Desktop Dyno Woes

[probert]

I had some great replies to my last post so here goes again...I have Dyno2000 version 3.1 on my PC and I'd LUV to believe what it's telling me...414hp at 6,000 rpm??
It's a 355 with a 600 cfm Holley, 1.94 camel hump heads, 64cc, headers with 2.5" exhaust and a Comp XE274H cam. I think maybe I screwed up with the cam specs? It has gross valve lift of 480 int and 490 exh.Cam installed at 106 intake centre line, duration at .050 inch...230 int, 236 exh,lobe lift, .3250 int, and .3270 exh. Lobe separation is 110. I know 414 horse is too high, so give me the truth, I can take it....I think http://www.yenko.net/ubbthreads/images/graemlins/no.gif

[68ys8030]

these desktop dynos make me crazy. ok... try changing from your 64 cc double humps with 1.94's to a vorteck 1.94
with 64 cc's. probobly a 30 hp diffrence. but the desktop
cant tell you that. theres too many variables. i had a customer tell me that if he advances his cam 2 degrees he'll pick up 80 hp cuz the desktop dyno told him so. http://www.yenko.net/ubbthreads/images/graemlins/rolleyes.gif steve

[Mark_C]

Accurate head flows are the key to using DD dyno. You need to make sure the flows you are using accurately reflect the heads you have. Don't just pick the Wedge/Pocket Porting, Large Valves head flow file if your running 186 stock camel hump heads. You'll end up with some highly optimistic numbers. If you can get the head flows right you'll be within 5 to 10% of the peak numbers. The programs real use is to see the relative differences small changes in cam timing, or changing a cam can have on your engine more than telling you that you have a 411.5HP engine at 6500RPM.

[NCGuy68]

The DD dynos are fun, interesting, and at times can give good ballpark results. As has been said, theres' too many variables that the software can't account for.

In the end, a real time engine or chassis dyno is the way to go. Of course, the 'acid test' is to run it on the 1/4 mile!

[The Body God]

I have an older version that I played with. I entered info about the engine I had in my 58 vette and the cyl head tech was never to my likeing in this program. There are so many variables to cyl. heads. the configuration I entered was as close as I could enter as to my engine and I thought it was telling me a HP rating that seemed a little High? I have not tryed the new version though.

[Mr. T]

This program seems interesting, although it is not 100% accurate. Where could I pick up a copy?

[Belair62]

Hey Probie....did you play for the Hawks ?

[NEATSS]

I have a very similar combo and it makes 262 HP to the rear wheel at 5600 rpm. The car weighs 3850 lbs. with me in the seat and has gone 13.31 @ 100 mph. I'm sure it could benefit from some better tuning.

[probert]

The Hawks? Do they still have a team?? Hahaha.....ok, you guys kicked my Wings' butts the last time so I can't laugh too much.....nope, I ain't Bobbie but that's where the nickname came from. Go DEEtroit!! http://www.yenko.net/ubbthreads/images/graemlins/haha.gif

[probert]

Ok, back to the dyno thing...I entered "low performance, large valves" 1.94 int and 1.5 exhaust, did the compression math and it gave me 10.48/1 at .028 deck height and .025 head gasket.13's? Man. I'd LOVE that!!I ran a "street" 1/4 mile once at about 102 mph with an ET of about an hour and 10 minutes ....my 245/60 BFG's don't hook up so good in 1st gear http://www.yenko.net/ubbthreads/images/graemlins/3gears.gif

[Mark_C]

Heres an link to a site with all kinds of cam, and cylinder head files for you to use. The Unofficial DD2000 File Page (http://www.chevyasylum.com/dyno2000/Welcome.html)

Extract the stock SBC 186 file from the head flow ZIP file and use it. See if your numbers change any.

[SMGCO]

I've found destop dyno is fairly accurate if you enter everything accurately and make sure you enter the header size properly. You would be surprised how much power ( peak power ) is effected by smaller headers with muffler. Run it again with mufflers and see.

[probert]

I ran the Dyno test again with the head and cam files from the unofficial dyno2000 page(an enormous help, thankyou) and the max hp came in at 360 and the max torque at 400ft lbs. This seems more realistic. Thanks guys for the input....you can't put a price on knowledge! http://www.yenko.net/ubbthreads/images/graemlins/scholar.gif