As the topic states...I have the 4t60-e trans with some vacuum control on the TB. Are the sensors compatible too (especially the MAF)? I was thinking about a cheap performance upgrade, but before I get too excited, I wanted to see if it'd even work
When I get time (and resources) I'll eventually polish my TB, but I figured polishing a '99 would be even better...

Edit - while somewhat on the topic of polishing: How soon before the effects of polishing will be negated by carbon buildup? Will polishing make it easier to remove the gunk next time around too?

Yes the L67 TB will work, you need to open the bolt holes up a tad so the TB sits in the correct location.

However just to bolt one on the gains are negliable w/o port work to keep the L36 intake/TB angles. You will also need to upload a 99+ MAF file to get correct readings.

To run it with the VAC controled 4T60, you will need to remove the port on your current TB and have it pressed into the L67 TB. There is a plug on the L67 TB that wil need to be drilled out.

Your current TB should have bar in the middle? If so Remove that bar and smooth it out, upload a 99+ MAF file (while running a 97 MAF), and you'll see more gains with less time involved. We have one the on MANY 97/98 GT/GTPs, and all run better afterwards.


We have been running an 99 L67 TB for a while on our project GT (99), and still need to do some work on the TB and crappy plastic intake.

-Jeremiah

Dilcc...do you mean L67 or L36 for the 99 TB?

Check out this thread:
http://www.bonnevilleclub.com/forum/...ic.php?t=50403
I know I was the first to bring up the whole bolt hole alignment thing on CGP and I think it'* definitely as important as port matching the exit to the UIM.

Mike, thanks for the link.

Well since you brought it up, would would the difference between the 99+ TB'* on the L36 and L67 be? Obviously one bolts to a SC and the other a plain UIM, but I'm trying to remember from Bill'* TB comparison thread....
If I need to tune for new MAF tables this mod might be a little out of range for me at this point :(

Basically the L67 TB has a round outlet into the SC, while the L36 TB has an oval outlet into the UIM. There would be an adapter involved in fitting the L67 TB to the L36 UIM. However, it has been done many times.

If you're talking about using a '99 L36 TB on your '97, there is only one vacuum port on the '99 TB as opposed to the two ports on your '97. I'm not sure if you could use some kind of "T" fitting in order to use the '99 TB, but it might be possible.

You will definitely need different maf tables going to a L67 TB. IIRC the TB is larger overall throughout with the exception of the opening.
If you don't want to mess w/ any pcm changes, you may just want to go the bill w route.

Either way its PCM work or an AFC (you loose trans pressure with an AFC).

The MAF doesnt matter much L67 or L36, as the PCM is just using it a reference point.

If you:

1-cut the bar and use a 97/98 maf, you need a 99+ MAF bin (or AFC)
2-Upgrade to a 99+ L36 TB, you need the 99+ BIN
3-L67 TB you will still need a 99+ bin


In some cases(very few) even with a 99+ bin file you will need to scale the MAF table for correct fueling. Worst case you run rich....

-Jeremiah

Thanks for the help guys. Obviously it'* not as straight forward as I was hoping, but if it was, everyone would be doing it, right? In any event, I should probably save my money for modding a 99 SSEi (<- the itch is killing me and hopefully I'll have a second car in a few months )

Just find someone with a PT and its not to hard