Airbox App

[Ceola Roefaro]

Older engines drew air directly from the surroundings into each individual carburetor. Modern engines instead draw air into an airbox, which is connected by individual hoses to each carburetor or directly to the intake ports in fuel-injected engines, thus avoiding an extra intake manifold.[1]

The airbox allows the use of one air filter instead of multiples, reducing complexity. Developments arising from concerns about engine emissions during the late 1970s allow the airbox to collect pump gases from the crankcase and the tank air vent and re-feed them to the engine.[2]

Many high-performance motorcycles have the airbox fed from funnels in the front of the bike, where increased pressure forces more air into the intake and thus improves power. Examples of this ram-air intake construction are the SRAD models of the Suzuki GSX-R750, the Kawasaki Ninja ZX-6R or the BMW S1000RR.

Secondly, designers exploit a property of air cavities known as Helmholtz resonance. Flow through the airbox is optimal at its resonance frequency, which depends on airbox volume and the inlet area and length of the snorkel. The resonance is typically chosen to be at a medium speed where torque otherwise drops, caused by valve timing overlap.[3]

Here is a carbon fiber subframe/airbox one piece unit made by CRM. Gives a clear idea (for those that don't know) how the stock Honda CRF air filter is mounted (the OEM air filter hardware is not installed at this point)

me personally... i prefer a highly cut up stock box over pods. the pods rubb on the frame get holes in them and are running right next to your super hot exhaust. you almost have to have those goofy slip over insulation thangy's/ if your just a cruiser or weekend warrior, trails, dirt, sand. i'd suggest a highly modd'ed box. maybe i could do a write up on how i do them.. they are easy to remove and its only one filter to clean..

Actually I DID dyno it both ways. There was less than 1hp between the two. Mind you this was a stock carbed bike,so it had the STD clamp on pods for stock carbs,,not the larger style you get with larger carbs.

I think this is where the biggest gain from running pods is... when running larger carbs but a intake set up that was meant to only supply 26mm carbs... I have thought about asking JD or someone in the possibilities of making a 2-1 intake set up for dual carbs that would flow and better match my carbs i was running (35pwk's) needless to say you can see which route I ended up with lol...

It's funny that we see plenty of posts where people remove the airbox lid and have to go up a pilot size or up one on the main.......That's on a fairly stock motor! If your motor is modded, airflow is an even more important factor.

I don't run air boxes. Working on stock carbs, with an air box is almost as annoying as messing with adjusting a stock rear carrier. LOL Way worse when your doing multiple jetting changes during a dyno session.

I run pods on a 370 long rod bike and that machine has been down the entire length of the river at "The Badlands" in Attica IN. Once going up stream and once going down. (Water deep enough that my nerfs and shifter were under water.)

See, we continue to agree. I can't tell you how many people end up with ripped and torn boots or stripped out clamps from all the BS that goes into jetting changes with the stock carb/airbox. Or worse, the boots end up slipping off on a ride and the guy "Dusts" the motor.

And windy... A lot of people told menot to run them if I trail ride ext.... I've been in a fair amount of mud where my see was covered head to toe... Looked at my pods and 1 pod had a spot of dirt that prob didn't hit it directly lol... On shees the pods are pretty well protected with the fenders on

I'm not going to paint it like pods are invincible. You hit a deep puddle at high speed and you might get the Outerwear's wet enough that the motor will die. (It's happened to me 3-4 times) But by the time you get done with your "dude did you just see that story".....it will be ready to fire up again. But you won't drown the motor.

I followed ROLLINRHINO all over The Badlands when he was on his 4X4 King Quad and I did just fine. (Now I don't try and treat my quad like it's a jet ski or 4X4 utility quad.....but I put it anywhere you could without risking needing a winch.)

Filter boxes let you go into a little deeper water, and protect from splashes......but if the airbox gets a quick dose of water....it can only drain so fast out that little hole in the bottom. Untill it does....your filters and carb mouths are under water.

i think both parts have its own spot. when i was younger i was more into deep water and muddy riding. now a days i stay away from it if possible and enjoy faster passed ridding. me personally i had a air box but ever since i went with pods i never looked back. wish i went with pods earlier....

And I also understood that somehow the airbox is raising the air temperature and thus decreasing the possibility of carb icing. Does it make sense? If so, can you tell me some details how does the air temperature increases in the airbox please?

I indeed reviewed the OM of our engine before and couldn't find too much information about the airbox specifically, using the same manual as the link you provided here. I also reviewed the installation link now, which provided a bit information about the structure layout of the airbox.

I've the airbox mod and panel filter done myself. Intake temps did reduce and topend has more power. Does the very same thing as the R600, if not better as cold air being let into the engine bay that the R600 cuts off.

so sounds pretty pointless on the performance side of things, guess the intake gurus have worked there sales magic again on this car convincing us it's what we need to get the most out the remap, when all we need was the official titled, pikey mod!

Ryan804 Ive been trying to find out the exact same thing mate, Im currently Stage 2 with all the supporting hardware including Intercooler except for an aftermarket intake as I struggly to justify it. My set up at the moment Forge Turbo Inlet Hose, APR Panel Filter and Snow Grate Delete that's it and the car performs great. I think any benefits brought by the R600 after my set up as it stands will be somewhat negligible but happy to be proven otherwise.

it's all a bit frustrating with the mix of information about it and if it's worth it, I have seen a revo air scoop that seems to be just a fancy version of opening up the blocked side of the inlet for 249, as this still allows air into the engine bay as well as a new feed for the airbox, but as I said it's 249, quite expensive considering I believe I'd get it done with an old bread knife and a bent screwdriver!

I did exactly this and its brilliant with Stage 1 - did the air box mods well after the remap and noticed an improvement in throttle response and mid-range pull immediately. I'm sure it will be fine for Stage 2 next year ?

I'm going to go full fat with sports cat DP, FMIC and upgraded charge and throttle pipes. Fingers crossed for the magic 400bhp/400lbft but just can't wait for that relentless power delivery and torque that seems to be the difference between stage 1 and 2!

Cool! The TBs have a MAP sensor installed, so I'd expect the ECU to be able to perfectly compensate for the extra airflow. I know many claim it doesn't, so it would be great to see evidence one way or the other.

From a weight loss perspective even a 1/2 lb makes a difference, as the location is also a factor. Performance wise, always good to let a motor breath, air is just one item on the list in a much larger picture

My understanding is that the Hord box has stacks inside the filter, and the individual pods do not. When Hord was doing the testing of the bike, he commented about the extreme sensitivity of our bike to intake runner length, and you basically have none. Compared to Hord, I think you will be short on power everywhere. Compared to stock, I think you'll likely see a loss in most places with the possible exception of high-end. IMHO.

Many of us forget it's tuning the flow, not just opening it up. There is some potential gain to opening it up, but I've seen it many times that power is actually reduced because of this tuning requirement of intake/exhaust performance if it is not done carefully, or at least on an objective measure of result. Not to mention dialing in the components to an AFR with a dyno (or reflash to a known kit) - I think you'll be much happier with a Hord-based reflash than what you currently have.

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