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. DC-GT

    DC-GT New Member

    Joined:
    Nov 25, 2003
    Messages:
    312
    Likes Received:
    0
    Trophy Points:
    0
    JL, if you have it that far apart you really should do the cams. Why pull it all apart again to do it later?

    Bo
    #41
  2. D97GT

    D97GT New Member

    Joined:
    Dec 7, 2003
    Messages:
    8
    Likes Received:
    0
    Trophy Points:
    0

    Lets see,

    Your combo = approx $4000 and makes around 310 rwhp and around 300rwtq. Your combo is also going to need 3.73 gears or better to really take advantage of the new power band. Low RPM torque will be worse than stock. Gas mileage will suffer due to the gearing change. This combo will also need a custom tune.

    My combo w/comp cams = approx $2500(depending on where you get the used SC maybe less) and makes around 310 rwhp and around 345 rwtq. This combo has a lot more low end torque and will work fine with stock gears. If the SC is bought with the SVO computer no custom tune is needed.

    I know what I'd buy!
    #42
  3. GT98SVO

    GT98SVO New Member

    Joined:
    May 3, 2000
    Messages:
    25
    Likes Received:
    0
    Trophy Points:
    0
    SVO blower is a good blower for those that know. It won't produce max numbers like a centri(Paxton, Vortech, ATI) or Lysholm screw(Kenne Bell).

    300-320 rwhp is possible with stock non-PI heads and proper other parts. This is where most centri blowers fall flat as well.

    Aftermarket fuel pump, aftermarket MAF, 9 or 12 lb pulley, headers w/offroad exhaust, ported blower intake, cams and tune will hit 300+ rwhp no problem. All this can be had with a used blower for < 3000$. (My blower is for sale, I also have a Pro M 80mm race MAF + some of the other parts ) ;)

    Ported PI heads and cams will take the SVO blower to 350-400+ rwhp.
    Roxanne Shepard, 2 Cam Sam, and others have made these numbers with the SVO blower. I doubt there is much left in the blower after this point.

    It also looks kewl, and is different from the rest of the centri clones.

    Keep in mind, Roots/screw blowers make streetable horspower. Off idle to 3500 rpm will beat a centri any day.

    SVO blower is based on the M112 Eaton blower, same blower size that is in the 03 Cobra and Lightning. These cars make 390 hp.

    Yep, the SVO's intake manifold is a drawback as well as not having an intercooler. The intake can be opened up by porting companies, and the temperatures can be lowered with a proper cooling system and water/methanol injection.

    When I ran my blower, I ran TR6 plugs, Royal Purple Purple Ice, 160degree thermostat, and I never had a problem in Dallas heat. Temperature gauge was lower than stock.
    #43
  4. White360RFnSwee

    White360RFnSwee Founding Member

    Joined:
    Nov 4, 2002
    Messages:
    869
    Likes Received:
    0
    Trophy Points:
    0
    The SVO Blower is based off an Eaton M 90..

    -Ryan
    #44
  5. White360RFnSwee

    White360RFnSwee Founding Member

    Joined:
    Nov 4, 2002
    Messages:
    869
    Likes Received:
    0
    Trophy Points:
    0
    310 rwhp?
    300 rwtq?

    haha..
    Try 325+ rwtq...
    and about 315 rwhp..

    gas mileage will go down with a blower... 3.73s aren't bad whatsoever for gas mileage..

    $4000? Where are you shopping?

    Cams + springs = $600
    PI heads + necessary stuff to swap = $1100 if you know where to shop around.
    Chip + tune + dyno time = $300 or so
    Gear Change = $400
    Mass air = $250
    Exhaust = about $1000 all together.

    You'll want to do exhaust witht he blower regardless...

    And besides, if you want to do more with the car eventually, you now car. With your SVO blower you can't swap heads, and you'll be stuck with those weak 96-98 heads.
    #45
  6. GT98SVO

    GT98SVO New Member

    Joined:
    May 3, 2000
    Messages:
    25
    Likes Received:
    0
    Trophy Points:
    0
    I got 25 on the highway with 3.73's and SVO blower at 9lbs. All depends on how you drive it.
    #46
  7. GT98SVO

    GT98SVO New Member

    Joined:
    May 3, 2000
    Messages:
    25
    Likes Received:
    0
    Trophy Points:
    0
    Many folks are running the SVO blower with PI heads.
    #47
  8. White360RFnSwee

    White360RFnSwee Founding Member

    Joined:
    Nov 4, 2002
    Messages:
    869
    Likes Received:
    0
    Trophy Points:
    0

    Now, when I talked to the Ford Racing people about this..

    They said that I was unable to run the SVO blower with the PI heads...

    I'll admit I was wrong on that one.. But Im really happy to hear that it is possible. I notice you have an SVO blower..

    im considering getting a 97 Autumn Orange GT Automatic ( If I can find one!! )
    and Id love to do a headswap, and then put an SVO Blower on the car. Is this at all possible?

    -Ryan
    #48
  9. GT98SVO

    GT98SVO New Member

    Joined:
    May 3, 2000
    Messages:
    25
    Likes Received:
    0
    Trophy Points:
    0
    SVO/FRPP is a M112. I have one.
    Roush used the M112 for a time.

    AED/some Roush/Saleen use the M90.
    #49
  10. White360RFnSwee

    White360RFnSwee Founding Member

    Joined:
    Nov 4, 2002
    Messages:
    869
    Likes Received:
    0
    Trophy Points:
    0

    Roush used the SVO blower in their 99 Stage 3.

    -Ryan
    #50
  11. GT98SVO

    GT98SVO New Member

    Joined:
    May 3, 2000
    Messages:
    25
    Likes Received:
    0
    Trophy Points:
    0
    I am not a fan of mating the FRPP/SVO blower to PI heads. Too much work for too little reward. I wouldn't recommend it to anyone. I do commend those who have done it, but I'd rather go in different directions.

    One could find used FRPP/SVO heads and make them work or just live with the limitations of the non-PI heads. The SVO/FRPP blower is going to peak early on anyways.

    I would like to see non-PI heads that have big valves and a Stage II port. AFAIK, no one has posted this head setup online. I think these heads with the proper cams, could take the SVO blower to 380-400rwhp. And this would be cheaper than buying PI heads and porting them, plus adding cams. And dealing with the ports not matching up. But that is just my hypothesis, I don't have the dough to try it. Its as far as I would want to go with my 98.

    But that's just my opinion, I could be wrong. Dennis Miller.

    2camsam has made the blower work with PI heads, search on his name on Corral.
    #51
  12. GT98SVO

    GT98SVO New Member

    Joined:
    May 3, 2000
    Messages:
    25
    Likes Received:
    0
    Trophy Points:
    0
    #52
  13. hioc1098

    hioc1098 Founding Member

    Joined:
    Aug 18, 2002
    Messages:
    76
    Likes Received:
    0
    Trophy Points:
    0
    FWIW, I'm pulling the heads to send to Steen for a street port job. I'll then put the 9lb SVO on it with the long tubes and see what happens. I used to have a Vortech, but hated having to run it up on the streets just to get it going. I went with the SVO solely for the low end torque and the ability to drop back my gears so I can drive the car on long trips. We'll see where it takes me.

    In stock condition, the heads are crap. However, it's been proven through many, many individuals that the heads flow well with a good port job, PI valves, and better cams. Don't take my word for it, do a search or look at Steen's site. The ported NPIs flow almost as well as the ported PIs with the same port package. Is there a limit to the heads? Most certainly. But, for most street drivers, they're decent. (flame suit is on)

    Oh yes. What will I have spent for the blower and port job? A total of $2500.

    Tim
    #53
  14. Sam98

    Sam98 Founding Member

    Joined:
    Mar 15, 2002
    Messages:
    1,625
    Likes Received:
    0
    Trophy Points:
    0
    Good luck with your setup, but ported non-PI heads only slightly outflow stock PI heads and cannot compete with ported PI heads. Even so, you should be able to fry your tires on the street. Have fun and don't get any tickets... :D
    #54
  15. D97GT

    D97GT New Member

    Joined:
    Dec 7, 2003
    Messages:
    8
    Likes Received:
    0
    Trophy Points:
    0

    I agree 325 RWTQ is possible on some, but most I've seen fall closer to the 300-310 rwtq mark. Any way you slice it, it'll have less torque below about 3500 rpms than the stock car. And nowhere near my 300 rwtq avail from below 2000 rpm's.

    I said "gas mileage would suffer", that means it will get worse. It'll definitely be worse than it would have been with 3.27's. Maybe only by 1 mpg but no-less worse. I had 2.73's in my car at one time and remember hitting 26.5 mpg on highway trips with the SVO SC. The best I see now with 3.27's is 24.5mpg.

    There are a few discrepancies in your parts list. Chip + Custom tune with dyno time for $300? Maybe you have a friend with a dyno, I don't! Try $500-$600. I spent $500, 5 yrs ago to have my powerdyne combo tuned on the dyno at Dallas Mustang. Just a chip will cost you $300 or more unless you find one on sale. I also don't see head port work in there anywhere? 99% of the people out there don't have the facilities/knowledge to port the heads themselves. Good port work will cost as much or more than the heads. Steen Racing starts at $700 for port work.
    Your combo listed above was $3750, now its a whole lot closer to $5k.

    On the subject of exhaust, my only mods are a catted bassani-x. I don't think I'd need anything else on the exh side to get past the same HP level your talking about.
    #55
  16. GT98SVO

    GT98SVO New Member

    Joined:
    May 3, 2000
    Messages:
    25
    Likes Received:
    0
    Trophy Points:
    0
    Do the oversized Mod Max(Ferrea) valves head porters put in the PI heads fit in non-PI heads? Would it increase flow or be a restriction?
    #56
  17. hioc1098

    hioc1098 Founding Member

    Joined:
    Aug 18, 2002
    Messages:
    76
    Likes Received:
    0
    Trophy Points:
    0

    From what I understand, the PI valve is the largest valve that can be put in the NPI head. There simply isn't enough room.

    Tim
    #57
  18. hioc1098

    hioc1098 Founding Member

    Joined:
    Aug 18, 2002
    Messages:
    76
    Likes Received:
    0
    Trophy Points:
    0
    While I won't pretend to say the NPIs are great heads, Steen shows flow numbers from street ported NPIs and street ported PIs to be fairly close (not the same, but fairly close).

    However, when one gets crazy with the PIs (cobakiller) they see upwards of 243 cfm. That's crazy flow.

    Hopefully, I'll be able to do more than just fry my tires. I'm also tweeking the suspension a little to try to transfer weight better. As I said, we'll see.

    Tim
    #58
  19. Sam98

    Sam98 Founding Member

    Joined:
    Mar 15, 2002
    Messages:
    1,625
    Likes Received:
    0
    Trophy Points:
    0
    I've seen some good flow numbers from ported non-PI heads too, but even with the better numbers they don't seem to make as much power as ported PI heads do. I hope it works out for you...it sounds like you have a pretty decent setup.
    :nice:
    #59
  20. hioc1098

    hioc1098 Founding Member

    Joined:
    Aug 18, 2002
    Messages:
    76
    Likes Received:
    0
    Trophy Points:
    0
    I've read much of the same thing and that baffles me. I'd like to think much of it is contributed to the crappy intake (as Jonny L has proven with his tests), but I don't know if that's the whole story. As many have pointed out, I don't know of too many trying to really ring power out of these heads (other than Jonny and co.).

    I will probably be a PI head guy down the road (many more possibilities), but I don't see how to incorporate my near term setup (SVO) with them. Blown46 is planning to do it with a thicker gasket, but I haven't seen it done yet and I'm not rich enough to be a pioneer. I don't want to remove swirl dams, so that leaves me with two choices. Either throw the blower on with the PI cams and probably have less power than my previous Vortech setup (not really an option). Or, port my current heads and see where it takes me.

    I've got all winter to get it done, so I'll continue with my information quest for now.

    Tim
    #60

Share This Page