Performance Questions 225 vs. 360

Slant 6 Engines

  1. Bill Dedman

    Bill Dedman bill dedman Legendary Member

    Messages:
    4,006
    Likes Received:
    59
    Joined:
    Oct 16, 2007
    Location:
    Conway, Arkansas
    Local Time:
    11:52 PM

    I am not so sure that having those tons of low-end torque would be a blesssing (traction issues) from a 360 (I have a supercharged 360 in my '72 Valiant) and I am here to tell you, yes, it feels like a big block, right off idle. Hooking it up is a problem that is torque-related, and a turbo MIGHT be easier to get effective traction with on the street.

    I've never had a turbocharged "anything" so, can't answer your question about street driveability, but with a cam that is very close to stock in duration, and no boost to deal with at low throttle settings, it is my opinion that, yes, it really would be a lot like driving a stock-engined vehicle until you stepped on the "loud pedal."

    Sort of a Dr. Jeckyll/Mr. Hyde deal...

    Buying bottle after bottle of N20 might make that option less attractive, as time wore on. You only have to buy an intercooler once...
     
  2. Johnny Dart

    Johnny Dart Well-Known Member

    Messages:
    7,852
    Likes Received:
    2349
    Joined:
    Nov 30, 2006
    Location:
    So Cal
    Local Time:
    10:52 PM
     
  3. Bill Dedman

    Bill Dedman bill dedman Legendary Member

    Messages:
    4,006
    Likes Received:
    59
    Joined:
    Oct 16, 2007
    Location:
    Conway, Arkansas
    Local Time:
    11:52 PM
     
  4. 273

    273 Well-Known Member

    Messages:
    3,375
    Likes Received:
    1104
    Joined:
    May 14, 2012
    Location:
    Ontario
    Local Time:
    1:52 AM
     
  5. kittypancake

    kittypancake Well-Known Member

    Messages:
    623
    Likes Received:
    78
    Joined:
    Feb 3, 2011
    Location:
    ct
    Local Time:
    12:52 AM
    What he said!
     
  6. kittypancake

    kittypancake Well-Known Member

    Messages:
    623
    Likes Received:
    78
    Joined:
    Feb 3, 2011
    Location:
    ct
    Local Time:
    12:52 AM
    20#'s of boost? I don't think you need anywhere near 20#'s of boost to get a /6 equal or better power than a stock 360.
     
  7. Bill Dedman

    Bill Dedman bill dedman Legendary Member

    Messages:
    4,006
    Likes Received:
    59
    Joined:
    Oct 16, 2007
    Location:
    Conway, Arkansas
    Local Time:
    11:52 PM
    This video: [ame="http://www.youtube.com/watch?v=wd6hFGzLJMc"]Turbocharged Slant 6 Chassis Dyno - YouTube[/ame]

    Shows Tom Wolfe's (Shaker223) slant six on a chassis dyno making 259 rear wheel horsepower with 21 pounds of boost on an 80,000-mile engine that was stock except for having a Clifford 4bbl intake manifold and a Holley 4bbl carb that had been modified for blow-thru.

    That's IT.

    Most people use 85-percent as a reference figure to compare chassis dyno output with output at the flywheel when an automatic transmission is used. 259 is 85 percent of 305.

    So, the number 20, for boost, to get 300 horsepower with a 225 slant six is pretty accurate IF the test is run on a stock engine with those tiny valves and ports, with a stock cam and a cast iron exhaust manifold with a flange welded to it (no header.)

    I imagine that is you put a ported head with big valves (1.75" X 1.5") and optimized the cam for the turbo, and used a proper individual runner header, you could probably make that much power (300 flywheel horsepower) with a lot less boost. Maybe about 15 pounds?

    I am just guessing, but those upgrades would have to make a big difference in output, from stock parameters. Add an alky injector and the amount of booost necessary to make that much power would be reduced even further, I'd opine.

    I'm using 300hp (flywheel hp) as a nominal figure for a stock 360 based on their 300hp Magnum crate motor, which was a pretty good example of a stock 360, mechanically. Mopar released that figure on an engine that was dyno'd with a 750 Holley and headers.
    So, yes, I think you could probably equal that 300hp V8 performance with a semi-"built" slant six that had a ported head with big valves, a 4bbl, an alky injector and a turbo cam, using only about 15 pounds of boost.

    That is all strictly conjecture on my part; your mileage may vary! :cheers:

    I want to reiterate what I said about rear end selection for a slant six/turbo-equipped car vs. a V8-swapped car:

    The rear axle ratios in the two quickest A Body turbo slant six cars that I have seen evidence of, are 2.76:1 for the strip AND for the street. The turbo motors are weird, in that the car slows down with normally-"steep" rear gears, such as the 4.56:1 units often found in small-block cars. The turbo motor seems to make more power (not unlike a "fuel" motor) when it is "held back" and not allowed to increase rpm quickly. The significance if this is, the turbo motors also can use the same ratio for highway driving AND drag strip action. The small block "built" motor wouldn't much like a 2.76:1 rear end on the drag strip, nor would it perform up to its potential, with a 4.56:1 on the highway. So, if you build a small block and it does double duty, you really need two sets of gears; one for the drag strip and one of the highway. No problem; you can change third members in a couple of hours (or, less.) But, they don't give away 8.75" A-Body housings these days, and neither is it cheap to buy and maintain two sets of third members, with different ratios; one for racing, blah, blah, blah...

    The turbo slant six car can easily make do with a "one-ratio-fits-all" rear end. A late model, A Body 8.25" rear end from a junk yard will be lots cheaper (or, one out of an Aspen/Volare car) and will come with highway (and drag strip) gears already in it.... and is plenty strong for this application.

    So, in my opinion, the rear end situation is not at all "a wash" because of the foregoing...

    one more reason to keep granny's engine on its mounts!!! LOL!
     
  8. kittypancake

    kittypancake Well-Known Member

    Messages:
    623
    Likes Received:
    78
    Joined:
    Feb 3, 2011
    Location:
    ct
    Local Time:
    12:52 AM
    I thought the HP goal was 175 or better...what year 360 are we comparing to? Actually, a better question would be what was the highest stock 360 HP?
     
  9. 273

    273 Well-Known Member

    Messages:
    3,375
    Likes Received:
    1104
    Joined:
    May 14, 2012
    Location:
    Ontario
    Local Time:
    1:52 AM
    Highest is 5.9 magnum 245hp which is the same as the 300hp crate engine with a dual plane, LA timing cover and car oil pan and dyno's 320hp with a 650 and headers. But I think he wants what a late 70's 4bbl 360 has 175hp.
     
  10. Revhendo

    Revhendo Master ACME Tech

    Messages:
    12,969
    Likes Received:
    15733
    Joined:
    Mar 12, 2006
    Location:
    SoCal
    Local Time:
    10:52 PM
    Wow, I take a few days off......

    Wasn't the original scope of the question about bumping up a slanty to stock 360 V8 levels or something like that? I like the side track about spooling a /6, but it looks like you are building up the little motor to get to the mild performance level of a stock V8. In the endgame, you are still limited by the low flow characteristics of the stock slant head. The power adders overcome some of those limitations, but they are still limitations.

    Side note to the side track:
    I would think that there would be more that could be accomplished with the addition of EFI to the turbo'd 6 (with better tunability).
     
  11. Bill Dedman

    Bill Dedman bill dedman Legendary Member

    Messages:
    4,006
    Likes Received:
    59
    Joined:
    Oct 16, 2007
    Location:
    Conway, Arkansas
    Local Time:
    11:52 PM
     

    Attached Files:

  12. sleeper-oem

    sleeper-oem Well-Known Member

    Messages:
    432
    Likes Received:
    15
    Joined:
    Mar 19, 2011
    Location:
    Indianapolis
    Local Time:
    1:52 AM
    Go slant sir problem solved
     
  13. Revhendo

    Revhendo Master ACME Tech

    Messages:
    12,969
    Likes Received:
    15733
    Joined:
    Mar 12, 2006
    Location:
    SoCal
    Local Time:
    10:52 PM
     
  14. Revhendo

    Revhendo Master ACME Tech

    Messages:
    12,969
    Likes Received:
    15733
    Joined:
    Mar 12, 2006
    Location:
    SoCal
    Local Time:
    10:52 PM
    Oh, and Bill, that's a dang nice looking setup you got there.
     
    • Like Like x 1
    • kittypancake

      kittypancake Well-Known Member

      Messages:
      623
      Likes Received:
      78
      Joined:
      Feb 3, 2011
      Location:
      ct
      Local Time:
      12:52 AM
      I enjoy reading this thread everyday. BUT...I'm beginning to wonder if the OP'er just wanted to watch the fireworks...
       
    • moper

      moper FABO Gold Member FABO Gold Member

      Messages:
      15,728
      Likes Received:
      1855
      Joined:
      Dec 27, 2004
      Location:
      eastern CT
      Local Time:
      6:52 AM
      Sully - As an engineer you have to know the desired result must be well settled before any plan is designed. If you're testing the waters here, you'll find folks on both sides of the discussion who are ardent supporters of one or the other...lol
      As for me - I've swapped slants for small and big blocks, stick and autos, and been very involved in a GM stovebolt 6 turbo that runs 9s. Which is, once you reach that level, pretty much the same animal as any inline 6.
      Some of what I've found:
      You do not need more torsion bars or brakes. The differences in weight between a slant 6 and a 440 is about the weight of one passenger; the difference between a slant and a small block is a load of groceries.
      You do not need to replace the transmission crossmember. If you use a V8 904, you need no driveshaft.
      The cost to swap in a V8 is more - but not much more. You need the running engine. You need the support parts to make it work. You need exhaust work. But to build a slant, you need the same things, but the performance parts cost more. The cam, the manifold, the header, all cost a lot more than V8 stuff new, and are harder to find close by used. (I've tried myself for a year now) Swap meet V8 stuff is all over.
      No turbo setup is what I consider "cheap" or "easy".
      No supercharger setup is what I consider "cheap" or "easy".

      It comes down to what you want. You can have a great running slant and 95% of the public won't care. You can have a terrible running V8 and people will still be interested.
      So bearing in mind the desired result - what do you want to do? How much do you have to spend?
       
    • Sully1190

      Sully1190 Look. It's a Gold Duster.

      Messages:
      505
      Likes Received:
      17
      Joined:
      Oct 24, 2011
      Location:
      Clinton, MS
      Local Time:
      12:52 AM
      I like how it feels like we're standing in the eyes of the storm, watching everyone debate the merits and demerits of both.

      :happy1:

      Still enjoying the information though. I love having access to stuff like this, so that no matter what I decide, it'll be here.

      Nah. I really thought this one would leave no room for arguing, since it was a specific question. But if friendly debating brings more information, let the games begin!

      Indeed. Sometimes I wonder if I ask too many multi-faceted questions here. I don't want people to get tired of me haha.

      As for the weight, you make a superb point. I guess I just wasn't thinking when I was reading about the engine swaps and the weight increase and stuff. Wow I feel silly now ](*,)

      And I don't really care what other people think too much. Results is more of my concern than means. If putting a two cylinder motorcycle engine with a blower on it was the fastest option for the money, I'd be on it. (Which, if I ever talk that guy up the road into giving me that little Fiat...)

      But anyways, yes. Very good points. I will be keeping my eyes out for good deals on engines.



      As for budget, that's a difficult question to answer. Because, I don't really have a hard budget, but I still want to keep things cheap, because, with some of the rust issues and stuff that exist on the car, I'm not sure that if in the long run, I'll be keeping it as a daily driver, or selling it and trading up on an A-body of an earlier year that is a little cleaner. So I don't want to invest a great deal of money into the engine bay if it wouldn't have potential return. That said, I don't mind putting time in.

      So, my goal was to see if, for less money than swapping in a 360, my /6 could be made to produce comparable power to the stock 360 that I'd be swapping in. I think I've learned a lot of things about this whole deal, and while I love the idea of turboing a slant even more now, I'm thinking for this car, I may go with the 360, because if I do decide to sell it, that is money I will probably see added to the value. However, I would definitely be keeping my slant for use in a future car :D.

      Thanks guys for all the info, and if you want to keep going, by all means do so. I am enjoying getting the info together all in one place. I'll be just driving my slant for now and looking around for deals.
       
    • Bill Dedman

      Bill Dedman bill dedman Legendary Member

      Messages:
      4,006
      Likes Received:
      59
      Joined:
      Oct 16, 2007
      Location:
      Conway, Arkansas
      Local Time:
      11:52 PM
      Thanks, Rev! My partner in this venture built the header all by himself and did all the wiring (thank GOD!)

      He has enough patience for both of us... and, it shows up in his work.

      My part in this little exercise was parts procurement and cold-side plumbing design, along with engine component choices, which really, I can't take credit for because Tom Wolfe (Shaker223 on FABO) told me exactly what to buy. It's just a carbon copy of his engine with a few little detail differences here and there, and VERY similar to the motor in Ryan Peterson's car.

      This "project" is basically "finished" except for tuning (which is no small thing, in itself.) It my take us a year to get the carb jetting, accelerator pump shot, stall techique and adjustments to the waste gate, blow-off-valve and alky sprayer settings at the optimum levels for the best performance.

      Launching a turbo car is usually a problem because of the difficulty in building the right amount of boost at the right time, the propensity of driving through the brakes at stall, controlling the A/F ratio during the launch and tuning the chassis for maximum bite at the hit.

      None of that comes as a surprise to the two old fogies who built this rolling snake-pit of problems, though, as we each have over 50 years' experience on the quarter-mile in hobby drag cars (all normally-spirated V8s.)

      Our combined age (for the two of us,) is 148, so we are at a stage in life where there are few surprises.. LOL!:banghead:

      As we slip into our dotage, this technical exercise will keep us with our thinking caps on, pretty much 24/7, and that's good. You know, they say that idle hands are the Devil's workshop.... er, maybe not with us; I don't think we're going to be getting into too much trouble at this stage... LOL!:cry:

      Here's a picture of the two old fools installing the leaning tower of power into the engine bay for the first time... (I'm the idiot in the white coat.) Stay tuned... we'll have some test 'n' tune runs to report on in the near future, I hope.:wack:
       

      Attached Files:

    • Johnny Dart

      Johnny Dart Well-Known Member

      Messages:
      7,852
      Likes Received:
      2349
      Joined:
      Nov 30, 2006
      Location:
      So Cal
      Local Time:
      10:52 PM
      1974 Duster, warmed over slant six = A turd.
      1974 Duster warmed over 360 = A tire burning,street hooligan.

      Until you get anywhere close to putting a turbo slant in your car (which I got $ that it never happens) this thread is a complete Joke !!!!!!
       
    • kittypancake

      kittypancake Well-Known Member

      Messages:
      623
      Likes Received:
      78
      Joined:
      Feb 3, 2011
      Location:
      ct
      Local Time:
      12:52 AM
      You might as well say 74 Duster "BIG BLOCK"...the thread was started as a comparison of modified slant six to BONE STOCK 360...
       
    • 273

      273 Well-Known Member

      Messages:
      3,375
      Likes Received:
      1104
      Joined:
      May 14, 2012
      Location:
      Ontario
      Local Time:
      1:52 AM
      even a built 175 net hp /6 will lose to a bone stock 175hp net 360, the torque on the /6 is probably down around 100ft-lb less compared to the 360. The answer to this if you gonna build a /6 is cause you want too there is no other reason too, Mod for Mod, $ for $ the 360 will win even a 273 would win.
       
    • Johnny Dart

      Johnny Dart Well-Known Member

      Messages:
      7,852
      Likes Received:
      2349
      Joined:
      Nov 30, 2006
      Location:
      So Cal
      Local Time:
      10:52 PM
      Ok...Fine.
      1974 Duster motofied slant 6 = A turd
      1974 Duster bone stock 360 = tire burning, slant killer.

      That's roughly a 3300 lb car. You need to lose at least 400 lbs,if you want some performance with a slant.
      So,lose the bumpers,back seat,passenger seat,carpet,heater,spare tire,radio,door panels,mirrors,and your ready to go !
















      .
       
    • Bill Dedman

      Bill Dedman bill dedman Legendary Member

      Messages:
      4,006
      Likes Received:
      59
      Joined:
      Oct 16, 2007
      Location:
      Conway, Arkansas
      Local Time:
      11:52 PM
      Quote:
      That's roughly a 3300 lb car. You need to lose at least 400 lbs,if you want some performance with a slant.
      So,lose the bumpers,back seat,passenger seat,carpet,heater,spare tire,radio,door panels,mirrors,and your ready to go !

      This car in the video is a slant six car that weigh 3,300 pounds.

      It goes virtually 11-flat at over 120 mph.

      What is it about that, that you guys don't understand?


      [ame="http://www.youtube.com/watch?v=EAxRmoDgsdY"]Turbo charged Slant 6 11.02 @ 120.56 - YouTube[/ame]


      No fuel injection; no roller cam; no hi-stall converter; 5,500 rpm redline; 2.76:1 rear end. No exotic ignition.

      Just a a hairdryer...

      And this video was into a 15mph headwind.

      No 360 that is anywhere near stock is gonna run anything like that.

      How about giving credit where credit's due?




















      .[/QUOTE]
       
    • Bill Dedman

      Bill Dedman bill dedman Legendary Member

      Messages:
      4,006
      Likes Received:
      59
      Joined:
      Oct 16, 2007
      Location:
      Conway, Arkansas
      Local Time:
      11:52 PM

      Your 400 hp 273 is no match for the 500hp slants I have been showing videos of from You Tube on here (Tom Wolfe's and Ryan Patterson's '66 Valiant.)


      So, how can you say "The answer to this if you gonna build a /6 is cause you want too there is no other reason to."

      I'm not sure I know what that sentence means, but here are some torque figures for a turbo slant six that is a fairly mild build:

      [ame="http://www.youtube.com/watch?v=O4Kl9MBr15o"]Valiant Slant 6 Dyno 370 rwhp - YouTube[/ame]

      418 pounds feet of torque on a chassis dyno.

      The reason to buld a slant six is they are cheap, reliable and powerful.

      I can't see a normally-aspirated 273 coming anywhere close to an engine like Tom's or Ryan's on a dyno OR on the strip in the same car.

      Yes, you can make the slant six look like an also-ran by using forced induction on a V8. No argument there.

      But, that wasn't the premise of this thread.
       
    • 273

      273 Well-Known Member

      Messages:
      3,375
      Likes Received:
      1104
      Joined:
      May 14, 2012
      Location:
      Ontario
      Local Time:
      1:52 AM
      Yes the turbo sixes are Kool I'd love too have one if my Cuda was a /6 I might think of doing it but not everyone wants to mess or has the ability to go turbo but you still comparing apples to oranges ( turbo to N/A ) take that last car and drop in a stock 5.9 with a turbo thrown on like the six in the video and it would walk away from the turbo six car and be just as streetable as the /6 car, Mod for Mod, $ for $ the 8 will always be better.
      I agree with you if the OP'er wants to be faster than even one mildest of 360 he'll need some kind of power adder.
       
    1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
      By continuing to use this site, you are consenting to our use of cookies.