Possible Airbox mod?

[Tbird]

Here's a question for you guys-

A couple of months ago Sport Rider had an article on Lee Shiert's (sp) 197 horse gixxers. One of them had his new airbox, which apparently made a large (ie 10 horse) difference in the midrange. Now what was interesting was that the box itself had no top; it was designed to extend all the way up to the underside of the gas tank, and there had a rubber seal, effectively encompassing all that volume in a more or less air tight arrangement (at least some ram air effect left). Anyone think this could be effectively done on a TL? Thoughts?

Scott

[AdamTLS]

Seems like the Terry Shepherd frame for the TL's uses this design as well... That's just going from memory though.. You could dig up his site on the web and find out for sure I'm certain...

[Blue]

Could work, but on the standard TL it's going to take major work to get the box to seal correctly. Terry and the guys build a purpose frame and airbox to match. The TL suffers badley from air starvation.

Speaking to Terry their box is over what 21Lt?....HUGE!

[J-Bone]

Check out Renegades Air-kit for the Mille, does exactly what your´e describing. I guess it would work just as well with the same design for a TL.

[XtreamTLS]

talking about this mod. This is what im doing when i make my own fiberglass airbox for my TLS. I'm going to use a twin seal setup like what is used in aircraft fuel cells. no air will leak in or out.

[TLRDoug]

Hmmmmmmm

The TL suffers badley from air starvation

Hey Blue.

What do you base your statement on? Lot's of stock TL's actually are a bit lean....too much air. I have onlyput headers and an air filter on my TL's and a PCII richened it up nicely. I have never heard anyone characterize a TLS or TLR as "Air Starved" before. I am jsut curious as to you basis for the statement.

[horkn]

doug i think hes trying to say that the airboxes are not big enough on the tl. ive been told this by many people, tuners included. all twins have airbox needs. something to do with the piston size.

[sousa]

I have heard that the TL series has smaller than ideal airboxes, but not that they suffer badly from air starvation. Then again, I do recall reading that prototype TLS engines had huge airboxes, and made LOTS of power. Maybe that is where the 97 TLS legend began?

[Tbird]

Lot's of stock TL's actually are a bit lean....too much air.

Doug-while this may be true, you have to remember that TLs are a speed density fuel injection system-that is, the amount of airflow is not measured but inferred from atmospheric conditions, rpm etc on look up tables. Basically, the factory has told the engine how much air is coming in, and how much fuel it therefore needs. The motor's not running lean because it has some much airflow coming, but because the factory programmed it that way. That's why you need a remap when you install full exhaust-the motor has no idea that you are now moving more air in and out, and ergo is still fueling for the stock amount of air-lean condition ensuing.

Back to the subject-Jay stated a while back that virtually all liter twins are starved for airbox volume, this in conjunction w/ the impressive midrange results Lee Sheirts achieved was what led me to wonder about this...

[Jens]

So what happens if I remove the whole Airbox lid?

[Wingspan]

Originally posted by Jens
So what happens if I remove the whole Airbox lid?

You gain midrange (and a LOT of noise) and loose top end. There are many, many people here on the board that run without the lid.

I've ridden both ways, and currently have the lid off. I usually run without it for a week or so, then get tired of the noise and put it back on, then start to miss the noise and take it back off, then get sick of it again and put it back on...

[Rlbol]

There are a few companies that are making the airboxs like that but for the Gsxr1k. The only gains they are getting are from pretty heavly moded engines. But it wouldn't be to difficult to make one for the TLR, i have never seen the airbox on a TLS.
Just get an extra airbox lid, cut the top of it, measure and extend the sides up to the bottom of the tank,with fiberglass and then get some type of gasket or weather striping to seal between the tank and the top of the airbox. If have been planing on trying this when i get some time. When I do I will let you know how it works.

[Zipp]

Originally posted by horkn
doug i think hes trying to say that the airboxes are not big enough on the tl. ive been told this by many people, tuners included. all twins have airbox needs. something to do with the piston size.

Air box size is mainly determined by 2 things - 1, swept volume of the piston and 2, piston maximum velocity.

[Tbird]

Rlbol-thanks for the response. That was how I was figuring on doing it-sounds like a winter project...

[Duken4evr]

I recall Sport Rider did an article awhile back where they attached a mercury pressure gauge to various bikes, including a TLR, and graphed the air pressure level inside the airbox at varying speeds. The I4 bikes developed positive pressure that was smooth at higher speeds. The TLR had a very jagged curve, positive and negative.

The 4's draw air in smaller even intervals. The twin takes less frequent big gulps. The air box ideally needs to be designed large for twins for the size of the gulp and the exhaust similarly needs to handle large exhaust pulses.