Are the desktop dynos worth the cash?

[Nik]

The time has come to order the parts for my son's 396 and am looking at the different variables and was wondering if forking over the cash out for a desktop dyno program was worth it or not. With the 177 Blower, and 150 shot of Nitrous on it, I would rather try and figure it out on paper before I get stuff that makes it go boom because of my stupidity.

[Beagle]

The most uber-comprehensive one I've seen was Engine Analyzer Pro, but at ~460.00 I'd have to be building all day every day to justify it. They had a 10 day demo that I could never get to work right on anything after XP. Their new release should work up to Windows 7 according to their web page. Performance Trends is the parent company. I would not try any of the "cracked" versions for a couple of reasons... like I believe developers should be allowed to eat, and the "cracked" junk is likely a virus saying it is a cracked version.

There's a couple of folks running DesktopDyno I think - 50.00 from Summit seems reasonable. Some of the magazine articles I've seen in the past did a DD sim before putting their stuff on a real dyno and they've been suprisingly close. I don't know if it will simulate a nitrous backfire... does the 177 have a burst panel?

[TheSilverBuick]

I've wondered this too, but really wonder how they do with non-chevy/ford engines on the port stuff. Especially since I'm not smart enough to figure out how to quantify port volume and shape.

[milner351]

We used DD years ago in college projects - and with GOOD DATA INPUT - the output was within a few percent of what we got on the dyno - but - like any program - garbage in = garbage out. There are lots of rules of thumb in play to determine the program default values for things like port flow, etc, that most folks don't have a real number for.

I think they are a great tool for determining the right direction to go in - but probably not a great tool if your goal is to acurately predict the final power level to within a few HP, unless you have flow bench data on the heads, exact compression ratio measurements, complete cam data, etc etc.

They are great for choosing camshafts - as you can use the iteration tool to chose between a huge number of variables and hone in on something that makes sense....

[Mater]

I've wondered this too, but really wonder how they do with non-chevy/ford engines on the port stuff. Especially since I'm not smart enough to figure out how to quantify port volume and shape.

not vary close. at least not when i tryed to put in my 3800 from the GP came out way under what it dynoed

but that is mostly do tot he fact they have no intercooler option on the roots style blower

[1970camaroRS]

Fun to play with, a bit of a novelty, but honestly not worth the money. I did find it enjoyable to run several camshafts on the same engine, take the power curve and plug it into the drag sim on the same car and see the differences in theoretical 1/4 mile times. Other than that, nothing beats doing it for real.

[TC]

Comp Cams has a Cam selection program that is free, it is basically a desk top dyno type program that will recommend camshafts for your combo and give you an estimate of the the power production, along with plotting it out on a graph. I'm not sure which Magazine did an article on it, but they punched in the numbers and then dyno'd the motor on an actual dyno and the number were extremely close to what the CompCams program estimated. In fact the torque and HP peak number happened at the same rpm as the program stated only difference was the motor actually made MORE power than the program suggested, which I don't take as a bad thing.....

[dieselgeek]

Our Engine Masters Challenge design boss (legendary Gene Adams) is using Dynomation. After we figured out a few new EFI tricks, our engine began making *exactly* the predicted power, with the power and torque peaks at exactly the predicted RPM. Gene was pretty excited to see us be able to hit those numbers.

I have never used any of these programs myself, and I don't trust magazine dyno tests anymore, so take it for what it's worth.

[TC]

Our Engine Masters Challenge design boss (legendary Gene Adams) is using Dynomation. After we figured out a few new EFI tricks, our engine began making *exactly* the predicted power, with the power and torque peaks at exactly the predicted RPM. Gene was pretty excited to see us be able to hit those numbers.

I have never used any of these programs myself, and I don't trust magazine dyno tests anymore, so take it for what it's worth.

You don't trust Freiburger or Westech Performance??..........Hmmmm......maybe you know something we don't.......

[dieselgeek]

You don't trust Freiburger or Westech Performance??..........Hmmmm......maybe you know something we don't.......

Brule and Freiburger are standup guys. Both of them would give you the shirt off their backs on a cold December day at the North Pole. It's not the people I have problems with when it comes to magazine tests, it's the "things we could not cover" that people don't think about much.

For example, when I see these giant manifold comparison tests - the first thing I want to know when one of them performs badly, is: what were the AFRs doing on each cylinder? Is the manifold down because of air distribution problems, or is it just a general restriction.

I know from what I am learning at EMC, one manifold can be KICKASS on one engine and a turd on the other. It's impossible for magazine guys to take tests to the level of detail that REALLY answers questions.

Do I think some test results are bogus? probably, but I've been present for a few of DF's and other tests at Westech, and I don't think those guys are cheating. Maybe smaller shops who have something to gain or lose. but DF and Brule are great guys - I wouldn't doubt their integrity ever.

[SpiderGearsMan]

[SpiderGearsMan]

get out the jet box and lets go to raceway park

[dieselgeek]

get out the jet box and lets go to raceway park

awesome. there's nothing quite like taking 7 years to get a tune dialed in.

[A/Fuel]

You don't trust Freiburger or Westech Performance??..........Hmmmm......maybe you know something I don't.......

Yeah, like how to tune a race car, LOL!
I figured you would be a big fan of desk top dynos

[TC]

awesome. there's nothing quite like taking 7 years to get a tune dialed in.

Last time I was at Firebird for the test and tune, by the end of the night guys where pretty much hot lapping it.....I think with an AFR meter and good assortment of jets you could dial the car in with-in 4 or 5 laps......First run get your baseline and make jet change accordingly, Second run see how much of a change was made by the jet change, then change jets accordingly, Third run see how much of a change was made, if AFR's are on the money leave alone, or make minor change in jets to fine tune the AFR's, Fourth run check AFR's, if they are good your done, if not make fine adjustments.......

Thing is by recording the difference between the first and second runs you'll be able to determine how much of a change you'll do to the AFR's by stepping up or down to the next jet size, after that it's pretty much simple math to determine what jet to run to get the AFR's where you need them....

Carbs are pretty simple and at that Holley's have been around since like the 50's, no rocket science involved..........