Question about porting MAF post

[sped214]

I've heard of several people porting/removing the post that the MAF sensor goes into in the throttle body and removing the little "plate" that goes on the back of the post. I would like to do this. My question is, Can I just do this, or do I need a MAFT+ or something like that to adjust afterwards? As always, any help would be appreciated. Thanks.

[sped214]

Anyone? Magnus? (TTT)

[John_D.]

<blockquote>quote:</font><hr>Originally posted by sped214:
I've heard of several people porting/removing the post that the MAF sensor goes into in the throttle body and removing the little "plate" that goes on the back of the post. I would like to do this. My question is, Can I just do this, or do I need a MAFT+ or something like that to adjust afterwards? As always, any help would be appreciated. Thanks.<hr></blockquote>

I cut out the bottom half at first. With this you have to remove the plate to get a good reading.

Before I put it back on, I decided to cut out the entire post (so I don't know how accurately it read with only half a post).

If you cut the whole post out, the stock maf sensor will not read correctly. I ended up having to buy a 99+ maf sensor (my car is a '98). Magnus did the same thing (his car is a '97).

The 99+ sensor is larger and duplicates most of the upper half of the post, so it defeats the purpose of cutting the top half of the post off. Plus it requires drilling a larger hole in the top of your tb.

I would recommend reading your o2's and your maf with something like autotap. A baseline before the porting, and compare to the readings you get after porting.

The tb port job changed the range of numbers my sensor reported, throughout the rpm range. I believe the numbers were higher, which caused the car to run richer. The readings were not as consistent either.

[ September 16, 2002: Message edited by: John_D. ]</p>

[WickEdSix9838]

did the car run any better after you ported it??

[sped214]

Thanks, John_D. I appreciate it. I think I'll give it a try this weekend...

[John_D.]

<blockquote>quote:</font><hr>Originally posted by WickEdSix9838:
did the car run any better after you ported it??<hr></blockquote>

I wish I knew for sure...

I did several things at the same time. 3" exhaust (including cat and s-pipe), cia headers, tb port, and egr disable. So it's hard to say.

I did have some driveability issues related to the porting, before the new maf sensor. A hunting idle, and a tendency to surge on takeoff. I even took another pass at it, by taking a dremel to the plastic part of the sensor and cut it all away, leaving only the wires, thinking that would improve the quality of the airflow over the wires. But that was even worse. Apparently those wires were designed/calibrated to have air gathered and funneled over them, instead of just hanging down there in the open. The top half of the post does that funneling. And the '99+ sensor has the funnel built in.

The only thing I notice now, with the new maf sensor, is a just a teeny little bit of hesitation/surge on a slow takeoff downhill with almost no throttle.

As far as wot operation, I don't know. I figure it's got to flow a little better (but probably was not needed, since the narrowest part of the tb is down by the butterfly anyway).

And I have tweaked the wot maf reading via a MAFT (2% lean), so even if it was off a little, I have brought it back in line, based on o2 readings. But how much of that is attributable to the post, and how much to the new exhaust, who knows...

Now I have 24lb injectors (as of Saturday), so I need to re-tune for those...

As far as e.t.'s, I ran 15.7 before the port and before the nitrous. I have only timed it with nitrous since then. Even when I do get new na times, it will include the exhaust mods too.

[John_D.]

<blockquote>quote:</font><hr>Originally posted by sped214:
Thanks, John_D. I appreciate it. I think I'll give it a try this weekend...<hr></blockquote>

The gasket will probably be a dealer item. If you don't have it lined up yet, this would be a good time to make sure you can get one.

[sped214]

Yeah. That's why I'm waiting until the weekend. The gasket will supposedly be in later this week. [img]smile.gif[/img]

[John_D.]

<blockquote>quote:</font><hr>Originally posted by sped214:
Yeah. That's why I'm waiting until the weekend. The gasket will supposedly be in later this week. [img]smile.gif[/img] <hr></blockquote>

Cool. It was a fun little mod to do. Just to be able to say I did it, if nothing else.

Hey, let us know how you like it after it's done...