Drivetrain
Oil Tip
These cars have an oil pressure problem under hard launches. An easy fix is to fill the oil to 6.5 qts., which is actually what Ford now specifies on the 2025 ST.
Oil Pan
FenFabrication is offering an upgraded, bigger oil pan for these vehicles. It practically eliminates the oil pressure drop on launches, and also replaces the plastic oil pan which is nice also.
Built Transmission
The 10r60 is probably the weakest part in the driveline. The stock transmission can last quite a while under a lot of abuse, but if you are launching the car often or especially if you have a trans-brake, then you will need a built transmission. Getting a built transmission will give you the peace of mind of knowing that the tranny can handle anything you throw at it. RSA Transmissions is my recommended spot to get a built transmission done. They build a really stout transmission, and also currently use theirs in their record-holding 10-second ST.
Upgraded Flex Plate
An upgraded flex plate is a most if you have already built your transmission. It replaces the weaker factory unit, rounding out a fully built tranny.
JXB Upgraded Driveshaft Carrier
The stock driveshaft carrier bushings prioritize comfort over performance. It reduces NVH but also allows the bearing to sag creates slop in the driveline during WOT. The JXB Driveshaft Carrier features harder bushings ensure the bearing cannot move from center, allowing for better launches.
Steeda Rear Pinion Bushings
Steeda offers an upgraded rear pinion bushing. I can not say how much I do not recommend these. So many people have experienced a lot of extra NVH, with no extra performance benefits. Also, they are a pain to install. Plus, a couple of people have had these parts fail.
HSF Billet Rear Differential Inserts
Houston Speed Freaks offer billet rear differential mount inserts. They are a fairly new product, with only a few people having reported to install them. They seem like an amazing product, with people claiming it added zero NVH, which is pretty amazing!
Transmission Mount Insert
FenFabrication offers an transmission mount insert that fills the voids of the stock insert. Multiple people have had the transmission mount slowly cave in on itself due to a lot of hard launches. This prevents that, with only a slight NVH gain.
JXB Transmission Mount Insert
A amazing product that will be stronger then the stock transmission mount. The stock transmission mount bushings have been known to collapse on itself after launching the car
Differential Brace
1-bolt Rear Subframe
In late 2021, due to supply shortages, Ford decided to put the 1-bolt subframe from the 4-cylinder Explorers into the ST. Bad choice, horrible choice in fact. The 100+ extra HP that even the stock form produces is too much for the subframe to handle. Even on mild launches, the bolt is known to snap, which can lead to a domino effect taking out the rear diff, shoving the rear driveshaft up the transmission and boom, you could have a cracked engine block. Not fun even with a warranty. So, if you have the 1-bolt, get a differential brace.
The good news is that with a differential brace, you will not have that problem. The best ones, though the most expensive types, are the ID-Speed brace, Livernois Motorsports brace, or DX Brace, but there are worth every penny. The AWR does an okay job too, if you’re on a budget, it will still help, but it isn’t as good as the options mentioned already. The AWR also has a bad twisting effect. Steeda’s offering is okay, but they have had lots of problems of the bolts snapping holding it to the subframe.
The 2-bolt alone pretty much handles anything you throw at it, but you can still add the same differential brace. It is a peace-of-mind part. I would personally purchase it if you are launching a lot on a tune. Especially with a trans-brake. It just never hurts to be too careful. Tyler Clark had his rear bushings fail after a lot of launches, so it is probably best to get a rear diff brace if you are launching a lot.
JXB Rear Subframe Insert
The JXB rear subframe is another part that attempts to limit the violent stock rear subframe movement. The part alone won’t fix the bolt-snapping problem on the 1-bolt rear subframes, but it definitely helps, and pairs well with a rear diff brace.
Rear Differential Bolt Upgrade
One of the repercussions of the violent subframe movement is the rear diff bolt snapping under the pressure. The upgraded bolts from Steeda, HSF, and Whoosh are all the same, but definitely add some strength over the weaker bolts.
Oil Catch Can
A catch can removes oil droplets from air circulating from crankcase to intake. It is very important, and every 5k miles usually nets two shot glasses worth of oil that would have coated the valves, had the catch not stopped it. The best catch can that does the job perfectly is the UPR Catch Can, but it is 4 times the price of the runner up, the JLT 3.0. The JLT will do 90%+ of the job that the UPR will do, but at a quarter of the price.
F-150 EcoBoost Engine Cover
The engine bay of our ST’s are pretty messy. So many lines and the big HPFP right on top of the engine bay, isn’t something I’m a fan of. A couple of people have put on an F-150 Raptor or similar EcoBoost engine cover. This requires a little trimming to the cover, which is nothing hard, and it definitely cleans up the engine bay.
Fenfab Coolant Reservoir
If you want to showcase the engine bay, the Fenfab Coolant Reservoir could be a nice upgrade. It looks really neat, and as always with all FenFab products, the quality is impeccable.
Oil Crankcase Breather
An crankcase breather attempts to remove pressure from the crankcase (obviously the name), but is quite useless. Doesn’t make a difference at all and will spit oil everywhere, which makes me hate it even more.
Under Tray (aka Skid Plate)
Kind of an odd part for a street-oriented performance vehicle, is an under tray. This protects the engine from being damaged by any objects from below. If you drive trails/dirt roads or just want the extra protection, skids plate might be a good peace-of-mind part.
Ford Performance
Ford Performance (panned from the Timberline) offers a skid plate, which offers an easy access hole for the oil plug.
Houston Speed Freaks
Houston Speed Freaks (which is designed better then the Ford Performance unit) also features an easy access hole for the oil plug, as well as an air scoop to try to cool the undervehicle components.
Colder Thermostat
An interesting part is an colder thermostat housing that will trigger at a cooler temperature (160 degrees vs stock 180 degrees) attempting to keep the engine cooler therefore preventing heat soak. I haven’t seen any numbers, but I don’t think it does much, but it is all speculation.
Upgraded Fuel System
Nostrum fuel systems and Extreme DI are options if you need more fuel to be dispensed than the stock system can provide. If you are running an ethanol mix anything larger then e50 or you are FBO, you will need larger system.
Upgraded Turbos
If you want to go all out, upgraded turbos are the first thing that comes to mind. There are not many options that are bolt on, and all those options are just a ported and revised stock turbo. Plus, the stock turbos are already efficient as it is. You would probably only gain 40 HP on pump gas with the upgraded turbos. If you are running some ethanol mix though, that is where you will see large gains. So that makes it a bad choice for daily driven cars on pump gas, due to the price. If you are a drag-strip hooligan, or run ethanol, upgraded turbos will squeeze every last HP from the car. The thing is though, with that extra power and harder launches on the drag strip, you will need a built transmission, most of the suspension mods described in the suspension section, upgraded fuel system. If you want to take advantage of the extra boost, you’ll also need all the other performance intake mods. There are only two upgraded direct-fit turbos for the ST, CRP and Pure. CRP is superior due to faster spool. This path is not for the light of heart, but if you are running ethanol, you could be running low 11’s all day long, and maybe high 10’s.
Upgraded Wastegate
Still a very new product to the market, is the Turbosmart and CRP wastegates. This is supposed to allow for a faster spool and more precise boost control. It is unsure if the stock turbos will be happy with this. I will update this section once more people have installed this.
Thanks for reading!
Thanks for reading! Hope this guide is useful to many of you. Make sure to subscribe to keep up with all our latest content!
Explorer ST Enthusiasts 