John Speed cobra manufacturer...anyone heard of them????

[eschaider]

A couple of thoughts,


Torque vs Horsepower

Torque not horsepower is what breaks transmissions (and rear ends). If I have 800 hp but it comes at 10,000 rpm that only requires 420 ft/bs of torque. If I have another 800 HP engine but it comes at 3000 rpm that requires 1400 ft/lbs of torque. Guess which one is most demanding on the drive train?

Worthy of mention, but not a fix, is the fact that if you can't hook up (usually the case) it may not matter until you actually get to a better road surface and then it will — big time.


Fidelity to the Original Cobra's Appearance

The longer you own your car the more self critical you will become. Things like fit and finish that perhaps did not bother you initially become more of an issue the longer you own the car and the more often you park near high fidelity examples. This frequently accounts for the resale and repurchasing activity that some owners find themselves all too frequently engaged in.

When you look at his website the first car on the first page has a fit and finish problem with how the door and body fit together. This is uncool and the longer you own it the less cool it will become.

Some of the other pictures of his cars on his site show cars with a body that appears to 'droop' in the front and the back. Park your car near another car that does not 'droop' and you will begin your own journey down that replacement path where you sell the current Cobra and buy that 'next' Cobra.

Take your time, be critical of obvious visual departures from accepted visual and construction norms (whatever that means) and don't be shy about spending a bit more to get what you are looking for because you will spend a lot more later if you begin the sell and re-purchase syndrome.


Ed

[strictlypersonl]

Originally Posted by eschaider

A couple of thoughts,

Torque vs Horsepower

Torque not horsepower is what breaks transmissions (and rear ends). If I have 800 hp but it comes at 10,000 rpm that only requires 420 ft/bs of torque. If I have another 800 HP engine but it comes at 3000 rpm that requires 1400 ft/lbs of torque. Guess which one is most demanding on the drive train?
Ed

Not quite accurate. You have to figure in the transmission and differential ratios in the torque that's delivered to the axles.

Torque to the axle= engine torque x transmission ratio x differential ratio.

[patrickt]

Ed & Bob, are you guys on the right thread?

[rodneym]

And then if I'm being more daring, I'll add a touch of cinnamon before a speckling of brown sugar.

[eschaider]

Originally Posted by strictlypersonl

Not quite accurate. You have to figure in the transmission and differential ratios in the torque that's delivered to the axles.

Torque to the axle= engine torque x transmission ratio x differential ratio.

You are right about the trans and differential ratios and their effect on the load the transmission and rear axle internals see, Bob. I was just trying to dumb it down.

For the readers who are trying to understand what we are talking about, it goes (simplistically) like this;

If the transmission has to pull against a tall ring an pinion the internal loading the transmission gears will see is greater than if the transmission has to pull against a short ring and pinion. Tall means a ratio like 3.08 and short means a ratio like 5.12 to sort of put markers on the fairway.

When you have a 5.12 ring and pinion you take load away from the transmission and the ring and pinion sees the increased loading with a corresponding reduction in load on the transmission internals.

Similarly when you have a 3.08 ring and pinion the load on the transmission internals to produce the same torque at the tire patch on the ground goes up in proportion to the reduction in rear end gear ratio.

That said it takes substantially more strength to process a 1400 ft/lb torque load at the flywheel than it does to process a 400 ft/lb torque load at the flywheel. In the end, increased torque loading will be what precipitates the component failure for the weakest component in the drivetrain.

There is also an impact effect that is more significant to pay attention to in drag cars than other types of performance cars. When you are at the starting line and the engine is at 6,000 rpm or higher when the light goes yellow and you drop the clutch there is a sudden and frightful impact that all components in the drive train need to be able to absorb without failure. The stickier the tires and the more aggressive the clutch friction materials the more significant this phenomena is.

The moment you get away from big sticky tires and high rpm launches this phenomena basically disappears.


Ed