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Chevy Impala 2004 Redesign

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Comments

  • 02lssport02lssport Posts: 75
    Damn I don't remember that engine. What car was that in? But you are right - car makers can do many things. It about what makes sense at the time and is cost effective. I can't wait to see what they in store too. Its sounds like they have some great engines coming soon.
  • vcjumpervcjumper Posts: 1,110
    I thought it only made 215.. Was a rework of the 3.1L OHV with new heads.
  • atbearatbear Posts: 322
    It wasn't put into cars in that incarnation due to not having a FWD automatic tranny that could handle 275HP. The engine was ready, but no tranny, so they detuned it to 210HP 215TQ for production. Go here: http://www.angelfire.com/ca2/34Performance/dohc.html

    Here's some quotes:
    "The 3.4 was concepted as a V6 version of the Olds 2.3L "quad 4"."
    "The 3.4L DOHC was actually the forerunner of many current motors. The Cadillac Northstar 4.6L 32 Valve V8, and later the Aroura 4.0L 32-Valve V8, were sons of the V6 program."
    "Well, the GM engine gurus went to their counterparts at GM Hydramatic, with a challenge. Build a FWD auto trans, that will take 275 HP. You have 2 years to be in production. In a car."
    "and it was by far, the BEST motor that GM engineers could build for its application. Emission certification verifed an honest 281HP on the sheets. Emission 7000RPM screamer. This was in early 1990, January I believe. Transmission? Anyone? Hydramatic had its own challenges to conquer."
    "Hydramatic went to the market with their finished product just days before the deadline. Will it take 275HP? NO! Will it take 250HP? NO! How bout 225Hp? Maybe. GM engine ground was peeved! All this effort, just to be cut down at the flywheel....225HP? I want 275! Well, the rest is corporate decision making at its worst. Cut the horsepower of the 3.4L to 200 with an automatic. You can have 210 on a stick. Makes a guy want to cry, don't it?"

    It's a damn shame they couldn't get it out then... but at least we have good trannies now... GM and Ford are even now working on a 6 speed FWD tranny right now together. Should be good. Now all we need are some manual trannies!!!

    Also, for more GM DOHC, check out the Northstar, and the ZR-1 Corvette.
  • regfootballregfootball Posts: 2,166
    that 3.4 twin dual cam was designed to adapt the 3.1 pushrod motor into a DOHC in order to utilize some existing tooling and factories.

    In other words, a half butt approach to engine design.
  • atbearatbear Posts: 322
    Sorry, but that's just not true.... It was designed from top to bottom to be a fully performance engine in FWD form... You are wrong.
  • regfootballregfootball Posts: 2,166
    no, you are. I'm gonna have to dig through my old car and drivers to find that article.

    I think if you look you will find the bore centers are exactly the same which is part of what enabled them to utilize some existing tooling from the pushrod version.

    A way to cheap out on the design in other words.
  • atbearatbear Posts: 322
    Are you saying that this engine was supposed to be anything other than a full out performance engine? If you are then you are way off. This engine was based off a quad four, not a pushrod six.
  • I don't believe that's the case.

    The 3.4 DOHC is a separate engine, one that evolved from the Quad 4 and was used in several other cars in the late 80's and early 90's.

    The 3.4 pushrod in the Impala is based off of the 3.1, 2.8 pushrod series which is a completely different engine that I believe debuted in 79 with the Citation.
  • atbearatbear Posts: 322
    Yeah... I didn't even think he could be talking about the wrong engine... LOL...

    I'm talking about the DOHC 3.4L V6, not the 3.4L Pushrod V6 which is based pretty much on the 3.1L Pushrod V6.
  • vcjumpervcjumper Posts: 1,110
    Here is some info.. Too bad the engine was practically stillborn with the reliability issues and unsuitable trannies.
    3.4
  • regfootballregfootball Posts: 2,166
    I didn't get a chance to look through my magazine archives today at home, but the link vc posted above I read through last night. I also found another web link where someone had experimented with using the OHC heads on a pushrod block or something. Also, many Fiero sites have info on where people have swapped the Fiero 2.8 v6 for the Twin Dual Cam which suggests they have near identical block configurations and sizes.

    http://www.geocities.com/MotorCity/Garage/5007/fiero_osg/60-degre- - e-V6.html

    this link also suggests the 3.4 TDC was an evolution of the far too ubiquitous Citation engine.

    I don't disagree that perhaps the head design for the Twin Dual cam was modeled after the Quad four, but from what I have read in the past, the block design started with the pushrod v6 because of the desire to utilize some existing tooling and manufacturing capabilities. The oiling system was modified to work with OHC and a complete DOHC top end was half@$$ed on top of the modified pushrod block.

    I will find the tech report in Car and Driver that breaks this out in detail. I've seen it / read it. Just need to dig some boxes up in the bedroom to get to it and find it.

    Besides, in the early 80's to mid 90's GM never designed an all new v6, much less an OHC, so it was par for course for them to take a half hearted approach. So like them.
  • atbearatbear Posts: 322
    The 3.4 Pushrod and 3.1 Pushrod engines are very similar, I'm not saying they aren't. But the DOHC 3.4 and Pushrod 3.1 are completely different.

    Also, the 3.4 DOHC is a pretty good engine with pretty good reliability... it was just coupled with a poor alternator, and a poor tranny... vcjumper just posted the same article I did......
  • Why are we talking about the DOHC 3.4? It's not being offered anymore, and is certainly not the engine in the Impala.
  • atbearatbear Posts: 322
    Because we are talking GM engines, and DOHC engines. And that is a GM DOHC engine.
  • One that hasn't been used in years and shows little of GM's supposed engineering prowess...
  • atbearatbear Posts: 322
    So? You asked a question and I gave you an answer... If you want GM's engineering prowess, look at the new Cadillacs, the Northstar, the LS6, the new GM 3.6L DOHC, the 4.3L Vortec V6, and the Ecotech 4 cylinder.
  • The 3.6 DOHC isn't out yet, so I can't attest to it. The inline six on the trailblazer is a good engine...the Ecotec 4 cylinder is smooth but underpowered and generally no better than its competition.

    Wow, I'm so overwhelmed.
  • atbearatbear Posts: 322
    The Ecotech 4 cylinder is just a good reliable durable engine with good power and the ability to take boost from superchargers or turbos.
  • regfootballregfootball Posts: 2,166
    the only force fed Ecotec so far is the Saab. Its too early to tell yet if it will spill its innards or not when its getting rammed.
  • atbearatbear Posts: 322
    They sell factory/dealer installed superchargers on all Ecotecs, reggie.... Esp the Sunfire.
This discussion has been closed.