In order to get the best results from a custom tune everything must be in the best possible condition.
Below is a comprehensive list but may not be all inclusive.
Engine should be in top mechanical condition. Good compression, no abnormal noises, no fluid leaks, etc.
Basic maintenance and tune up should be recent. Proper type and level of engine oil. Clean air and fuel filters. All ignition components, especially spark plugs should be in proper working order. Spark plugs should be of proper heat range and gapped for application. (Boosted engines will typically have a colder heat range and smaller gap.)
If fuel injected, fuel injectors should be of the proper sizing for horsepower levels expected. They should be properly matched and in in good working order. Fuel pump(s) and regulator should be in proper working order. Mass airflow meter and or MAP sensor should be in top condition. Throttle body should be clean. No vacuum leaks.
If carbuerated, it/they should be in perfect working order, no worn linkage or throttle body bushings, good float(s) and float level(s) set properly.
No exhaust leaks and properly working oxygen sensors (if equipped).
Extra bung(s) for the dyno's wideband sensor(s) pre-installed into the exhaust can be handy. (Please inquire as to prefered locations.)
Tires must be in safe condition. (See tire FAQ)
Proper fuel and adequate amount. If using pump gas, please make sure that it is recent and that the tank is full. (Most race fuels have a much longer shelf life if stored correctly.)(If pump gas, it is highly recommended to use 91 octane, or higher to take the most advantage of a custom tune.) If there is any chance that a full tank of fuel may not be enough for the tuning session, please bring extra fuel in proper containers.
Battery, battery terminals & cables and and all electrical wiring and connections in vehicle must be in excellent condition. Alternator and drive belt(s) should be in good condition.
Entire drivetrain should be in good condition. (Transmission, differential, drievline & u-joints, CV joints, motor mounts, etc.)
At the time of dropping your vehicle off, we require that any and all tuning credits (if applicable) be paid in advance in addition to a two hour minimum tuning fee. (Please be advised that many tunes can take 4 to 6 hours. Your expectations and budget should be discussed prior to scheduling.)
This can vary greatly! Quite frequently we have seen a 10% gain over no previous tuning. In some rare cases, there may be little to no gain.
If modifications have been done at the same time as a re-tune of the ECU, then substantial gains may be possible!
Regardless of peak power improvements, often times a properly performed tune can help with driveability issues, cold start, efficiency, etc.
This one is very subjective!
If everything is in adequate condition and properly matched, then there is no reason to not expect good results.
However, if your combination is not properly matched (such as too big of a camshaft) then less than ideal results may happen.
Although a tune might be able to mask underling issues to a point, it cannot, and should not, be expected to fix an inefficient combination or compensate for worn or defective parts.
This question can be broken up into two sections.
First the actual time spent tuning will depend upon a lot of factors. If it's a system and platform that we are familiar with and you just need a little improvement made in some areas, it may only take a couple of hours. If it's a system that we have to learn or it's a complete tune because of major changes on the vehicle, than it could potentially take a considerable amount of time. (Unless prior arrangements have been made, we will typically cap the tuning costs at 6 hours provided that there are no mechanical, electrical or other issues beyond "simply tuning")
Also bear in mind that custom dyno tuning can be a tedious process of fine tuning each load cell to get as close as possible to perfection. Since many setups can and do closed loop running, the computer can continue to monitor and correct as variables such as fuel quality, wear and tear, etc. play in. How close to perfection the tune is done, will be up to the customers expectations and budget.
The second aspect of time goes beyond just the time on the dyno. Often having an exact window of say 4 hours to tune your car is not practical. Unless prior arrangements have been made as such, typically it is best to leave the vehicle for a period of time with an agreed upon approximate finish date. This will allow us to prioritize our tuning jobs by not only "first come, first serve" but also urgency to their schedule.
We are most familiar with stand-alone ECU systems, and prefer to work with those. By stand-alone, we mean HolleyEFI, FuelTech, Haltech, etc.
We are also set up for HP Tuners, and are open to tuning other systems, so long as we are provided with the software for said system and are granted time for the learning-curve involved, as not every tuning system is the same.
Due to the legality surrounding emissions regulations and emissions-related automotive components, we will not tune on vehicles that have had emissions components removed or modified, and that are intended to be registered for street use.
Please refer to https://www.epa.gov/sites/default/files/2020-12/documents/tamperinganddefeatdevices-enfalert.pdf for clarification.
If the Diagnostic Trouble Code (DTC) is activated for a non-emissions component or system, we may be able to reset it, however if it is on because there is a component that is failing and needs repair, it is almost certain to come back. We recommend repairing the base cause of the DTC.
We will not turn off/tune out DTCs for emissions-related bypasses or defeat systems.
In most cases what ever tires that you run on the vehicle can be run on the dyno.
Proper tire condition and air pressure is the first thing to keep in mind.
As our dyno is rated to a maximum of 190 mph, it's paramount that your tires are rated for the maximum speed that you may intend to run on the dyno.
In higher horsepower applications, some tire slippage may occur resulting in a little tire wear. (Softer compound tires will grip better on the rollers, but will definatly experience more wear as compared to a harder tire.)
Although more often than not, drag slicks have been successfully run on chassis dynos, it is possible for damage to happen due to the excessive flexing of those tire designs. Especially if the inner fender wells have any sharp edges, bolts, screws, rivets, etc. and/or if they don't have adequate clearance.
If unsure, please contact your tire manufacturer.
RE Performance & Tuning shall not be held liable in the unlikely event that any damage happens to your tires.
If you are able to do your own tuning, bring a tuner with you or have a remote tuner, we can run the dyno for you at a reduced cost.
Some brands of dynamometers give you flywheel horsepower at the wheels.
Also some dyno owners/operators have changed settings to give inflated numbers.
If the dyno has a weather station to correct to SAE standards, current condition of the dyno (including calibration), strapping down techniques, etc. can all effect the results. In higher horsepower vehicles traction issues can also play into getting accurate results.
If you are wanting to compare numbers between two or more vehicles or are wanting to see what gains have been made after modifications and/or tuning, it is advised to use the same dyno.
Although the actual losses vary dependent on vehicles' drivetrain, typically we have found that on our Mustang brand dyno, if we divide the wheel horsepower and torque numbers by .85 (Effectively compensating for an average of 15% drivetrain loss, then we seem to be pretty close to rated engine power.