Throttle Body

[NickCats]

I was talking to one of my coworkers about mods, and he suggested I port and polish the throttle body.

He told me he did this to his Z-06 and it dramatically increased throttle response :

http://www.s2performance.net/

http://forums.corvetteforum.com/showthread.php?t=1548531&highlight=shaner

http://custom.autos.yahoo.com/gallery/photos-car-8202;_ylt=Aq0EL53HMqAKSy6B35VPC7BK.ckF?photo_cat=a ll&start=10&sel=14

Anyone ever done this to their Boxster, or know anything about it ?

Nick

[blue2000s]

Originally Posted by NickCats

I was talking to one of my coworkers about mods, and he suggested I port and polish the throttle body.

He told me he did this to his Z-06 and it dramatically increased throttle response :

http://www.s2performance.net/

http://forums.corvetteforum.com/showthread.php?t=1548531&highlight=shaner

http://custom.autos.yahoo.com/gallery/photos-car-8202;_ylt=Aq0EL53HMqAKSy6B35VPC7BK.ckF?photo_cat=a ll&start=10&sel=14

Anyone ever done this to their Boxster, or know anything about it ?

Nick

I've not seen a larger throttle plate offered for the Boxster. If you can't find a bigger plate, you can't port the body. Polishing, however, is still do-able. Probably a little flow gain but won't cost much if you do it yourself either.

[NickCats]

Originally Posted by blue2000s

I've not seen a larger throttle plate offered for the Boxster. If you can't find a bigger plate, you can't port the body. Polishing, however, is still do-able. Probably a little flow gain but won't cost much if you do it yourself either.

Blue,

I think an enlarged throttle body is mentioned in the third link and offered here :

http://www.scargoracing.com/

( Click products - Parts for the Boxster )

Nick

[Sammy]

I have heard of and seen this mod done before in the past, but not on a Boxster. I've actually seen where people open up their MAF body (this was done on a supercharged vehicle and everything was opened up as much as possible) in addition to intake kits and a larger throttle body. The idea being that the more air in and out of the motor the more power.

However, despite the theory of more air in and out, the more power, I have experienced where the exhaust on a 4 cylinder (Nick, the red 240SX with the turbo) when opened up to 3" all the way (new header, and full exhaust) actually dropped the power (theory that there wasn't enough back pressure?). This was done before the turbo was added to the car.

I'm hoping MNBoxster can chime in here and explain some stuff...

[blue2000s]

Originally Posted by Sammy

I have heard of and seen this mod done before in the past, but not on a Boxster. I've actually seen where people open up their MAF body (this was done on a supercharged vehicle and everything was opened up as much as possible) in addition to intake kits and a larger throttle body. The idea being that the more air in and out of the motor the more power.

However, despite the theory of more air in and out, the more power, I have experienced where the exhaust on a 4 cylinder (Nick, the red 240SX with the turbo) when opened up to 3" all the way (new header, and full exhaust) actually dropped the power (theory that there wasn't enough back pressure?). This was done before the turbo was added to the car.

I'm hoping MNBoxster can chime in here and explain some stuff...

Part of making good lower RPM torque is through air velocity. This helps to fill the cylinders and aids in mixing. The larger the intake path, the slower the intake speed, thus reduced low engine speed torque. This is typically most sesitive to port sizing and valve timing.

Exhaust size is tricky. You're not just trying to open the exhaust path from the engine to the air but you also need to take resonant sound pressure waves into account. These sonic waves can hurt or help cylinder evacuation depending on design. Also, valve timing is designed with a certain amount of back pressure. Changing the backpressure can lead to reductions in power and economy without internal timing changes.

[blue2000s]

Originally Posted by NickCats

Blue,

I think an enlarged throttle body is mentioned in the third link and offered here :

http://www.scargoracing.com/

( Click products - Parts for the Boxster )

Nick

That's the entire throttle body, not just the plate, but it does sound like it's larger. Then you polish from there.

[CJ_Boxster]

Originally Posted by blue2000s

That's the entire throttle body, not just the plate, but it does sound like it's larger. Then you polish from there.

Without increasing the plate size.. You would be just widening the outer surface and tappering it up to the plate then polishing it... While the air will flow through much smoother, you are still bottle necking the air at the plate, so im not sure how much power you can get out of it.

[blue2000s]

Originally Posted by CJ_Boxster

Without increasing the plate size.. You would be just widening the outer surface and tappering it up to the plate then polishing it... While the air will flow through much smoother, you are still bottle necking the air at the plate, so im not sure how much power you can get out of it.

Exactly, that's why I made my original comment about the larger plate.

BTW, it looks like an exchange program with the throttle body, so they're probably just reworking stock parts and adding their own throttle plate.

Also, throttle plates can be modified to be more aerodynamic when fully opened. Things like knife-edging and shaft smoothing can be done to improve flow.