Airbox lid removal

Kirkish_Delight

fast rider
Joined
Mar 7, 2021
Messages
32
Location
UK
Anyone tried this long term and had any issues?

Apparently you get a 5% power boost right across the rev range.

However, i have concerns about debris entering the engine &/or air fueling computer issues.
 
I run mine with the air box lid off, Rottweiler fuel dongle, and an Arrow mid pipe and muffler. I don’t have any issues with surging or popping on decel. Seems to run great!
 
My bike is currently restricted A2 here in France (despite 30 years of riding all over the world!) I don't fully understand how the digital choke works, a remapping I suppose. Does anybody know what effects removing the airbox lid will have on the restriction? Will it affect the restriction by making it 1) no longer legal, and 2) forcing the computer to make things, as the subtitles in Max Cool's excellent video call it, "wonky"?
 
While waiting for a reply to my comment above (Feb 20) I took off the airbox. Low-end chugging is noticeably less and it definitely has more get up and go down there, too. Haven't had a chance to get it out and really open it up, but I'd say this cheap mod is a no-brainer. I used to occasionally hear popping on deceleration. I haven't really ridden it long enough to say for sure it is gone. I'm definitely pleased with the results.
 
Seeing as our bikes have throttle by wire, I'd expect the ecu won't let the throttle body open beyond a certain % at certain revs if it's A2.
That makes more sense than some other explanations I've heard. One explanation said that the computer shuts off the gas when the bike reaches the HP limit, but that explanation doesn't work because the bike doesn't measure its own HP. The combination of revs and throttle matches my experience: the bike just kind of runs out of breath in the straights. What this means is that the revs-to-throttle ratio limit is determined by a known value established with the air box on, which puts me just over my HP limit for the next two years. Man, the absence of that low-end chugging is noice 🤟, tho....
 
So i modified the airbox (conservatively). Can confirm that the engine has a bit more grunt, especially at lower revs. No obvious ecu blips either.
 

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I had my Vit 701 run and adjusted in dynojet bench with PC5, decat, O2 mod, akra pipe and did messurements with and without lid (got the graphs from both tests printed), with lid, I got 2 extra hp on top, the last 1000 rpm, but lost a lot of the gains in the mid and low rpm on both hp and torque. I went for without the lid, and got the stronger mid and low range and the technican said it was a no brainer to chose to go without the lid. As ppl say, if you have no PC5 and keep the cat on the bike, it is safe and nice boost to remove the lid and also mount a O2 mod.
 
@Fredde - can you post the dyno runs? Would love to see what you're getting.

Also, the PCV tunes - Can you take a screen shot of the final tune and post it? I eventually am getting up to 2WDW in WA for a dyno tune but haven't made it yet, and have a stock map from Dynojet in there now. I'm curious how it is different than yours. If you can do that, it would be great. I think I'm a little soft at 4k . . . .

Thanks.
 
While waiting for a reply to my comment above (Feb 20) I took off the airbox. Low-end chugging is noticeably less and it definitely has more get up and go down there, too. Haven't had a chance to get it out and really open it up, but I'd say this cheap mod is a no-brainer. I used to occasionally hear popping on deceleration. I haven't really ridden it long enough to say for sure it is gone. I'm definitely pleased with the results.
if you want to remove the rattle at low revs, take out the db killer
 
@Fredde - can you post the dyno runs? Would love to see what you're getting.

Also, the PCV tunes - Can you take a screen shot of the final tune and post it? I eventually am getting up to 2WDW in WA for a dyno tune but haven't made it yet, and have a stock map from Dynojet in there now. I'm curious how it is different than yours. If you can do that, it would be great. I think I'm a little soft at 4k . . . .

Thanks.
Nel’s is great & I say that from personal experience. But Rottweiler performance will sell you a custom map for only $50. They have way more experience with these engines than most and can provide a custom map for your personal configuration.
 
Nel’s is great & I say that from personal experience. But Rottweiler performance will sell you a custom map for only $50. They have way more experience with these engines than most and can provide a custom map for your personal configuration.
You have a good point on downloading a tune. For my triumph I got a tune for it from a triumph guru but wanted to double check it with my mods and individual bike. When Nels was in town he ran it and said it was spot on. He also gave me a couple of tips to tweak it and just charged for the run, great guy and really did a good job tuning my buddys Kawi.
 
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