HP calculation based on ET

[Bruce]

Source, UNK:

(Trap speed) times (Trap speed), divided by ET, times (weight in pounds divided by 1,000), divided by 9.1

So if you have a 10.0 that runs 125, and weights 3,500 lbs.

(125) times (125) = 15625
divided by ET (10) = 1562.5

times

(3,500 divided by 1,000 = 3.5)

5468

and that divided by 9.1

equals 606 rear wheel HP.

I didn't round off the numbers in the calculator.

Just an approx..

[Vacuum 6]

Source, UNK:

(Trap speed) times (Trap speed), divided by ET, times (weight in pounds divided by 1,000), divided by 9.1

So if you have a 10.0 that runs 125, and weights 3,500 lbs.

(125) times (125) = 15625
divided by ET (10) = 1562.5

times

(3,500 divided by 1,000 = 3.5)

4464

and that divided by 9.1

equals 490 rear wheel HP.

I didn't round off the numbers in the calculator.

Just an approx..

Bruce,

Things not adding up...RWHP 600.9615?

[Turbo Archie]

I made a conversion in excell along time ago and now I can't find it. Anyone have the old TRX HP calc they can send me??

Also, If that is in RWHP, whats the conversion to get to crank HP. Thats what the injectors are rated at right??

[Turbo Archie]

Works for me ~441 HP

114 - 11.84 - 3660

I thought you were good at math.

[Bruce]

Bruce,
Things not adding up...RWHP 600.9615?

OK, then I posted my math, where's the difference in what you do?.

[Bruce]

Also, If that is in RWHP, whats the conversion to get to crank HP. Thats what the injectors are rated at right??

There's at least 10 theories about drivetrain loses, and it's always going to vary by dyno, at least some. On the DIY-EFI list some years ago there was some heated debate about the loses, and there was a compelling arguement that at over 500 HP, a 15% Drivetrain lose, was enough to start burning up parts, from the heat generated. Then on the Syclone list, there was a documented lose that just blew that away.

IMO, just use .6 BMFC, and look at the DC of the injector, and move along <g>....

[BoostKillsStress]

For a 10.0 your going to see around 134mph and figuring weight in a 3650 range should give a decent HP number needed aka 720 at the wheels. Prime example:
Car owner; Jason Cramer (Race Jace)
Best E.T. 9.89 @ 136 @ 2500 ft. Ele.
Best 60' 1.37


This car is no lightweight, tipping the scales at 3610lbs with driv

[Bruce]

ETs are about HP AND how well the chassis/ tires are working.

MPH is mostly about HP.

The numbers I picked were just easy to use, and for others to be able to follow the math.

That formula is as good as it gets, from what those that I've seen posted, and lines up HP wise. IMO, folks are way too hung up on bench racing HP. It almost seems like that's two standards for HP, magazine, and real world. One of the Compact Car Mags, went around to several dyno shops, and none of them were very consistant (IMO). If folks were working to some sort of standard, the results should have ALL been within 1%, IMO, and as I recall the differences even between those of the same brand were well off from that.

Dynos are great for making back to back runs, or at least using the same dyno to notice TRENDS. Final tuning is always going to take going to the track, and seeing what the slip says. BTW, once you look at a real dyno, like what an oem uses, you'll see what it takes to get pretty repeatible, pretty accurate results on a dyno. And even they then take them to the streets/ track for final tuning.

[pacecarta]

i have the TRX calculator if any one needs a copy


using it this is what i get

[Bruce]

i have the TRX calculator if any one needs a copy
using it this is what i get

If you look at the injectors, it says that with 100% DC you can make 690 HP, that would have to be some of them Magic HP, IMO. At .5 BMFC the best you could do would be 660.

How much HP does it show for a 120 trap speed?.

Can you change the file extension to say a .bmp, and post it, if it's freeware/shareware?.

[Vacuum 6]

OK, then I posted my math, where's the difference in what you do?.

I get 5468.75 when I multiply 1562.5 by 3.5. How are you getting 4464? Everything else looks fine to me.

[Bruce]

I get 5468.75 when I multiply 1562.5 by 3.5. How are you getting 4464? Everything else looks fine to me.

I was using a Windowz calculator <G>

I dunno how I did that, I edited my original post, and stand corrected......

[Turbo Archie]

I thought you were good at math.

See I was right again, you are good at math.

Gezz, correcting Bruce and all.

Remember to let the wookiee win wally.. :hanged:

[Vacuum 6]

I was using a Windowz calculator <G>

I dunno how I did that, I edited my original post, and stand corrected......

No problem. I just wanted to make sure I was not missing something.

[Vacuum 6]

See I was right again

It’s easy being right when talking to yourself.

[Bruce]

It’s easy being right when talking to yourself.

Not around here..... :)

I only stand a 50/50 chance..

[Bruce]

See I was right again, you are good at math.
Gezz, correcting Bruce and all.
Remember to let the wookiee win wally..

Correcting my math, really isn't *that special*, LOL.
I just wish we were allowed calculator instead of having to use an abacus, when I was in school. :)

At least in High School for our Senior Year, we got to use Slide Rulers.