This brings up a really interesting question, one which no one who is into the RS platform can agree on.
Why 5w50? And does the brand matter?
Ford spec'd 5w50 for the Focus RS in the US and Australia. Same as the GT350/500 and GT. But why? Officially, Ford says its because of the increased...
It’s an absolute weapon. The acceleration and handling feels like a proper rally car.
Honestly though, I still do miss my Fiesta ST for around town now and then.
With the RS, you either need to be on the track or breaking the law to really push it for more than a couple seconds.
Randy at TuneWerks did the tune. Peak 342 hp and 407 torque at the wheels with a street dyno.
Hard to say what it is at the crank. With the drivetrain on these cars, parasitic losses are high and variable. The PTU is always engaged to the crown gear, and the RDU clutch packs switch on and off...
I previously did a longer term interval stress test here
Thought I’d share a longer term update. Decided to go with just 5k for the OCI after the fuel dilution I saw last time. Ford’s intelligent oil life monitor said 25% at time of sampling. It does seem to be more than just a simple mile or...
Pretty much this. It’s tuned for 93, and there are no issues with it at this point. It holds at -1.00 OAR without issue and there are no serious negative corrections under WOT through an 3rd gear pull.
That being said, it’s always going to find knock. Even on the stock tune it knocks a bit now...
This is part 3 of the saga ...
Part 3 is available here.
Part 2 is available here.
This will be the last entry. I could have gone longer, per the lab, but the fuel dilution was unacceptable for me given the application and how hard this car gets run. The real grim reaper for these cars isn’t...
Probably it would shear less? But I’m more worried about LSPI in this engine than the shear and fuel dilution. Dominator is a great oil but its additive package isn’t designed with LSPI and daily driving a GTDI engine in mind.
And I’m in the northeast.
If this was a track only car then I’d...
Ford Australia also spec’s it with 0w40. There have been countless forum pages spilled on debating oil on this car, hence my experiment. It is interesting that it sheared the 5w50 down almost immediately and then stabilized.
The prevailing wisdom was that motorcraft didn’t make a 0w40 in the...
Yes, head gasket was done by the dealer before delivery. It was a later production date 2017 and not sold to the first owner until 2018, so it was caught before it was put on the road. I got the paperwork from Ford OASIS (or whatever it’s called now) to confirm.
They did a poor job and created...
To add another data point for the ongoing debate on air filters. This car is running a K&N filter the entire life of this oil. So interpret the silicon and sodium/potassium numbers with that in mind.
About three months ago I started an ongoing maintenance interval testing program for my Focus RS. I am trying to determine the actual OCI for this vehicle.
Part one is available here, with all the background on this car. It’s a 2.3 GTDI car, conservatively tuned, used for daily driving in the...
I bought the car last year at 16.7k miles. At 19k I swapped out all the fluids (Trans, PTU and RDU, coolant and brake fluid) & went to AMSOIL Signature Series. I changed engine oil again at 24.6k for an ~5K OCI, and that’s the same lube it’s running now.
I was concerned even when I bought it...
I didn’t send a virgin sample, but there was a letter sent via email along with the UOA that had an even longer form of the commentary. It had this for the boron:
I bought this as a 4 pack UOA kit from AMSOIL called the “maintenance improvement program” and the letter referenced the program as...
I’ve decided to start doing maintenance program where I take an oil sample every 4k miles on the oil before I ultimately change it to determine the actual proper OCI. Amsoil 5w50 SS, Amsoil 20 micron filter, supposedly good for 25k miles or 1 year per Amsoil.
Baseline information: Sample is...