Removing Bottom of TB Column

[The Crunge II]

Is removing the bottom portion of the TB/MAF sensor column worth it for an L36?

[mylittleblackbird]

I would strongly advise against altering the MAF metering area. It will give you fits to no end as the calibration will no longer be correct, and I don't believe many if any people would be able to tune for it.

If you would like to modify your throttlebody, do so past the post, not at or before.

Another option would be to install an 96 L67 throttle body. It retains the vacuum line for your trans modulator.

Or you can get a 97-99 L67 throttle body, remove the freeze plug that blocks the vacuum port, install a nipple and run from that.

You will need to have your PCM modified to recognize the L67 MAF frequencies instead of the L36, if you choose that route.

[willwren]

I did it. TWICE. Bad results both times. Shave a flat on each side of the throttle shaft to decrease cross-sectional area, and clean up the bore a bit. Don't muck with the MAF support or the area where the throttle plate seals.

[95naSTA]

I wouldn't bother with the L36 TB.
This is what I did to a 99+ L67 TB a while back. The L67 TBs aren't bolt up and go as shown below.

You have to fill inthe coolant ports with jb weld or some other epoxy. Then make a template ftom the UIM and port the rear of the TB to match the UIM. Then drill the bolt holes on the L67 TB down so you can move the up TB to line it up with the UIM.
Now the pics:
ported and jb welded:

Rough:

Polished:


Comparison to my old TB:

Now to show you what I'm talking about whne you have to drill out the bolt holes down...
Here is how it would sit if you don't:

There is a step up to the UIM
But, drilled out it looks like:



Tou can p&p the front too:

I drilled out where the second vac port would be and added one since I have a 4t60-e too.

If you do modify the area around the MAF sensor, you will need to recalibrate it via tuning.

[SuperSLE]

Whoa, that's a heck of a port job there . I know a couple of guys running ported L36 TB, and have no issues, but I think it is like skating on thin ice. You might get away with it, but who knows for how long. I have ported out a couple of L67 TB that work great but not as extensive as the photos above. So that might be an option, but I don't think I would mess with one unless you have one sitting around for fun just to try out.