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Thread: Engine "HEAVY" hai

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    Default Engine "HEAVY" hai

    A bit tricky but i have this very important question in mind which needs deliberate answers.

    You plan of putting a 1C/ 2C in a suzuki jeep, 3L in a cj 5, 1KZ in a willys, 2B/ 3B in a cj 6 or in any equivalent jeep, the answer will be, "Is gaari kay liye, ye engine heavy hai".

    I can understand the problems of fitting/ adjusting gears in the body, making/ modifying engine foundations, but if that is catered for, what do we actually mean by "heavy" or at times, "engine bara hai"? Don't we have more leaf springs/ stronger coils/ coil over springs available which can handle the issues?

    By putting in these so called heavier engines do we really have a negative effect on frame/ suspension/ high speed handling?

    Input required from all friends.

    Noman

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    Good thoughts Noman Bhai, subscribed to the thread
    The trouble is that too often there is forty horsepower under the bonnet and one asspower at the wheel

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    Arrow Weight distribution

    This question can be approached from two POV:

    1. The important thing is weight balance. No amount of increasing & decreasing the numbers of springs would help if the car in the first place does not have a balanced weight distribution.

    A very heavy engine will disturb the weight balance (make it front-heavy) and the handling will be pathetic.

    2. OTOH, if the engine is too powerful for the car, due to less weight on the drive wheels there will a lot of wheelspin, since you know F=uR (formula of friction) and the car will be difficult to drive.

    EDIT:
    3. Sometimes the engine is too big (over-size) for the engine room. Not necessary that it will be heavy enough to disturb the weight balance. E.g an old cast iron push rod I4 may be heavier than an aluminium block and aluminium head V6, whereas the V6 is wider and would be difficult to fit if the engine bay is too small due to large wheel wells.

    You just have to remember that: overload is of two types: overweight and over-size.

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    I've seen engines moved towards center for better balancing of weight, considering other fab works
    The trouble is that too often there is forty horsepower under the bonnet and one asspower at the wheel

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    It is a term coined by local ustaads. The legitimacy to it is that most vehicles don't have structural strength and their drive train does not have a torque rating high enough to safely absorb the energy of the oversize engine.

    In light of the post question:
    Three things matter for a vehicle.
    Power-Weight Ratio
    Weight Distribution
    Structural Strength

    Root of all above, how efficiently can the power be delivered to the pavement, dirt or any other form.
    Most vehicles are designed around a certain power criteria. Therefore their structural elements are built according to that rating. Static friction is a very little discussed force when ustaads are fabricating a vehicle and countless others.

    The point being, for example take a Suzuki Potohar and put a V8 in it with a bit of cut and weld. But can the frame and the body resist 400nms + torque to deliver it to the transmission. Can the transmission handle that torque with out shearing gears? Is the prop shaft hardness scale high enough to resist twisting into a jelly bear? can the diffs pinion and crown safely transmit torque to the wheels without disintegrating?

    There are countless other questions in dire need of answers or solutions but we rarely give them a thought when tunneling through the thought of channeling maximum power to the wheels.

    Our society is very much used to running Japanese vehicles. Japanese vehicles are built with a certain sense of dedication and the Japanese as being one the world renowned experts in steel manufacturing. Makes their metal much more resilient to additional energy being put through them but that doesn't mean its unbreakable.

    It is a complex matrix to which most have no answers but rather very vivid opinions.

    Just my 2 cents.

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    Default

    To begin with, I have never really heard the term to be honest which is probably because I have mainly dealt with CJs and FJs which come with pretty heavy engines to begin with. Even the 2B is perhaps only marginally heavier than the original CJ5 engine and is not "phara" as such....

    Nevertheless, front / back weight ratio is an important factor in high speed handling. It's not however a fatal shortcoming as such if bandaged up with suspension compensation etc. nevertheless it will probably never handle as well as a similar car with a lighter engine. For off-roading however, a slightly heavier front is perhaps more desirable than a very light one.
    "If YOU don't believe in what you're doing it'll never work."

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    Default

    engine ain't heavy, its all about aerodynamics + momentum ; p=m x v ( p=momentum, m=mass, v=velocity)
    because if the car was'nt moving, the term HEAVY is eliminated.
    because SUV's have a greater ground clearance compared to cars, they are more likely to cause a roll-over.
    to avoid roll-over, the ride must be lowered, to make-up a stiffer suspension rather than bouncy one.
    coil springs play a negative role here, as these suspensions are bouncy with more suspension movement etc,
    the reason u must've seen ol'skool supercharged muscles with leaf backs.
    & dont put those big big tyres, make'm shorter & wider insted, with less air(psi) too.
    also put a performance balance rod.
    installing ESC ( Electronic stability control ) is also an add-on option, but not enuff reliable until u slam the center of gravity.
    Vehicle History: Pajero 1 & 2 (4d55 Non-Turbo - 4d56 Turbo & 4M40 I-C Turbo) / Land Cruiser BJ60(13B-T Turbo) / Nissan Patrol GQ(Td422 Non-Turbo)

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    Thinking about it some more, when you swap a 1HD-FT into an CJ7 or an FJ40 you can encounter the particular issue. The CJ7 frame is likely to crack with prolonged use or heavy abuse because of the weight and the torque. The FJ40 frame can handle the weight and torque but like the CJ7 one it will twist and warp a bit more than it was probably designed for and make for poor handling and a bit of a hairy ride....

    One example is a typical speed-breaker jump (which we all indulge into here and there). It took me quite a while to figure out that in most aggressive speed breaker engagements, a leaf sprung vehicle invariably jumps up in the air and lands down on the tarmac. In such situations, the more weighty the engine, the more load is placed on the frame. In extreme cases you could probably see the frame bend around the firewall area, if you took slow motion pics or something....
    "If YOU don't believe in what you're doing it'll never work."

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    Quote Originally Posted by SuhaibKiani View Post
    It took me quite a while to figure out that in most aggressive speed breaker engagements, a leaf sprung vehicle invariably jumps up in the air and lands down on the tarmac.
    An inherent flaw of the short travel suspension design. Leaf sprung designs are more tense and less reactive.

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    Default

    Thanks everyone. Very informative.

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