The Subaru FA24DIT MGT22 Turbo is equivalent to the Garrett GT2259 Turbo and compressor graph possibly looking like the one shown below:
The FA24DIT in the Subaru Ascent run a Volumetric Efficiency (VE) of around 95% from 4400-5600rpm, dipping to less than 90% @ 6000rpm. Due to the turbo size and other engine factors, it is very efficient from 2000rpm to 4000rpm. The PR at 5600rpm from logs is 1.8 (11.5psi).
The Garrett representation could be off a little for the compressor being used and it is very possible the shape of the graph will be different and extend a little more to the right. Based on Subaru data and engine flow data, I see around 30lb/min. Given that Subaru’s tend to run rich, I would expect the flow to be around 27lb/min. That being said, I would expect the MGT22 could flow up to 32lbmin at high compressor speeds with a lower efficiency of 65% or less. That is more hot air. To achieve a flow of 32lb/min, the turbo will need to push 16psi of boost at 5600rpm. That will net 320chp or around 270whp. A good avg of 250whp could be expected on the stock exhaust system. For those searching for more torque, this can be easily had since the turbo is small, but the turbine will be spinning a little faster. That implies a little more heat and a nice water spray would help keep the Intercooler cool.
If XRT had to tune, we would run 18-20psi in the sweet spot and taper down to an efficient boost of 15-16psi at 5600rpm and obviously lower to rev limit.
A good stock upgrade for the Subaru ascent and possibly for the Outback and the Legacy when it comes out with the FA24DIT is the Garrett GTX2860R. It will operate well within the shift points of the CVT transmission.
XRT started R&D Tuning on the 2020 Subaru Ascent on October 22nd, 2019 with a number of Subaru Ascent owners as part of an online group to keep communications and developments consistent and communicative. In addition, a FB group was created to represent our desires to highlight from a tuning perspective (like what we always do on our forum) the capabilities of the engine and general tuning issues. https://www.facebook.com/groups/subarufa24tuning/
To show our willingness and collaboration in the development of tunes for such models/engine, I reached out to Cobb Tuning as a Cobb Protuner to Alpha/Beta test any new products, as we have already started.
Please see below our minor tuning results for a current vehicle we are working on, before we encourage other to spend money to attain the necessary tools in tuning. As you will see below with the current engine configuration of Cams, heads etc, this engine will be nice for boosted models to raise the level of performance, once twin-scroll turbos are developed, due to the small engine size. It seems way more efficient than the EJ257 and somewhat on par with the EJ207. From discussions online, it really does seem like a over bored FA20.
I do not see the FA24F used in the STI, but a variant of it like all highlight turbocharged models for the STI. But we will see over time. I myself would love one to go into my GC8 utilising the Syvecs S7Plus.
Update: November 11, 2019 The boost of the Subaru Ascent cannot be adjust. The system is of mechanical type with a electronic feature to switch the boost off or on for Limp mode purpose. This is why the boost curve appear as it is below, which does not represent the wastegate duty cycle operations to bring the boost under control when reviewed.
XRT offers tuning for the 2010+ Subaru NA models using the CVT Transmission and all 2015+ Subaru’s utilising special software that better support these models. The following tools are needed beside a windows Laptop/Notebook:
Cobb V3 Accessport
XRT Stage 3 Full Speed Density Cobb Tuning
Custom NVS rotated turbo kit.
3in Custom NVS down pipe and cat back to Stromung Y pipe and Quad tip mufflers Garrett GTX3076R Gen I W/ Tial .63AR Hot side, 4in Anti Surge inlet
4in custom NVS intake with K&N air filter
Custom NVS up pipe
Perrin 3.5in front mount intercooler
PTP Turbo blanket and titanium heat wrapped up and down pipes
Stock exhaust manifold
44mm Tial external waste gate plummed back to exhaust.
EJ257 case halves
Cosworth Stock bore pistons 9.5:1
King rod and main bearings
Killer Bee oil pickup tube and oil baffle
11mm high flow STI oil pump
Stock 2007 OBXT cylinder heads and camshafts
Supertech Sodium Filled Inconel exhaust valves (stock size)
Supertech stainless intake valves (stock size)
Supertech Titanium dual valve springs, seats, and retainers.
Cometic .040mm thickness head gaskets
ARP 625+ headstuds
STI rotated intake manifold
Grimmspeed 3 port EBCS
Stock Map sensor
JDM TGV deletes
Tial vent to atmosphere BOV
IAG Competition AOS
DW300 Fuel pump Hardwired to battery
Stock topfeed fuel rails and FPR
ID1300X fuel injectors
Parallel routed fuel lines
Koyo Radiator and cap
Perrin overflow tank
Optima Red top battery
SPT oil cap and battery tie down
AEM UEGO AFR gauge mounted in AVO dash pod
2006 USDM Spec B full interior swap
2010 LGT rear view mirror
LGT suspension with rear upper and lower control arms
All subframe and rear cradle spacers removed.
2004 Subaru STI Brembo front brake calipers
DBA 4000 T slotted STI front brake rotors.
Stainless steel front and rear brake lines
18X8.5 +44 SSR GTX01 wheels
SSR Aluminum lug nuts
255/40/18 Bridgestone Potenza RE760 tires
– decat uppipe
– 3″ downpipe with sports cat
– 3″ straight through exhaust with Fujitsubo RM01A muffler
– Pre97 GC8 WRX/STI TD05H-16g turbo with stock wastegate
– 550CC stock injectors, yellow, side feed
– Deatschwerks DW200 fuel pump
– STI Intercooler with Forge BOV
– Cobb 3-port boost controller
What has been checked:
– valve clearance
– new plugs (NGK ILFR6B, 0.8mm gap)
– new oil
– intake leak test
Other interesting stuff 😉
– STI hood scoop with STI air splitter
– Cusco Zero 2 suspension with pillowball mouns and camber plates
– STI calipers both front and rear, DBA T2 brake discs with CL5+ pads front, DBA Street Series with DS2500 pads rear
– Rear STI sway bar
– Titanium STI front strut bar
– Rays Gram Lights 57S 17′ wheels
Town driving–Throttle response is still nice and strong-nothing changed there and that is good. A little jumpy in S# at ~25% throttle around 3K in 2nd and 3rd BUT** it’s very responsive to input and i don’t have the most steady foot on bumpy roads:-) doesn’t do it in S mode so yeah…my foot lol!
3rd gear pull– Only 1 single instance (single cell) of ping (-1.5) right before peak boost. a few -1.5 cells as I lifted off throttle at 6000rpm. Feels Strong.
How it feels on the 3rd gear pull–pulls harder as the boost spools up–perfect!. It feels like it hits a shot of Nitrous about 4600RPM as it transitions from 8.5degrees to 10.5degrees of timing. It’s subtle, not a surge, but I thought I’d point that out.
Roll on acceleration about 3000rpm—amazing in all gears. I don’t really feel that transition in this circumstance.
2nd gear is just nuts. I never really tried it before at WOT. SO yeah, nice one!
Shifting–under load, nice and sharp and quick. I don’t know if it’s possible to tune this—-> but it would be nice for the trans to respond faster to paddle inputs, especially at light load around town. No big deal though;-)
Alright, well where do I start? As we are getting close to the end of the tuning process I’m thoroughly impressed. Ed’s knowledge and feedback to my queries has been fantastic. He’s quick to respond and I challenge any tuner to provide such good customer support! Feedback is nearly immediate and revisions come daily (sometimes more often!).
I urge any Cobb tuned customer to consider XRT. If you have an 5EAT or if you are Cobb tuned on Canadian petrol, you need to contact XRT tomorrow!!
My Cobb stage 2 provided predictable, modest power improvements as advertised from Cobb. However, as predicted, the pinging (feedback knock, fine knock learning) was endemic, over all grades of petrol. Only after a couple revisions he had the power far above Cobb’s tune, and a transmission that provides strong, fast shifts. We are onto Rev 5, and the power keeps building and I’m getting zero pinging under all conditions, on standard Canadian 91 petrol! And the shifting and throttle response are unreal. Night and day over an Off The Shelf tune…. BRAVO Edward!!!!
By the way The AVO turbo kit and the raptor supercharger kits are not available for the 2015+, due to no tuning or fuel pump solutions
Thanks to XRT Ed, I have been given the confidence to move forward with the project. I live by multiple Subaru tuners, and was turned down by all of them. Ed said he was up to the challenge, and I like working with people that have a can do attitude
Now the car is running great. I have made some decent pulls to collect data for ED. He is doing an outstanding job!!! This is the first time anyone has tuned a 15+ NA for turbo and there are a lot of hurdles to overcome. ED is knocking it out of the park. Every time he sends me a ROM it gets better and better. His CVT tune is awesome, makes it feel like a sports car not a grocery getter.