Upgrading to 52 mm throttle (Porting Question)
Thread Starter
Racer
Joined: Jan 2002
Posts: 469
Likes: 0
From: Clifton NJ
Upgrading to 52 mm throttle (Porting Question)
Fellow members,
Ive done alot of porting on intakes prior to this project but Im curious. Instead of enlarging the holes to a circular 52 mm diameter, would it be just as good if not better to make one large oval shaped (SIAMESED LIKE) OPENING? Of course I would follow the outside diameter of the openings, just hog out the middle. Its an 85 so I would be leaving the egr on the bottom intact. Almost like when you look through binoculars.
Thanks,
Your oppinions will be greatly appreciated.
Ive done alot of porting on intakes prior to this project but Im curious. Instead of enlarging the holes to a circular 52 mm diameter, would it be just as good if not better to make one large oval shaped (SIAMESED LIKE) OPENING? Of course I would follow the outside diameter of the openings, just hog out the middle. Its an 85 so I would be leaving the egr on the bottom intact. Almost like when you look through binoculars.
Thanks,
Your oppinions will be greatly appreciated.
Drifting
Joined: Oct 2003
Posts: 1,594
Likes: 0
From: CALGARY ab
Originally Posted by hoot85
Fellow members,
Ive done alot of porting on intakes prior to this project but Im curious. Instead of enlarging the holes to a circular 52 mm diameter, would it be just as good if not better to make one large oval shaped (SIAMESED LIKE) OPENING? Of course I would follow the outside diameter of the openings, just hog out the middle. Its an 85 so I would be leaving the egr on the bottom intact. Almost like when you look through binoculars.
Thanks,
Your oppinions will be greatly appreciated.
Ive done alot of porting on intakes prior to this project but Im curious. Instead of enlarging the holes to a circular 52 mm diameter, would it be just as good if not better to make one large oval shaped (SIAMESED LIKE) OPENING? Of course I would follow the outside diameter of the openings, just hog out the middle. Its an 85 so I would be leaving the egr on the bottom intact. Almost like when you look through binoculars.
Thanks,
Your oppinions will be greatly appreciated.
that sounds like it will work...in my opion..
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
As the unproud owner of two BBK 52mm TBs, let me just say that I hope you purchased an AS&M 52mm TB!
I simply port & gasket matched the front of the plenum to the new TB. I'm not sure how it will work if you cut out the center wall. For sure you will have a little more plenum volume.
I simply port & gasket matched the front of the plenum to the new TB. I'm not sure how it will work if you cut out the center wall. For sure you will have a little more plenum volume.
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
I'm using an AS&M 52mm so I too am using a larger than stock TB, but if you'd siamese the two openings together as you've described, you'll have to make a special butterfly valvem otherwise you'd get too much bypass. Also between the two openings, there are more vacuum routings inside the tb for the crancase ventillation I think.. Be carefull, use a spare TB, and let us know how it went.. 
Thread Starter
Racer
Joined: Jan 2002
Posts: 469
Likes: 0
From: Clifton NJ
Originally Posted by 65Z01
As the unproud owner of two BBK 52mm TBs, let me just say that I hope you purchased an AS&M 52mm TB!
I simply port & gasket matched the front of the plenum to the new TB. I'm not sure how it will work if you cut out the center wall. For sure you will have a little more plenum volume.
I simply port & gasket matched the front of the plenum to the new TB. I'm not sure how it will work if you cut out the center wall. For sure you will have a little more plenum volume.
Thanks
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Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
First of all, the OEM TB is 48 mm, but the holes in the intake are 52 mm! No porting necessary for the new TB.
Second of all, if your car is similar to my 96 (85 model?) then the center divider is full of IAC passages that will destroy your idle air balance between the left and right side of the engine.
That might not be the case for the earlier TPI's I don't have specific experience...otherwise I don't think there will be much gain-the TB is still only 52 MM. Never know though!
Second of all, if your car is similar to my 96 (85 model?) then the center divider is full of IAC passages that will destroy your idle air balance between the left and right side of the engine.
That might not be the case for the earlier TPI's I don't have specific experience...otherwise I don't think there will be much gain-the TB is still only 52 MM. Never know though!
Thread Starter
Racer
Joined: Jan 2002
Posts: 469
Likes: 0
From: Clifton NJ
[QUOTE=No Go]First of all, the OEM TB is 48 mm, but the holes in the intake are 52 mm! No porting necessary for the new TB.Second of all, if your car is similar to my 96 (85 model?) then the center divider is full of IAC passages that will destroy your idle air balance between the left and right side of the engine.
That might not be the case for the earlier TPI's I don't have specific experience...otherwise I don't think there will be much gain-the TB is still only 52 MM. Never know though
Thanks alot for that info! Yes its an 85. That explains why there isnt much to port.
Ill just even things out and keep the 2 holes going.
Thanks to all for the help!
