As some of you may have read, I purchased my first dyno simulation program recently. Mainly just to be able to put in various cam specs, and be able to look at the open/close points, and overlap, at various specs for duration and lobe center. But, since I have a rack of actual dyno sheets here, for motor I have built, it was pretty easy just to pump in all the right numbers, and see what the program said.. As I have seen in the past with folks talking about these programs, this one is pretty optomistic. This is the latest offering from Motion Software, the makers of the desktop dyno and dyno 200x programs. This program is supposed to be much better than those, and the price refects it. This was a $130 program, vs $40 for those other programs. it is nice for what I wanted to do with it though... but this particular program, and anything simpler, does not ask for enough info to really correctly simulate the engine, it must make a bunch of assumtions, based a Chev, as to port volumes, runner lengths, ect.. I took the 600 HP/TQ street motor we just built specs, and used those.. I wish these numbers were reality.. but... um... no.. Just saying that we need to take computer sims with a grain of salt.. JW
and the real graph... This is this motors best pull, with the water cooling the SPX.. Nothing to sneeze at for sure, but no where near what this particular program thinks it can do. Now, I can manipulate the program factors, for intake, carb, cam timing ect to make it come up with the right numbers But that's just garbage in/garbage out..
Why? I have long had a theory that the folks who market and sell the lower priced versions of this type of software, want the end user's motor to look like it makes more power than it really does.. Because then the guy is happy.. he tells his buddies, and everyone shells out $40 for the program.. good marketing tactics. Now, I understand there is a sim program called engine analyzer pro, that is much closer to reality. And at $500 for that program, they can afford it to tell the truth, due to the fact that very few "hobbiest" are gonna shell out that kinda cash. Maybe the inacurracy is just simply due to the program's fixed parameters, which are not consistant with the engines us Buick boys play with, but I am prolly a bit too jadded to think that is the only reason.. Bottom line.. you know how much HP your motor makes when it twists the water brake, with a competent operator, on accurate equipment. Every other way of attempting to determine power, is subject to set 'standards', which may or may not be accurate. JW
Jim, Why not challange the software company that developed it. I would say that you deserve a product that more clearly shows the real thing. Oh yea, I am sure they will say it works for the chevy engines just fine. Still, I hate not getting what I pay for.
Jim, I use a program cqalled VDPro. Local racer/ computer guru has developed it. Although it is much simpler to use (not as many variables) than other programs, I have found it to be VERY accurate. For example, Bryan Sharer's Twin Turbo fairmont, with his specs, was predicted to run 9.84. His best run has been 9.86 with the combo used. A twin turbo BBC boat was calculated to make 1230HP. It made 1226 on the dyno. With the information you listed, (I could not determine some of the specs, so I guesstimated), I came up with 599.54 HP and 637 lb/ft. The HP/TQ peaks were different, but again, I didn't have the exact cam specs. I agree with you on the software theory...heck of a money maker... Anyone who would like me to run their combo, let me know.
I always enjoy seeing Sharer's Fairmont run at the Buick-Ford shoot out at Noble,OK.Too bad his tranny was broke this year.Saw him run a 9.91 a couple of years ago.I guess hes running one turbo now.Sure is a nice guy to visit with.
I always used these programs more to show the difference between proposed setups than to show absolute numbers. I wonder how accurate the programs are for that function. I think the grey areas are the source for most of the differences. Most numbers guys are usually pretty good, it's the bean counters that mess things up. Interesting post Jim. Mike D.
Dyno 200X is definitely not qualified for simulating actual engine, but the average guy doing a buildup can still find it pretty useful. It's a great educational tool, and parts comparison system for the uninitiated. A simulation package for a simple compressor & diesel engine system runs just over $50k for the flow dynamics analysis and has about 20 years of development in it. It gets very accurate models (within 5%) but also takes about 200 hours to create a model, then 10-20 hours to run the sim on a good dual-processor workstation. We need these kinds of models to determine 1M+ projects that can't be done via experience or testing. Now, if you are building a 1M+ engine I highly reccomend simulating for accurate result numbers. The dyno is the most cost-effective way to get accuracy for the automotive-level engines. That being said, the cheapo sims will still show you the difference in one system over another. For those curious about what different cam specs, head flow numbers, and intake types will do it's a great way to compare and see what effects certain parts have. It won't tell you how well an overall combo will do, or what parts work well together, but it will give you a rough idea of what your next upgrade is really worth. Just my 0.2... flame away...
jim I found On the dyno 2000 that you can not use big tube headers you must use the small tubes and it will work out to be closer. I found horse power within reason put torque was usealy high. if you play with it you can find the combo that hits close to the true numbers and always use that. that will let you use the program the way you planned.
Hey Jim, I have found over the years of using these dyno simulation programs that the same combinations are showing more and more HP for a given set of parameters. And yes... its probably so they can sell more of the programs. Below are the numbers from my older version of Dyno 2000. Still not the same as yours but a bit closer. RPM TQ HP 3500 500 333 4000 527 402 4500 548 470 5000 554 528 5500 542 568 6000 518 592 6500 483 596 7000 434 579 The above numbers are using a camshaft @ .050 of 240/240 with the flow numbers from my Stage 2 heads. I tried to get the parameters from your sheet to fill in the rest. Also I noticed on your dyno sheet that the air/fuel ratio is really close to 14:1. What were the EGTs? Lean is mean. Keep up the good work!!
Jim I decided that I would run the numbers on my 2000. I used mY ta stage 1 Aluminum numbers with just bowl work and Stage one valves. I don't know how they compare to the heads on this combo but they look almost exactly like the number you have on your web sight. Here is what I got with only one-change small tube headers and muffs. Hp torque 2500 196 411 3000 238 417 3500 301 451 4000 373 490 4500 441 515 5000 509 534 5500 571 545 6000 593 519 6500 607 491 Not exactly were you were but pretty close. I took the numbers right off your sheet and added them into mine. I think for what you want to do that would be darn close. I did some cam comparo on here before my last time on the gse motor and it was right the lsm cam I had ground was an overwhelming piece of junk and the Scott Brown unit was by far the better stick and that is what the program showed. Defiantly not a true pump but does send you in the right direction. When we ran the ta 500 HP cam the 290 It showed that on the engine we were building the difference between the 500 and 525 HP were like 3 HP so we went with the smaller one just for the sake of it being a street car and I believe over camming is one of the biggest mistakes made in engine building. That smaller cam made 518 HP I was glad I went with
