September issue of GMHTP 3.8 Throttle body/ MAF and underdrive pulley upgrades

[John_D.]

<blockquote>quote:</font><hr>Originally posted by jonny985:
All you need to do is replace it with a 99+? Why would that make a difference?<hr></blockquote>

The 98 and down is made to sit inside a post that directs additional air over the sensor.

The 99+ is made to go in a tb that has no post, and has the additional plastic to direct the correct amount of air over the sensor.

It does have only 2 bolts, which did mate up to my '98.

If you port out the top half of the post, be very careful not to take that ridge off the top-front, because the corners of it will penetrate the tb housing when you try to take them down. (jb weld is holding up for now, but may not hold up to boost when the time comes...)

[pgriffith]

Mangus, Hook me up with a ported TB. Do the '99 TB's sit streight? Really I want one.

[TheBlackSwordsMan]

<blockquote>quote:</font><hr>Originally posted by pgriffith:
Mangus, Hook me up with a ported TB. Do the '99 TB's sit streight? Really I want one.<hr></blockquote>


it sits straight 99+

[Magnus]

I'll port 97-98 TB's for $250. That includes the cost of a new sensor. Thats about how much my time is worth right now.

I pretty much remove the post and smooth it out, widen out the hole on top and put in the new sensor. I don't touch the butterfly area at all.

[supersixjohn]

<blockquote>quote:</font><hr>Originally posted by John_D.:


The 98 and down is made to sit inside a post that directs additional air over the sensor.

The 99+ is made to go in a tb that has no post, and has the additional plastic to direct the correct amount of air over the sensor.

It does have only 2 bolts, which did mate up to my '98.

If you port out the top half of the post, be very careful not to take that ridge off the top-front, because the corners of it will penetrate the tb housing when you try to take them down. (jb weld is holding up for now, but may not hold up to boost when the time comes...)<hr></blockquote>

Can you post some pics? I have a dremel. It doesn't sound too bad. I think GM parts direct has the MAF sensors for around $100.

[John_D.]

<blockquote>quote:</font><hr>Originally posted by supersixjohn:
Can you post some pics? I have a dremel. It doesn't sound too bad. I think GM parts direct has the MAF sensors for around $100.<hr></blockquote>

I had a couple on f-body.net, but they apparently have let their site go away... I may have some on the home computer, I can check later.

It was a lot of work. Remove the butterfly, and then stick a hacksaw through the tb. Cut the post as close to the tb as possible (and that post is very thick), without nicking the angled sides of the tb, especially in the butterfly sealing area. The post is probably an inch and a half thick at the widest point including the fin at the bottom, and an inch wide at the very top.

Then mill and grind for a long time to get the excess remnant of the post out. Also round and smooth things out some. And in my case, get jb-weld and fill the 2 places where you penetrated to the outside of the tb...

Then smooth out and polish.

Then find a drill bit the exact size of the new sensor (it seals with an o-ring that fits inside the hole, so getting the hole size correct is important). Again, in my case, get a slightly thicker o-ring because the hole is about 1/16 too big now...

Now fit the sensor in the hole, and find the part on the top of the tb in the front, that is obstructing the larger base on the new sensor, then grind the outside of the tb so the sensor will sit down flat. (I cheated and ground some off the corners of the sensor, but if I ever replace the sensor, I will have to modify the new sensor too.)

Clean everything out really good, including the area around the butterfly bushings, and the idle air passage.

Reinstall the butterfly, the tb, and the sensor and all the wires and linkage, and you're good to go...

[SLOWBRAEATER]

Magnus rat said in the past that they calibrate the sensor so it doesnt throw an ses light, how will you do this w/o haveing ses light problems from it?

[Magnus]

Simply replace the sensor with one thats calibrated for the TB.

When you remove the post on 97-98 TB's they are just like the 99+ tb's so you can use a 99+ maf.

[SLOWBRAEATER]

would you then be able to use a 99+ pcm? [img]smile.gif[/img]

[jamie]

no, its driven by wire, and cable.

[Amped96]

<blockquote>quote:</font><hr>Originally posted by Magnus:
Simply replace the sensor with one thats calibrated for the TB.

When you remove the post on 97-98 TB's they are just like the 99+ tb's so you can use a 99+ maf.<hr></blockquote>

What's different about the 96 TB?