FWD Tech Guides '95-'07 Guides/How-To information for FWD Montes 1995-2007

Mod Guide: Throttle Body Half Shafting

  #1  
Old 08-29-2016, 11:10 PM
The_Maniac's Avatar

Monte Of The Month -- December 2011
Monte Of The Month -- September 2014
5 Year Member
3 Year Member1 Year Member
Thread Starter
iTrader: (2)
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 10,957
Default Throttle Body Half Shafting

I have done this with my L67 throttle body that is adapted to my l36 (3800). I now did this to my LA1 (3400) on my '04 Grand Am.

I'm going to focus on the LA1 throttle body. Even though I did this for a 2004 Grand Am, it also applies to a 3400 powered Monte and any other GM 3400 vehicle. Please note, if you decide to get a donor throttle body for the 3400, GM made minor changes through the years. This link has some 3100/3400 info about the throttle bodies and other items:
https://wot-tech.com/94-99-3100-large-port-swap.html

On this throttle body, I did more then just half shafting. About a month ago when I did numerous services to my cooling system, I bypassed the coolant connections to the throttle body with a piece of hose (no coolant flows in/out of my throttle body. That being said, I opted to cut off that section on my project piece. Allows that bypass hose to rest a little better, not so cramped.

In the pic below (photo found on the Internet) you can see marks of what I wanted to cut.


In my project piece, I removed the throttle plate (I found it would have been handy to mark it's orientation prior to removal, it seems to only fit one way). Before I removed the throttle shaft (which holds the plate), I marked off were I wanted to cut. You want to cut only the side that has the heads to the screws. I also did not cut as tight as I could to the edges. I did this so I could still have a complete shaft protecting the bearings of the throttle body.

Removing the throttle shaft took a small smack with a hammer and it slide out.

Before I performed any grinding on the throttle body housing, I taped off the bearings for the throttle shaft (I did not want metal debris getting in to them).

Using the Dremel, I feathered down any steps or rough castings in the air flow path (not many). I uses a metal cutting disc to cut a section of the throttle shaft out. I used an angle grinder and removed the coolant passage.

When I re-installed the throttle plate, I used a dab of red loctite on the screws. Once installed, I grinded off the excess.

Below are various project pics. Once completed, I installed into the Grand Am.

So far I have been very happy with the results. I have improved throttle response, a little more pep. Watching fuel trims on my Scanguage II, not much has changed, but the car would benefit from being completely re-tuned (right now it's mostly a factory tune short of some transmission changes).
The work to mod and install this throttle body was very brief compared to other mods I've done and cheap (free if I wanted to mod the throttle body that came with the car).











 
Attached Images
File Type: jpg
LA1 - Marked.jpg (88.2 KB, 118 views)
File Type: jpg
IMG_1959.JPG (2.19 MB, 122 views)
File Type: jpg
IMG_1961.JPG (1.57 MB, 113 views)
File Type: jpg
IMG_1962.JPG (1.64 MB, 112 views)
File Type: jpg
IMG_1983.JPG (1.53 MB, 108 views)
File Type: jpg
IMG_1984.JPG (1.59 MB, 107 views)
File Type: jpg
IMG_1985.JPG (1.61 MB, 110 views)
  #2  
Old 08-30-2016, 11:43 PM
Join Date: Dec 2013
Location: Indianapolis
Posts: 212
Default

If i was to send you a throttle body to do this how much would it cost?
 
  #3  
Old 08-31-2016, 12:49 PM
The_Maniac's Avatar

Monte Of The Month -- December 2011
Monte Of The Month -- September 2014
5 Year Member
3 Year Member1 Year Member
Thread Starter
iTrader: (2)
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 10,957
Default

Brendocee55 - I sent you a pm.
 
  #4  
Old 08-31-2016, 07:29 PM
JuniorCar's Avatar

Monte Of The Month -- January 2013
10 Year Member
5 Year Member3 Year Member1 Year Member
Join Date: Aug 2008
Location: London, Ontario
Posts: 5,566
Default

Nice work Jason!

I've never heard of "half shafting". To be honest, I wouldn't think that it would make much of a difference, but cleaning everything up would certainly help. You'd know better than I. Did you invent this idea? That tb looks a little thin walled to bore out more - have you tried? You may have yourself a nice little niche market - it seems customers are lining up already.

Great job of photo documenting. This is always such a useful step for everybody else, but requires significantly more patience to do. Thanks for sharing.
 
  #5  
Old 09-01-2016, 12:52 AM
The_Maniac's Avatar

Monte Of The Month -- December 2011
Monte Of The Month -- September 2014
5 Year Member
3 Year Member1 Year Member
Thread Starter
iTrader: (2)
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 10,957
Default

Thanks for the kind words. I did not invent the half shafting idea. I saw bonneville guys do it to the 3800 and when you dig deeper people have done this to numerous other cars for years.

But the concept makes sense. It is essentially allowing a small amount of more air in. So in terms of throttle response, it would behave as if you had your foot into it a little more and at wot, it simply give a little more air. When you look at larger bore throttle bodies, many times they are not larger by much, possibly the same amount of air flow change as half shafting.

I have done this to both my Monte 3800 and now my Grand Am 3400 and I have been happy with the results.

As for boring it out, supposedly there is room to enlarge the bore, but I lack the equipment to do it (I would want solid precision and I don't have the tools for that).
 
  #6  
Old 01-30-2019, 08:35 PM
Join Date: Mar 2015
Location: Vegas Baby
Posts: 40
Default

Originally Posted by The_Maniac View Post
Thanks for the kind words. I did not invent the half shafting idea. I saw bonneville guys do it to the 3800 and when you dig deeper people have done this to numerous other cars for years.

But the concept makes sense. It is essentially allowing a small amount of more air in. So in terms of throttle response, it would behave as if you had your foot into it a little more and at wot, it simply give a little more air. When you look at larger bore throttle bodies, many times they are not larger by much, possibly the same amount of air flow change as half shafting.

I have done this to both my Monte 3800 and now my Grand Am 3400 and I have been happy with the results.

As for boring it out, supposedly there is room to enlarge the bore, but I lack the equipment to do it (I would want solid precision and I don't have the tools for that).
Thanks. Now you are gonna make me heat the throttle body out tonight! Im already coating a bunch of bolts right now,now lol. Got to get to the exhaust first while i have room to wirk on it. I'll post more pics tomorrow once its more together
 
  #7  
Old 01-30-2019, 09:08 PM
Join Date: Mar 2015
Location: Vegas Baby
Posts: 40
Default

Originally Posted by The_Maniac View Post
Thanks for the kind words. I did not invent the half shafting idea. I saw bonneville guys do it to the 3800 and when you dig deeper people have done this to numerous other cars for years.

But the concept makes sense. It is essentially allowing a small amount of more air in. So in terms of throttle response, it would behave as if you had your foot into it a little more and at wot, it simply give a little more air. When you look at larger bore throttle bodies, many times they are not larger by much, possibly the same amount of air flow change as half shafting.

I have done this to both my Monte 3800 and now my Grand Am 3400 and I have been happy with the results.

As for boring it out, supposedly there is room to enlarge the bore, but I lack the equipment to do it (I would want solid precision and I don't have the tools for that).
Thanks. Now you are gonna make me heat the throttle body out tonight! Im already coating a bunch of bolts right now,now lol. Got to get to the exhaust first while i have room to wirk on it. I'll post more pics tomorrow once its more together
 

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.