engine building? Hp or torque for the street...

Discussion in 'Classic Mustang Specific Tech' started by stangman67, Sep 17, 2006.

  1. I guess this could be a tech question, but sort of talk.

    What would result in a more fun street car:
    flat tq curve around 450 with 350hp
    or
    flat tq curve around 450 with 500hp

    The difference is pretty much a smaller cam in a 393/408 vs. a turbo 302. Cost isnt really my defining motive, i just want to build something other than my 289, which has roughly [email protected] and [email protected], with 350 [email protected] It just doesnt feel strong, even though its mid-13s at 104 quick. Honestly, my turbo volvo runs 14.7s at 96 and seems to pull harder in everyday driving. Thanks for your input.
    Mike
     
  2. I've read that torque is what counts.
     
  3. torque is nice but when that runs out and your car falls flat on its face then youll be wishing you had some more HP.
    torque will come with HP, my cobra makes plenty of tq and hp (over 500 at the wheels with both......off the spray) but i wish it had more top end.

    so its all on how you drive and what your gonna use the car for.
     
  4. You can have fun with either engine as long as you plan your build. Anything that can put 300hp or more at the rear wheels will be a blast to drive and both engines can do that.

    What are you end goals for the car? Are you going to want more power down the road?

    Turbos are great. You don't need a radical motor to run one. Slap a turbo on a motor with about 9:1 compression, add a decent carb and be done. The turbo can overcome mismatched parts and still run decent. The down side is that you would be using a 302 block which can only contain so much HP. A stock block has a working range of around 400-450hp. It is not capable of much more before the big split. Other parts, like the drivetrain, will have a long and useful life because the turbo won't hit hard off the line.

    The 351w can handle 500hp easily and do it at a lower RPMs. Good aluminum heads/intake and a small cam will get you there with a 408. It will have all the torque that you need from stoplight to 6000+ to have a good time. No concerns with the block unless you are trying to spin high RPMs (which are not needed with a street stroker.) Other parts of the car will experience extreme shock due to the expectant torque. It won't be as economical to drive on the street though as the 302.

    So I think it all comes down to what you want in a motor now and what your long term goals may be.
     
  5. That seems like a no brainer; 500hp would be WAY more fun than 350hp :D IMO there is no substitute for cubic inch, yes size matters. Why going w/such a wimpy cam? I'd just opt for a good cam, ie one that mathces well w/the combo to take advantage of the increased cubes. Maybe a custom cam that will make it have nice street manners, but pulls to 7200 rpms w/no problems.
    I'd take the stroked 351 over a turbo 302, but like Lucafu1 said; it depends on how you are going to use the car. NASCAR or 'ricer style' is all about hp, but from a dig it's all about TQ.
     
  6. Tq wins races. HP is what you lie to your friends about !

    (Not mines btw, someone else says that to me all the time. And I think someone on this forums has it in his sig !)

    But never the less, its true !
     
  7. It really comes down to what use you are going to put vehicle to. There are very few places around town that you can run at 5,000 RPM. If you are running on a drag strip, then you went more on the top end and that is where the HP comes in. for fun around town, go for torque. This months issue of Mustangs and Ford has a good article on mistakes people make when building the engine.
     
  8. You can build a well-mannered 392 or 408 making 475/475. The most expensive parts would be the heads. The rest can be pretty mundane, so long as the cam is well spec'd for the heads. This would be much cheaper than a turbo motor and easier to maintain. Just my $.02.
     
  9. Thanks for the replies. I already have a set of 1.90 Edelbrock RPM heads, and looking at other engine builds, they seem too small for a big 351 engine. It almost seems that a 331 or 347 would fit the bill for me, breaking the 400 ft.lb. mark fairly easily.
     
  10. Not. Approximate speed through the quarter and/or acceleration can be calculated given horsepower, but torque means nothing.
     
  11. Hack: that's a little strong since HP is a function of torque and RPM. If you start giving up torque, you will spend a pile on parts and machining in order to get the RPMs up for equivalent HP.
     
  12. I would focus on torque. I think it will give you more flexability regarding gearing to create a useable powerband. TQ gets you going and HP maintains the acceleration. There are plenty of dyno queens out there but there are reasons why 350HP mustangs are rolling with 500 hp turbo civics... at least from a dead stop. hehe
    Kevin
     

  13. yeah, a stroked 302 or even a standard stroke 351w will be plenty of engine and make well over 300hp at the wheels and over 400lb/ft of torque as well. even the 1.90 e'brock heads would work well on a stock displacement 351w and not require fly-cutting the pistons. they would also work well on a 392 but there are better choices for a bigger cube windsor but for a 90% street motor they'd be fine. depending on your budget a stock displacement 351 might be the better choice and will bolt right in place of the 302 with only some different brackets and pulley for the accessories like ac and ps.
     
  14. If this was any kind of induction rather than a turbo, I would say thats pretty close to accurate. However, for some mathematical reason a turbo is much easier on the motor. Barry D of turbomustangs (works down the street from me) used to toss in hyperruetectic (85-87,93-95) and forged (88-92) stock bottom ends from junkyard mustangs. At the time with the junkyard motors he would trap 135ish through the quarter with an Incon twin t3/t4 setup, TFS stage 2 cam and box stock twisted wedges.

    So at a weight of 3200 lbs and 135 MPH, you can equate the HP.

    These motors would last 5-6 months then it let go across the lifter valley and in went another $100 shortblock. Without racing it and with a easier tune, a stock roller block (50 or so less HP capable than a 2-piece non-roller) should support 500fwhp in a turbo situation.

    However, it is up to you what you want to build going by your budget.
    302 with a turbo will be good on the gas and pull up top.
    393 will probably have enough torque to be somewhat wasteful on the street.
     
  15. people always say things that confuse people.

    engines DO NOT make horsepower! everything you feel in your car, rather it be daily driving or romping on it down the track is torque

    the only thing an engine makes is torque, horsepower is not an actual force...
    horsepower is only the figure of torque under a curve
     
  16. I don't think it's strong. Torque really doesn't mean anything. That's why people take the time to calculate horsepower. Yes HP is a function of torque, but you can safely look only at HP. You don't have to look at the average HP of a motor and then check to make sure it's making enough torque. Just look at the average HP in the rpm range you will be running.

    Want to estimate how quick your car will be through the quarter? You can't figure it out using torque. You can figure it out using HP. Why is this? Because torque doesn't mean anything. You can have a huge amount of torque and if it comes at 1,000 rpm it does very little for you.
     
  17. I have two engines in otherwise identical cars. One engine makes 1,000 lbft of torque. The other makes 500 lbft of torque.

    Which is faster?

    You can't tell because there isn't enough information. That's the truth about torque. Now if you know the average HP of each engine, then you're good to go.
     
  18. I have one of those stock 302 blocks that I have been waiting to split since 2002......and I am making 398ft lbs of torque at the wheels on 347ci.... on a not so radical build...

    tq / hp discussion I leave to you guys to hash out cause I am a rookie and I think its been beat dead on this forum around 5 different times.
     
  19. :bang:
    As the original poster is probably aware, the subject of HP vs torque here is very Zen--reincarnated under various subject headings and just about always a mental exercise in futility. See the quoted post, but reworded:

    See? We are comparing mathmatical formulas which apply to motive forces. In a real world sense, what Hack and others point to with horsepower really is torque at higher RPMs. Torque = HP *5252 / RPM. You feel torque, you measure torque on dynos-- you calculate HP. For two cars with the same value and curve of peak torque, the one with the curve shifted up to higher RPMS, the higher one will make more HP. There's a quote on the net that says: "It is better to make torque at high rpm than at low rpm, because you can take advantage of gearing." Make sense? I thought not. I'll wait for the next reincarnation... ;)
    Daniel
     

  20. 33,000 lb.ft./minute
    745.699 watts

    1 horsepower