cudaeh
02-26-2007, 05:38 PM
http://i129.photobucket.com/albums/p204/cudaeh/subaru/TB002.jpg
I got to looking at the similarities between the GM LS1 throttle body and the 2000 Subaru 2.5rs one. The conclusion I came to is that they have the same type of sensors and the LS1 is a whole heck of a lot bigger. After taking a look at it I have come to 3 conclusions.
1: the idle air control valve for the ls1 has a bigger valve head, but the exact same throw and mounting as the 2.5RS one.
Solution to 1: I am going to find or make a washer with the same inner diameter as the 2.5rs port but with the outer diameter of the LS1. This way I can just press it in and call it a day.
http://i129.photobucket.com/albums/p204/cudaeh/subaru/TB005.jpg
http://i129.photobucket.com/albums/p204/cudaeh/subaru/TB004.jpg
2: The throttle positioning sensor on the LS1 is a key style where as the 2.5RS is a bar style (see pics for clarification).
Solution to 2: Luckily because of the difference the LS1 shaft is longer and protruding from the mount surface of the TB. This will allow me to make an adaptor plate and punch a hole in the shaft to accommodate the bar.
http://i129.photobucket.com/albums/p204/cudaeh/subaru/TB003.jpg
3: the LS1 TB is way bigger than the 2.5RS and has a different bolt pattern to it.
Solution to 3: Easy, I am using the WRX intake manifold which has a mostly a flat mounting surface. All I have to do is mill down the old mount surface, blend and smooth it into the manifold face, punch the new TB hole, and the new screw holes.
http://i129.photobucket.com/albums/p204/cudaeh/subaru/wrxmanafold001.jpg
I got to looking at the similarities between the GM LS1 throttle body and the 2000 Subaru 2.5rs one. The conclusion I came to is that they have the same type of sensors and the LS1 is a whole heck of a lot bigger. After taking a look at it I have come to 3 conclusions.
1: the idle air control valve for the ls1 has a bigger valve head, but the exact same throw and mounting as the 2.5RS one.
Solution to 1: I am going to find or make a washer with the same inner diameter as the 2.5rs port but with the outer diameter of the LS1. This way I can just press it in and call it a day.
http://i129.photobucket.com/albums/p204/cudaeh/subaru/TB005.jpg
http://i129.photobucket.com/albums/p204/cudaeh/subaru/TB004.jpg
2: The throttle positioning sensor on the LS1 is a key style where as the 2.5RS is a bar style (see pics for clarification).
Solution to 2: Luckily because of the difference the LS1 shaft is longer and protruding from the mount surface of the TB. This will allow me to make an adaptor plate and punch a hole in the shaft to accommodate the bar.
http://i129.photobucket.com/albums/p204/cudaeh/subaru/TB003.jpg
3: the LS1 TB is way bigger than the 2.5RS and has a different bolt pattern to it.
Solution to 3: Easy, I am using the WRX intake manifold which has a mostly a flat mounting surface. All I have to do is mill down the old mount surface, blend and smooth it into the manifold face, punch the new TB hole, and the new screw holes.
http://i129.photobucket.com/albums/p204/cudaeh/subaru/wrxmanafold001.jpg