Not not the oem, it only gets that hood inlet (but the engine is putting suction on it too). I was getting at the the air flow in the engine bay, which of course will be none when stopped which is where the sri is worst. Once moving it, at least on our car around here in 85 - 100 weather, it's about 10 degrees higher than ambient (accordijg to the dash) from what I've logged with the torque pro app.
Yeah the SRI is at a huge disadvantage when stopped because it is just surrounded by hot air. 10 degrees above ambient while cruising on the highway seems about right for a SRI. I see 7-10 degrees above ambient for the SRI on my Speed3 when cruising on the highway.
So I did some more research and here are my findings:
- There is definitely some extra pickup gained at high RPMs with just a SRI on the 2.5 engine. This is based on reviews I've read from Mazda3 and Mazda6 owners who installed CS and K&N SRIs.
- The drawback to the SRIs are loss of low end torque in city driving. The same Mazda3 and Mazda6 owners are reporting that after going from the SRI back to the stock airbox, they noticed much better low end torque/grunt/pickup (though they also report losing the extra pickup at high RPM).
- The 2.5 engine with its high compression ratio is even more sensitive to high intake air temps. A cold air box is a must if you do a lot of city driving.
- The Corksport Cold Air Box has rubbing and rattling issues. This is being reported by both Mazda3 and Mazda6 owners.
- The stock airbox is getting air from the hood seals above the headlights. A common mod suggested by Mazda6 owners is to cut off part of the hood seal above the headlights to increase the amount of air that gets fed to the stock airbox.
- SRI airflow at high RPM is around 170 g/s, while stock airbox is around 130 g/s. Looks like all the bends in the stock airbox/inlet setup and the relatively small access to air is a restriction compared to SRIs.
- Improved throttle response is reported by owners who fuel up with 93 octane vs just 87 octane. I tried this recently and it seems like the car is running smoother and has better throttle response, but I really have no way to qualify that.
- A tune is the best power mod you can do for the 2.5 engine. You can pair it with a SRI or just a drop-in filter and it would still be a good mod. I have not read any reviews that said a tune didn't do anything positive for their car.
So I've come to the conclusion that it is best to pair the SRI with a tune and a cold air box if available. If you're not getting a tune, then it is better to just get a drop-in filter like the AEM dryflow or K&N oiled drop-in filter. Since no one makes a SRI for the CX-5 with a cold air box, I've decided to just get the AEM dryflow drop-in filter for now. The CS airbox is a no go since it has on-going issues even for cars it was made for. I'll revisit the possibility of installing a SRI once I drive past 32k miles on our car, but more than likely I'll keep using the drop-in filter. I'll also be more open to tuning the engine once it gets past 60k miles.
Other possible mods that I will look into, that can help with highway passing power:
- Racing Beat axle back exhaust. Their dyno graph shows small gains at high RPMs.
- BC coilovers will improve handling and allow you to lower the car, which could help reduce drag at highway speeds. I am finding that the CX-5 has trouble keeping up highway speeds above 65 mph.
- Lastly, lighter wheels that are not much wider than stock should help as well. Some options here are the TSW Nurburgrings at 19x7.5 or 19x8.5. I've also seen TireRack list the Enkei Raijins at 19x8 for the CX-5.