I was pretty sure on the cam i was going to order until my friend and i were playing with his desktop dyno. It is set up as accurate as we could and has the airflow numbers for my heads. The cam that AFR reccomends makes pretty good power but then i plugged in a nitrous cam i was considering and i totally blew away the cam for all motor. They both peaked at the same rpm but the notrous cam had about 20 more hp and up to 50 more ft lbs down lower and higher volumetric efficeincy.

How accurate is this program? According to what i have heard the single pattern tight LSA cam should run better on motor. If it was only slight difference than no big deal but 50 FT LBS
What do you guys think?

I wouldn't put too much weight on the Desktop dyno. It is more of a toy than a tool.

Build both cams using the same method. Do not use a cam file from who knows where. They are all over the place when it comes to specs. You need to be sure you have the same cam type (high performance street vs dual purpose street/track) etc. Use the @.050 timing numbers unless you have better seat-seat data. In the end, it is only useful as a comparison between parts. You can see what changing out the cam should do to the torque curve but you need to be careful to compare apples to apples. The HP/torque numbers are not accurate by themselves.

Engine analyser is a better program and on my Christmas list :cool:

-Mark.

DD2k does no real computing for N20 other than add whatever HP you select to the NA HP. Not useful for N2O IMO.

As for cams I stick with advertised duration numbers (instead of .050 duration) and select camshaft type depending on how agressive the lobes are. This seems to work decent for me - the program is better for comparative numbers (seeing what a different cam does to the power band) rather than trying to get an accurate real life number.

Although I will admit that DD2k is within 5% accuracy for my combo when compared to other HP estimation techniques.

I compared the cams with everything the same but the cam specs and i entered the cam specs myself. It just seemed like the nitrous cam with 114 lsa would run better on motor and way better on nitrous but all of the cam manufactures reccomend 108 or 110 on motor.

Has anyone ran a 114 lsa on just motor and what is bad about it being so wide. The guy at Crane said it was because it would bleed off too much pressure and would rev very high because of it.

Thanks

Its close but...

My 502 made 625HP on the dyno.
DD showed 608HP - on the low side.

My 383 made 490HP on the dyno.
DD showed 510HP - on the high side.

(I always run it with large tube headers and no mufflers)

It can be off - one way or the other graemlins/clonk.gif

After playing with DDD several years ago and putting the buit motor on a real dyno, I found DDD to be within 10% (usually). I feel it is a good tool for trying combinations but to rely on it would not be wise.

I took the opportunity to compare a couple magazine engine builds along with DD2K and they were pretty close on HP. DD2K, in these instances was very liberal with torque, though. To compare these it takes pretty well detailed specs from each engine.

Engine Analyzer is the one to have. I played with Desktop dyno and really did not like it.

EA has fairly accurate numbers, but I only use it to tell me about where the torque and power will peak at when comparing camshafts. Very good tool.