Supercharger quirks (4Runner vs other Toyota/Lexus)

[2021nightshade4x4]

We are all familiar with the delays in release for a 2020+ 4Runner supercharger kit, specifically the tuning part delayed the release of complete kits.

However, in my Googling, not all kits required a tune. There was a TRD supercharger for the LX570, believe it or not, that for some reason listed only the 2014 model year as being compatible.

There were two configurations, low boost at 6 PSI which did NOT require a flash, and high boost at 8 PSI which did.


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[Bobby12many]

The ability to boost an engine without tuning relies primarily on the stock vehicles MAF/MAP configuration and fuel system (injector size, pump type, etc). You can likely add up to 5psi without tuning somewhat safely, but are asking for trouble in doing so; atmospheric + load condition changes in the real world make detonation a serious concern.

The engine isn't really working any differently with a supercharger installed; the MAF senses air flow/density and the ECU adjusts fuel and timing accordingly to ensure proper A:F. But as the amount of air increases (more boost), you quickly begin to push the limits of what the OEM ECU is able to adjust to using the factory mapped values (or what the fuel/ignition system is able to deliver)

To NA-T anything, the fuel system always needs to be addressed, typically starting with injectors. New injectors will basically require a tune in most cases.

 

[Whippersnapper02]

We have Runners though.

 

[2021nightshade4x4]

The ability to boost an engine without tuning relies primarily on the stock vehicles MAF/MAP configuration and fuel system (injector size, pump type, etc). You can likely add up to 5psi without tuning somewhat safely, but are asking for trouble in doing so; atmospheric + load condition changes in the real world make detonation a serious concern.

The engine isn't really working any differently with a supercharger installed; the MAF senses air flow/density and the ECU adjusts fuel and timing accordingly to ensure proper A:F. But as the amount of air increases (more boost), you quickly begin to push the limits of what the OEM ECU is able to adjust to using the factory mapped values (or what the fuel/ignition system is able to deliver)

To NA-T anything, the fuel system always needs to be addressed, typically starting with injectors. New injectors will basically require a tune in most cases.

I wonder why these kits (for Toyotas, specifically) exclude the FFV vehicles (for example only the non-FFV Tundra could be tuned). I would think these had bigger injectors, not smaller, and would be a benefit instead of a roadblock. Maybe they didn’t want to write a separate tune / too small a market?

Thanks for the insight on this issue regarding mappings. Learning every day.


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[Bobby12many]

I wonder why these kits (for Toyotas, specifically) exclude the FFV vehicles (for example only the non-FFV Tundra could be tuned). I would think these had bigger injectors, not smaller, and would be a benefit instead of a roadblock. Maybe they didn’t want to write a separate tune / too small a market?

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Typically vehicles setup for FlexFuel from the manufacturer carry some advantages over standard gas engines, as you alluded to. Because E85 (and other FFs) naturally combusts at a lower temperature than gasoline, it is well suited to higher boost and advanced timing (more aggressive mapping).

I am not familiar enough with Toyota's specific FlexFuel system, so I cant speak to why there are inconsistencies with the SC install kits being offered for them. Based on a quick google, it sure looks like you can purchase tuning/SCs for FFV Tundras, however many kits will likely get rid of your ability to run FF once the tune is completed.

Ideally one would use a piggy-back or full standalone engine management system with an in-line fuel sensor capable of actively adjusting to E85, gasoline and any mix therein.

One thing is certain - if you want to SC your vehicle, you can. Whether you are able to buy an off-the-shelf kit to do so, is another story...