i'm in garland, let me know.. i'd love to see this too

 

Altiain,

As I said, your logic is flawed. I understand what you are trying to say perfectly, and know that it is wrong. When force is applied to a series of inline components, the force is not proportionally divided among the components; rather they all experience the total force. It doesn't matter if you hang 100 lbs from a chain that has 2 links in it or 4 links. Each link will have to withstand the full 100 lbs of force. Adding or changing the links won't change the amount of force the other links have to handle.

You can explain your fingers and keyboard to death, but that doesn't make it correct. In the case of towing something, the weak link is really the engine, since it will stall if it doesn't provide enough force to move the vehicle and load. The clutch is really an intentional / temporary weak link to prevent the engine from stalling. Once the clutch is engaged, the torque provided by the engine (if it hasn't stalled) will cause the car and load to accellerate at some rate. The rate of accelleration is the variable component, not the force.

I know that you are an intelligent guy, but this doesn't seem to be your area of expertise. I don't know how else to explain it to you. I also know that you aren't going to give in on this matter, so please just drop it.

 

[QUOTE=BlitzSRM,Sep 13 2004, 01:21 PM] if the other end is free to rotate, the same amount of torque applied, and you double the mass.

 

Not to mention, trucks designed to tow also have much stronger steel 'ladder' frames under them, which the hitch receivers are typically bolted or welded to.

Now, while I don't condone towing nearly 3000lbs with an S2000, I will say this...

I once had a 1998 Acura Integra GS-R that I put a class 1 hitch receiver on. The maximum weight rating was 200lbs of tongue weight and 2000lbs total trailer weight. With that hitch receiver and car, I pulled a race-prepped 1988 Honda CRX with a tow bar attached to it. The total weight I pulled was around 2100lbs or so, with literally about zero tongue weight. I was able to drive with this setup down the highway at 75mph without any problem whatsoever, WITH the A/C on. Keeping in mind, that was with a 1.8 liter VTEC engine with slightly taller gearing than an S2000. I also didn't have any problems with slowing up traffic... I could shift at ~4000rpm and although I didn't beat anybody in any races, I wasn't terribly slow on the road, either.

Now, the result of this? When I went to sell the car, I removed the hitch receiver (#1 so that nobody would know the car was used to tow, but mainly because #2 I knew I would have another Integra one day, which I do now, and the hitch is back on it) and noticed that a couple of the bolt holes were not quite as 'round' as they were previously. I think the hitch receiver mounting hardware had slightly shifted, despite being torqued to proper specs when I installed it myself. Needless to say, the metal framing it was bolted to was not cut out for it. Also, keeping in mind, I only towed a CRX two separate times with this Integra while I owned it, and each time was about 10-12 miles of driving straight down a highway.

The bottom line is, I was operating beyond the capabilities of what the car was designed to do, and it, in fact, did do damage to the frame rail under the rear of the car where the bolt holes were (the hitch used pre-existing holes -- I did not have to drill any new holes).

Needless to say, although our current 1994 Integra GS-R now has the hitch receiver on it, I use my 1998 Chevrolet Blazer to tow anything substantial (such as the 2000lb solid steel car hauler with 1500lbs worth of car sitting on it this last weekend) -- but then again, that vehicle is rated to tow 5500lbs from the factory, so I am nowhere near its limits.

As much as I am a fan of doing the most with as little as possible, I am going to have to go with the folks that are saying you are crazy/stupid/an idiot/whatever, based on my personal experiences of towing at or beyond a vehicle's rated capacity.

Regardless of whether or not your situation is ideal (flat road, only a mile, max speed 30mph, etc), you are still WELL beyond the manufacturer's rated towing capacity and will do damage to the car. I fully have faith that your driveline (engine, clutch, tranny, driveshaft, differential, axles, tires, etc) will be fine, as I have put my S2000's through some serious stresses in the AutoCrossing I do, but other components of the frame will suffer stresses from this excessive towing that you are doing.

If you can afford a boat of that size, you can afford a small $3000-5000 S-10, Nissan, or Toyota truck that will be able to PROPERLY handle the towing you are trying to do.

 

That's just it, gernby - you're not adding or changing links. You're increasing the amount of load that the "chain" is trying to support. So tell me again, because I seemed to have missed it in your reply - what happens when we exceed the load that the chain is rated for?

 

The problem is that he is trying to use "intuitive physics" on an engineering analysis. He still thinks that if the boat weighs enough, it will suddenly become an immovable object. In theory this is not true. In practice it is effectively true, but only because either the engine would stall or the tires would spin.

If the driveshaft were weak enough to be the limiting link in the chain then yes, it could fail. But the drive shaft isn't weak enough. On a wet boat ramp, wheelspin is probably the weak link in the chain.

 

Rigid body motion describes the Car and Boat system. same force, 2x mass equates to half the acceleration.

Rotation about a fixed axis describes your 2"x4" rotating. same torque, 2x mass equates to half the tangential acceleration.

again your missing the point acceleration is very slow, so no more stress on the components than accelerating as fast as you can.

 

your not changing the spring.

i agree mike, "intuitive physics"

 

And again, you're missing the point. You've changed the resistance in the system by increasing the load you're trying to move. Since the drivetrain is not infinitely rigid, the stress it sees is increased by the increased resistance. That stress causes distortion of the driveline components, or - in the case of the clutch - it will cause slippage.

I fully understand that with a given force if you increase the mass, acceleration decreases. What you're failing to see is that the driveline components will feel that increased resistance, no matter how slow you're trying to accelerate.

Try thinking of it another way. Would it be OK to try and tow an 80,000 lb trailer with an S2000? If not, why not? What do you think would happen? Would the clutch hold? Would the engine stall? Do you think that load might cause some damage to the drivetrain? If so, how could it?

According to your logic, if I accelerated slow enough, it ought to be just fine. After all, with a non-zero force and a non-zero mass, acceleration can never be equal to zero. I could tow a house with an S2000, as long as I accelerated slowly enough.

 

Damn, you guys get really worked up over this whole thing....

Stop trying to bring physics, science, analysis, and brain power into this. Read my post above and take the advice from somebody who HAS towed more than what a Honda was rated for.

SHUT UP AND DRIVE YOUR CAR!!!

If you want to pull buildings off their foundations, get a 1-ton dually with a turbo diesel and be done with it. The bottom line all the 'naysayers' are trying to say (including myself) is to use the proper tool for the job. When was the last time you used a 1/4" drive torque wrench to torque your lug nuts?