Should I install a Fitch Fuel Catalyst?

It's a 2013 Forester XT auto with the 2.5L engine. EJ 255 I believe. A detuned normal WRX engine, basically, with a somewhat smaller intercooler.

The tune seems to be for mid-rpm range performance. The turbo boost comes relatively early and strong but quickly runs out of steam, wherby in the WRX it keeps increasing boost more progressively and into much higher rpms.

Basia

OK - on a EJ255T in a Forester XT automatic has 4.11 final drive ratio. at 65MPH in 3rd gear the engine is turning at 3362 RPM. In 4th gear it is an effective final drive ratio of 2.85:1. will be doing

2331 RPM.. The engine produces max torque at 2800 RPM and max HP at 5200 RPM At 54MPH in 3rd gear the engine is running at it's most efficient (Max torque) RPM. At 60MPH it is turning about 3100 RPM - nicely into it'd power band, while if in 4th gear at 60 MPH it is well behind the power curve at only 2150 RPM. At 2100 RPM the engine is MUCH more likely to detonate than at 3100 RPM.

Your Forester XT has a "manual mode" which allows you to lock the transmission into 3rd gear, which is recommended for running in hilly country or towing a trailer.

I can almost guarantee you will NOT experience detonation at 3100 RPM in 3rd gear - and I can almost guarantee you WILL at 2100 RPM under load, with much more throttle opening and much higher boost.

For long climbs at high altitude I'd try to maintain 60 MPH - mabee push it to 65, in third gear. Pushing it to 70MPH in third you are still only running 3625 RPM - WELL below the Max HP rating of 5200 RPM. If the boost gets too high on real steep climbs, shift down to second gear and at 60MPH you will be running 4800 RPM - still well within the safe rpm range of the engine. Do the sensible and drom to

55 MPH and you drop to 4375 RPM, or at 50MPH,just under a leisurely 4000 RPM.

DO NOT be afraid to let that little eng>>> >>

Interesting info, and very practical too, thanks.

I will for sure start using the sport-mode, especially when driving in hilly terrain which is more than half of my driving. The regular mode prefers early upshifts and low rpms for better fuel economy. I've completely ignored this sport-mode feature, almost forgot its there. Didn't see any reason to use it.

I must admit on manual transmissions I have a tendency to lug. This is because I learned to drive in the 80s in Poland when fuel was rationed and the preferred way to save gas was to keep the car in very low rpms. Also coasting in neutral whenever possible was another way to save fuel. My second car in Poland was a low revving diesel, which reenforced my low rpm style of driving.

I almost failed my driving test in Arizona in the mid-late 80s because I would habitually be dropping the car out of gear into neutral and trying to coast. The law in US requires a moving vehicle to always be in gear. Always.

Basia