Oil recommendation for a Fiesta ST

May 19, 2022
Long time lurker. First time poster.

Things you should know about the car.

2015 Fiesta ST. 141k miles. The car has been tuned since 20k miles. It has whats called a hybrid turbo installed on it for the last 30k miles. It dynod 307whp and 315wtq. I use a mix of 91 and e85 fuels to run E30. And ive been mixing fuels for pretty much the entire life of the car.

I've always used boutique oils on this car. Always used 5w30 (as opposed to 5w20). The car has always been happy. I change oil every 5k. I've mostly used Amsoil Signature and Redline (red bottle) oils. I use either a FL400s or the Amsoil equivalent (depending if I remembered to order one or not). The car is my daily driver (300 miles a week) and my weekend canyon carver.

This car is supposed to suffer from LSPI as it makes 26lbs of boost at 3200 rpm. Ive never had an LSPI incident as I try to avoid the scenarios that can trigger one. But even using Redline (SN rated and high calcium) Ive never had an LSPI incident.

My question is:
Can an off the shelf oil protect this engine as well as a boutique oil? I'm not interested in switching viscosities, the car runs great, and still has perfect compression. Cost isnt the issue.

Should I just keep doing what Im doing? I know a UOA can tell me things but I also know it wont tell me everything

Thank you folks
I believe Ford still sells their Motorcraft brand in 5w 30 syn. blend, and also 5w 30 full syn.
I don't think you can go wrong with the Ford Motorcraft branded oil, since your Fiesta is a Ford product, even though it is likely no longer covered by the factory warranty.
There are quite a few, myself included, who would say that this is a good choice:

Either that^^^, or join the Porsche A40 club with Mobil1 0W-40. Or any other oil that is Porsche A40 certified.

Here is Porsche A40 testing procedure:
This test will last 203 hours. The engine, and the oil, will go through:
- 4 times the simulation of 35 hours of summer driving,
- 4 times the simulation of 13.5 hours of winter driving,
- 40 cold starts,
- 5 times the simulation of 1-hour sessions on the “Nürburgring” racetrack, A full lap of the Nordschleife, bypassing the modern GP track, is 20.832 km (12.944 mi) long. A stock Chevrolet Corvette C5 has a lap record at Nurburgring @8:40, stock Honda S2000 has a record@8:39, and stock Honda NSX is @8:38. Considering these numbers, this Porsche A40 simulation is equal to 80-90 miles of flatout track use. Or 100-120 miles if you drive Porsche 911 GT2 R with its lap record @6:38.
- 3.5 hours of “running-in” program
Measurements on the engine and on the oil will be done at regular intervals, and the following parameter
will be taken into account to grant the approval or not:
- torque curve (internal friction),
- oxidation of the oil,
- Piston cleanliness and ring sticking,
- Valve train wear protection. Cam & tappet wear must be less than 10 μm.
- Engine cleanliness and sludge: after 203 hours, no deposits must be visible.

- Bearing wear protection: visual rating according to Porsche in-house method.
One more thing for comparison. Just a rough idea of how the numbers stack up. Take everything with a grain of salt.
Most daily driven cars have an average speed (over the course of an OCI) of about ~35mph. That would make the 203hr test an equivalent to 7,105 miles of driving.
Assuming the average speeds are higher, let's say 50mph, and the 203hrs are now equivalent to 10,150 miles of driving.
Plenty of choices available..

Mobil 1
Valvoline - NAPA
Even motor craft syn-blend will do well.
Any good full synthetic 5w30 should be fine. The Motorcraft syn-blend is just as costly as some full synthetics so why bother IMO. I do like the Mobil 1 EP but Valvoline, PP, QS, Castrol etc...are all good choices. The 0w40 suggestion isn't a bad idea either..

PS: I wish Ford sold the 1.5T dragon Fiesta ST here in the states. They seem to like it in Europe.
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Most 0w40 oils are a blink away from being considered a w30. I strongly recommend making the switch to one of these stout Euro oils. Your American engine has no idea what ethnicity even is.
Nice car, BTW. I bet it is a blast.