Does anyone have a link to any free software like this? I don't want to pay $40 for something I'll use once.

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I have found that the horsepower numbers put out by these desktop dyno programs are highly inaccurate. You cannot compute horsepower and get an accuate estimate unless you have exact parameters on an engines breathing ability.
A dyno determines torque and horsepower by measuring the RPM rise with time for a predetermined load and takes into account some environmental correction factors.
Without spending $40,000 for a real chassis dyno, I believe that the closest "real world" results can be obtained with a system called the Road Dyno. This device is a data logger which inputs it's results to your PC, then calculates the power with the measurements taken under conditions of actual level road acceleration. Used properly, it produces remarkably accurate results. See it at:
[url]http://www.charm.net/~mchaney/roaddyno/ [/url] It cost $149.00 and the company usually ships promptly.

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87GT 3.4 Turbo Best 0-60 5.2 seconds
http://turbofiero.fierojoe.com/turbo.htm

All I'm looking for at the moment are estimates. The engine is not installed, therefore I cannot dyno it. Mainly I am interested in parts compatability.

Allow me to explain:

I have a 355 chevy with 1:6 ratio rockers and a cam with .488" lift and 316* duration (277* @ .050"). It has large chamber (smog) heads with 1.94" intakes and 1.60" exhaust valves.

What I want to know is this- will a 600 cfm carb and a dual plane intake be enough for that cam or do I need to put in a less radical cam? I will be using 1-5/8" primary tube headers with 2-1/2" exhaust.

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quote Originally posted by Dennis LaGrua: I have found that the horsepower numbers put out by these desktop dyno programs are highly inaccurate. You cannot compute horsepower and get an accuate estimate unless you have exact parameters on an engines breathing ability.

As Dennis says, Unless you have real flow data for heads, intake and exhaust, the data on the desktop programs can be as much as 25% off or more. As I was building my engine I was able to get the real data, So the desktop is about 2% difference from "real world". I have experimented with a few real engines and compared them to real dyno data.
When I first ran my engine with the default flow in the program, I was getting 240hp, once the real numbers were put in, it dropped down to about 220hp. Using a friends Mustang with a supercharged V-8 who also had all the flow data, The Desktop Dyno calculated 362hp, His real dyno showed 368hp.
Even if your flow data is off by 1%, the calculations can be 5-10% off.

If you just want to "build-up" an engine, Email or PM me the specs and I'll run it across Desktop Dyno 2000. I do have lots of flow data for the 2.8L/3.4L stock H.O. heads and what mine have been ported to.

The program is good even just to play around with it. Also, once you have real data, You can experiment with different cams and such to "tune" the engine for your needs. I wouldn't say the program is an absolute test, But it is a useful tool for setting up an engine. I actually bought the package that has Desktop Dyno, Desktop Drag, Thelatest Cam spec disk, and the Desktop Simulator (the game). That way you can build an engine, see what the car should do, then pick a famous dragstrip, pick a car (or make your own) and run it. In the game I've gotten a Fiero to run the 1/4 mile in just under 6 seconds with a built V-12. (yes it's not a real simulation since a supercharged V12 would never fit)

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Happiness isn't around the corner...
Happiness IS the corner.

I paid $40 for my copy of Desktop Dyno 2000. Sure you can make a 500000 HP 850 cubic inch V12, but if you do things realistically, you can get a fairly accurate reading. Remember, DD2K displays flywheel horsepower and torque, not rear wheel power.

With that consideration taken into thought, without a flow file loaded, I can build my Ford 300 4.9L L6 to fairly accurate. Actually the one I just did two minutes ago, considering the average drivetrain loss in my truck, put it within 6 RWHP of the actual dyno I had done the other week.

If you want just an average guess of what that carb or intake change or valve job will do to your powerband, then DD2K is for you. If you want a dead-on guess, there is nothing but an actual dyno chassis for you.

Learn to take things with a grain of salt.

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1985 Pontiac Fiero 2M4