twist wires together the connection can and will fail, especially while tuning!

  3. Chassis grounds should be bare metal and cleaned.  Poor ground will cause major electrical problems!

  4. Have the battery ground cable the same gage or larger than power cable.  Often times we see a smaller gage battery ground cable cause voltage or charging problems when tuning. 

  5. Make sure battery voltage is 13~14 volts when engine is running.  We see alternator charging issues often on race vehicles as a result of poor grounding or bad alternator.  The battery voltage MUST be between 13.5~14v when engine is running.

Fuel Issues

In a performance race application fuel system delivery and operation is paramount for fueling super high power levels.  One small issue in the system can cut you short of your desired horsepower level.  Check out the list below to make sure you are ready!

Fuel Pumps: 

  1. Do not install an in tank style fuel pump with dirt, rust or debris inside of the gas tank.  You will be sure to either ruin the pump or clog the pre filter and have fuel pressure starvation while tuning!

  2. If you are adding a fuel sump tray to your OEM fuel tank make sure you clean out any metal chips, weld slag or debris after you are done. 

  3. If you are running an external fuel pump, you will need to run a pre and post fuel filter.  The pre and post filters should be stainless material so you can service and clean them over time.  

  4. Pre-filter fuel filters should be 40-75 micron rating, post-filter fuel filters should be 100+ micron rating.   

Fuel Pressure:

  1. Base fuel pressure should be between 40-50 psi for most any application.  

  2. We recommend having a fuel pressure gauge for monitoring the base fuel pressure before tuning begins.  You should note this fuel pressure value incase there are issues with the AFR at some point.  This is the first thing to check.

  3. When possible we recommend using a fuel pressure sensor wired into the engine management system you are using.  Some systems do not support this.  Many systems offer fail safe protection based on fuel pressure.  Having a fuel pressure reading while tuning is invaluable information that can allow us to troubleshoot a fueling problem instantly.

  4. When installing any super high flowing fuel pumps you need to upgrade the OEM fuel pressure regulator.  The stock regulators in most cases cannot bypass enough fuel, and the base fuel pressure becomes way too high.  Fuel pumps that absolutely require an aftermarket regulator are Walbro 400 lph+ pumps, Weldon, Fuel lab or Bosch 044 fuel pumps.  If you are in doubt, just upgrade the regulator. 

  5. Many newer OEM fuel systems are a return less style system, and lack an external fuel pressure regulator.  Because the fuel pressure does not increase at a 1:1 rate under boost, the fuel delivery under boost can be substantially decreased.  You may need to upgrade to a return style fuel system in order to achieve much higher power levels. 

  6. Make sure the vacuum line going from the intake manifold to the external fuel pressure regulator is secured with zip ties or similar, and is free of cracks or tears. 

  7. Make sure you have a 1/2 tank of fuel for the tuning session.  If you run low on fuel, fuel pressure will drop which could damage the engine while doing high rpm pulls!

Mechanical Issues

Engine:

  1. All cylinders should have good compression.  A general rule of thumb is not having more than 20 psi of compression variance between cylinders.  

  2. If engine compression is 20 psi or lower in a cylinder (s), pour a small amount of oil into the cylinder.  Redo the compression test "wet" and see if the compression increases.  If the compression increases you have a piston ring sealing problem or damage.  If it does not, your compression issue is related to the valves. 

  3. Make sure your engine oil is full, and bring extra oil with you at the time of the tuning appointment.  We have limited oil in stock at the shop. 

  4. Make sure your coolant level is full in the engine/coolant system.  The cooling system MUST be bleed before the tuning appointment.  This can take 1-2 hours to bleed in some cases, which will be billed to you at our shop labor rate of $150.00/hr to resolve before tuning can resume.

  5. Check valve lash before tuning.  Too tight of valve lash will lose compression, and reduce power.  Too loose will make noise.  If using aftermarket cams make sure your valve lash is set to the manufacturers suggested specs.  Many engines do not have adjustable lash, ignore this step. 

  6. Timing chain or timing belt need to be installed correctly, or engine will be out of "time".  In these cases we cannot tune the car for you until the problem is resolved. 

Clutch:

  1. Make sure your clutch is rated for the torque capacity of the power you plan to make.  

  2. We recommend a "sprung" clutch disc when possible to allow for smooth engagement and driving characteristics.  

  3. Stock clutches on many higher power applications will not "hold" the torque the engine is producing.  Please be aware that if the clutch slips during the tuning session you will be charged for the tune, and will need to return at a later date at a retune rate.  This has happened numerous times over the years, so please do yourself a favor and ours and upgrade the clutch if you think there may be an issue!

  4. Some aftermarket clutches require a break in period that you will need to do for "bedding" the clutch disc material.  Follow the manufacturers suggested break in period. 

Turbocharged Issues

Common problems:

  1. Boost "leak" as a result of improperly tightened clamps on charge piping.  If possible, we recommend to boost leak test BEFORE the tuning appointment.  

  2. Vacuum line routing needs to be correct for wastegate lines and bov.  Many times we we see over boosting problems due to incorrectly configured waste gate line routing.  

  3. If using a Tial MVR/MVS, Turbosmart or Precision waste gates make sure you plug the spare/alternative vacuum holes.  If left open these can and will create a over/under boosting problem.  We suggest putting loctite on the plug threads to ensure the plug won't shake out with vibration over time. 

  4. If you are having your EMS system control boost, and installing an aftermarket boost solenoid, only use a 3 port boost solenoid.  The 4 port solenoids that are often used make boost control ultra sensitive, which makes closed loop control almost impossible in most cases.  Stick to the 3 port solenoids, if you are in doubt what you need for your application email tech@evans-tuning.com.

  5. Check your waste gate spring size BEFORE your tuning appointment.  If too large of a spring is used boost cannot be "reduced" down.  Too large of a spring can also create boost control to be ultra sensitive.  If you are in doubt what you need for your application email tech@evans-tuning.com

  6. Use a 3" or larger exhaust when possible from the turbocharger, this will achieve the best spool and power possible. 

  7. If your car is equipped with a top mont intercooler, we always recommend to switch to a front mount style.  Cooling and efficiency are almost always better in comparison. 

Ignition Issues

Common problems:

  1. Make sure you are using at least one step colder spark plug in your performance race application.  Stock heat range spark plugs can lead to pre ignition can cause engine damage very quickly. 

  2. If running colder spark plugs, don't start and stop your engine when cold.  The spark plug takes longer for self cleaning to occur.  If you don't bring the engine up to operating temperature be prepared to change spark plugs more frequently. 

  3. Spark plug gap often times needs to be reduced in a forced induction application over the pre set plug gap.  Generally in a forced induction application 0.025~0.030" plug gap works very well.  

Miscellaneous 

Automatic transmission:

  • If your car has an automatic transmission, we are only able to tune if the transmission will stay "locked" into a desired gear.  This is not an issue with most modern automatic transmissions.  

Wheel Lug Keys:

  • Tuning with a Dynapack Dyno requires us to remove the wheels from your car.  If you have "locking" style lug nuts, you will need to bring the mating key with you at the time of the tuning appointment. 

Summary:

Paying close attention to detail when addressing the points above will save money and time when at a tuning appointment. We can only fix certain issues on the day of an appointment depending on scheduling for that day. If you come to an appointment with a vehicle that is not working properly we may not be able to complete your appointment. If the problem is minor enough to be fixed at the shop during the day we can fix it. Our labor rates apply for time spent troubleshooting of $150.00/hr.  If the problem cannot be resolved, you will still be responsible for the full tuning fee as we have set aside the time for your car in our schedule.  No exceptions!

If after reading this you still don’t have the answer you are looking for, please send an email to tech@evans-tuning.com.