4.9 performance - Page 6

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

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 6 of 6 FirstFirst 123456
Results 76 to 77 of 77
HT4100 4.1, 4.5, 4.9 Discussion, 4.9 performance in Cadillac Engine Discussion; What got me thinking was.... when people swap 4.9 in Fieros, they can keep them either auto, using the 3speed ...
  1. #76
    Night Wolf's Avatar
    Night Wolf is offline Cadillac Owners 10000+ Posts
    Automobile(s): Unicycle
    Join Date
    Mar 2003
    Where I park it
    Thread Starter

    Re: 4.9 performance

    What got me thinking was.... when people swap 4.9 in Fieros, they can keep them either auto, using the 3speed Fiero tranny, or 4speed using the Cad tranny... OR make it a 4/5 speed manual using either the getrag (sp) or Isuzu tranny.... I would think then you could get something rigged up in a Cad to accept it also....

  2. #77
    ckucia is offline Cadillac Owners Fanatic
    Join Date
    Feb 2003

    Re: 4.9 performance

    I did a bit of research on this for my Allante. Here's what I've found:

    There are really only two GM 5-speed manual transaxles that will bolt up (with modification for the starter) to the Cadillac block. They are the Getrag/Muncie 282 (the 5-speed used on V6 Fieros and Berettas) and the Isuzu used on I4 Fieros (and other vehicles, I suspect).

    Other potential transaxles are the Muncie 4-speed used on V6 Fieros, and the ultra-rare Getrag 284 used on the 5-speed GTP and Z34 with the 3.1 circa 1989-1992.

    Couple of issues:

    First, the "easy ones".

    1) You would have to modify or otherwise adapt the speed sensor
    2) You would need to fool the ECM into thinking the transaxle was attached (for when it attempts to electronically shift it)
    3) You would have to adapt the gear selector and neutral safety switches

    More difficult:

    1)Two of the three transaxle/engine mounts would have to be completely fabricated.

    2) Driveshafts would have to be adapted/fabricated as the distances would all be different

    3) The manual transaxle doesn't have a "snout" running across the back of the engine. Berettas had either a pillow block or a cast extension.

    4) A flywheel would have to be custom made (or gotten from the Fiero guys)

    5) The transaxles have to be cut to accept the stock Cadillac starter.

    Even if you could accomplish all that...

    1) Fieros have a hard time getting the clutch to handle the torque. There's not much space in there for a larger diameter one. This is a problem because

    2) Cadillacs weigh a lot more than Fieros. It takes more torque to accelerate them, all things being equal, because there's more weight to haul around, thus more torque has to be transmitted and the clutch is already borderline, plus

    3) Its easy to spin the tires in a Fiero with a Cadillac engine. This acts as a "safety valve", preventing the full torque of the engine from being channeled through the transaxle. That's not going to happen on a FWD Cadillac and it increases the odds of breaking something.

    So, yes, you could probably do it. It may even last a long time if you don't abuse it, and rebuild the trans before installation. There are a lot of issues to sort out though. I suppose the first person that does it will gain some interesting experience!

    Another avenue I've thought of pursuing was to adapt the manual trans off a Taurus SHO. That car weighs about the same as the Allante and it might last a bit longer than the Getrag 282, and certainly the Isuzu. Then, though, you have to deal with physically bolting it to the engine, and mixing Ford and GM driveshaft pieces.

    Part of me would like to give it a try when I finish remodelling the house. If the trans wasn't such a PITA to drop out of the Allante, I might think about it more.


  3. Remove Advertisements
    Cadillac Forums

+ Reply to Thread
Page 6 of 6 FirstFirst 123456

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

What Cadillac(s) do you own? (Or type NONE)

Please select your insurance company (Optional)

Your date of birth and age are displayed in several places on the forum. Only the administrator will have access to your date of birth should you choose to hide it via the privacy option below.


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Cadillac Posting Rules

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