Like many car guys, I indulge in squeezing the most that I can out of my beloved Lancer. Originally built as an economical sedan that found itself catapulted, and winning, in the world of rallying, the Lancer will always be synonymous with above average performance and reliability.
While the A17x platform Lancers released locally in the Philippines were all meant to be reliable and economical cars, they have long been touted as “fast” and “sporty” in comparison to its contemporaries. The 4G32 / 33 engines that powered these little cars have proven themselves to be fairly easy to tune, reliable and almost bulletproof, and they have a seemingly cult following among the elder generation.
All locally released Lancers (SL / GT / GSR) all had engines powered by carburetors, that magical box will almost no moving parts yet makes the joy of driving a Lancer possible. Almost everyone though will immediately suggest that the easiest “upgrade” you can do for an A17x Lancer would be to ditch the oem airbox and replace it with a more free flowing one. The logic is to allow more air in so the car can breathe easier, and produce more power in the process.
But is there really that much of a gain from simply replacing the air filter?
Like almost everyone, I was told of this and have gone this route. I’ll discuss here the things that I’d found out along the way, and the various ways I’d looked into gaining (or probably losing) power by letting the engine “breathe” easier.
Below is how the 4G32/33’s engine bay looks like when stock.
The black thing over the carburetor is the factory air filter box that contains the air cleaner element, and prevents dust from going into the carburetor, ensuring that only clean air goes into the engine.
A lot of people frown upon this set up because they say it’s restrictive, and the engine cannot make good power with this. There are quite a few options that people would normally throw down the table to “make the engine breathe” easier.
Some would tell you to outright ditch the air cleaner to make sure that the engine is fed with gobs and gobs of air. The idea is sound – an air filter will restrict air going into the engine. Removing it allows all the air in the entire planet to fill the engine with every intake stroke, and makes for faster drawing of the air into the carburetor…
…which is all cool if you don’t have to daily drive the vehicle, or if you are cool changing the oil and cleaning your carburetor more often. Oh yeah, in case you haven’t known yet, you know where the dirt particles go when they get sucked into the engine? It goes into the engine oil. Over time, all that dust will collect within the oil and make it into a sludge that has no cleaning nor lubricating purposes for the engine. See, the oil also helps cool down the hot interiors of the engine. If there’s a lot of dust particles within the oil, those will store the heat instead, making the oil hotter and unable to lose the engine’s heat at a faster rate.
A more popular idea is to replace the air filter box with an open time air filter, like in the picture shown above. That chrome plated UFO thing is the air filter “box” which has the air filter (dry) exposed without all the metal casing around this. The idea is to again present all the air of planet Earth for your car to breathe in, but with a filter to make sure that only clean air passes through. This one is a good idea and a fairly cheap upgrade to make as well. This can pass for everyday driving, and has the added benefit of making you hear the engine’s induction noise eg. sucking the air in, and makes you feel that the engine had suddenly gained power by tenfold.
A less common idea would be to ditch the filter element and use something called a velocity stack, or air trumpet / horn for the less car finesse people. What it is it completely disregards the air filter element and whatever casing it’s in, and instead uses a funnel through which the air can be sucked in. The simple idea is that such an arrangement will allow smoother entry of air into the carburetor. The more complicated idea and one that is less understood by a great majority of people is that velocity stacks act like a resonating pipe that “tunes” the resonating frequencies of the pressure pulses within the engine and I have no idea what I just typed there. There’s a handy explanation here.
Ideally, the length of the stack is measured to correspond with the pulses within the engine, which ideally should be in tune with whatever the heck you’re trying to do so you can channel not just all the air in the planet, but the magic of the universe in order to grant hitherto unknown powers to your engine. Again, I have no idea what I just typed there, but if I can tell you anything cool, this will make your engine sound even better with all the glorious noises that the engine will make while sucking in all that air. It is especially enjoyable when you’re accelerating since you get to hear that “whoooooosh”, and you instantly feel you can slay even Bunta Fujiwara. Below are some other examples of velocity stack setups.
Now velocity stacks are mostly seen on race only set-ups, but a few daring souls have gone and daily driven with it. I have as well, the only thing was since there is no air filter, the engine oil gets dirty really quick. But with my car producing that really nice sucking sound, who cares about changing oil right?
Now you’d seen some of the options you can do about the air intake thing, it’s time to do some thinking about things. Let’s go with a stock engine for the time being since that’s what I have, and its easier to start with the basics.
Your engine will suck in a specific amount of air per cylinder per cycle. Ideally, your carburetor should be able to flow in the require amount of air into the engine, normally rated in terms of cfm, which is cubic feet per minute. Unfortunately, this is where I’m going bro science because I don’t have the flow rates for the stock Aisan and Solex, although a very handy cfm calculator here can give us an idea.
The calculator asks for the displacement and maximum rpm of a given engine, and Saturn engines can go to 8,000 rpm as some of my friends have done with their heavily modified units. For a stock 4G33 (1400cc but actually 1395 but you get the picture) that should give us 167.25 cfm at 8,000 rpms. But my idea about this is that while maybe the stock 4G33 can get up to 8,000 rpm, it wouldn’t work out as well as we thing due to issues like valve float. I know my stock engine can get up to 6,000rpm before encountering that issue so let’s pretend that you’ll only hit that high up. That should give us 125.43 cfm, which can be cross checked using this other calculator. For the VE or volumetric efficiency, stock engines are anywhere between 70 to 85% efficient, so you can use those figures – I used 85% even though I have current blow-by issues. Unfortunately, I have no flow ratings for the popular Mikuni Solex 28-32 DIDTA carbs that some earlier Lancers came stock, nor the similarly sized but unappreciated Aisans that came one later ones.
However, the above figures are enough to kind of give you an idea of how to go about your air intake upgrade.
Here is my advice though – if you’re using a bone stock engine, you may as well leave the oem air cleaner box in place. For one, it makes the engine quiet since you won’t hear the engine making that sucking sound. Another is that if you’re not really gunning for high rpms, my bro science mind thinks that it can give adequate flow into the carburetor, especially if you’re running at highway speeds.
These past few months, I’ve been rethinking my ideas about Aska because I’m enjoying a nice quiet ride nowadays, which was also the main reason I had my old glasspack removed, and the stock-ish chambered muffler re-installed.
How am I liking this now? I love the current set-up! Truth be told, I feel like the car has a little bit more power from the low end up, although as of late since the stock muffler had been back in place, it seems a little hard to push the engine to 6,000 rpms. Although the trade off is that the “sweet” spot of the engine went down and I get decent power for city driving, and some spirited cruising around. And actually, the car didn’t slow down as much as I’d thought it would.
One last thing I’ll probably do before I sit down on this for another long while is to get better headers made because the ones I have on now had been with the car since forever, are cheaply made and generally just pieces of crap.
If you want to just max out for the lolz of if, I would especially recommend a velocity stack although you may find it easier to have one made since it’s quite rare to find them for stock down draft carburetors. The one I own was a very lucky find, and was also custom made by the previous owner / seller.
If you want some of the lolz but you’re concerned about the health of your engine, and you’re not the kind to tear down the carb for cleaning every so often, go for the dry type air cleaners. Simota makes good ones for cheap and you can find them easily enough online – just make sure you check the opening on the bottom plate since it needs to match the throat diameter of your carburetor.
If you want just the lolz but have none of the two mentioned above, go ghetto and ditch everything. Just don’t expect your oil to last long, nor your engine bay to look nice and “powerful”.
Back when I had either of these things on the car, it was easier to push the engine to higher rpms. But then since I am running a stock engine with a stock carburetor and cam, there’s really no point in pushing the engine that far up the rpm range. I used to only do it for lols, but honestly, the stock engine cannot seem to make power beyond 5,000 rpms, which is really as much range as one would ever need on the road sans track day activities. So I’m keeping the oem airbox for now, and revel in the fact that when someone asks to pop my hood open, they’ll see a factory stock engine with the correct stuff on the engine, which is quite a rarity nowadays. I’ll test it out on the highways once the holidays are here because it’s been like seven years since I last drove full time with the oem airbox installed.
Ah, c’est la vie.