Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

Results 1 to 5 of 5

Thread: Convert 98 SLS motor into STS motor?

  1. #1
    bajarails is offline Cadillac Owners Member
    Automobile(s): 98 sls Northstar
    Join Date
    Mar 2009
    Posts
    14

    Convert 98 SLS motor into STS motor?

    I have a 98 Seville SLS, and I am going to have to take it all apart to fix the head gaskets. I also have access to STS heads, which have less miles, and a STS ECU. Can I convert by changing heads (and therefore cams) and ECU?


  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    chubbyranger is offline Cadillac Owners Connoisseur
    Automobile(s): 99 Seville STS, 08 STS4 N* 1SG F55
    Join Date
    Apr 2007
    Location
    The Ocean State
    Age
    53
    Posts
    3,516

    Re: Convert 98 SLS motor into STS motor?

    IIRC the final drive ratio in the transmissions are different from SLS to STS so it would not buy you much to add the 25 HP. Given the complexity of these cars, trying that conversion could come back to bite you.

  4. #3
    zonie77 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 ETC,97 STS
    Join Date
    Sep 2003
    Location
    Arizona
    Posts
    3,531

    Re: Convert 98 SLS motor into STS motor?

    You would lose torque. If you change the differential gears and computer you are OK. If you only change the heads you will be sorry.

  5. #4
    bajarails is offline Cadillac Owners Member
    Automobile(s): 98 sls Northstar
    Join Date
    Mar 2009
    Posts
    14

    Re: Convert 98 SLS motor into STS motor?

    OK, so I can put a STS transmission in also to get the right final gearing, it will work. I have access to the transmission also.

  6. #5
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS - 67,500 miles, 2014 Explorer XLT FWD
    Join Date
    Feb 2006
    Location
    MD Eastern Shore, Kent Island
    Age
    77
    Posts
    56,808

    Re: Convert 98 SLS motor into STS motor?

    Not only the transmission PCM section but also several other vehicle control and security modules have the original VIN in memory. They will have to be programmed to work with a different PCM, or the substitute PCM will have to be reprogrammed to work with the original vehicle controls. It ain't all that easy........and OBD-II isn't as programmer (there aren't any) friendly as OBD-I or later CAN electronics.


Bookmarks

Cadillac Posting Rules

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Read about Lincoln | Buick | Kia Forte Forum