High RPM or High Boost? You Tell Me.. | FerrariChat

High RPM or High Boost? You Tell Me..

Discussion in '348/355' started by michael66899, Oct 18, 2013.

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  1. michael66899

    michael66899 Karting

    Jul 12, 2004
    119
    Bellingham
    Full Name:
    Michael
    Had some engine issues with my 348 so I'll begin tearing it down here in the next couple weeks and unfortunately for the purists she won't be going back together anywhere close to the way she came from the factory. My issue is I'm currently torn between building a high strung n/a motor and building a turbo set up.

    I just bought a spare motor to play with so I might go one route now and take the other later but we'll see, part of me just wants to do it once and be done with it. I can obviously make a lot more power with a pair of turbos without spending a lot of time/money on the heads/cams and intake but the thought of an n/a motor turning 9500+ rpm breathing through some individual throttle bodies really has me second guessing. I'm confident I could get the motor in the low 400 crank hp range n/a which is obviously no slouch but I track this car a lot along with my Audi that makes over 700hp and I really want some more kick in the rear.

    If I go n/a I've already got a source for getting the heads CNC'd, custom cams, high rate springs etc. but can't decide if I should go to a higher compression ratio. This also means getting creative with the pistons to make sure I've got enough PTV clearance especially with the big cams. I've read a lot about the infamous 6 Le Mans motors that they built based on a 355 block but have never seen a definitive answer on the compression ratio used. I've also got a good plan for some individual throttle bodies but they're still not cheap.

    Now on the other side of things I could build a motor with some off the shelf pistons, go to a flat deck, copper head gasket, ARP studs, relatively factory heads with just some high rate springs, along with factory intake and exhaust manifolds. From the research I've done this combo should have no problem handling 20 psi. From there its just a matter of fabing up all of the turbo plumbing which for me is cheap and easy and then slapping on a pair of disco potatoes (GT28RS turbos). I have no doubt this set up could make 600+ hp on pump gas and I think it will ultimately cost less money than the n/a motor.

    My biggest issue with going the turbo route is not knowing what it will ultimately sound like. My biggest pet peave is the way a car sounds and I know with the turbos and "only" 8K rpm it won't scream like the high strung n/a motor but surely it will still sound like a proper Ferrari right? I've searched far and wide for videos of turbo 348's and have had no such luck.

    And just to clarify both set ups will be tuned by me using a standalone engine management program.

    Any input is greatly appreciated, if there are any experts on here that have built one or the other or both please share, the more info the better!

    So, build for boost or build for RPM...
     
  2. vvassallo

    vvassallo F1 Veteran
    Silver Subscribed

    Aug 4, 2006
    8,281
    Palos Verdes
    Full Name:
    Vince V
    Boost to get the power earlier and the huge torque gain.

    Trailed a boosted 348 and it definitelty wasn't a stock sound. Of course the 3 foot flames out the pipes was one indicator.

    I don't know how much power you need, but the N/A version is going to get you what 450 HP maybe for all that cost while with the boosted model the sky's the limit. The car I followed had 700 HP. I would be happy with 500 myself. :D
     
  3. NeuroBeaker

    NeuroBeaker Advising Moderator
    Moderator

    Oct 1, 2008
    38,821
    Huntsville, AL., USA
    Full Name:
    Andrew
    Keep guessing. ;)

    If I ever entertained the idea of any serious modifications to a 348, then that would be it. Massive power wouldn't be my objective, but I'd bet that'd sound amazing. :)

    All the best,
    Andrew.
     
  4. Samy

    Samy Formula Junior

    Dec 2, 2005
    603
    In my opinion a mix of rpm and turbo is the best solution for the 348 and 355. Because there are on the one hand the syncronisation problems of the gearboxes wich limit the fun in high rpm. So i would stay at 8000rpm. On the other hand the input shafts and second gear are weak and dont like too much torque. So i would stay under 550-600nm torque. With a rpm limit of 8000rpm it is atleast enough to get in the 600hp range. For me this is the best combination.
     
  5. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,576
    The Brickyard
    Full Name:
    The Bad Guy
    Here is a video of a twin turbo 348 challenge dyno pull. It put down 609hp to the wheels on a Dyno Dynamics (aka: the heart breaker).


    [ame=http://www.youtube.com/watch?v=hfrjm8kBE7M&sns=em]Ferrari 1994 348 Challenge 609 HP - YouTube[/ame]

    I also had the pleasure of going for a ride in this car. Here is the Link to my thread about it. http://www.ferrarichat.com/forum/348-355/371973-348-challenge-twin-turbo.html
     
  6. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,576
    The Brickyard
    Full Name:
    The Bad Guy
    As far as boost vs rpm.

    N/A power has more bragging rights in my opinion. But you what they say RPM stands for = Ruins Peoples Motors. :p

    It is gaggon hard if not impossible to beat the power a boosted engine can make. But then again if you show up with a high powered n/a motor making big numbers, that is so much more impressive.

    Why not do both since you have a spare engine? Build the boosted engine, and build the n/a engine. Problem is you're gonna have to figure out which one you want first. Know what? Screw it, boost the biatch. That's what you really wanna do anyway. Just know that you are gonna break stuff if it's putting out a bunch of torque. Ask Samy.
     

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