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Can Your Pushrod Do This?

Discussion in 'Other Off Topic Forum' started by Paul Vincent, Apr 9, 2004.

  1. Paul Vincent

    Paul Vincent Formula Junior

    Apr 3, 2004
    474
    For some of you these statistics aren't news, but for the rest (especially because of the recent pushrod thread), I thought I ought to share. These stats are from the April 12th AutoWeek article entitled Aye, Carrera! :
    (00:01*April*12,*2004)
    ¡Aye, Carrera! The First Full Test of Porsche's Carrera GT Supercar

    By MIKE DUFF

    2004 PORSCHE CARRERA GT
    ON SALE: Now
    PRICE: $440,000
    POWERTRAIN: Mid-engine, 5.7-liter/350-cid dohc V10;
    605 hp @ 8000 rpm, 435 lb-ft @ 5750 rpm; six-speed manual
    CURB WEIGHT: 3043 pounds

    Now, is there any question as to whether it is the dohc or the pushrod ohv engine (of the same size) that makes more power? I will concede that I do not know the weight of this Porsche engine. It may weigh considerably more than the LS6. I do know that the engine weight was an important consideration for the argument that pushrod engines are superior.
     
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  3. C. Losito

    C. Losito Formula Junior

    Dec 12, 2003
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    Chris Losito
    *Hands out flame shields*

    You know, there's no point in arguing this, as there's nothing inherently wrong with either valvetrain design. Both have strengths and weaknesses.

    To answer your question, yes, you can get 600+hp out of a 350cid pushrod V8. Not only that, but you can do it for a lot less than the cost of that Carrera engine.

    Oh, and you can also get one to rev to 8 grand.
     
  4. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,012
    Yes, no and maybe:

    605 HP from 5.7 litres in an emissions complient engine is remarkable.
    435 TQ from 5.7 litres is remarkable

    NASCAR 355 engines do 850-900 HP at 9,000+ RPMs when not restricted on superspeedways.

    I don't know of a single N/A 350 CID pushrod engine that can do 600 HP in street trim; 525-550 seems doable.
    I know of lots of 396, 409, 417, 427, 436 CID engines built from LS[16] blocks, many of which do have 600 HP, few would survive an emissions certification, maybe half would survive a tight emissions test, the vast majority would pass a typical state emissions test.
    In the realm of american V8s, to get HP you throw Cubes at the problem.
     
  5. C. Losito

    C. Losito Formula Junior

    Dec 12, 2003
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    You can build a perfectly streetable 600hp smallblock. How do you want it done? Blower? Turbo? Twin-turbo? NA?

    Most states don't test older cars. Illinois, for example, doesn't test cars older than 1968, and that's actually a bit rough. Even if you have to get it tested, most american cars didn't have cats until 1973. A well built engine may be more likely to pass than an original 30 years later.
     
  6. sherpa23

    sherpa23 F1 Veteran
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    May 28, 2003
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    After reading the title, I thought this was just another NWS porn thread.
     
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  8. docdavid

    docdavid Formula Junior

    Jan 23, 2004
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    Mike D
    I'm not very technically inclined and am therefore not capable of offering any substansial rebutle, but it seems obvious that a lot more time / money has been put into the $400 000 porsche dohc, as opposed to the LS1 that is used in the $70 000 corvette and $40 000 camaro, (until last year). In my opinion there kind of differnet leagues.
     
  9. damcgee

    damcgee Formula 3

    Feb 23, 2003
    1,864
    Mobile, AL

    At first I was like, "Where does this guy buy his vettes and camaros?" $70k for a Corvette! Then I realized you were referring to Canadian dollars! Whew!!
     
  10. bostonmini

    bostonmini Formula 3

    Nov 8, 2003
    1,881
    carrera gt engine weighs 472 lbs. also, dont forget that if you really want to go nuts in the dohc vs pushrod argument, dont be fooled into thinking "pushrods make torque" as todays valve timing can more than compensate for this, see the torque/liter. viper has FAR less than M3, a good torquey 24 valve 6. furthermore, dont think that the carrera GT is all it could be if emissions (as mitch indicated) werent a factor. that one that was crashed by a french journalist maxed at 15,500 rpm before breaking, new cams and ecu would probably make this a realistic 750 hp engine...think of the F50 GT1 that had 720 out of 4.7 liters! impossible with a 289 small block.
     
  11. Mr Payne

    Mr Payne F1 Rookie

    Jan 8, 2004
    2,870
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    Some people seem to be completely disregarding cylinder size...A 5.7L DOHC V8 would have trouble making 600hp, much less than a 5.7L OHV V8...keep the variables equal people...
     
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  13. anotherguy

    anotherguy F1 Rookie

    Feb 22, 2004
    2,574
    This is a largely flawed assumption. Porsche probably spent less on this engine the GM did developing the LS1, as the LS1 was to become the foundation for most of GM's V8's. As someone else has already pointed out, cylinder size does play a roll in this. Smaller pistons can rev to higher RPMs and the faster the engine is pumping air in and out, the more power it should be able to make. The ability to rev that high for a large displacement engine is based on many factors, but one of the most important is simple. Money.

    Chevy, in designing a corvette engine has to limit their per engine cost i to fit within the guidelines set out during product spec'ing, which places limits on what types of components and processes they can use.

    I would be willing to be that if anyone would build a $440,000 car that anyone would take seriously, they would give us power output somewhere north of 600 ponies.

    There is a fairly common assumption that Ford, GM, etc. can't build anything fast and desirable, and that the best engineers for performance work at Ferrari, Porsche, Lambo, etc. The problem is the limitations created by everything having to be interchangable across models and brands. With the exception of Lamborghini, name another performance car other than the Corvette that shares any part of its engine design with a real honest to god, work truck.

    -ag
     
  14. FrostCS

    FrostCS Karting

    Mar 3, 2004
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    Vegas
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    Christopher
    GM does spend more working to improve/create their engines. They actually spend more time and money on concept engines then most companies spend on researching production engines. I know of a few nice little articles that stress this point, but since it's soon to be easter, I'll let you do your own little egg hunts. However, I will give you a quote from what I am speaking of, and at it's source (I'll make you look for it, *cackle*) is a nice little article on the workmanship that goes into GM products, and idea's.

    "GM is recognized as a leader in computer-aided design, which allows engineers to extensively test, analyze and optimize designs in math before moving to expensive hardware. Computer-aided design also accelerates the development process as evidenced by the remarkably short time required to develop this engine."

    With the other egg's from this "basket" (source) is a long list of technologies GM uses to actually improve their pushrod engines to keep up with the OHC engines. Though the article itself will not be boring, since it's about a very interesting, and attractive automobile.
    Yes, GM is at the top of their field when it comes to R&D.
    Enjoy the hunt,
    CS
     
  15. Paul Vincent

    Paul Vincent Formula Junior

    Apr 3, 2004
    474
    Not that they are the same engine, but I'd be willing to bet that the Ford Lightning engine does share a part or two with the Ford GT engine. Not that it would bother me if it didn't; it's just that I'd be amazed if a couple parts weren't shared.
    Also, on the weight per hp (for those of you who care) LS6 = 405 hp/450 lbs = .9 hp/lb. The Carrera = 605 hp/472 lbs= 1.28 hp/lb.
     
  16. SkizoACE

    SkizoACE Formula Junior

    Mar 24, 2004
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    So are you saying you get more power out of a DOHC engine? If you are I dont disagree or agree.

    Ive seen pushrods with upwards of 800HP with no blower. And ive seen DOHC's with 800HP with no blowers. Ive noticed that more DOHC's are supercharged or turbocharged than pushrods.

    It depends on the tuners I guess.
     
  17. Paul Vincent

    Paul Vincent Formula Junior

    Apr 3, 2004
    474
    skizoACE, It is the manufacturers who are getting more hp (for a production vehicle) out of the dohc engines than the ohv-pushrod engine. As of right now, this is how it stands: Chevy/GM gets 67% of the Carrera's horsepower using an engine that weighs 95% of the Carrera's and is 99% the displacement of the Carrera's. As I could own a ZO6 and never ever a Carrera, I wish that Chevy would match the hp per liter of the ZO6 engine to that which Porsche gets from the Carrera's engine (and I'll bet I'm not the only one).
     
  18. Hubert888

    Hubert888 F1 Veteran
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    May 14, 2003
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    that's why u decided to click on the link, eh? :)
     
  19. Mr Payne

    Mr Payne F1 Rookie

    Jan 8, 2004
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    I hope you mean Carrera-GT, much different than a Carrera. and certainly cost of the engine is a factor in this...I've heard 996 Turbo engines are installed at the tune of 50K...LS6s are installed at 8-10K?
     
  20. SkizoACE

    SkizoACE Formula Junior

    Mar 24, 2004
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    Thomas
    If GM did that, then Porsche wouldnt be able to brag.

    I heard that the new C6 Z06 is around 500HP. But you cant compare a Chevy to a Porsche, thats like comparing McDonalds to Jack-In-The-Box. Chevy cant compete in reliability and wearing.

    And on another note, the GT is a 'super-car'. The Corvette is nowhere near a 'super-car' and yet almost as fast as some.
     
  21. maranelloman

    maranelloman Guest


    New Z06 will have 3 valve heads with pushrods, as well as some other tricks. Plus, primo brakes (finally), etc. Will also continue to get ~30 MPG highway. Find me another car as fast, at any price, that gets such excellent economy.

    As for this comment, "Dixie Normous" (I snicker at your delusions of edequacy): "Chevy cant compete in reliability and wearing." I say BS. Chevy small blocks have been around for 50+ years, and are much more reliable that any import engine of V8 or V12 configuration.
     
  22. Mr Payne

    Mr Payne F1 Rookie

    Jan 8, 2004
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    If the F40 is considered a supercar surely the next Z06 will be considered one as well. I predict the Z06 to be faster than an F40 in all aspects. In fact, the performance gap between 300K+ cars and ~100K cars is so minimal at this point in time, I'm just wondering when buyers will catch on. Previously cars like the F40 were leaps and bounds better than cars like the ZR-1 or NSX. Now the gap between an SRT-10 (read: convertible) or Ford GT and an Enzo is not nearly as large as price difference would imply and certainly not as large as the F40 vs. ZR-1, NSX.
     
  23. Paul Vincent

    Paul Vincent Formula Junior

    Apr 3, 2004
    474
    Yes, Carrera GT.
     
  24. SkizoACE

    SkizoACE Formula Junior

    Mar 24, 2004
    884
    Houston
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    Thomas
    I know that they are reliable, I own a car with a 350. The only thing that ever gives up on it is the alternator, but my engine has nearly 100,000 miles.

    My dad owns a Porsche Turbo that has 25,000 miles on it and it hasnt had any mechanical problems. But, the Carrera Turbo is not a V-10, its Porsches famous 3.6 liter flat-6.
     
  25. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,398
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    BMW and cedes V12s are pretty good and regularly get 150,000+ miles. Sure parts are more $, but the blocks are pretty solid.
     
  26. stephens

    stephens F1 Rookie
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    Feb 13, 2004
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    Recently GM Australia toyed with the idea of putting a 427ci small block, in the GM Monaro. It was a street legal version of the C5 race motor, which is being succesfully raced in the Production car catagory over here.
    They were only able to get around 520hp in emissions legal trim, so talk of 600+ out of a PRODUCTION 5.7 Chev motor without forced induction is complete BS.
     
  27. Mr Payne

    Mr Payne F1 Rookie

    Jan 8, 2004
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    Weren't they predicting 600hp+ for that bad boy? The info on that just kinda died......you know what the specific problem was?
     
  28. stephens

    stephens F1 Rookie
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    Feb 13, 2004
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    They had prototypes running around and even took 50 deposits. There were major cost blowouts making the project ot feasible. I checked on the power figures and they were struggling to get over 400kw (around 540hp) in production trim.
     

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