Air Box Lid - On or Off??



17 replies to this topic
  • Guest_Guest_*

Posted May 06, 2000 - 10:04 PM

#1

Does romoving the air box lid really give a increase in HP?? A friend told me that a magazine did a test and found no HP gain by removing it?

The lid looks like it flows properly and adds protection for all of the creek crossings.

Thanks,
Lance '00WR, Wife '00kx125

  • JamesD

Posted May 06, 2000 - 11:02 PM

#2

It may or may not improve HP. Removing the lib makes the bike louder and people generally perceive louder as better. Have a blindfolded person listen to two stereos that are identical but with one slightly louder on the volume control. Ask them which sounds better and almost everyone will pick the louder one. Weird but true.

So, block the bike's sound with some sort of ear protection and they probably won't be able to pick the bike without the airbox lid.
It probably just ends up as more wheelspin anyway. If there is an improvement it's on the top end and a new pipe would make a bigger difference.

Having said that... I did remove the snorkle on mine and removing the lid does save some weight placed high on the bike for free and if conditions aren't wet I doubt it adds any additional protection.

However, leaving it on certainly won't hurt.

  • Dougie

Posted May 07, 2000 - 03:30 AM

#3

I remember a Dirt Bike article on "uncorking the WR" from a '99 issue. They said remove the lid BUT they also said there is no real noticable gain in HP because of it. So why remove it right? Well, I'm a lemming and because everyone else did, I jumped off the cliff also. I figure it is one less step to get to the air filter.

Speaking of the air filter, does anyone else spend hours trying to get that screwed back into the airbox? I think I actually go a little mad everytime I try to get it back on. First I get pissed, then I get a little giddy, then I start mumbling to myself like a homeless crazy person. Is there a trick to this? After one year, I still have not figured it out.

------------------
Dougie, '99 WR400
Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics, Renthal bars, 14/52 gearing.

  • Kyle

Posted May 07, 2000 - 04:14 AM

#4

I know what you mean Doug. After a few minutes and some new words you finally get it back on. My prob is by the time I get it right, all the grease I put on it to seal to the rim is no longer affected. For this reason I was speculating purchasing a neoprene gasket (Dennis Kirk pg.173) that bonds to the rim.
On the other hand, is it even necessary to seal the rim of the filter to the airbox if you clean it regularly? I clean it every 1-2 rides depending how the conditions were the first day. And BTW, I keep the lid installed.

  • Bryan

Posted May 07, 2000 - 09:00 PM

#5

When I removed my air box top I was very sceptical that it would help and I was wearing ear plugs. I was pleasantly surprised by the increase in HP.
But, I'm gullable.

It's easy and it's free so why not try it yourself and decide.

Bryan...

[This message has been edited by Bryan (edited 05-07-2000).]

  • JamesD

Posted May 07, 2000 - 09:20 PM

#6

One thing to consider is that it may have more of an effect at altitude than sea level.

Removing the snorkle on my '98 VFR800 definately changed the power... but it's got EFI.

  • mcarp

Posted May 07, 2000 - 01:23 PM

#7

Lance, I have only had my WR for a few months. I don't feel any power increase with the lid off. I still have the stock pipe for now (rest. removed). In fact it runs better on the lower end (but my jetting may have been a tad off). I put the lid back on because mud/water DID enter the airbox, and started to clog the filter mid-ride. Then the last 1/2 of the ride it ran rich -sputtered, bottom end hiccup, flat on top.

Even on a dry dusty track my filter became clogged quickly.

Now the filter is a little dirty after full days ride, and is good enough to have 2 rides (unless both are sloppy). It has been wet and sloppy this year, so I can't speak for how clean it can stay in dry conditions.

I believe the pros for me are more important than any small power gain. Less mid-ride flow inconsistency and less cleanings. Also the airbox itself doesn't become caked, needing cleaning less. Just my $.02. Maybe a racer or a more modified bike can feel the difference, I sure can't.

  • Tennessee_Thumper

Posted May 07, 2000 - 05:59 PM

#8

If you remove the snorkel.Wouldn't you need to re-jet(richer) to get the full effect of it sucking more air???

[This message has been edited by Tennessee Thumper (edited 05-07-2000).]

  • mcarp

Posted May 07, 2000 - 06:41 PM

#9

Yes, you should rejet when removing the cover. I was running 1 step richer on the MJ and the PJ screw out a little more with the ABlid removed.

What I didn't mention, though. At the same time I put the airbox lid back on, I changed from a stock filter to a WB powerfilter. So any flow difference has probably offset one another or at least come close. At least I was consistent in the amount of filter oil applied in both situations. Since I went leaner in jetting and found no performance change (except low end more consistent), I am leaving it on for awhile. Maybe when the trails dry up I'll try it again w/o the lid.

There is much debate on this subject-I would really like to hear about a dyno run testing this.

Any other takers here? I can't be the only one running the lid on due to water/mud..

I still stick with my story above-if your in muddy conditions, leaving the lid off will start to clog the filter faster and WILL produce a richer mixture probably during that ride.

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  • Tennessee_Thumper

Posted May 07, 2000 - 08:19 PM

#10

mcarp...Thanks for the reply.I got a drz 400e a few months ago.I rejetted and removed the air-lid,It made a huge difference.But I don't really think removing the air lid did it.The drz has a 142main stock so its really lean from the factory.I agree with you,id like to see some dyno test done on a few bikes just to see the outcome.

  • Eric_in_WA

Posted May 08, 2000 - 10:56 AM

#11

On the airbox lid issue. To install or not to install, tis the question.

I have not seen clear evidence that there is a big difference in terms of performance.
1) I have not read or heard of any dyno result showing the improvement. Anybody have any objective data???
2) I have not felt a difference. Perhaps it is because I wear earplugs and can not hear a noise difference.

My experience is that with a lid in place minus snorkel, it keeps a lot of mud, water and dirt off the filter. Which is going to be more restrictive the no lid and plugged filer combo or the lid and cleaner filter combo? I suspect the lid and cleaner filter combo will be less restrictive overall in actual use.

Thanks,
Eric in WA
==========
’99 WR400, YZ timing, IMS Tank, YZ Seat, Acerbis Handguards, Scotts Steering Damper, Renthal Bars, Devol Rad Guards, Dunlop 755F & 756R Tires
’99 Polaris 400 Scrambler –“Trail Couch, Toolbox and Lunchwagon”, ’99 Honda Z50R, ’97 Honda XR70R, Kubota L275DT and an assortment of farm equipment.

  • mcarp

Posted May 08, 2000 - 11:08 AM

#12

The debate continues. I would rather have a somewhat clean airfilter for my entire ride..

  • Bryan

Posted May 08, 2000 - 11:24 AM

#13

Yeah, well, you sea level guys don't need any more air anyway!

These bikes are fast in Colorado. When we drop from Denver to Moab, only 2500 feet, we can feel a big power gain in our machines. I can only imagine how fast these suckers are at sea level.

We 'air challenged' riders up high can use all the help we can possibly get whether real or imagined. Not only do I ride without the air box top and like it, I'm thinking about removing my seat for even further air flow! :)

I've ridden in driving rain storms and through rivers with the box top off and have had no problems. But, Dougie in Moab had an air box full of water after riding the famous Kane Creek trail with about 20 river crossings. Maybe he dumped it and didn't tell us?

Bryan...

[This message has been edited by Bryan (edited 05-08-2000).]

  • JamesD

Posted May 08, 2000 - 02:25 PM

#14

Originally posted by Bryan:
We 'air challenged' riders up high can use all the help we can possibly get whether real or imagined. Not only do I ride without the air box top and like it, I'm thinking about removing my seat for even further air flow! :)


Just drill holes in the seat. Whenver you notice a loss of power stand up or join a weight loss program. :D

  • mcarp

Posted May 08, 2000 - 03:14 PM

#15

I'm not a high altitude rider, but I would have to agree with Bryan. You guys need all the air you can get!

  • Bryan

Posted May 08, 2000 - 03:22 PM

#16

James! You've got it!

I'll drill holes in the seat. Then I'm comfortable unless I need extra power. Then I can stand up and it'll rip! I wonder if that suction..., never mind...

By the way, do you think I really need that exhaust header thingy? I'll bet I could get more exhaust flow if I remove it?

Sorry guys. I'm just dissing myself since I'm the only one that seems to think removing the air box top made a difference.

Bryan...

[This message has been edited by Bryan (edited 05-08-2000).]

  • Dougie

Posted May 08, 2000 - 05:52 PM

#17

Dumped it and didn't tell you??!! If I remember right, I was out front that entire trail. OK, except for ScaryMyth. But still, I was the lead WR. And if I would have dropped it, you guys would have came up on me. Unless you were so far back that I had time to pick it up and kick it over. Or maybe it was because I was blasting through the water instead of picking up my feet and rolling through it, huh? :)

No, seriously, I never dropped it on Kane Creek. I'm sure it was just water accumilated from the splash made by going through all those creek crossings.

------------------
Dougie, '99 WR400
Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics, Renthal bars, 14/52 gearing.

  • JamesD

Posted May 08, 2000 - 06:44 PM

#18

Originally posted by Bryan:
James! You've got it!

I'll drill holes in the seat. Then I'm comfortable unless I need extra power. Then I can stand up and it'll rip! I wonder if that suction..., never mind...


Hmmm... it might work if... naaaaa.

By the way, do you think I really need that exhaust header thingy? I'll bet I could get more exhaust flow if I remove it?


Hmmm... I don't know if that's forest service approved. And then there is that whole mud and dirt thing.

Sorry guys. I'm just dissing myself since I'm the only one that seems to think removing the air box made a difference.


You removed the air box??? Gee... doesn't dirt get in the engine without the airbox and filter? :)

On second thought, you should remove the headpipe. If there's dirt going in the back why keep it out of the front? Besides... it's gotta save 10lbs or more!!!! LOL




 
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