Mod Guide: L26 UIM/L67 Throttle Body Swap Guide (Pic Heavy)
#21
06-02-2014, 11:03 AM
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,153
Yeah I had to change my pic, and the l26 uim just looks cool 
So far it's running great. It will be some time before I have any mpg data.
So far it's running great. It will be some time before I have any mpg data.
#23
06-02-2014, 09:49 PM
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,153
Thanks MAMONTE and NightHawk.
I wanted to share this build as I did it, but for the longest time my progress was disgustingly slow due to other things going on at home. So, this became one massive write up of start to finish.
I wanted to share this build as I did it, but for the longest time my progress was disgustingly slow due to other things going on at home. So, this became one massive write up of start to finish.
#25
06-03-2014, 12:47 PM
So Jason:
When do we get started on mine?
Looking Great!
Nicely done on the tech side as well
Lots of love and labor in exchange for a highly appreciated effort!
I gotta say...
That's one hell ova a nice job!
When do we get started on mine?
Looking Great!
Nicely done on the tech side as well
Lots of love and labor in exchange for a highly appreciated effort!
I gotta say...
That's one hell ova a nice job!
#26
07-12-2014, 07:03 PM
And here is a final test fit of the UIM with the adapter, throttle body and the brass fittings. So far, looking good!
Next I disassembled everything, removed the brass fittings and masked off what I did not want hit with high temp clear coat and went to town. These parts have a crazy amount of clear coat on them.
Once I finished, I put the brass fittings in, but added a dab of red Loc-Tite to help hold them in.
When I put everything together, the new UIM gasket had a piece I did not care for. This piece of plastic was going to stick out. So, I removed it.
The last "mod" was the throttle body gasket. I trimmed excess material that was going to stick out and be seen over the adapter plate. Also, I trimmed where the air flow passes through (as the gasket actually obstructs the air flow)!
Next I disassembled everything, removed the brass fittings and masked off what I did not want hit with high temp clear coat and went to town. These parts have a crazy amount of clear coat on them.
Once I finished, I put the brass fittings in, but added a dab of red Loc-Tite to help hold them in.
When I put everything together, the new UIM gasket had a piece I did not care for. This piece of plastic was going to stick out. So, I removed it.
The last "mod" was the throttle body gasket. I trimmed excess material that was going to stick out and be seen over the adapter plate. Also, I trimmed where the air flow passes through (as the gasket actually obstructs the air flow)!
#27
07-13-2014, 01:08 AM
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,153
Keep in mind, I did not go chrome or even polished, my L26 aluminum UIM has a bit of a "brushed" look to it. Something I feel is a bit more unique and looks just as classy
The intake and L67 throttle bodies are pretty cheap to pick up (either a you pull it style junk yard, which is where the throttle body came from or eBay which is where the L26 UIMs came from). But the clean up, custom porting and prep work took HOURS of work. I can't begin to tell you how much time is invested in that setup, but I'm very happy how it turned out. And hopefully this thread helps anyone else looking to do a L26 swap mod.
#29
08-25-2014, 12:04 AM
Thanks man
Keep in mind, I did not go chrome or even polished, my L26 aluminum UIM has a bit of a "brushed" look to it. Something I feel is a bit more unique and looks just as classy
The intake and L67 throttle bodies are pretty cheap to pick up (either a you pull it style junk yard, which is where the throttle body came from or eBay which is where the L26 UIMs came from). But the clean up, custom porting and prep work took HOURS of work. I can't begin to tell you how much time is invested in that setup, but I'm very happy how it turned out. And hopefully this thread helps anyone else looking to do a L26 swap mod.
Keep in mind, I did not go chrome or even polished, my L26 aluminum UIM has a bit of a "brushed" look to it. Something I feel is a bit more unique and looks just as classy
The intake and L67 throttle bodies are pretty cheap to pick up (either a you pull it style junk yard, which is where the throttle body came from or eBay which is where the L26 UIMs came from). But the clean up, custom porting and prep work took HOURS of work. I can't begin to tell you how much time is invested in that setup, but I'm very happy how it turned out. And hopefully this thread helps anyone else looking to do a L26 swap mod.
and actually ZZPerformance sells used L26 UIM under "Used" on they're sight so it'll either be from there or ebay! And getting an old l67 sounds way better than paying a ton of money for a so-called "High-Velocity" throttle body from zzp. I didn't know l36 and l67 TB's are interchangeable with just an adapter adapter plate! Which also seems to function as Throttle Body Spacer! To be completely honest, i might just copy your custom porting ideas to a T lol except my UIM and TB are gonna be a higher polished look. Kinda like the finish on zippy02's UIM and the adapter plate ill prolly have be blue maybe, or chrome. Sorry I'm just responding to you now I'm coming back to this thread because I've been reading horror stories about warped UIMs and leaky UIM gaskets and busted coolant elbows so i had the idea that id make my next mod a UIM swap with new gaskets, maybe even lower intake gaskets while everything is apart, and replace the coolant elbows with ZZP's aluminum ones so that i prevent any future coolant problems with it getting into the oil! Figured it would be the "smartest" mod i could do considering UIM issues seem to be inevitable in the 3800's. And i drive mine pretty hard sometimes, but theres something I've always done that people call me stupid and make fun of me for, and thats whenever I'm driving, i just put my windows down, turn my vents away from me, and turn the heat on full blast like u would if u were overheating. I know thats not necessary by any means, but Ik my car, and she always feels to run better when shes cooler! So i like to keep the engine bay temp as low as i can and in all honesty, i think its beneficiary if my car doesn't get as hot as fast in the summer. If i can keep my engine cool without coolant running through it, why wouldn't i? Seems like its hard to have coolant problems if its not used a ton, plus the warping of the manifold is caused by hot temps obviously so theres something else i could be slowing the deterioration of! But anyway with that in mind and wanting ti save myself while also adding some looks and performance, i wanna replaced all the intake manifold gaskets and the UIM, so while everything is off the car, imma use a L26 UIM, put in an HV3 Intake insert, replace the subpar coolant elbows with some nice fail-proof aluminum ones, and with your ideas, drastically improve the function and performance and looks of my throttle body. So imma start saving up and imma use your wright-up to guide my next major mod. After this it will be a ZZP Cold Air Intake to make use of that perfect airflow path that you've shown here. Have you noticed any positive affects with this mod? Acceleration? Responsiveness? Idle? Sound? (I love the sound of air being sucked into the engine so if its loud then id love that, i gotta imagine this allows the air to flow so much faster and plentiful). I also wanna try and figure out something to do with all that ugly wiring that sits in front of our UIMs if theres a way to group it together better or dress it up er hid er reroute some of it er something. Sorry for the long response lol.
#30
08-25-2014, 05:42 AM
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,153
Glad to read this right up is of value for you and I have zero issues with anyone wanting to mimic what I did.
As for performance gains, bear in mind, I did this 90%+ for looks and a little % for security that the aluminum will never crack or damage like the old plastic. Despite that, I do feel the car is a bit "peppier" then it was. It just "feels" better. But I have no proof to the claim, it's just my perception (and some may claim it's a the placebo effect). I'm currently working on re-tuning the car my self by street tuning it (which is another learning experience).
As for the plastic UIM warping, I believe that is an extremely rare situation (and probably a sign that the UIM was improperly torqued down). The plastic L36 UIM is more likely to explode due to issues with a failed fuel pressure regulator or have EGR stove pipe and the coolant erode the coolant passages that feed the throttle body (spraying coolant into the intake). I never had the happen, but helped someone who did and read a good amount of people on the Internet that had this happen. The plastic UIM was a bad idea, it's eventually going to get brittle and fail. And I agree, while you are changing the UIM (or any reason to have it off), replace the LIM gaskets with the Fel Pro aluminum backed gaskets.
As for the throttle bodies of an L36 and L67. They are interchangeable even with the L36 UIM. I was running one for a while but I did a lot of work to make it blend in the same manner as the L36. Here's a link to my info about that project on my web site: '04 Monte Carlo SS - L67 Throttle Body. One thing I don't think I have on the web site, I had to oblong the 3 mounting holes (otherwise the L67 throttle body hangs a little low and does not line up right). You could use an L36 throttle body on this mod (a member Frank put an entire L26 engine in his Monte to replace a failed L36). But I was already running an L67 throttle body (as an inexpensive alternative to the ZZP High Velocity Throttle Body). Keep in mind, as I understand, porting the inlet of the throttle body as I did requires re-tuning of the MAF because you have changed the MAF readings. And if you check the link about my first L67 ported throttle body, I do mention, there are two different generations of the throttle body.
As for the adapter plate between the UIM and the throttle body, some type of adapter is a must (unless you can weld aluminum). I wish it did not need the adapter, as the snout on the L26 UIM is already longer then the snout on the L36 (which makes mating the air duct for the CAI more challenging the longer the throttle body is pushed out). But there really is no good way around it. I had one idea, but I did not like it, so I did not even attempt it.
If you are going to go through all this AND change the LIM gaskets, you may want to fab a port matched LIM (and expand the coolant bypass on it). Here's info on the LIM in my car now (been in since 2011, with a host of other mods that went in at the same time):
'04 Monte Carlo SS - Port Matched LIM
And the ZZP aluminum coolant elbows. It's just a guess, but I am betting those are just Dorman aluminum elbows you can buy at any local parts store these days (ZZP just takes them out of the blister pack). I am still running plastic elbows I replaced a couple years ago (and then had to replace with genuine GM a year later), pre-dating any of the aluminum elbows.
As for performance gains, bear in mind, I did this 90%+ for looks and a little % for security that the aluminum will never crack or damage like the old plastic. Despite that, I do feel the car is a bit "peppier" then it was. It just "feels" better. But I have no proof to the claim, it's just my perception (and some may claim it's a the placebo effect). I'm currently working on re-tuning the car my self by street tuning it (which is another learning experience).
As for the plastic UIM warping, I believe that is an extremely rare situation (and probably a sign that the UIM was improperly torqued down). The plastic L36 UIM is more likely to explode due to issues with a failed fuel pressure regulator or have EGR stove pipe and the coolant erode the coolant passages that feed the throttle body (spraying coolant into the intake). I never had the happen, but helped someone who did and read a good amount of people on the Internet that had this happen. The plastic UIM was a bad idea, it's eventually going to get brittle and fail. And I agree, while you are changing the UIM (or any reason to have it off), replace the LIM gaskets with the Fel Pro aluminum backed gaskets.
As for the throttle bodies of an L36 and L67. They are interchangeable even with the L36 UIM. I was running one for a while but I did a lot of work to make it blend in the same manner as the L36. Here's a link to my info about that project on my web site: '04 Monte Carlo SS - L67 Throttle Body. One thing I don't think I have on the web site, I had to oblong the 3 mounting holes (otherwise the L67 throttle body hangs a little low and does not line up right). You could use an L36 throttle body on this mod (a member Frank put an entire L26 engine in his Monte to replace a failed L36). But I was already running an L67 throttle body (as an inexpensive alternative to the ZZP High Velocity Throttle Body). Keep in mind, as I understand, porting the inlet of the throttle body as I did requires re-tuning of the MAF because you have changed the MAF readings. And if you check the link about my first L67 ported throttle body, I do mention, there are two different generations of the throttle body.
As for the adapter plate between the UIM and the throttle body, some type of adapter is a must (unless you can weld aluminum). I wish it did not need the adapter, as the snout on the L26 UIM is already longer then the snout on the L36 (which makes mating the air duct for the CAI more challenging the longer the throttle body is pushed out). But there really is no good way around it. I had one idea, but I did not like it, so I did not even attempt it.
If you are going to go through all this AND change the LIM gaskets, you may want to fab a port matched LIM (and expand the coolant bypass on it). Here's info on the LIM in my car now (been in since 2011, with a host of other mods that went in at the same time):
'04 Monte Carlo SS - Port Matched LIM
And the ZZP aluminum coolant elbows. It's just a guess, but I am betting those are just Dorman aluminum elbows you can buy at any local parts store these days (ZZP just takes them out of the blister pack). I am still running plastic elbows I replaced a couple years ago (and then had to replace with genuine GM a year later), pre-dating any of the aluminum elbows.
