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Thread: How much HP can the THM125C AWD version take???

  1. #1

    Default How much HP can the THM125C AWD version take???

    I happen to come across this article while browsing the web.

    Pontiac built a concept crossover in '89 called the Stinger. I thought I was familiar with all the concepts they put out in that era, I had never seen or heard of this one. An interesting excerpt I found was they stuffed the AWD system from the STE complete with it's THM125C in this concept vehicle, backed by a 170HP engine.

    The 3.1L currently in my '89 STE AWD is 135hp, and could benefit from some mods to up that number a bit or perhaps significantly. But I thought I've read in some places where it's probably not a good idea to up the numbers of anything going into the THM125C. I don't remember where I read that but I remember it.

    Quote Originally Posted by HotRod Magazine
    The engine also featured multiport fuel injection and a low-restriction exhaust system featuring a four-tube header. In normally aspirated form and in a rather mild state of tune, it delivered 170 hp at 6,500 rpm, though it certainly had the potential for far more. It was fitted to a special three-speed automatic transmission with all-wheel drive. The driveline was based on the AWD system used in the Pontiac 6000 STE.

  2. #2
    Join Date
    Oct 2013
    Northwest Lower Michigan
    1989 Celebrity CL 4 door 3.1, 1989 Cutlass Cruiser 2.8


    Wow the memories. I remember reading a similar article about the Stinger in a different magazine, Car and Driver I think. Not as in depth as this one IIRC. But I was 13.

    Some reading on Fiero pages say it's tougher than the 4 speed auto, it can be built up for drag racing, there isn't a lot to it. The article did say the trans was modified, not sure whether that modification was just for the tailshaft or built up stronger as well.
    Last edited by tlc1976; 08-02-2018 at 05:28 PM.
    1989 Celebrity CL 4 door, 3.1 MPFI, 4 speed auto, summer daily driver
    1989 Cutlass Cruiser wagon, 2.8 MPFI (future 3.1), 4 speed auto, future summer ride
    1996 Cherokee XJ 4 door, 4.0, 5 speed, winter daily driver & towing vehicle
    1991 Tracker 2 door, 1.6, 5 speed, needs work
    Previously several Celebritys, 6000s, & 2 U-vans

  3. #3
    Senior Member Century7667's Avatar
    Join Date
    Dec 2008
    Sugar Land, TX
    1996 Buick Century Limited 3100 V6 / 1995 Buick Century Special 3100 V6 / 2001 Chevy S-10 LS 2.2L


    I don't think the 125C or the 3T40 ever saw more than 160HP out of production engine, so I'd say 200HP tops. Just a guess though. I'm betting it's a sliding scale though. The more HP applied the shorter the life, your mileage may vary, etc.

    Ken T.

  4. #4
    Senior Member CorvairGeek's Avatar
    Join Date
    Dec 2014
    The Gem State
    1992 Century Special 1996 Century Custom


    I could be wrong, but I suspect it handles high revving horsepower far better than it would increased torque.
    Last edited by CorvairGeek; 08-04-2018 at 02:02 AM.

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