roots/centrifugal style blowers on a 4.6 SOHC vs. heads/cam/intak mani.

Discussion in 'SN95 4.6L Mustang Tech' started by Johns96SS, Dec 4, 2003.


  1. Johns96SS

    Johns96SS New Member

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    Researching for a friend:

    We are not lookin for gobbs of power, but somwhere around 330-350rwhp/tq and deffinitly still a daily driver.

    4.6 SOHC car has boltons, either looking to put on a used or new roots or centrifugal style blower for some kick. Any known problems/difficulties anyone has run into with this setup? Particular brands to aviod?

    I thought it best to do Heads/cam/intake mani. as far as price and i thought it safer, but i have heard results on heads/cam cars in a 4.6 are not very good.....what is yalls advice?

    We would be doin the work ourselves so cost of labor is irrelivant. All help is greatly appreciated.

    Thanks
    #1
  2. ReVeRsE

    ReVeRsE New Member

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    what year is the mustang?
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  3. GinoGT

    GinoGT Founding Member

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    BTW - The previous idea of cams without head work on a 4.6 being a waste just got blown out the window. :D

    A nice P&P with cams, Fox Lake intake, and some long tubes topped off with a good tune would make a :drool: N/A car. Then get a forged bottom end and rev that sucker. :banana:

    I'd definately say it's possible to get into the low 300's at the wheels N/A right now.
    #3
  4. Johns96SS

    Johns96SS New Member

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    1997 year model,

    I know it's possible i also for got to mention cost is an issue, so we're lookin at cheaper parts/used if necisarry...about a 2k budget.
    #4
  5. mrvax

    mrvax Stay thirsty my friends Founding Member

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    The only way you will even come close to those numbers on a 97GT is with nitrous.

    Headswap will bring you near 250rwhp.
    #5
  6. Johns96SS

    Johns96SS New Member

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    both a headswap and n2o...ic, any other suggestions...we are tryin to stay away from n2o.
    #6
  7. Sam98

    Sam98 Founding Member

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    The 97 can get close to 300 RWHP with a good blower and exhaust, but don't expect 350 with the stock heads. A cheaper alternative might be to get a used 99 or newer GT motor from a junk yard and swap the engine before you get the blower. Then you will be in the 350 RWHP range. Good luck...
    :nice:

    As for blower brands...

    Centrifugal: Vortech, Paxton, and ATI all make good power on the 2V 4.6L with 8-12 psi boost.

    Roots: don't bother, especially with a 97, but the Kenne Bell twin screw is an excellent alternative.
    #7
  8. J98GT

    J98GT Founding Member

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    Don't listen to this guy. Roots blower compliment the power characteristics of the non PI motors better than centrifugals.

    This year I've had BOTH of the following combos (Note all dyno numbers are MUSTANG dyno, not dynojet):

    OLD:
    98 2V (non PI) with SVO roots blower
    stock headers
    Off Road H pipe
    11lbs max boost
    280rwhp 310rwtq

    CURRENT:
    ENGINE SWAP 02 PI 2V with Voretch SQ
    BBK LTs & off road X
    Steeda Boost pipe
    11lbs max boost
    367rwhp 367rwtq

    Without PI heads, you won't be able to take full advantage of the top end power that a centrifugal blower makes. So you be near the same rwhp as my old combo, but your low end torqe will be severly lacking in comparison. Hell, the low end of MY new combo is lacking in comparison. Granted it screams on top, but again that is due more to the breathing capability of the engine itself.

    With my SVO, I beat several vortech'd 96-98GT's and even a vortech'd 5.0 AT THE TRACK. I outran C5's and Lightnings on the street with no problem. And on top of that, full boost at 2000 rpm is hard to beat.
    #8
  9. J98GT

    J98GT Founding Member

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    I do agree that a PI motor with Vortech is the BEST option, but it can be pricey. I spent ~7K on my combo, not including fuel, MAF, and chip. Also, I wouldn't recommend a junkyard motor with a blower unless you KNOW the history. I tried that with my SVO. It lasted about 2 months. After that I got a brand new complete 2V for $2300.
    #9
  10. J98GT

    J98GT Founding Member

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    btw, you should be able to find a used roots blower (they are bulletproof) for less than 2K. I just sold mine for $1650.
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  11. Ruffrider

    Ruffrider Founding Member

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    I say go with the blower. Not an easier way to make a lot of power quick, except Nitrous.
    #11
  12. kirkyg

    kirkyg Founding Member

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    I say screw boltons (besides catback exhaust) and go straight for a non-intercooled Kenne Bell kit...it'll cost $3799 and everything you need is included. You can expect a flat torque curve with boost off idle. Id guess with catback you would get about 340-355 rwhp and 380+ ft/lbs. of torque. Oh btw, this is just with a 6 psi pulley.

    kirkyg
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  13. J98GT

    J98GT Founding Member

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    340-350 from 6psi on stock non-pi heads? I doubt it. Maybe more like 300rwhp. The intercooled kit may get you to 350 with a good tune.
    #13
  14. kirkyg

    kirkyg Founding Member

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    Oh yea your absolutely right. I missed that it was a 97 model. I just dont see 300+ n/a without forking out over 8-10k which is rape. I still think a supercharger is the best bet. You could probably get PI heads and not get any work done on them for a reasonable price and supercharge it. Then you'll be in the 300s easy depending the kit you choose.

    kirkyg
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  15. J98GT

    J98GT Founding Member

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    Yeah, but untouched PI heads will give you a 10.x:1 CR, which is not good for boosted applications.

    I'd recommend to pick up a roots blower kit. Send it to www.magnumpowers.com to be ported, and slap it on with a good exhaust and 9lb pulley. You'll have a corvette killer that drives just as good as stock and has big-block torque. Plus the roots blower's whine is possibly one of the greatest sounds known to man. The Vortech whistle sounds like crap in comparison.
    #15
  16. kirkyg

    kirkyg Founding Member

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    I think 10:1 would be fine if you were only running 6-9psi. Id definitely run 94 octane though. You could always use a thicker headgasket but im not sure how much of a loss in compression you would get from that.

    Roots are nice because they have low rpm boost like twin screws but they are VERY inefficient to say the least.

    kirkyg
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  17. RedGTvert

    RedGTvert Founding Member

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    I'd like to see the dyno sheets for this please.
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  18. J98GT

    J98GT Founding Member

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  19. kirkyg

    kirkyg Founding Member

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    It sounds like you think the Kenne Bell is centrifugal...Its NOT roots NOR is it centrifugal. It has boost at all rpm ranges. Its the best of both worlds so get your facts straight. Everyone knows the PI heads are going to hold him back. He can choose one of two paths...he can just boost the engine more than normal to get the power he wants or he can do the swap and get a supercharger (probably the most reasonable option).

    Only problem for this situation is the pre 99 model kits are not available yet.

    kirkyg
    #19
  20. J98GT

    J98GT Founding Member

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    I am familiar with the concept of twin screw superchargers. I'm not talking about them at all. However, Don't be so quick to dismiss roots blowers, especially considering the price you can get them for. For a stock headed 96-98, I would recommend a positive displacement blower, whether roots or TS. Maybe I misunderstood you.
    #20

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