TEST
SPRINT FILTER AIRBOX ON HONDA CIVIC TYPE R
HORSES
IN A BOX
The new Sprint Filter airbox with dynamic intake gives 15 hp of maximum power to the Honda Civic Type R, with an even more noticeable gain at low RPMs. Can you get so much from an air filter? The answer is yes, and we'll explain why! Pierluigi Mancini
W
e’ve talked about the importance of air filtration and the efficiency of the airbox on a tuned-up engine countless times. If I’m not mistaken, one of the first issues of the most popular magazine in the 20th century that I bought in a newsstand was about air filters. Then, one day, with a phone call I joined the team and still today I enjoy testing cars on the track and on the bench, looking for that final horsepower and that last tenth of a second. The secret behind the success of the magazine Elaborare, something that we all share, is surely a common passion and stubbornness
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ELABORARE 251
Igor Gentili in always looking for the most interesting developments, to get to know them better and analyze them. And I think I’ve never worked so hard as in this case to understand how a simple filter – if you can call it “simple” – can transform the character of a car that’s already exceptional on its own. Let’s talk about the latest evolution of the Honda Civic Type R: a 320 hp “beast” that is loved for its incredible engine, combined with a chassis that is fantastic, to say the least. For me, it’s the best frontwheel drive car with a 2,000 cc turbocharged engine on the market, with all due respect to the Golf Clubsport and in spite of a somewhat
baroque look. Skeptical by nature, I have to say I was incredulous when I was called in to do this test and was told, “You
won’t believe your eyes... it improves performance by a lot!” Ok, anything’s possible, but 15 hp from an air filter.... But in the
end, I had to accept the facts, because not only is there a boost of 15 hp, but what’s truly amazing is how much you recover The Sprint Filter C-Tech airbox for Honda is made of autoclave molded carbon fiber, very strong and extremely lightweight. It can be supplied with different types of filtering panel for special needs. The kit distributed by Motorquality and sold for €1,550 + VAT includes everything you need for installation. Note the excellent quality of the finish.
in terms of maximum power along the arc of rotation. But let’s go step by step.
The kit The Sprint Filter kit for the Honda Civic Type R is a product of the highest quality. It’s so light that I might have thought the box was empty if I hadn’t heard something moving around inside when I shook it. Then I opened the box and...wow! It’s
one of those things that gives us motor fans goose bumps. I took out two carbon shells of the finest workmanship, perfectly made and beautiful to look at. Then three different filter panels, depending on the type of use, produced by Sprint Filter with their most advanced technology that uses polyester fabric as a filtering material (lightweight, easy to clean, practically
eternal, highly efficient as a filter). The kit comes complete with all the accessories for mounting, including the original Honda clips for anchoring the airbox. Beautiful and light as a feather, considering that it weighs only 810 g compared to the 2.3 kg of the standard airbox.... Truly exceptional!
Bench test The first part of the test took place on the
track, with acceleration and pickup tests in the original configuration. Then at the Abbasciano garage we locked the Civic into the test bench in the early morning to take advantage of the cool air and, with the first firing we got a maximum power of 297 hp. That’s less than the declared 320 hp, but a number of reasons can explain the lack of horsepower. First of all, the car was fueled with 95 RON gas,
which, compared to 100 RON, causes a loss of a dozen or so horsepower on this engine. Second, the control unit doesn’t accept on the bench the R Plus mode, which provides for a more powerful ignition advance curve that can also deliver a bit more horsepower. Without pulling the car off the bench, to avoid any doubts of a different tension of the strops, we started to ELABORARE 251
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TEST mount the Sprint Filter kit, choosing the P08 airflow, made with a fabric capable of filtering 5,050 liters per square meter per second, retaining particles up to 80 microns in diameter. Installation is very simple. The most timeconsuming part is the removal of the standard air filter: an operation that is completed in no more than 20 minutes. Once everything’s been removed, you need to reuse one of the rubber plugs of the original airbox on the Sprint Filter. Mount the MAF sensor, the hoses, and you’re ready to go. Interestingly, the airbox now sucks entirely from the front grille without the nasty U-turn of the standard filter. The curve that popped out
SPRINT FILTER AIRBOX ON HONDA CIVIC TYPE R with the first test left us all stunned. What surprised us was not the extra 15 hp of maximum power: we’re too shrewd not to look at what happens before, with a curve that is decidedly unrecognizable for how many horsepower was gained at low and medium rpms, just where it is more difficult to get it. We ran a second test: the power dropped due to the overheating of the intercooler, but the gain was still there. My motto is “Believe half of what you see and nothing of what you hear”, but in this case I even found it hard to believe my eyes. There was only one way to figure out what had happened: compare the acceleration data!
Dynamic test Just off the test bench the car had a very irregular idling: 1,500/1,600 rpm, then bouncing between 1,600 and 1,300. Only after running for about 10 kilometers, when I was so discouraged and convinced that this filter couldn’t be used without recalibrating the control unit, the engine stabilized at 950 rpm. It’s crazy what a modern control unit can do.... If I think back to a few years ago it’s like I discovered teleportation! Once the engine was running smoothly, I started the countercheck. I was expressly asked to check the 0-100 km/h and 0-400 meter ranges, but as usual I did whatever I wanted. I also tested pickup in 5th
and 6th gear, from 80 to 140 km/h, and 100/200 km/h: these serve to understand how much the engine has gained “in the middle”, while 100/200 is a test of pure power. Actually, my dear
friends, the difference was so big that I didn’t even need to do the test: push it to 4,000 and you feel like you’re driving another car! In fact, in addition to the 9/10 of a second on the 400
meters and 2.2 seconds on the 100/200 km/h acceleration tests, take a look at the pickup tests: 1.7 seconds less in 5th gear and 1.9 seconds in 6th gear. A gap that you can feel when you open the throttle to 3,000 rpm. Driving is smoother, the engine is fuller at all rpms and the speed rises significantly faster. And the intake sound is also pleasant to hear. Never annoying, it’s definitely more guttural, wicked, pleasant, and suited for a car that combines a
look worthy of Mazinger Z with a sound that is practically demure.
Final thoughts Can you get so much power out of a “simple”... if you can call it that...air filter? The answer is yes! Modern emission regulations are extremely strict not only for gaseous emissions, but also for noise. Exhausts are increasingly closed (so much so that some people use the ploy of an electronic valve to choke it only when necessary),
muffled and silent. But the intake also plays a key role in reducing noise emissions, which is a kind of damnation for the engineering teams that have to design, test, and approve it. I think that each dB reduced on a sports car is rewarded with a vacation to a tropical island with hula dancers! But those of us trying to get the final horsepower out of the meanders of the various homologations follow a very different path, where sound has its importance.
Kgm 315 288 260 233
HP 46 38 31
3.000
4.000
5.000
6.000
ORIGINAL
297 HP at 6.476 rpm 39,9 Kgm at 4.164 rpm WITH AIRBOX 8 Max power 312 HP at 6.477 rpm 8 Max torque 45,6 Kgm at 4.278 rpm
8 Max power 8 Max torque
Test conditions Temperature 27°C|Relative humidity 58% Atmospheric pressure 1.016 mbar [98]
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to this extent). Now the system cap is no longer just the exhaust, but also the intake!
The range There are two other types of cartridges in addition to the P08: the most efficient in terms of filtering is the P37, which can retain particles up to 37 microns in diameter and treat 4,500 liters of air per square meter per second. The other model is the P08F1-85, made with a fabric capable of filtering up to 15,000 liters of air per square meter per second, while preventing the passage of particles larger than 85 microns in diameter.
Acceleration Test
Power Test
rpm
So you just have to analyze how the Sprint Filter airbox has no baffles, how the air is sucked in completely through the grille, and that strange U that you notice when you open the hood has disappeared (surrounded by a seal to avoid sucking in water): here we’re just looking for power, and you can see that from the shape of the Venturi intake tube upstream of the MAF. The air filter is a panel type to reduce the negative effects of further internal turbulence and to better exploit the RAM effect and resonance. Small details, the result of extensive studies: on the one hand, those who try to silence the car in every possible way, just correct the mapping a little to recover the lost horsepower...on the other hand, those who try to turn an air filter into a work of art that also knows how to “sing” well! It’s not the first time I’ve witnessed this kind of miracle on the latest generation of cars (although never before
Km/h
Original
Sprint Filter
0-100 0-140 0-160 0-200
6"4 10"6 12"9 21"9
6"2 10"1 11"2 19"5
meters
Original
Sprint Filter
0-100 0-200 0-400 0-1000
6"4 9"5 14"2 27"9
100,2 km/h 133,6 km/h 168,9 km/h 214"3 km/h
6"2 9" 12"9 25"
100,4 km/h 135,7 km/h 173,6 km/h 220,4 km/h
Pickup test km/h
Original
Sprint Filter
80-140 80-140 100-200
8"3 in V 11" in VI 15"5
6"6 in V 9"1 in VI 13"3 ELABORARE 251
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