horsepower predictors programs

[feracer]

do these programs like desktop dyno ,come anywhere close to reality?

[jayb]

My experience with them has been that they are rather optimistic about the HP and torque numbers.  I think they might be accurate if you are running a 400 HP small block Chevrolet, most of them were probably designed around something like that 

[Stangman]

Ya know when you use the Wallace calculators and you put your times in and get your horsepower I think they are on the low side, although maybe my car doesn’t have that much HP. That’s why going to the track really is the equalizer. Maybe not the exact thing as a desktop Dino but I think they can only be so close. Whatever Werby uses is close.

[Rory428]

Actually, I have found the Wallace calculators to be very generous when it comes to HP. I have found the old Moroso Power Speed Calculator to be very close , when using realistic engine dyno numbers, and a good working, well sorted out chassis and combination is used. Compromised or poorly set up combinations can easily be off a full second from their optimum potential.

[My427stang]

The issue I have seen with the dyno guessers is not enough ability to input everything.  Most use .050 or adv duration, but not generally both, they are usually pretty good at allowing flow numbers, but not all allow port volume, and most make more power with whatever you make bigger, which is not really the case in reality.

I will say though, Desktop Dyno, EA Pro, generally can do OK on the TQ/HP RPM peaks if you are careful with all the inputs, but they are almost always significantly higher than reality in value

I have some files on EA Pro that I adjusted with actual dyno data, examples are the iron 461s, and the TFS headed CJ.  I was able to back into the numbers pretty closely without a lot of fudging and it allowed me to play with some cam changes, etc.  In the end though, I wouldn't call it precise, but something to play with on a rainy day LOL

[Stangman]

A while back I had Werby do his thing and I was off time wise but after getting everything right I was hundredths off what he said. And if I put all my times and MPH  and weight in it always comes out to about 490 horse. Unless I’m off on the weight I would have to imagine my 485  has 520 to 550 horse. Maybe I’m wrong but it runs great.

[WerbyFord]

Ya know when you use the Wallace calculators and you put your times in and get your horsepower I think they are on the low side, although maybe my car doesn’t have that much HP. That’s why going to the track really is the equalizer. Maybe not the exact thing as a desktop Dino but I think they can only be so close. Whatever Werby uses is close.

I was hunting for old dyno data & just found this.
Thanks for the remarks on the Gonkulator.
I wrote the Gonkulator myself, starting back in the 1980s at college in Ann Arbor.

The horsepower "wheel" estimators, Wallace, Moroso, etc, all come from the theoretical equations showing that AVERAGE rear wheel power is proportional to MPH cubed, with a fudge factor. The ONLY thing they can provide is AVERAGE REAR WHEEL POWER. The timeslip has no idea what the losses are from rear wheel to net, or from net to gross. So the "wheel estimators" just guess, with a one-size-fits-all fudge factor. That's still ok, and I do find that with a correction, one for sticks & one for automatics, the "wheel" horsepower corrected to net, correlates pretty well with Gonkulated or even factory rated NET horsepower from period road tests.

But as noted, if you already have the timeslip MPH, that "wheel" method doesn't really give you any more added info.

I don't really trust any of the Gonkulators (even my own!) but they're a lot cheaper than a dyno or a day at the track, and can raise & try to answer some good questions. Good for planning a test or track session. If in doubt, run a couple different ones as noted (DD and EA, etc).

[frnkeore]

The one I use, is called Dyno Sim6.

With it, you can use the actual cfm head flow numbers and the actual Comp Cam, lobe profiles. It has a PDF file of all of CC lobes. You pick your lobe and inter the lobe number, into the sim. All the cam events can be changed.

The exhaust systems can also be changed but, you can't specify the tube sizes, stepped primary's or a merge collectors. You pick the system type (manifold, triY, large tubes or small) then you pick the torque range and it out puts the tube and length.

I've been able to match posted dyno pulls but, the rpm may be off 100 rpm, both HP & TQ and the actual torque can be off as much as 30 lb ft, on a 600 lb ft, dyno reading.

It's sensitive enough to add or subtract  HP & TQ for rod to stroke ratio's.

You can check some the input/output screens in the FE vs 460 thread.

I also use Pipe Max but, you can't use actual lobe profiles or actual head flow, just max flow but, it will go a little beyond your head flow and tell you what you need, in both head flow and cam profile, then you have to find a profile that will match. BUT, you can't change it's cam numbers, even though you input your own. It tells you how wrong you are.

I use it to compare the Sim6 and to get basic, header info and try to find a header that matches, as close as possible.

The basic HP range (max HP & TQ), seems to be good on both but, I don't use it for actual HP & TQ. I look for areas to improve performance, such as low end streetability and highest average HP & TQ in the rpm range, I'm interested in.

I do antique tractor pulls, also and use it for 1000 - 2700 rpm engine improvements, too.

[DubyaTF]

    What about Camquest from Comp Cams? Has anyone done comparisons with it?

[WerbyFord]

    What about Camquest from Comp Cams? Has anyone done comparisons with it?

It's been a while but the last time I compared Camquest to the Gonkulator, Camquest came in too high.
But, it's probably pretty good for comparing cam changes which is their whole business.

Back when I worked in Strategic Weapons, one of the guys had on his door:
"My job isnt rocket science - it's more complicated than that"

That's how I feel about engines - especially ones with a carburetor, or power-adders, or both.

[cjshaker]

Ya know when you use the Wallace calculators and you put your times in and get your horsepower I think they are on the low side, although maybe my car doesn’t have that much HP. That’s why going to the track really is the equalizer. Maybe not the exact thing as a desktop Dino but I think they can only be so close. Whatever Werby uses is close.

I was hunting for old dyno data & just found this.
Thanks for the remarks on the Gonkulator.
I wrote the Gonkulator myself, starting back in the 1980s at college in Ann Arbor.

The horsepower "wheel" estimators, Wallace, Moroso, etc, all come from the theoretical equations showing that AVERAGE rear wheel power is proportional to MPH cubed, with a fudge factor. The ONLY thing they can provide is AVERAGE REAR WHEEL POWER. The timeslip has no idea what the losses are from rear wheel to net, or from net to gross. So the "wheel estimators" just guess, with a one-size-fits-all fudge factor. That's still ok, and I do find that with a correction, one for sticks & one for automatics, the "wheel" horsepower corrected to net, correlates pretty well with Gonkulated or even factory rated NET horsepower from period road tests.

But as noted, if you already have the timeslip MPH, that "wheel" method doesn't really give you any more added info.

I don't really trust any of the Gonkulators (even my own!) but they're a lot cheaper than a dyno or a day at the track, and can raise & try to answer some good questions. Good for planning a test or track session. If in doubt, run a couple different ones as noted (DD and EA, etc).

Werby, is your program available for public use, or are you the only source? Over the years, I think your program has proved to be fairly accurate. About as accurate as is possible, given the hundreds of minute variables that can never be accounted for.

[My427stang]

    What about Camquest from Comp Cams? Has anyone done comparisons with it?

I play with it now and then, because it is on a computer I use a lot,  but it is miserable LOL  You cannot adjust cam timing, you cannot input cam specs, you simply use their cams, and yes it seems high most of the time.  I do think it is a limited version of Desktop Dyno, seems to be anyway

It does allow more specific head flow files than most, but even then it ignores a lot of details

After each dyno run, I go back and massage EA to correct it, mostly for fun, and if the build doesn't change a lot, on the next one, I feel like I can see what may happen if I change a parameter or two (lots of if, may, etc LOL) 

What I feel a good predictor needs, assuming good programming, is more lift and duration inputs, lash adjusted when required, better flow files, which can easily be updated for cross section and volume, and better runner length and header dimension inputs.  I supposed the expensive programs do that, but it gets to a point that the tool may be more expensive than benefit and not exceed what experience tells you anyway