Results 1 to 17 of 17

Differences between 98 ls1 and 99 + ls1

This is a discussion on Differences between 98 ls1 and 99 + ls1 within the Internal Engine forums, part of the LSx Technical Help Section category; Hi- first time post for me. I am putting a 98 ls1 in a 1954 mercury. I noticed that the ...

  1. #1
    Junior Member
    Join Date
    Apr 2008
    Location
    Southern Illinois
    Posts
    5

    Differences between 98 ls1 and 99 + ls1

    Hi- first time post for me. I am putting a 98 ls1 in a 1954 mercury. I noticed that the listings for aftermarket harnesses are different for the 98s vs. the newer ls1s. I would like to know the difference between the 98 ls1 (engine, computer, harness) and later years.

  2. #2
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    The 98 has a different ECM ( computer ) with different pin locations on the plug. So, if you have a 98 ECM, order the 98 wiring harness.

  3. #3
    Member 2-bowties&abird's Avatar
    Join Date
    Jan 2008
    Location
    lancaster,va.
    Age
    38
    Posts
    505

    cam/lt headers
    blue 2000 ws6 m6

    i'm pretty sure the heads are different too. 98's had centerbolt style.

  4. #4
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    Quote Originally Posted by 2-bowties&abird View Post
    i'm pretty sure the heads are different too. 98's had centerbolt style.
    No, outer bolts. I think that is a higher year... I have a 98 & it's not center bolts. It will be when I put the 5.3 heads on it !!!

  5. #5
    Member Ryanandybob's Avatar
    Join Date
    Jul 2007
    Location
    Louisville
    Age
    29
    Posts
    116

    Red
    98' Camaro

    Any Changes in HP/TQ between the years?

  6. #6
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    Not that I know of...

  7. #7
    Firebird Encyclopedia 9T8W66's Avatar
    Join Date
    Oct 2006
    Location
    St. Clair Shores. Michigan
    Age
    49
    Posts
    1,605

    Navy Blue Metallic
    `98 Formula M6 HdTp

    Craig
    Semi Retired Street Racer
    2012 Lava Red Mustang GT Coupe Brembo/3.73's
    Build Date 3/17/11, Last Lava Red GT

    Gone but not forgoten
    NBM `98 Formula M6 HdTp
    1 of 1 Build Date 3/12/98

  8. #8
    Member 2-bowties&abird's Avatar
    Join Date
    Jan 2008
    Location
    lancaster,va.
    Age
    38
    Posts
    505

    cam/lt headers
    blue 2000 ws6 m6

    yeah 5hp 98-00 rated 320, 01-02 rated 325

  9. #9
    Firebird Encyclopedia 9T8W66's Avatar
    Join Date
    Oct 2006
    Location
    St. Clair Shores. Michigan
    Age
    49
    Posts
    1,605

    Navy Blue Metallic
    `98 Formula M6 HdTp

    Quote Originally Posted by Ryanandybob View Post
    Any Changes in HP/TQ between the years?
    Only the bogus ratings by GM
    All LS1's make Approx 345-350 FWHP.

  10. #10
    Junior Member
    Join Date
    Apr 2008
    Location
    Southern Illinois
    Posts
    5
    Thanks for the info especially the link. Since I did not get a computer or harness with the engine, can I use a 1999 and later computer and harness - any advantage to doing so?

  11. #11
    The Demon Demon_Z28's Avatar
    Join Date
    Feb 2008
    Location
    WA
    Posts
    648

    Bright Rally Red
    2001 Camaro SS

    Quote Originally Posted by 9T8W66 View Post
    Only the bogus ratings by GM
    All LS1's make Approx 345-350 FWHP.
    front wheel horse power???

    yea we all know we all have around 330 to 350 crank hp not 320 and 325...but it cant be fully determined unless you get a good base wheel # and then calculate your power train loss and ect then do some more calaculations and find your true crank hp, or get it bench tested.

    I know that my Gas Cap on my 98 is different then all of the 99's and above, I also know my fuel tank is the smallest of all the years, I know my fuel injectors are the biggest of all the years...atleast thats what ive read, I believe I have the smallest cam of all the years, I know my exhaust tips are the square type like the older vettes had and mid 90's camaro had. My cruise control is attached to my throttle unlike the seperate unit everyone else has... we could go all day I guess.

  12. #12
    Member 2-bowties&abird's Avatar
    Join Date
    Jan 2008
    Location
    lancaster,va.
    Age
    38
    Posts
    505

    cam/lt headers
    blue 2000 ws6 m6

    Quote Originally Posted by Demon_Z28 View Post
    front wheel horse power???

    yea we all know we all have around 330 to 350 crank hp not 320 and 325...but it cant be fully determined unless you get a good base wheel # and then calculate your power train loss and ect then do some more calaculations and find your true crank hp, or get it bench tested.

    I know that my Gas Cap on my 98 is different then all of the 99's and above, I also know my fuel tank is the smallest of all the years, I know my fuel injectors are the biggest of all the years...atleast thats what ive read, I believe I have the smallest cam of all the years, I know my exhaust tips are the square type like the older vettes had and mid 90's camaro had. My cruise control is attached to my throttle unlike the seperate unit everyone else has... we could go all day I guess.
    umm....not front wheel horse power, fly wheel horse power.

    thats what our cars were rated at from the factory so thats what i told him. if i had said 345 hp someone would have chimed in and said no they were rated at 320-325 hp.

  13. #13
    Member 2-bowties&abird's Avatar
    Join Date
    Jan 2008
    Location
    lancaster,va.
    Age
    38
    Posts
    505

    cam/lt headers
    blue 2000 ws6 m6

    Quote Originally Posted by bills98ta View Post
    No, outer bolts. I think that is a higher year... I have a 98 & it's not center bolts. It will be when I put the 5.3 heads on it !!!
    i'm pretty sure the majority of 98's had centerbolts, they may have started to use perimeter bolt later in the production year.

  14. #14
    Junior Member
    Join Date
    Nov 2005
    Posts
    32

    Red
    1998 Pontiac Trans Am

    Quote Originally Posted by 2-bowties&abird View Post
    i'm pretty sure the majority of 98's had centerbolts, they may have started to use perimeter bolt later in the production year.
    No, the 98's had a perimeter bolt pattern. The 99+ has the center bolt design that you speak of.

  15. #15
    Firebird Encyclopedia 9T8W66's Avatar
    Join Date
    Oct 2006
    Location
    St. Clair Shores. Michigan
    Age
    49
    Posts
    1,605

    Navy Blue Metallic
    `98 Formula M6 HdTp

    Quote Originally Posted by Demon_Z28 View Post
    front wheel horse power???

    yea we all know we all have around 330 to 350 crank hp not 320 and 325...but it cant be fully determined unless you get a good base wheel # and then calculate your power train loss and ect then do some more calaculations and find your true crank hp, or get it bench tested.

    I know that my Gas Cap on my 98 is different then all of the 99's and above, I also know my fuel tank is the smallest of all the years, I know my fuel injectors are the biggest of all the years...atleast thats what ive read, I believe I have the smallest cam of all the years, I know my exhaust tips are the square type like the older vettes had and mid 90's camaro had. My cruise control is attached to my throttle unlike the seperate unit everyone else has... we could go all day I guess.
    My dyno #'s were 300 HP and 322 TQ done 2 yrs ago at 109K miles on the original clutch. Calculate a 12-15% driveline loss (manula trans) and I'm right in the ballpark of 345-350 FLY WHEEL Horse power
    On a side Note
    Too many people use their Dyno numbers as bragging rights. Dyno numbers mean very little in respect to how fast a car is in a drag race. Cause the more powerfull car is NOT always the winner.

    `98 have an on demand fuel systewm with No return line. 28# Injectors (Same as `01-04 LS1's), All `98-00 F-bodies have the same cam 198/209 500/500 119.5 LSA. And your cruise comes off your throttle body cause you don't have Traction Control.

  16. #16
    The Demon Demon_Z28's Avatar
    Join Date
    Feb 2008
    Location
    WA
    Posts
    648

    Bright Rally Red
    2001 Camaro SS

    Quote Originally Posted by 9T8W66 View Post
    My dyno #'s were 300 HP and 322 TQ done 2 yrs ago at 109K miles on the original clutch. Calculate a 12-15% driveline loss (manula trans) and I'm right in the ballpark of 345-350 FLY WHEEL Horse power
    On a side Note
    Too many people use their Dyno numbers as bragging rights. Dyno numbers mean very little in respect to how fast a car is in a drag race. Cause the more powerfull car is NOT always the winner.

    `98 have an on demand fuel systewm with No return line. 28# Injectors (Same as `01-04 LS1's), All `98-00 F-bodies have the same cam 198/209 500/500 119.5 LSA. And your cruise comes off your throttle body cause you don't have Traction Control.
    oh ok, now I see, I was still wondering why my cruise control was hooked up like that, I like the fact i dont have traction control thanks for the info.

    the Front wheel hp was a joke...

  17. #17
    Member vannatte's Avatar
    Join Date
    Jun 2007
    Location
    Noblesville, IN
    Posts
    440

    Black
    1998 Pontiac Trans Am A4

    Quote Originally Posted by Demon_Z28 View Post
    front wheel horse power???

    yea we all know we all have around 330 to 350 crank hp not 320 and 325...but it cant be fully determined unless you get a good base wheel # and then calculate your power train loss and ect then do some more calaculations and find your true crank hp, or get it bench tested.

    I know that my Gas Cap on my 98 is different then all of the 99's and above, I also know my fuel tank is the smallest of all the years, I know my fuel injectors are the biggest of all the years...atleast thats what ive read, I believe I have the smallest cam of all the years, I know my exhaust tips are the square type like the older vettes had and mid 90's camaro had. My cruise control is attached to my throttle unlike the seperate unit everyone else has... we could go all day I guess.
    Here are the items specific to 1998's:

    1. Had differnet casting heads which had perimeter bolts and valve covers.
    2. Ignition coils were mounted to the valve covers one at a time.
    3. The water temp gauge actually works.
    4. 98's do have an oil life monitor, they just don't tell you anything when its time for a change. You can find it in Auto-Tap
    5. WS6s had single outlet exhaust (all others had duals)
    6. Only year that Purple, Gold, and Green were available
    7. Some very early Trans Ams came with LT1 style headrests
    8. Rear hatch release was poorly designed and often caused problems releasing mechanism
    9. Early model 98 Monsoon stereos didnít have capability to control 12-disc CD changer
    10. 1998-1999 automatic transmission LS1s could be started in 1st gear even with the shifter in 2nd. Starting 2000, if you put the shifter in 2, it would start off in 2, even from a stop.
    11. 1998-1999 LS1 cars had a smaller throttle body cam, which caused the throttle to open to WOT faster than 2000+ cars
    12. 1998 cars had 28 lb fuel injectors from the factory
    13. 1998-1999 cars had more restrictive exhaust manifolds
    14. 1998-2000 cars had an LS1 intake with EGR
    15. 1998 and some early 1999 cars had blue outside rear view mirrors (TA/Formula only)
    16. 1998 only LS1 blocks had a much smaller cylinder sleeve that only tolerated a .005" hone
    17. Last year F-body to use the old 15.5 gallon steel fuel tank.
    18. Only year LS1 F-body to contain a gascap with a tether long enough to actually hang from the fuel door while open
    19. Only year LS1 F-body to not contain the famous GM black box used in the event of an accident to record up to 5 seconds of pre-crash data
    20. 1998 only cars had a different PCV system with the PCV valve located above the passenger side valve cover
    21. 1998 most cars did not have an idle adjustment screw on the throttle body. Some 98 cars do have the idle throttle stop set screws.
    22. 1998 cars have a completely different PCM from 99+ cars
    23. 97-98 LS1's used a paper water pump gasket. The only gasket that isn't reuseable
    24. SSs did not ALL go to SLP starting in 98. Y2Y was the RPO code that sent them to SLP for additional options
    25. SS option did not "include" the Synthetic oil package, it was a SLP only Option

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. differences
    By TA98 in forum External Engine
    Replies: 1
    Last Post: 12-06-2009, 06:51 AM
  2. Differences?
    By Eric1987 in forum Firebird / WS6
    Replies: 6
    Last Post: 01-04-2009, 06:01 PM
  3. 98-02 differences
    By anfking6908 in forum Camaro / SS
    Replies: 2
    Last Post: 07-06-2008, 11:52 AM
  4. Differences between 98-00 and 01/02
    By lvlustang in forum Camaro / SS
    Replies: 13
    Last Post: 04-04-2007, 07:32 AM
  5. Any differences at all?
    By ATCharming in forum Firebird / WS6
    Replies: 23
    Last Post: 03-27-2007, 01:15 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •