|
Ported Throttle Body
I currently have a polished throttle body on my Monte, but I've never been satisfied with that giant lump of metal obstructing a good amount of airflow. So, since the parts car wont be needing its throttle body anymore, I ported that one. I used tiny carbide burrs on a dremel to remove the boss that the MAF sticks through. I knew that I'd break through the top of the TB. So before hand, I bought some J-B Weld steel stick putty. I pushed that through the two holes in the top, and covered most of the top to reinforce it. I also used that putty to fill in some of the unnecessary holes inside the TB. The MAF sensor seals against the boss that I removed with an O ring. I didn't know for sure, but I figured it did. So I'll be laying down some gasket maker under the MAF sensor before I put this TB back into service. I also don't use the throttle body screen, so I widened the inlet of the TB as well. As for the backside, I blended the sides a small bit, but not near as much as ZZP does for their high velocity TB. What do you guys think?
https://cimg0.ibsrv.net/gimg/monteca...c89ea58932.jpg https://cimg3.ibsrv.net/gimg/monteca...4e49480184.jpg https://cimg7.ibsrv.net/gimg/monteca...5f30b7f9ec.jpg https://cimg5.ibsrv.net/gimg/monteca...5ae20bf4fb.jpg https://cimg1.ibsrv.net/gimg/monteca...21cad3b398.jpg https://cimg0.ibsrv.net/gimg/monteca...ec207fbddb.jpg https://cimg0.ibsrv.net/gimg/monteca...94f2cc763a.jpg https://cimg1.ibsrv.net/gimg/monteca...dcbb08c149.jpg |
The work looks nicely done, but IMO the focus was in the wrong places if better flow is the goal.
-Mirror polishing isnt impactful over a smooth cast surface. -The hump isnt there to reduce power, it's to control airflow during low speed drivability. Theres a reason most professional port shops leave them on the GM TBs that have them. -The MAF screen has a pretty important purpose, I'm not sure why youd delete it permanently. The tiny flow increase from removing it isnt worth the downsides. -The #1-driver for flow - the blade area, looks completely untouched. A bigger blade / modded shaft will give you the majority of the flow gains to be had with a ported TB. Given the mod plans you've talked about in the past though, I am curious- why spend time on the TB at all at this point? Since the turbo will be responsible for almost all of the power gain, I wonder why not focus on getting that going first vs the 'drop in the bucket' kind of stuff like this that can be easily changed later. |
Originally Posted by bumpin96monte
(Post 720028)
The work looks nicely done, but IMO the focus was in the wrong places if better flow is the goal.
-Mirror polishing isnt impactful over a smooth cast surface. -The hump isnt there to reduce power, it's to control airflow during low speed drivability. Theres a reason most professional port shops leave them on the GM TBs that have them. -The MAF screen has a pretty important purpose, I'm not sure why youd delete it permanently. The tiny flow increase from removing it isnt worth the downsides. -The #1-driver for flow - the blade area, looks completely untouched. A bigger blade / modded shaft will give you the majority of the flow gains to be had with a ported TB. As for the hump being for low speed drivability, is there any evidence to support that? I'm not trying to say you're wrong, I just can't see how that's the case. To me it looks like its only purpose is to seal the MAF sensor. I've read that the MAF screens purpose is just to straighten the airflow to the MAF sensor for better idle and fueling. Since I'll be boosting the engine, I opted to delete it, while leaving the MAF for tuning in conjunctiion with a 2 bar MAP. I worked on this inbetween waiting for things. Like a mount to cool after welding, and in between paint coats. I'm starting on the engine/trans mounts today. As for why I even bothered to spend time on the throttle body. That goes back to my philosophy of improving everything I can. Even if the engine is turbocharged, an airflow restriction is still an airflow restriction. |
So there are a couple of things. First, Bumpin' is right that the shape of that "hump" is to control air flow to some degree. But tuning can compensate, not a big deal in the end. But, I would opt for a method that avoids compromising so much of the throttle body requiring JB Weld filler. You have some options. One is use a 97-99 throttle body. Instead of the "hump" you have a post. Plus the MAF for the 97-99 (and there might be other years included) is made for a different MAF, so some rework on the opening for the MAF has to be done. I adapted the L67 Throttlebody to the L36, following what another person did. Here's my web page on that (lots of info):
'04 Monte Carlo SS - L67 Throttle Body I would honestly make this a bit easier on yourself. Get a L26 UIM (the aluminum one and GM has two different styles of these, tiny differences) and adapt an L67 throttle body to it. I did that years later. Which caused me to start my throttle body project over from a new donor piece. https://montecarloforum.com/forum/fw...c-heavy-48949/ Some JB Weld was required (for the L36 plastic UIM, it was to help match the mating surfaces and in the L26 it was to fill in holes no longer needed). But never to re-pair a punch through. When I did the one to match to the L26 UIM, I went over board on the inside and punched through. I junked that one and started over. On my 3800 stuff, I really did not go into much about half shafting. But, on the 3400 throttle body (happened to be for my Grand Am), I did a little write up (because the Monte also has the 3400). But in the L67 throttle body on the L26 UIM, I did half shaft it. https://montecarloforum.com/forum/fw...hafting-56966/ |
Originally Posted by The_Maniac
(Post 720044)
So there are a couple of things. First, Bumpin' is right that the shape of that "hump" is to control air flow to some degree. But tuning can compensate, not a big deal in the end. But, I would opt for a method that avoids compromising so much of the throttle body requiring JB Weld filler. You have some options. One is use a 97-99 throttle body. Instead of the "hump" you have a post. Plus the MAF for the 97-99 (and there might be other years included) is made for a different MAF, so some rework on the opening for the MAF has to be done. I adapted the L67 Throttlebody to the L36, following what another person did. Here's my web page on that (lots of info):
'04 Monte Carlo SS - L67 Throttle Body I would honestly make this a bit easier on yourself. Get a L26 UIM (the aluminum one and GM has two different styles of these, tiny differences) and adapt an L67 throttle body to it. I did that years later. Which caused me to start my throttle body project over from a new donor piece. https://montecarloforum.com/forum/fw...c-heavy-48949/ Some JB Weld was required (for the L36 plastic UIM, it was to help match the mating surfaces and in the L26 it was to fill in holes no longer needed). But never to re-pair a punch through. When I did the one to match to the L26 UIM, I went over board on the inside and punched through. I junked that one and started over. On my 3800 stuff, I really did not go into much about half shafting. But, on the 3400 throttle body (happened to be for my Grand Am), I did a little write up (because the Monte also has the 3400). But in the L67 throttle body on the L26 UIM, I did half shaft it. https://montecarloforum.com/forum/fw...hafting-56966/ I'm not that concerned about the throttle body failing under boost. It wont be put into service for quite a while, and I could get around to presure testing it if I find the time. |
L26 UIM works fine with the factory L36 fuel rail. You do need to address a vacuum line that originally attaches to the throttle body. I followed what a Bonneville guy did, drill and tap the snout of the L26 UIM, so I can retain the factory lines the way they are. Item #2, the PCV. My link explains how I solved it (I am pleases with it). There are a couple other ways to solve it, but I feel the way I did it is the easiest and almost looks factory.
As for the catch can, I am sure you can. This is the best explanation I have found yet about catch cans on the 3800: The PCV Thread |
| All times are GMT -5. The time now is 07:24 AM. |
© 2026 MH Sub I, LLC dba Internet Brands