Follow Up to L36 to L26 UIM mod

[GT in Kennesaw]

This is a follow up to my post Questions about swapping a L36 plastic UIM to L26 alloy. I've gone through 4 different plumbing configurations for the PCV air inlet (on top left of UIM). The first one was a total bust, didn't work correctly. The second one worked briefly but the parts I used split or leaked air. The third configuration worked perfectly, but I didn't like how it looked. The fourth and final one, works perfectly and looks great.

This is the original setup. Do not repeat this mistake.

This was the second attempt. I used plastic tubing and fuel line for the vacuum tubing. For whatever reason, real vacuum tubing cannot be found in the Atlanta area.

This was the third attempt. I ordered an expensive silicone vacuum elbow and some HPS High Temp Silicone vacuum tubing. It worked great. I just didn't like the look.

And finally, I ordered the stock L26 vacuum tube that would have been on a Series III engine. GM part #12596451.

I cut the off the end that goes into the intake tube grommet.

And in place. The "bumps" that are left on the cut off end makes a perfect barb end for the vacuum tube. Only 2 parts required, no clamps. Nice and clean looking— like a factory setup (my goal).

I'm finally completely happy with my new setup. However, I neither recommend or discourage this mod. I don't believe it adds anything to the power, mid-range throttle response is pretty good (maybe no more than just cleaning the throttle body would get you), has a bit raspier sound (metal vs. plastic?) and didn't seem to effect the fuel mileage.

 

[pshojo]

I hooked the hose from the top of the Intake manifold to the nipple coming out of the Throttle body. so the vacuum comes out of the thrrottle body, splits to the fuel regulator, the trans modulator, and the same top port on the manifold. Is that not correct?. Looks like you have yours hooked up to evap system.

 

[GT in Kennesaw]

My GT is an 01 and doesn't have a nipple for the trans modulator. I do have a vacuum connector for the FPR and EVAP solenoid, but I didn't use that one. I basically used the same throttle body port that the original setup used. But that required drilling out the plug in the bottom of the throttle and putting a elbow there.

The tube goes under the throttle body and connects there.

Your setup is probably correct also. It seems that as long as you're taking vacuum between the MAF sensor and the throttle plate, you should be fine.

 

[pshojo]

Here is my set up. I noticed the vacuum hose going from TB to UIM is sucked closed. I'm Running L26 with S/C TB connected to 4t60e.

 

[BillBoost37]

Not sure exactly what you hooked to in the 2-4th setups. But the correct placement is after maf and before throttle plate.

http://www.grandprixforums.net/how-get-pcv-work-instead-valve-cover-breather-44478.html

 

[pshojo]

I used the same port that feeds fuel pressure and Trans modulator. Wonder if I have those hooked up right.

 

[pshojo]

I don't know if its before fly plates. But it is 1998 s/c TB with no mods. On some I see two nipples coming out, this one only had one and appears in junk yard it's same vacuum that feeds fuel pressure and evap.

 

[TimMcCallum]

So for this I have a tapped throttle body adapter. Do I have to still hook my stuff up to that stock evap tube that hangs over by the booster? And what do I do with the purge it comes with that bolts to the intake.
I need help asap