Hi Brendan;
Unfortunately, I as the tech answer guy, have no way of knowing if anyone has obtained a field approval for this engine upgrade.
And even if I could pass on the paperwork of a field approved change, there’s a possibility that your local FAA Flight Standards District Office (FSDO) would not sign off a field approval like this unless it had thorough documentation from a Designated Engineering Representative (DER)
DERs are private engineers that you would pay for a engineering study that would be acceptable to the FSDO.
One pretty simple horsepower upgrade you could bolt on in a few hours is a PowerFlow exhaust system. Powerflow sells exhaust systems that are much less restrictive than the Piper systems; opening up the exhaust system restrictions increases fuel/air charge entering the cylinders. The result is more power.
I installed a PowerFlow system on a C-172 12 years ago and after a before and after test flight wrote that installing a Powerflow system is the quickest and least expensive way to boost engine power.
You can learn more here: https://www.powerflowsystems.com/products/piper.
I can’t contact them right now, but it appears as if it doesn’t have an approved system for your Archer II. But I would check as soon as they re open after the new year.
Please let me know what you find.
Best,
Steve
