[Motor Daddy]

Originally Posted by John Langer

Acceleration is also Newtons 2nd law of physics.

Newton was clueless!

[John Langer]

Originally Posted by Motor Daddy

The car limits the acceleration of the motor too, no? The air limits the car too, no? Gravity too? Friction? Rolling resistance from bearings? U joints/angle torques? ...

HP=Torque*RPM/5252
ET= What the timeslip indicates. (Note: A timeslip is a record of the past. It already happened and the time elapsed.) Knowing HP from ET is virtually impossible.

The sum of the forces = mass x acceleration. All of the above attributes to the forces, being positive or negative.

[Daniel Barton]

Originally Posted by john marcella

Hahaha voodoo.

So it has happened 5 to 10 times over every day of 23 years of dyno time, and you are making this big of a deal about it? I dont get it? Sounds like you have a taste for voodoo Kool Aid.

In the end we all have our own way, results are what counts(not methods) and those are found at the track, not dynos or flow benchs.

Sorry, I cant agree with you that just because I don't see or understand something it is voodoo kool aid, and yes, results on the track is ALL that matters. It is perfectly fine if you don't get why I make any sort of deal about it, like I said I personally have not seen the pyramids, but I don't call it voodoo or refer to people as clowns that say they have seen them and believe they exist.

[Daniel Barton]

Originally Posted by Stan Weiss

cosgrove,
He is talking about the opposite here. A very high load very slow acceleration rate condition.

Dan,
Was this a very small engine high lbs per ci type class?

Stan

Stan, some were but not all.

[Motor Daddy]

Originally Posted by John Langer

The sum of the forces = mass x acceleration. All of the above attributes to the forces, being positive or negative.

Acceleration is the RATE OF CHANGE OF VELOCITY.

In other words - Acceleration is a measure of the time it takes to go from one velocity to another velocity. The RATE of change (acceleration) of velocity is measured by measuring the time it takes to change from 0 MPH to 140 MPH. The acceleration is greater if the time is less. A 0-140 MPH change in the elapsed time of 10 seconds has a greater rate of change of velocity (acceleration) than an elapsed time of 11.28 seconds to do the same change from 0-140 MPH.

It gets a little tricky because the greater the rate of change, the greater the velocity in the same distance, and the less time it takes to travel that same distance, hence my equations, which are 100% accurate!

[Chris Uratchko]

Originally Posted by John Langer

It is all about acceleration. Would a motor with a very light piston,pin,rod combination accelerate faster then a motor with a very heavy piston,pin, rod combination? I'm not talking about gram differences but pounds. They could make the same power on the dyno since the dyno limits acceleration but one would go faster on the track. Same goes for cylinder head and intake design. Dynos limit the acceleration of a motor but the motor accelerates the car.

Just to side track from the healthy discussion here, Been thinking about this for a bit and always go back and forth on bob weight vs acceleration.

Dumb question but If I put the car in neutral will the engine accelerate faster than if it is in gear? So based on that result, is the heavier rotating mass the acceleration limiter, or is it the rest of the rotating assembly - Converter, Transmission, Driveshaft, Rear End, Wheels, and Vehicle weight doing more limiting that a heavy set of rods and crank.

I just bought a set of Carr pro stock rods from Book and they have been ranging in the 600-620 gram max window... doesn't seem to have hurt their acceleration vs a mid upper 400 gram aluminum rod.

Not debating, as I don't feel like I have a consensus on it, just thinking out loud in discussion.

[john marcella]

I'm sure what Dan is talking about is engine acceleration not vehicle acceleration like you guys are talking about. Two totally different things.

And engine has a power curve and the faster the engine accelerates the faster it gets through that curve getting into the higher horsepower levels of the curve sooner. Same thing I want of the lifter on my camshaft.

Dan, yes if two motors have the identical power curve but one motor accelerates faster against the same load than that motor will absolutely be faster in the car. But imo you can't produce those two motors with identical power curves!!!! Hp is work vs time. If work is the same but time is lesser ,,,,,,then hp is greater.

[mike leech]

Originally Posted by John Langer

It is all about acceleration. Would a motor with a very light piston,pin,rod combination accelerate faster then a motor with a very heavy piston,pin, rod combination? I'm not talking about gram differences but pounds. They could make the same power on the dyno since the dyno limits acceleration but one would go faster on the track. Same goes for cylinder head and intake design. Dynos limit the acceleration of a motor but the motor accelerates the car.

John, You have already given examples of drivetrain switch from one car to another but picked up over at .10 and 2 mph At the same weight. How then do you judge the engines horsepower accuracy versus Dyno? It seems you are contradicting yourself.

So we have transmissions that improve ET and make zero difference in mile-per-hour. And cars that affect ET and mile-per-hour with the same drivetrain. Yet it is better to "judge" hp from mph?

Originally Posted by Daniel Barton

Clearly more than 1 to 1 1/2 like I said... We aren't talking about something that shows within 20 or 30 horsepower as that could be more easily excused away by aero issues, that is kind of my point.

Were you personally involved in sorting out these cars that make more horsepower yet go slower? Were they given sufficient effort to utilize the power? Four instance, Are you 100% sure there was not a issue. Like insufficient hood clearance? Or fuel delivery problems? Or wrong converter/excess of slippage? Transmission issues? Or a spun rod bearing?

Just trying to learn from the pros. We all evaluate combinations and their effectiveness whether it's against a dyno sheet versus ET or other Car/combo.

Of course us "novices" Are incapable of properly judging horsepower. We are only smart enough to "trick" a dyno and build unicorn engines that are anomalies.

That might be a good business venture for you and John L....www.horsepowerjudges.com

Submit a combo and wait for the "judge" to explain what's wrong with an engine based on a professional opinion. Not sure how that would go for the guy not building his own engine combos though. Just a thought.

[Motor Daddy]

Originally Posted by john marcella

And engine has a power curve and the faster the engine accelerates the faster it gets through that curve getting into the higher horsepower levels of the curve sooner. Same thing I want of the lifter on my camshaft.

That's not how it works. An engine has a torque curve. That is, A virtual torque reading was taken at every RPM, and a line was drawn connecting the dots, making a torque curve across an RPM range.

That is: Virtually, a load was placed on the engine at every RPM until the RPM did NOT change, ie, the maximum TORQUE for that RPM was measured, and the RPM was not changing. It was "loaded to the max" at that RPM at that torque reading.

HORSEPOWER is a unit of measure of power, which is work divided by time, ie, (force*distance)/time. 550 ft-lb of WORK per SECOND (33,000 ft-lb of work per minute (33,000/6.28 ft-lb=5252 (1 lb-ft of torque at 5252 RPM equals 1 HP))), so HP=Torque*RPM/5252.

If you are doing work at the rate of 33,000 ft-lb per minute, at an RPM of 5252, the torque is 1 lb-ft.

It is simply all a measure of mass, distance, and time. It is how we MEASURE.

[Daniel Barton]

Originally Posted by john marcella

I'm sure what Dan is talking about is engine acceleration not vehicle acceleration like you guys are talking about. Two totally different things.

And engine has a power curve and the faster the engine accelerates the faster it gets through that curve getting into the higher horsepower levels of the curve sooner. Same thing I want of the lifter on my camshaft.

Dan, yes if two motors have the identical power curve but one motor accelerates faster against the same load than that motor will absolutely be faster in the car. But imo you can't produce those two motors with identical power curves!!!! Hp is work vs time. If work is the same but time is lesser ,,,,,,then hp is greater.

John, the difference is in how the dyno works, most but not all set the acceleration by the servo valve allowing the water to leave the pump at a certain rate, it sets the acceleration, not the engine that accelerates hard versus one that doesn't accelerate hard setting the rate.

[Chris Uratchko]

I've had numerous torque converters, 2 different manuf. both the same size, similar stall speeds, one is 2 tenths faster than the other, and some mph.

We've all seen many swings in results in et and mph with no engine changes so any debate in it is invalid.

[John Langer]

I have a magic box in my car that measures rate of acceleration in g-force vs time. You can look at that data and determine the rate of acceleration at different points on the track.

[Daniel Barton]

Originally Posted by mike leech

John, You have already given examples of drivetrain switch from one car to another but picked up over at .10 and 2 mph At the same weight. How then do you judge the engines horsepower accuracy versus Dyno? It seems you are contradicting yourself.

So we have transmissions that improve ET and make zero difference in mile-per-hour. And cars that affect ET and mile-per-hour with the same drivetrain. Yet it is better to "judge" hp from mph?



Were you personally involved in sorting out these cars that make more horsepower yet go slower? Were they given sufficient effort to utilize the power? Four instance, Are you 100% sure there was not a issue. Like insufficient hood clearance? Or fuel delivery problems? Or wrong converter/excess of slippage? Transmission issues? Or a spun rod bearing?

Just trying to learn from the pros. We all evaluate combinations and their effectiveness whether it's against a dyno sheet versus ET or other Car/combo.

Of course us "novices" Are incapable of properly judging horsepower. We are only smart enough to "trick" a dyno and build unicorn engines that are anomalies.

That might be a good business venture for you and John L....www.horsepowerjudges.com

Submit a combo and wait for the "judge" to explain what's wrong with an engine based on a professional opinion. Not sure how that would go for the guy not building his own engine combos though. Just a thought.

In many yes I was and that would of course be why I feel that this "voodoo kool aid" exists in real life.

[John Langer]

Originally Posted by Chris Uratchko

Just to side track from the healthy discussion here, Been thinking about this for a bit and always go back and forth on bob weight vs acceleration.

Dumb question but If I put the car in neutral will the engine accelerate faster than if it is in gear? So based on that result, is the heavier rotating mass the acceleration limiter, or is it the rest of the rotating assembly - Converter, Transmission, Driveshaft, Rear End, Wheels, and Vehicle weight doing more limiting that a heavy set of rods and crank.

I just bought a set of Carr pro stock rods from Book and they have been ranging in the 600-620 gram max window... doesn't seem to have hurt their acceleration vs a mid upper 400 gram aluminum rod.

Not debating, as I don't feel like I have a consensus on it, just thinking out loud in discussion.

Force x distance. Where is the majority of the weight of the aluminum rod with respect to the steel rod in comparison with the center line of the crankshaft. Pro stock has a minumum bob weight. If i had to distribute weight between the rod, pin and piston, I would want the most weight by the crank, not at the furthest point away. Force x distance.

[John Langer]

Originally Posted by mike leech

John, You have already given examples of drivetrain switch from one car to another but picked up over at .10 and 2 mph At the same weight. How then do you judge the engines horsepower accuracy versus Dyno? It seems you are contradicting yourself.

Weights were different. CD was different. No contradiction. More aero car went faster with same exact drive train. I believe that was the purpose of the comparison. I could go into more detail but I dont really care.

[John Langer]

Originally Posted by Motor Daddy

Acceleration is the RATE OF CHANGE OF VELOCITY.

In other words - Acceleration is a measure of the time it takes to go from one velocity to another velocity. The RATE of change (acceleration) of velocity is measured by measuring the time it takes to change from 0 MPH to 140 MPH. The acceleration is greater if the time is less. A 0-140 MPH change in the elapsed time of 10 seconds has a greater rate of change of velocity (acceleration) than an elapsed time of 11.28 seconds to do the same change from 0-140 MPH.

It gets a little tricky because the greater the rate of change, the greater the velocity in the same distance, and the less time it takes to travel that same distance, hence my equations, which are 100% accurate!

I agree and the rate of acceleration is not constant during a drag race competition.

[Daniel Barton]

okay I'm off to work, whats a circus without the clowns?

[mike leech]

Originally Posted by Daniel Barton

okay I'm off to work, whats a circus without the clowns?

Ditto here. Lol.


Got a love a full moon

[Motor Daddy]

Originally Posted by John Langer

I agree and the rate of acceleration is not constant during a drag race competition.

You start in a specific gear ratio which reduces the total load on the crank proportionally. Less load on the crank means it can increase RPM at a greater rate, ultimately making the car accelerate at a greater rate in that gear. That soon (the more gear the sooner!) turns to running out of RPM and having to change gears to a lower numerical ratio, which ultimately puts more load on the crank, reducing the RPM, and making it climb slower this time around than it did in that other higher ratio gear (which accelerated quite nicely for the few feet that it traveled in.)

You need more POWER to make your car run less time in the 1/4. More power means more work in the same time, or the same work in less time.

See how the gear changes the time in the pic?? The RPM is the black line. The gear changes are shown as different angles, and time is along the bottom.

Notice how time is absolute?

[J.C.you]

Originally Posted by Daniel Barton

John, the difference is in how the dyno works, most but not all set the acceleration by the servo valve allowing the water to leave the pump at a certain rate, it sets the acceleration, not the engine that accelerates hard versus one that doesn't accelerate hard setting the rate.

is this a hard water dyno or soft water unit?