Hey everyone, I've had a few people ask me how I went about modifying my stock throttle body so I decided to do a how to on it.
If this is your first time doing something like this it's really pretty simple so relax. I've done a few of these types of projects ranging from TB's to cylinder heads and it's fun, but time consuming.
What you need:
-Throttle Body assembly
-Dremel Rotary style tool or Die Grinder
-drum sanding attachments, flap wheels, finish-abrasive buff, polishing wheels/cones, polishing compound.
-compressed air and/or a shop-vac
-TB cleaner
-optional: dial caliper to keep track of your progress (really not needed)
I picked up a spare TB from a local salvage yard for $70. I started out removing the TPS and the AIS motor that came with the unit. Now would be a good time to mark the Throttle shaft where it comes through the body and into the throttle port. This is going to be used later when cutting the shaft.
Remove the two torx screws that hold the blade in place. Open the the throttle and pull/push the blade out and set it aside. Now you have to remove the snap-ring that holds the throttle shaft in place. It's where you just removed the TPS from. Snap ring pliers are nice here, I'm used to using automotive picks by now (they're magnetized, so it's nice to have that peace of mind, just in case you slip)
Now you can remove the throttle shaft assembley, along with the return-spring.
Looking at the bare throttle body you can see that it chokes down just inside the opening, then opens back up just before the blade. The idea here is to open this all up, within reason. You can go as far as you want, but DO NOT remove any material where the blade sits.
I placed the body in a vice and used a Dremel with drum sanding attachments to remove most of the material. Before doing so I packed the shaft bearings with grease, so as to not get shavings/dust in them. I started with 60 grit and went to 120 grit. Some people will use a die-grinder, but I don't really feel that it's necessary. The aluminum is so soft that you don't really need much torque. When grinding I usually have a shop-vac running next to my work, to keep the aluminum dust out of the air.
GO SLOW. Just take your time and work the port open little by little. After I was done with the 120 grit, I went to flap wheel and then to a finish-abrasive buff, and finally to a polishing cone with some polishing compound/sealer.
As you can see I left a slight bevel at the bottom of the port, just before the blade, hoping to keep some low speed port velocity.
For the throttle shaft, I used a hack saw and very slowly and carefully cut the shaft, half way through, at my marks. Be carefull not to bend the throttle shaft when you're cutting it. Test fit it with the blade in place and the screws in it. Trim it if necessary.
The blade is a little more tricky. You really don't have to do this part of it. I did because I had the tools to do it and have done it before.
I placed a piece of tape over the holes in the blade. Then, using a properly sized suction cup (can be found at body repair shops, and cups for valve lapping are normally too small), I worked the blade on a belt sander with a very fine belt. I did very little to this blade, just really touched it up and smoothed it out. It started out at around 63 thousandths and ended up around 53 thousandths.
Now, clean the TB good with cleaner and compressed air. Remove the grease from the bearings and then lightly re-grease them. Re-assemble the rest of the TB (don't forget the snap-ring), and install it.
I hope I didn't forget anything, and I'm sorry I didn't have more pictures. Please ask questions or give extra information if you have it.
If this is your first time doing something like this it's really pretty simple so relax. I've done a few of these types of projects ranging from TB's to cylinder heads and it's fun, but time consuming.
What you need:
-Throttle Body assembly
-Dremel Rotary style tool or Die Grinder
-drum sanding attachments, flap wheels, finish-abrasive buff, polishing wheels/cones, polishing compound.
-compressed air and/or a shop-vac
-TB cleaner
-optional: dial caliper to keep track of your progress (really not needed)
I picked up a spare TB from a local salvage yard for $70. I started out removing the TPS and the AIS motor that came with the unit. Now would be a good time to mark the Throttle shaft where it comes through the body and into the throttle port. This is going to be used later when cutting the shaft.
You must be registered for see images attach
Remove the two torx screws that hold the blade in place. Open the the throttle and pull/push the blade out and set it aside. Now you have to remove the snap-ring that holds the throttle shaft in place. It's where you just removed the TPS from. Snap ring pliers are nice here, I'm used to using automotive picks by now (they're magnetized, so it's nice to have that peace of mind, just in case you slip)
You must be registered for see images attach
Now you can remove the throttle shaft assembley, along with the return-spring.
Looking at the bare throttle body you can see that it chokes down just inside the opening, then opens back up just before the blade. The idea here is to open this all up, within reason. You can go as far as you want, but DO NOT remove any material where the blade sits.
You must be registered for see images attach
I placed the body in a vice and used a Dremel with drum sanding attachments to remove most of the material. Before doing so I packed the shaft bearings with grease, so as to not get shavings/dust in them. I started with 60 grit and went to 120 grit. Some people will use a die-grinder, but I don't really feel that it's necessary. The aluminum is so soft that you don't really need much torque. When grinding I usually have a shop-vac running next to my work, to keep the aluminum dust out of the air.
GO SLOW. Just take your time and work the port open little by little. After I was done with the 120 grit, I went to flap wheel and then to a finish-abrasive buff, and finally to a polishing cone with some polishing compound/sealer.
You must be registered for see images attach
As you can see I left a slight bevel at the bottom of the port, just before the blade, hoping to keep some low speed port velocity.
For the throttle shaft, I used a hack saw and very slowly and carefully cut the shaft, half way through, at my marks. Be carefull not to bend the throttle shaft when you're cutting it. Test fit it with the blade in place and the screws in it. Trim it if necessary.
The blade is a little more tricky. You really don't have to do this part of it. I did because I had the tools to do it and have done it before.
I placed a piece of tape over the holes in the blade. Then, using a properly sized suction cup (can be found at body repair shops, and cups for valve lapping are normally too small), I worked the blade on a belt sander with a very fine belt. I did very little to this blade, just really touched it up and smoothed it out. It started out at around 63 thousandths and ended up around 53 thousandths.
Now, clean the TB good with cleaner and compressed air. Remove the grease from the bearings and then lightly re-grease them. Re-assemble the rest of the TB (don't forget the snap-ring), and install it.
You must be registered for see images attach
I hope I didn't forget anything, and I'm sorry I didn't have more pictures. Please ask questions or give extra information if you have it.
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