[Troika]

Hello, I've been searching around on the internet for a bit, and sadly have not found any reliable information on this. So I've come to ask y'all.

As the title says, I'm wondering what the maximum horsepower number could be on a 4A-GZE stock with the stock boost of 7-8PSI that the ECU regulates.
I'm also interested in what numbers you could get if you delete the Supercharger and install a Turbocharger instead, as I've heard the Supercharger is small and low power.

Extra questions would be the maximum safe boost pressure to use on a stock 4A-GZE without changing any components.

 

[teranfirbt]

Stock GZE is limited by the blower, not by the bottom end. I've heard legend of factory GZE's holding 20psi of boost without any issues, but that requires good tuning. Manon Racing builds crazy A engines, 600+hp 1.9 liter stroker type builds.

 

[edmcguirk]

The ECU doesn't really regulate boost. The blower supplies 8 PSI of boost if the ECU engages its clutch. So the blower will get about 145 HP on 8 PSI. Changing the crank pulley to overdrive the blower will get 10 PSI or 13 PSI or whatever the pulley ratio commands. I haven't seen any reliable reports of more than 200 HP on the stock blower regardless of what pulley, cams, or ECU changes have been used.