DIY: 82mm throttle bodies
08-23-2017, 11:09 AM
#1
MBWorld Fanatic!
Thread Starter
DIY: 82mm throttle bodies
This all started out with my engine stalling problem so I decided to check my air filters. At the end of the evening I have the intake manifold off the car and apart on my garage floor.
The inside of the intake manifold is absolutely disgusting. It's covered with oil and gunk. All eight intake ports and injectors are also covered in gunk. The lower intake manifold is covered with a thin charcoal film (my car is 150k miles and still have the charcoal filters).
Anyway, I have some spare 82mm throttle bodies from my E55 days so I want to see if I can make them work.
-All the electronic and hoses plugged in fine.
-The 82mm are physically bigger but they still fit in the stock 74mm holes with some minor trimming.
-The ports on the bottom of the 82mm are longer so that will also need to be trimmed so the hose can be fitted.
-The bolt pattern are also different so that will need to be re-drilled. Make sure the 82mm throttle bodies are flat on the mounting surface when you drill. Of course the stock bolts will no longer work so you'll have to get new hardware to make them work.
-After you bolts the 82mm throttle bodies up and happy with the way they seat, flip everything over and start open up the stock 74mm holes to match the 82mm.
-Clean up and bolt everything together and that's it.
The intake manifold is made of some very soft material, so be careful when you drill. I did all this with a dremel and a hand drill. The whole process was rather easy, but it's an irreversible process so proceed with caution.
The inside of the intake manifold is absolutely disgusting. It's covered with oil and gunk. All eight intake ports and injectors are also covered in gunk. The lower intake manifold is covered with a thin charcoal film (my car is 150k miles and still have the charcoal filters).
Anyway, I have some spare 82mm throttle bodies from my E55 days so I want to see if I can make them work.
-All the electronic and hoses plugged in fine.
-The 82mm are physically bigger but they still fit in the stock 74mm holes with some minor trimming.
-The ports on the bottom of the 82mm are longer so that will also need to be trimmed so the hose can be fitted.
-The bolt pattern are also different so that will need to be re-drilled. Make sure the 82mm throttle bodies are flat on the mounting surface when you drill. Of course the stock bolts will no longer work so you'll have to get new hardware to make them work.
-After you bolts the 82mm throttle bodies up and happy with the way they seat, flip everything over and start open up the stock 74mm holes to match the 82mm.
-Clean up and bolt everything together and that's it.
The intake manifold is made of some very soft material, so be careful when you drill. I did all this with a dremel and a hand drill. The whole process was rather easy, but it's an irreversible process so proceed with caution.
08-23-2017, 11:17 AM
#2
MBWorld Fanatic!
Thread Starter
Intake port
https://i.imgur.com/nfYXJZc.jpg
Intake manifold apart
https://i.imgur.com/vCYotNB.jpg
Lower intake manifold soaked in oil, no good
https://i.imgur.com/FGI3z1X.jpg
82mm in
https://i.imgur.com/m6SL57m.jpg
https://i.imgur.com/KDGcJdU.jpg
https://i.imgur.com/nfYXJZc.jpg
Intake manifold apart
https://i.imgur.com/vCYotNB.jpg
Lower intake manifold soaked in oil, no good
https://i.imgur.com/FGI3z1X.jpg
82mm in
https://i.imgur.com/m6SL57m.jpg
https://i.imgur.com/KDGcJdU.jpg
08-23-2017, 11:48 AM
#3
MBWorld Fanatic!
RTV to seal the mounting surface?
Mine was very difficult to seal via this method, but your way seems tidy nevertheless. Nice work
Out of curiosity....what's your idle vacuum and ign timing? Can you please let me know?
Mine was very difficult to seal via this method, but your way seems tidy nevertheless. Nice work
Out of curiosity....what's your idle vacuum and ign timing? Can you please let me know?
The following 2 users liked this post by Adi-Benz:
cls55 (08-25-2017),
Forrest Gump 9 (08-23-2017)
08-23-2017, 09:16 PM
#5
MBWorld Fanatic!
Thread Starter
My idle vacuum is -8.8 psi and ignition varies from -1 to 5
08-25-2017, 07:42 PM
#7
MBWorld Fanatic!
Thanks guys. Mine with the big TBs is 13-15 whereas it used to be 17-18 (at idle). My timing is also at -7 to -9....definitely a vac leak of some sort, just not a huge one.
I'll take it to a shop soon if I can't make progress.
