Engine/Transmission (1998.5 - 2002) 0-60 horsepower calculations

[dieselshadow]

I've looked for calculators to figure out hp from 0-60. My results were 7 seconds at 7750 lbs. How much hp is that? BTW I had to be in 4WD and turbo brake to achieve these numbers. It started snowing after my last run. I did not get a 1/4 mile run and I don't have a true 1/4 mapped out:{

 

[Cummins4Life]

I'm not aware of any calculators that can find horsepower from 0-60 times, you can probably do it mathematically but that is beyond me.



Do you have a 1/4mile time?

http://www.smokemup.com/auto_math/hp_mph.php

 

[Sky]

I tried to figure that out too. I had Borrowed a G-tech could only figure out the 0-60 times to work. I had 5. 84 sec at 7000lbs. Still dont know to this day what my true HP is. I am guessing around the 380-400 mark

 

[dieselshadow]

Did I stump the Roundtable with this simple math problem?:--)

 

[work2muchplay2little]

It will be a lot easier to estimate your HP if you build yourself a signature containing your modifications and base truck configuration. For reference, with stock tires, DDIII's, DTT 91% TC and VB, the FMS, and an HX-40 and building 10psi of boost my 0-60 was 6. 1 seconds - this configuration - except with 35" tires and a different torque convertor did 490 HP.

 

[dieselshadow]

I could, but that would "influence" the numbers one would get from a mathematical formula. I want to know from the numbers I posted what horsepower/torque that would equate to. I can "guestimate" all day long but in the end but I want to know what the numbers say. I want to know how much or how little What I really need is a dyno. I know somebody can figure it out.

 

[Opz01]

Originally posted by sixkill

Did I stump the Roundtable with this simple math problem?:--)

Too many variables too little info for it to be a simple math problem. Simple would be to goto a dyno. I seriously doubt that your 0-60 time was exactly 7 seconds. But then again I am not into simple problems.





Opie

 

[andrewkoperdak]

If this is a simple math prob then make sure you include me in the answer. You are assuming a static solution to a dynamic problem. What about Xmission type, gear ration, clutch slip, torq conv slip, driver error in shifting, altitude, air temp, on and on and on. I like a challenge but... . I can work with one or two unknowns but you have more than that. finally without knowing what you have anyone's solution would be a WAG wild XXX guess.

All kidding aside... let me know if you find your answer.



I did my HP the easy way using a dyno.

R,

Andy

 

[ptraufler]

I little math here first,



(Force)(Distance)/Time = Power



Horsepower = 550(ft)(lb)/s



The crankshaft converts the linear form of power to a rotational form of power.



(Torque)(RPM)=Power



Horsepower = (Torque)(RPM)/5252



Force = M*A (Mass times acceleration)



Here is the trouble, the A is NOT constant and how the gTech works is by sampling over a small time interval the acceleration and then intergrating that to determine the force. SImple math will not do it, at least not very well. The time it takes to get to 60 MPH is not going to get you what you need here.



What if this vehicle had VERY low gearing, you may never get to 60 MPH even! One word, DYNO.

 

[dieselshadow]

I wanted to "quiz" the collective mind of the TDR. I'll give you a couple of details about my truck. It is a 95 reg cab with an auto slush box, 3. 54 limited slip rear, 4x4, with BD's x-converter, valve body, and pressure lock. The engine has been modified with 370 injectors, 4" exhaust, 16cm turbo housing, a ---censored--- modified injector pump, and full gauges.



I have to ask the collective mind (24v guys because there is more eyeballs here) because there is no dyno around. I can reproduce these numbers time and time again. I had my neighbor time everything while riding in the passenger seat. There is no real good place to do a real 1/4 mile around here this time of year.



The facts still remain. It takes X amount of HP to get a 7500lb truck to 60mph in 7 seconds. (I'll bet I can get better times if I could get the shifting just right)



I sure one of you fellers out there can answer this question. I thank you for your time. I really appreciate the the TDR and it's members

 

[Boldt's Wagon]

The TDR magazine has not published formulas for 0-60 times as far as I know. TDR issue #27, pg 35 published formulas for 1/4 mile elapsed times and mph.



HP = W/(ET/5. 825)^3



HP = W*(mph/234)^3



Where W is weight in lbs, ET is in seconds, and ^3 means cubed or to the third power. The HP numbers appear to be flywheel HP and should be multiplied by 0. 85 or a drivetrain efficiency of your choice to get wheel HP.

 

[ptraufler]

Given:



W = 7500 lbs

0 to 60 MPH = 7 Sec



? Hp





We also know this:

Gravatational constant (g) = 32. 2 ft/s/s OR we will use 21. 95 mph/s

(32. 2 ft/s/s) * (1 Mile/5280 ft) * (3600 Sec/1 Hour) = 21. 95 mph/s



One HP = 550 ft-lb/s OR we will use 375 lb-mph

(550 ft-lb/s * (1 Mile/5280 Ft) * (3600 Sec/ 1 Hour) = 375 lb-mph



Force = Mass*Acc





Acc = (60 mph - 0 mph)/7 Sec = 8. 57 mph/sec



Force = (W/g) * Acc



Force = (7500 lb / 22 mph/sec) * 8. 57 mph/sec = 2921 lb



Avg Speed = (60 mph + 0 mph)/2) = 30 mph



Power HP = 2921 lb * 30 mph / 375 lb-mph/hp = 233 hp



This looks pretty high are you sure of the time and weight?



Paul

 

[Big_Daddy_T]

The math is flawed. Im sub seven and under 800 hp. I agree too many variables. 1/4 mile is different.

 

[ptraufler]

The math is not flawed it is correct, the trouble is you have to account for drag, rolling and wind and several other things to get the correct values. It is ONLY as good as the data input! If F = MA is not right then we are in a world of trouble! Mr. Newton you were wrong?

 

[Big_Daddy_T]

If you count all those other things in wouldnt the outcome be even higher hp #s?



P. S. I agree math is not flawed. Just the circumstances fed into the problem. Thats why no one tries to get an accurate hp reading by using 0-60 times.

 

[ptraufler]

Yes!



I figure the weight and the times are not spot on, also if the speed is based on the speedometer and watching it you will be off for sure. I would say use a GPS to get the speed and log the data so you could get a better time. If the wheels slip a bit the speed would read higher than actual. Maybe a radar gun to get the speed but I do not thing that would be very easy to do. The weight can be set pretty well on a truck scale. The old saying garbage in garbage out still works!

 

[Big_Daddy_T]

For a more accurate calculation you would need to include the distance. If it was 62 mph in an 1/8th mile with a 7600 lb truck a figure would be easily obtained. But because he didnt specify distance you are left with an inaccurate answer. I am sub 500 hp and can run sub sevens. Find an equation that will explain that and you will have an accurate math problem.

I like that garbage in garbage out. Ive never heard that before. But Im a drop out not likely to come up with math solutions.

 

[ptraufler]

Opps I did make a math error, pushed buttons on the calculator and did not look at it! 233 HP is what I came up with now. This is at the wheels more or less. No drag or wheel slip or measurement errors. It would be a good guess that at least 20% loss for the drive line would be in order so maybe 280+ HP. As for tire slip and drag those are NOT simple to figure at all!

 

[ptraufler]

If we looked at time errors:



Assumes 7500lbs weight



Sec to 60 MPH, HP

6. 0 272

6. 1 268

6. 2 264

6. 3 259

6. 4 255

6. 5 251

6. 6 248

6. 7 244

6. 8 240

6. 9 237

7. 0 233

7. 1 230

7. 2 227

7. 3 224

7. 4 221

7. 5 218

7. 6 215

7. 7 212

7. 8 209

7. 9 207

8. 0 204

 

[Big_Daddy_T]

Still it isnt quite right. A stock truck has about 190 to 210 rwhp and it cant make it up to 60 for about 11 seconds. It took my truck 13 seconds to get to 60. Now I do it in a little over half that time.