Airbox flap

[CelicaBoss]

Does leaving that flap in your airbox in there make your car accelerate in surges until about 4k rpms??? It seems like my car accelerates in jumps until about 4k and I heard that thats when that flap opens all the way. Does it cause any problems to take it out??? Also, is there an instructional about it. Not sure what its called so its hard to do a search. I just remember reading something about it once.

[2zzTahara]

What your is asking about is known as the "butterfly mod"; do a search and y'll get tons of hits back.

[CelicaBoss]

Can this cause that though???

[2zzTahara]

Doing a simple search on this site produced this link; pretty much sums it up:

http://www.newcelica.org/forums/showthread.php?t=192680&highlight=butterfly+mod

DO NOT TAKE OFF THE BUTTERFLY valve!!!!!! it will not give you any more hp

"Last month we tried removing the flap door assembly and thought we felt a significant improvement in both power and drivability, but subsequently found no power on the dyno. it was all in our minds" article from sport compact car

when engines run in the low rpms they need high speed air to produce low end torque while in the high rpm ranges they need a high volumetric flow rate (large amounts of air). Thats why most free flowing aftermarket intakes increase the top end hp (deliver a greater amount of air) but most of them dont do anything for the torque (some of them even lower your low end torque). Thats why the newer engines (including the gt-s and typeS come with these valves) (besides this, they also help reduce engine noise). Below 4000rpm the valve is closed and the air is FORCED through the SMALL hole on the side. when this air is forced through such a small opening, the velocity of the air is increased and thus the engine produces more torque. After 4000rpm,the valve is opened and a high volume of air is alowed to flow in to produce more top end HP. Do you realy want to loose low end torque???? after all, the valve is 2mm thick how much air do you think it can block when open????? just my .02

oh yeah about the hot air, I covered my whole stock intake with isulation(the kind they use in refrigetators and ovens (made out of heat reflective metal) . lowered the intake air temperature by over 13F after 15mins of idling. not bad for a nearly free mod!!!!!!!!!!!!!! it also looks realy kweel!!!! i even spraypainted a red TRD emblem with a stencil i made. LOOKS LIKE A REAL TRD ACCESORY. everytime i get ma oil changed, the mechanics always make a coment on how bad ass my car must be for TOYOTA to have heat shielded the intake ducts with a TRD "REFLECTORS"
:rofl:

[2zzTahara]

You might find these links interesting as well:

Induction Systems

http://www.grapeaperacing.com/GrapeApeRacing/tech/index.cfm

INSTALL: PERFECT CAI (Hybrid Aftermarket Intake/Stock Airbox Mod)


http://www.newcelica.org/forums/showthread.php?t=127861

[CelicaBoss]

That seems to be a little opinionated. Plus, I realized that where I read about the 4k rpm mark was in this article that was quoted on the Sports Compact Car website. They also went on to say in that article that an owner could take it off or leave it on. It didnt make any difference on the dyno. So I wouldnt think that you would lose any low end torque since they dyno tested it and found no gains or losses.

[2zzTahara]

I can only offer information; it's up to you to draw your own conclusions and do what works best for you.

Continue the search and see what else you can dig up.

[CelicaBoss]

No man, nothing against you. Thanks for your help. I still would like to know though it other people have experienced this. It went away, or so it seemed, after I cleaned my MAF. Now its back and I happened to watch my tach the last time and noticed it cleared up around 4k and thats what made me think of this. Thanks though for what you have found so far.

[card00d85]

Nope it's not that. I took off the butterfly valve and I still get a rough acceleration. The needle goes up when I'm accelerating, but it bouces or jumps when it's moving up. Like a shaky rpm needle.

[CelicaBoss]

No I can actually feel the car accelerate in surges. Its not just the needle on the tach. I cant figure out what is doing this.

[CelicaBoss]

Ok well I know everyone is going to say its all in my head, but my car accelerates smooth now after I took out the butterfly valve. I just thought I would let you guys know it did do something. I dont feel more power or anything, but the louder sound is pretty cool.

[Nova_gts]

it is all in your head if you think it went away b/c that mod, my car jumps sometimes too, and i have a CAI, its something that doesnt have to do anything with the intake, the jumps come and go, i really dont know what it is... my guess tho is blue bomber could tell ya something

[CelicaBoss]

Oh another thing. My butterfly valve didnt open all the way after I took it out. It felt like there was something making it stick about half closed. With a little pressure it made a snap sound and then it would open all the way. I am guessing this was restricting my airflow a little. But that still may not solve the jumping. I think it did however solve my weak lift problem. Lift now seems stronger and I can actually hear the change in sound that everyone talks about when it kicks in. Has anyone elses butterfly been stuck before???