07 Apex airbox mods

[KnappAttack]

I'll give you the real deal on airbox mods as I have tested them and seen the results first hand. I have gone back to the stock box to pickup fuel mileage and added midrange power and consistency.

For the guys that have the lid done up on the outer hood, (Fix style) The ONLY advantage with them is they make more power if you make a pass on the first run, say a drag race or speed run. Why? Because they allow cold air into the engine immediately. The factory stock airbox is sucking hotter underhood air in until you get the sled moving and force cooler air into the nose of the machine and it can get into engine. If you run a stock airbox it will run just as fast as on the second run as long as it's getting the cooler air from not setting still too long and allowing the air to stagnate and warm up.

Fuel Spitback- using a modified box you can't recapture the fuel and air reversions due to a decreased resonance in a now altered state of tune. This shows up as decreased fuel mileage and reduced midrange in part throttle. It isn't much, but its there. This is one reason some machines with modded airboxes need to add fuel is it can't recapture some of the reversion fuel.

I have found the stock box to out perform a modified box in all areas other than a first pass scenario when there is still, hot underhood air being sucked into the engine. If the sled is moving the stock airbox will be drawing in cold air and accelerate slightly faster than a modified box.

One more thing is the obnoxious noise a modified lid makes. I personally don't care for it and don't know how a person could ride with it for any length of time without being wore out from the noise. I can hear it if someone in the group is running one. If you like the noise thats great, just don't expect much from a performance standpoint with a modified airbox on a 150 EFI engine.

 

[SledFreak]

What if you have an exhaust and airbox mod and you are giving it the fuel it needs?

I also do agree about the inconsistency from letting it sit and trying to run it, where one run might be good and then you let it sit for a couple of minutes and then do another run and the results are less. But once you are moving all the time (trail riding), it seems to work quite well. Sitting around drag racing with the boys may alter the results with when the motor gets hot sitting there, but with an exhaust and fuel controller, there is defintely a benefit. I also think that it loses power from sitting there even when the stock box is on. The motor is just absorbing the warm air and It is still inconsistant with the stock box, just not as bad.

 

[race24x]

I guess coming from a bike stand point I have seen the tests of ram air on bikes like my Hayabusa and gains with ram air at speed. So why wouldnt the ram air lid make power when moving down the trail, and wouldnt you be able to with the fule reprogrammer make adjustments to help with it. More air and more fuel is more power.

 

[Yamadog]

Re: sounds good

[quote=".

>>>
How about a few pics from under neath and with out the hood etc. Thanks ![/quote]

I am still in PA sleds in MN will be back by next Thursday. I will post them then.

 

[MUSKIE]

I see in the performce of MY sled that the cold air being rammed in to the box makes a difference in the sled for sure.. The colder out it is the better the sled works..I will say that there is a differnce between a warm afternoon and a cold nite..As of someone saying that you still need the KN filters while running this lid--no.......As of noise levels --it is only there when one is hitting it hard..And yes then you have a BARK...If you take of easy there is not alot above stock..I have been stop buy OPP with our group many times on the trails and when sled is at idle there is no difference .and i have NEVER had problems with the law or home owners.. The (noise) of a airbox mod. is nothing near what i hear from pipes on sleds..I have REVS. in my area that are piped and THAT is loud at all times......All changes that are done to my sled and the guys i ride with are checked over & over & over with radar gun so it is not a butt gauge that we are going bye..In my opinion any air box mod. with fuel works.......this is just my opinion ........

 

[Charged RTX]

Just another note on Fix. My brother in law ordered coils from them and 2 of the ones thay sent were very obviously used. They did not admit the mistake and it went as far as having to fight it out with the CC company. I did have good luck with the fix style lid though.

 

[KnappAttack]

I guess coming from a bike stand point I have seen the tests of ram air on bikes like my Hayabusa and gains with ram air at speed. So why wouldnt the ram air lid make power when moving down the trail, and wouldnt you be able to with the fule reprogrammer make adjustments to help with it. More air and more fuel is more power.[/quote


I did extensive testing with ram air and pressurized airboxes on My V-Max 4 at over 150 MPH and can tell you there is not much of a gain at that speed, like less than a half of a MPH, and it had a restriction on the intake up to that speed.

The ram air on a bike is tested extensively in the wind tunnel and designed to operate at over 170 MPH. What you have in the airbox lid could hardly be of any use for ramming effect on the apex. Besides that, how could it possibly pressurize the box when the bottom factory intake is still open? It can't possibly provide pressure, only cold air.

The reason it won't provide additional power is you are loosing the tuned reversion and reverberations from opening the box and taking away the reversion pulses and allowing them to spit out the intake. Much the way a tuned exhaust pipe works to stuff the charge back into the cylinder before the piston closes the exhaust port on a two-stroke.

For a trail sled moving down the trail, the ram-airbox lid gains nothing for HP. I have tried this in the field, swapping lids and boxes and have found the stock box to be superior in performance in acceleration and fuel mileage.

Using an open box for over 600 miles last year decreased my fuel mileage by around 2-3 MPG. As soon as I went back to stock box the mileage instantly cam back up to my normal 15-16 MPG.

I had a RX-1 that would give me fits using the open box on my Attak, it was then that I figured I had best get to the bottom of things, going back to the stock box allowed me to beat him again. It was a win win, mileage came back as well as the performance the minute I went back to stock.

As for the question about adding a pipe, I don't know as I didn't add a pipe with a modded box. One thing I do know, I have outrun machines that have had pipes, airbox lids, and power programers with my stock Attak only geared down to a 23/40. In my opinion these items don't do a whole lot if that is the case.

One thing I know is, it's easier to slow these sleds down than it is to make them faster in a naturally aspirated configuration

 

[Iceman57]

I did extensive testing with ram air and pressurized airboxes on My V-Max 4 at over 150 MPH and can tell you there is not much of a gain at that speed, like less than a half of a MPH, and it had a restriction on the intake up to that speed.

The ram air on a bike is tested extensively in the wind tunnel and designed to operate at over 170 MPH. What you have in the airbox lid could hardly be of any use for ramming effect on the apex. Besides that, how could it possibly pressurize the box when the bottom factory intake is still open? It can't possibly provide pressure, only cold air.

The reason it won't provide additional power is you are loosing the tuned reversion and reverberations from opening the box and taking away the reversion pulses and allowing them to spit out the intake. Much the way a tuned exhaust pipe works to stuff the charge back into the cylinder before the piston closes the exhaust port on a two-stroke.

For a trail sled moving down the trail, the ram-airbox lid gains nothing for HP. I have tried this in the field, swapping lids and boxes and have found the stock box to be superior in performance in acceleration and fuel mileage.

Using an open box for over 600 miles last year decreased my fuel mileage by around 2-3 MPG. As soon as I went back to stock box the mileage instantly cam back up to my normal 15-16 MPG.

I had a RX-1 that would give me fits using the open box on my Attak, it was then that I figured I had best get to the bottom of things, going back to the stock box allowed me to beat him again. It was a win win, mileage came back as well as the performance the minute I went back to stock.

As for the question about adding a pipe, I don't know as I didn't add a pipe with a modded box. One thing I do know, I have outrun machines that have had pipes, airbox lids, and power programers with my stock Attak only geared down to a 23/40. In my opinion these items don't do a whole lot if that is the case.

One thing I know is, it's easier to slow these sleds down than it is to make them faster in a naturally aspirated configuration

Plain and simple, the Apex air box has three (3) jobs. 1. It houses the air filter 2. It quiets down the noise of the air rushing into the engine. 3. It helps keep warm or hot engine air from entering the intake resulting in a loss of power. Actually the result of a larger air box opening is as the air enters the box it expands and slows down, which makes it easier to enter the filter because it enters in a larger area of the filter because of the larger opening in the air box and the result…. MORE POWER. Actually I have true air tunnel testing experience just an FYI. We used to flip the air cleaner covers over on our cars in the 70’s and we would get a noticeable increase in power but the air rushing into the carb. would be pretty loud so when we were done racing we would flip them back. When you are referring to tuned reversion and reverberations they are only affected by the length of the intake funnels or boots and have nothing to do with the size of the opening of the air box. As I see it you are calling out Allen from Ulmer Racing who dynoed his air box mod and posted the results. Basically you are expecting people to believe your field testing on one sled (your sled) over Allen’s dyno results from his testing. I for one have experienced better performance from opening my air box but I wouldn’t personally recommend it do to the lack of documented evidence, however I would trust someones dyno results.

 

[**sj**]

actually i think there are gains and losses like knapp illudes to in different situations...a pressurized box with a restriced opening will cause faster venturi speeds at everything but maybe WOT...also the pulse and reversion charge...well cant say for sure...but I've had extensive experience on the 2 smokes and have mostly lost when attempting to getting more air in....in short ...my guess on the lid mods is you can get some on top but sometimes at the expense of economy through losses in efficiency..now the bottom mods...I have one of my own as well...seem to have less compromises and gains as well...

 

[KnappAttack]

Iceman 57, I'm not calling out anyone, Just letting you know what I have found with my testing using my own mods and the mod airbox lid. I can see that it only adds power in a first run situation in the field. In the field it picks up approx. 200 RPMs. I have seen the Dyno sheet you refer to though and would not want to sacrifice the midrange loss for the slight bit on top. It can not be overcome in the field for the properly set up stock one.

We don't race dynos in the field, things that work on the dyno don't always prove true in the field. I have seen this first hand spending more time on the dyno than than most. The dyno will only give you wide open throttle runs on a fully loaded engine. It will not show part throttle and fuel mileage at every part throttle opening.

Your cars did not have an engineered airbox to allow the use of any tuned type of reversion. The Apex does. All the autos did back in 70's, was filter the incoming air. Things have advanced a fair bit since the 70's muscle cars.

I'll say it again. It's easier to slow the apex down than make it faster.

You won't know till you run against something close, how the mods perform, or until you set up the ET lights and can test the changes in a controlled condition and interpret the results for those conditions.

Hell I ran a mod airbox for 600 miles thinking it was better, till I was able to get beat by my neighbors RX-1 that I knew I could outrun before the mod airbox. That is when I went to work to figure out how and why I got beat. I acquired more lids and airboxes and tested for a day under controlled conditions. Well what I thought was a good mod was not. The end result was the stock airbox was better in the field by 2-3 tenths of a second in a quarter mile running hot laps.
The mod lid or airbox was better only the first run after letting the machine sit for a few minutes between runs. Even at that however, the mod airbox or lid was never as fast using the stock box making hot laps. The mod box was just giving away to much down low.

 

[actionjack]

I'd have to say that my experience matches Knapp's. My GT had clutching, windage plates, plugs, and air box mods. My cousin's bone stock GT was dead even with my GT. Same year 2000+ miles on mine, ~700 miles on his. Only difference was I was running USI VX301 skis with 10" carbides and his sled had stock skis with Duallys. I am saving my $$ on my next Apex unless he is killing me.

 

[SledFreak]

What type off traction do you both have?

 

[actionjack]

Stock ripsaw 144 down the middle same on both sleds. Probably installed by same mechanic at same dealer. BTW, one of my buddies has an all stock GT with no studs and definitely out ran me on top end. I'm sure thats rotating mass. Never got a good comparo on hole shot. Going for an RTX next and maybe an IceRipper track.

 

[Iceman57]

Knapp I used the air cleaner as an example. I don't know what to tell you, but I do have improved performance from opening the air box. Like everyone else who owns a snowmobile I ride with other sleds. I know how my sled performs against everyone of them so when adding mods I can accurately evaluate my performance gains or losses by how my sled performs against the other sleds after the mods are installed. Every time we get a chance its WOT so we get plenty of chances to evaluate the changes we have made. I removed the white secondary spring due to a loss in midrange and top end. The air box mod added a moderate gain without sacrificing fuel economy. With the air box opened I walk a little more on the sleds I run with and as far as the fuel economy I have always, from day one, gotten between 12 and 13 miles per gallon with my sled. I always ride my sled with the hammer down. Knapp you of all people should know that no two engines run the same or are built the same. There are slight to moderate differences in all engines, some may have a stumble down low like mine, some may run stronger on top, some may have a better midrange. I’m sure you know that Engines are built to certain specs, some engines could be close to tolerance and some could be on the high or low end. The tolerance specs cover all aspects of the engine from the intake to the valves to the pistions to the crank to the exhaust ect. Some engines may need more fuel then others at certain RPM’s, some could benefit much more from a exhaust that breaths better then the stock exhaust. Because of the inconsistencies in engines a balanced and blueprinted engine will out perform almost all that are not. Some engines may be as close to the factory specs right off the line but not many. Because of the differences one engine could benefit from a slight advance in the timing by installing an Ignition Module, another could benefit from more or less fuel and this could ge accomplished by adjustments from a Powercommander or opening the air box or aftermarket exhaust for better airflow or unrestricted the exhaust . The Powercommander eliminated my low end stumble by adding 8% fuel at the 2% and 5% throttle position. Bottom line is, with my sled, I do have a performance gain with the increased airflow. I’m not saying it’s a difference in night and day but its there. There are many people on there who claim gains in performance from their mods and I’m pretty sure they are not supplying us with false information. I’m sure you and I would get difference results from the same mods installed on both our sleds. I won't argue your performance claims good or bad without first hand knowledge and you shouldn’t argue mine

 

[BADSLED]

Opening the airbox on the bottom works plain and simple! I have done this modification and the difference is 2-3 sleds lenghts in our testing on the same day. We have two Apexes setup exactly the same except one did not have Allen's airbox mod and would consitently get beat. Half hour later we were back out to the strip and I had my handsful trying to stay even with him, 50lbs of weight difference.