How to tell if your tuner ripped you off
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How to tell if your tuner ripped you off
Here are some easy ways to spot some really half-*** tuning. You'll need EcuFlash, an OpenPort cable, and your current ROM.
1. They didn't rescale! (compare to your stock ROM)
All too often, tuners just leave the stock scale for the fuel & timing maps. This limits tuning precision, because the maps (especially Evo IX) are big enough to justify removing the redundant low-load cells and adding more resolution to high-load cells. For example, if you run about 23psi and are between 230-240 load during WOT, you should have columns for 220, 230, 240, 250, and 260 instead of the stock which is just 220, 240, and 260.
2. They didn't touch the MUT table! (compare to your stock ROM)
In order to view your 3D MUT table, you'll have to add the XML code to your ROM definition file. The MUT table is a list of fields that logging programs like EvoScan can retrieve their data from. If you paid for a custom tune in which the tuner examined log files, the MUT table should have at least some changes compared to the stock table to ensure they are logging all the important non-stock fields such as 2 Byte Load and 2 Byte Airflow.
3. They made violent changes to your fuel map!
Your fuel map is meant to be a smooth transition as boost and RPM's rise and fall. The fuel map loosely represents AFR values, meaning higher numbers are leaner and lower numbers are richer. There is no reason a tuner should be so lazy as to take a few blocks and change them drastically, while leaving everything else around it unchanged.
4. Your high and low octane maps are identical!
The stock ECU is a wonderful thing... it's smart enough to realize that if your car isn't running right, and is knocking up a storm, that it should fall back to a more passive configuration that will protect your engine. Setting the high and low octane maps to be the same completely disables this benefit. The low octane maps should be less agressive than the high octane maps... usually lower by 0.5 to 1.0 AFR points and by 3-4 degrees of timing in higher load cells.
5. You run low to moderate boost levels and fuel cut is disabled!
This doesn't really apply to big turbo or high boost guys, but it definitely does to stock turbo guys... Yet another great feature of the ECU is the ability to recognize overboost conditions and cut fuel when you are exceeding your predefined limits. Many tuners provide their customers with pump gas tunes between 20-25psi, and then DISABLE the fuel cut features by increasing the table values to their maximums. In a situation like this, if you were to pop the vac line on your WGA, you could easily overboost past 30psi and blow a freeze plug, lift your head, or even blow your engine.
1. They didn't rescale! (compare to your stock ROM)
All too often, tuners just leave the stock scale for the fuel & timing maps. This limits tuning precision, because the maps (especially Evo IX) are big enough to justify removing the redundant low-load cells and adding more resolution to high-load cells. For example, if you run about 23psi and are between 230-240 load during WOT, you should have columns for 220, 230, 240, 250, and 260 instead of the stock which is just 220, 240, and 260.
2. They didn't touch the MUT table! (compare to your stock ROM)
In order to view your 3D MUT table, you'll have to add the XML code to your ROM definition file. The MUT table is a list of fields that logging programs like EvoScan can retrieve their data from. If you paid for a custom tune in which the tuner examined log files, the MUT table should have at least some changes compared to the stock table to ensure they are logging all the important non-stock fields such as 2 Byte Load and 2 Byte Airflow.
3. They made violent changes to your fuel map!
Your fuel map is meant to be a smooth transition as boost and RPM's rise and fall. The fuel map loosely represents AFR values, meaning higher numbers are leaner and lower numbers are richer. There is no reason a tuner should be so lazy as to take a few blocks and change them drastically, while leaving everything else around it unchanged.
4. Your high and low octane maps are identical!
The stock ECU is a wonderful thing... it's smart enough to realize that if your car isn't running right, and is knocking up a storm, that it should fall back to a more passive configuration that will protect your engine. Setting the high and low octane maps to be the same completely disables this benefit. The low octane maps should be less agressive than the high octane maps... usually lower by 0.5 to 1.0 AFR points and by 3-4 degrees of timing in higher load cells.
5. You run low to moderate boost levels and fuel cut is disabled!
This doesn't really apply to big turbo or high boost guys, but it definitely does to stock turbo guys... Yet another great feature of the ECU is the ability to recognize overboost conditions and cut fuel when you are exceeding your predefined limits. Many tuners provide their customers with pump gas tunes between 20-25psi, and then DISABLE the fuel cut features by increasing the table values to their maximums. In a situation like this, if you were to pop the vac line on your WGA, you could easily overboost past 30psi and blow a freeze plug, lift your head, or even blow your engine.
Last edited by r3compile; Sep 20, 2008 at 10:03 AM.
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6. You have an aftermarket intake and/or injectors but they never touched the scalings! (compare to your stock ROM)
If your tuner ever told you that the car won't run right until it "learns the new idle", then that is a clear sign you are victim to a half-*** injector/MAF scale. When you significantly change your intake or make and injector size changes, these scales should be custom tuned so that, even if you lose your fuel trims (unplug battery) that your car starts right up and is drivable right away. A quick check to see if you are victim to this would be to disconnect your negative terminal to clear trims and then reconnect and start up the engine... if it has a rough idle or AFRs are way rich or way lean, then these were probably never tuned.
If your tuner ever told you that the car won't run right until it "learns the new idle", then that is a clear sign you are victim to a half-*** injector/MAF scale. When you significantly change your intake or make and injector size changes, these scales should be custom tuned so that, even if you lose your fuel trims (unplug battery) that your car starts right up and is drivable right away. A quick check to see if you are victim to this would be to disconnect your negative terminal to clear trims and then reconnect and start up the engine... if it has a rough idle or AFRs are way rich or way lean, then these were probably never tuned.
hey i get tuned by the mad genius himSELF... aka... he spits hot fire... AKA... 4WS Tuning... aka TAMER...
aka... he tuned me and i ran 11.9 in a MR full interior... hks intake... dc DP... hks exhaust... act full street disk... falken azenis...
aka... he tuned me and i ran 11.9 in a MR full interior... hks intake... dc DP... hks exhaust... act full street disk... falken azenis...
He makes very valid points. I'm not a tuner that sells my work, but I do my own and some "favors" for a few individuals where I live, and everything he's posted is correct so far. As far as the maf scalings, it all depends on the setup. I personally didn't have to rescale my maf seeing that I only logged a 2-5% difference. For that little of an amount, it's more of a pain that can be compensated for in other areas.
Best way to check how smooth your fuel/timing maps are is to look at the 3d display graphs...if those areas were tuned properly it should have smooth transitions from cell to cell, not choppy.
Best way to check how smooth your fuel/timing maps are is to look at the 3d display graphs...if those areas were tuned properly it should have smooth transitions from cell to cell, not choppy.
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I'm confused...
you have some valid points. good info for people such as myself with very basic knowledge of tuning. i know that my last tune from a big name shop was guilty of having identicle high and low octane maps.
