88-91 LN3 Performance Upgrades and Information - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

Reply
 
 
 
Thread Tools Search this Thread
Old 07-20-2007, 02:16 PM   #1
Junior Member
Thread Starter
 
Join Date: Aug 2005
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
wjcollier07 is on a distinguished road
Default 88-91 LN3 Performance Upgrades and Information

I would like this thread to be a good, solid, clean database for any 88-91 LN3 owner to get some more spunk out of their car and know all they should know so that no mistakes are made.

Please add any ideas that you know are available and fully compatible with these engines. Please keep your post neat, to the point and with minimal chit chat.


Before performing any mods. Do be sure that the vehicle has been fully tuned up.

Recommended tune up list:
Spark Plugs (NGK TR55/Delco/Autolite)
Spark Wires (Belden/Autolite Pro/Delco Spark Wires)
Air filter (K&N (Covered Below))
PCV Valve (Purolator, etc)
Oil Change (Mobil 1/Pennzoil Platinum and Purolator PureONE or Delco filter)
Clean MAF sensor (clean with rubbing alcohol and qtip very gently)
Run SeaFoam through engine.
Please add any items if necessary.


Specifically looking for information on the following:
(Who, when, where, how, pricing and capability)
THM440T4 Performance Rebuild/Buildup
Stroking
Cross compatible parts/upgrades between engine generations (such as coil swap already mentioned, what part on a newer 3800 is fully compatible with and can help performance/longevity of the LN3)
Brake Upgrades
Any and all information/links to L67 swap information

I will continue to add to this list as information becomes available.
wjcollier07 is offline   Reply With Quote
Old 07-20-2007, 02:48 PM   #2
Senior Member
Certified Car Nut
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default

I believe the Yella Terra Series I cams and roller rockers for the 92 should work for the LN3.
J Wikoff is offline   Reply With Quote
Old 07-23-2007, 02:47 PM   #3
Senior Member
Posts like a 4 Banger
 
chemicall's Avatar
 
Join Date: Feb 2007
Location: Canada, eh!
Posts: 112
Thanks: 0
Thanked 0 Times in 0 Posts
chemicall is on a distinguished road
Default

I was scrolling around the club, and found this site: http://www.technicalevolution.com/clunk440.htm

This explains how to fix the 2-1 downshift clunk in the 440T4 transmissions, It is a simple Gm replacement part(a spring). Seems like something I am interested in as I know the bad feel of a 440T4 2-1 downshift. The GM part number is at the bottom of the page.
chemicall is offline   Reply With Quote
Old 07-23-2007, 05:11 PM   #4
Junior Member
Thread Starter
 
Join Date: Aug 2005
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
wjcollier07 is on a distinguished road
Default

How about a heavy clunk for upshift? I wonder if that would work for that as well. Some 440 owners might know what I mean, say you're in town, just got off the gas, coasting down, usually about 25 ish, doesn't require any power at that speed, and then it feels like it DROPS into 3rd.
wjcollier07 is offline   Reply With Quote
Old 07-23-2007, 05:20 PM   #5
Senior Member
Posts like a 4 Banger
 
chemicall's Avatar
 
Join Date: Feb 2007
Location: Canada, eh!
Posts: 112
Thanks: 0
Thanked 0 Times in 0 Posts
chemicall is on a distinguished road
Default

Well downshifts are harder on the transmission than upshifts correct? So it is possible that not just the downshift will be better but possibly up-shifts?, I havn't experienced what you explain, but I know in my car coming to a stop sign when it downshifts to first with your foot off the throttle you can really feel it. Seeing as this is a GM part and fix for our transmissions it should work well.
chemicall is offline   Reply With Quote
Old 07-23-2007, 05:27 PM   #6
Junior Member
Thread Starter
 
Join Date: Aug 2005
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
wjcollier07 is on a distinguished road
Default

which is funny, because i feel absolutely NOTHING when downshifting on no throttle, i see the tach jump just slightly and thats it, extremely soft, never any harshness, but the upshift on no throttle from 2nd to 3rd is a nasty clunk, under throttle its fine tho
wjcollier07 is offline   Reply With Quote
Old 07-23-2007, 05:38 PM   #7
Senior Member
Posts like a 4 Banger
 
chemicall's Avatar
 
Join Date: Feb 2007
Location: Canada, eh!
Posts: 112
Thanks: 0
Thanked 0 Times in 0 Posts
chemicall is on a distinguished road
Default

it'* not a nasty clunk just going 2-1 coming up to a stop sign under gramma driving conditions but you can hear it a wee bit and deffinately feel it. my 1-2-3-4 up shifts and 4-3-2 downshifts are all nice and smooth, you don't even feel any of these shifts in my car at all. When it upshifts the tach falls super smooth and whether im into the throttle on the shifts or off it, there still beautiful shifts. The 2 of us should try this on our cars to see if it fixes these individual problems. If it does work for my symptoms and your'* then we may have another possible good mod for our old rides!

Edit to say: has anyone tried a solid front trans mount on these older cars?
chemicall is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
LN3 upgrades please help jagergirll Performance, Brainstorming & Tuning 19 04-10-2011 03:06 AM
n00b here looking for LN3 performance parts maybe2fast Performance, Brainstorming & Tuning 4 02-08-2005 09:17 PM
Please Help With My Performance Upgrades 96ssei Performance, Brainstorming & Tuning 4 06-10-2004 12:41 AM
looking for performance upgrades for 92-95 series I 3800 bon jcpenn Performance, Brainstorming & Tuning 7 05-10-2004 12:52 PM
good books for mainternace and/or performance upgrades rjkbills12 General GM Chat 6 07-23-2003 12:56 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 09:25 PM.


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.