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Thread: A powerful engine

  1. #1

    A powerful engine

    OK. Since no one seems to want to build a replica to blow the doors of an original......................... I will ask a different question.

    V-8 Archie says he has had no problems or breakage with V-8 conversions. The structural integrity of the rear suspension and frame assembly is of no concern. Shattering the case of the transaxle is of concern.

    What kind of power will the factory 5 -speed from a 2.8l V-6 take? I have seen many "estimates", I would just like to know if any of you have actually broken one.

    Has anyone pushed to 450-500 horsepower without breakage? If so did you use a kit or did you engineer your own installation?

  2. #2
    Junior Member
    Join Date
    Jan 2005

    Re: A powerful engine

    I went to school with a guy a few years back that had one of the few V6 5 gears (apparently they are rare?) He seamed to know his stuf, despite being a little cocky about his incredible Fiero.. : I think he said it was a Getrag transaxle and was probly good for around 350 horse.. one of his Fiero buddys did the 3.8SC (and tweeked it a bit) and fried his clutch in about a month, but the tranny held up. The guy aparently put a decent clutch in it and never had trany issues after that. He drag raced the car as well..

  3. #3
    Senior Member
    Join Date
    Oct 2004

    Re: A powerful engine

    I would like to know as well. I've let the idea of a longitudally mounted V8 go, apparently thre's not enough room in a 3" stretch. So, I will be using the factory 5sp bolted up to around 400 Hp.

  4. #4

    Re: A powerful engine

    My concern is with low end torque, If I build a 400hp engine, with modest RPM ranges (less than 5,800) then the torque will be relatively high from about 2,000-4,500. If I build a 450-500hp engine to peak around 6,500-6,750 RPM then that low grunt will be moved to a higher RPM range around 3,500-5,200. The normal operating range would be 1,500-3,500, for normal driving, being that the Fiero is such a light car the loss of low end should go fairly un-noticed, as there would probably still be gobs more torque than the factory 2.8.

  5. #5

    Re: A powerful engine

    Not sure how power from v8 will apply to this, how ever few years ago I had build a chevy citation x11 173 (2.8) bored it .060 over put some nice pistons with 11.5 compression, custom made bi-level intake, custom ground Cam and I think it was 390cfm Holley carb. I admit it was not the most powerfull engine around however I did managed to shatter couple CV joints with it and the trans was in one solid piece.

    So the moral of the story is if you are not going to start cracking CV joints you should be OK

  6. #6

    Re: A powerful engine

    True enough.................. But, I am worried about splitting the transaxle case. I split an aluminum T-10 case in a Corvette I used to own, I ended upgrading to an iron case T-10 with full Richmond internals, it didn't cause grief again, but, there also isn't an upgrade like this I am aware of for a Getrag. The Corvette was stupid fast and revved to 7,000 RPM, nothing was factory, so I did expect to break the occasional part. I just would like to build a very fast, exotic replica, that is kinda "reliable".

  7. #7

    Re: A powerful engine

    marcello has about 450hp in his koenig TR replica, and as far as i know he has a fiero tranny (probably modified in some way other than adaptor plate) but it hasnt seen much of any driving so i'll have to ask him
    Professional 3D, web, graphic, architectural, interior, and CAM design at affoardable prices.<br />Any questions: voicemail/fax (323)281-0583<br />sales @

  8. #8
    Senior Member
    Join Date
    Jul 2004

    Re: A powerful engine

    It depends on how you shift and how good your clutch is. I just took a SBC V8 out of a donor I built; it was stupid fast and felt very harsh on the drive train. I was running the five speed. I did not like driving the car it was great for drag racing but the weight offset was terrible cornering sucked, the front end was way to light any way I'm changing my 87 V6 auto to a 4.9 five speed this way I have great gas mileage, dependability, the same weight transfer as the 2.8 and all the v8 torque I need. This is just my experience and do not want to start anything it is just why I did not like the SBC in my Fiero. It also messed up the car after installing it you have a water pump sticking through the rear fender well and you have to cut out part of the frame rail. Iím like others I have learned the hard way and made a lot of mistakes in trying to build my car but I think this is the cost of most of us but we keep building on ;D

  9. #9

    Re: A powerful engine

    The weight offset was a concern, but, aluminum heads, aluminum intake, aluminum water pump, and headers make an SBC only marginally heavier than the factory 2.8, with complete cast iron parts.

    F355 Spider did you have any other issues? Did you engineer your own kit for installation or did you buy one from Archie?

  10. #10

    Re: A powerful engine

    I'm in the process of putting a reasonable hp small block Chevy in the car I'm building. It is a 4 bolt main, TPI converted to speed density with a decent Crane cam, roller rocker arms, and fair compression with 2.02 heads. I'm guessing somewhere between 350 and 400 hp at the crank, looking for something over 300 hp at the wheels. Not a world beater, but decent.

    The Fieros were plentiful with the 5 speeds and there were two basic types. The preferred is the Getrag/Muncie. It is considerably stronger than the alternate which is an Izusu. The easiest way to tell them is how the shift cables are routed. If they come in more from the top, with the ends pointing down to the trans, it's an Izusu. If they come at a more horizontal angle then it's a Getrag. Several ratios were available as well, but that's whole other story.

    Several people have done the SBC swap with both transmissions. Drag racing tends to be hardest on them, naturally. Either can split the case when overloaded. The trick to making them live is good clutch work and allowing some slip in the drivetrain either through tires or clutch. Most of the folks that have done this have been most happy with the Centerforce dual friction clutch from Archie. He's used this clutch for a long time with good results.

    If you're going to drag race or really get rough with the car, then the absolute strongest transmission was the Muncie 4 speed. The gears are much wider and the case is thicker.

    I'm using the Izusu but I don't intend to drag race the car more than a couple of passes just to see what it can do and satisfy my curiousity. I feel like the Izusu will be fine for me but if I wanted to drive in a more "spirited" fashion, I'd try to find a Getrag.

    John Stricker

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