Federal vs. California emission ECU's

[Meisner]

Does anyone know the actual differences between the Federal and California versions of the computers in our cars? Specifically the 5S-FE?

According to one site, the basic difference is that a California emissions ECU will turn the check engine light sooner than a Federal version. This will cause a failing component to be identified quicker and therefore reduce emissions. (the site is: http://www.epa.gov/fedrgstr/EPA-AIR/...11/pr-916.html)

I don't really care about that. I care about performance. Is there any direct or indirect hit to performance in using a CA emissions ECU?

The reason I ask is becuase I just got an ECU for the manual tranny swap I am doing and I went to verify it worked OK. When I hooked up to the OBD-II port, I saw it listed Calif emissions. I looked up the part # on the ECU in the Toyota parts catalog. It is a Jap-spec ECU. I wonder if this will provide any performance difference.

Steve

[Kensuke]

My understanding is that California switched to OBD and then everybody followed suit. So, there's probably not that much difference anymore. Most Toyotas imported to the US got the California emissions package or something similar to it. Back in the day, Toyota used a special "C" code to designate an engine to be exported to the US. That went defunt as of the early 90s. Nowadays, you will find that the maitenance schedules for "California" engines are more aggressive.

J-SPEC emissions packages typically provide more power than CA emissions packages, but it's more than just the computer. For instance, it wasn't uncommon for Toyota to use MAP sensors on JDM vehicles, and AFM sensors on US/CA vehicles. Exhaust is also different. Occasionally, the compression ratio is lower. The amount of power sapped from the vehicle can be anywhere from 5 to 20 hp depending on how extensive the changes are/were.

Ironically, some of the best engines were not JDM, but rather euro-spec. The 4A-GE in the Finnish MR2 had a 10:1 compression ratio (higher than JDM) and no catalytic converter whatsoever.

Looking at the specs, it would appear that the JDM 5S-FE only got 5-7hp more, and *less* torque. This sounds like a higher backpreasure exhaust fitted to the US models.

So you probably would just waste your money in getting a new ECU.

Hope this helps.

- John