Thread: 500 hp/550 lb-ft from a 390?

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Originally Posted by techinspector1

You know Jeff, not to make myself out to be a seer, but I saw this coming. The research tools at Comp so far exceeded those of Crane that it was a slam-dunk. After looking for a cam on Comp's site, then going to Crane's site, the Crane site was a joke. It looked as it it had been put together by a grade school kid compared to the Comp site.

As far as me using Comp on the Dynosims I run, the main reason is that the software came with 800 Comp profiles installed. I just pick a cam, click on it and it appears on the DynoSim screen with ALL and I mean ALL the specs on that cam. More info on my screen than is on the cam card for that cam. With any other cam that I use on the DynoSim, I first have to try to find the intake and exhaust centerlines and the duration at 0.050", then sit down at my calculator and figure the intake and exhaust closing points, then enter them into the DynoSim manually. Not a very attractive procedure when I can simply click on cams in the software and change cams in seconds.

But believe it or not, I am pretty easy to get along with and will help anyone who is halfway decent to me. If you can get me the intake and exhaust centerlines and 0.050" duration for both sides, I'll figure the timing events and install the numbers.

Here you go:Crower 16255 lobe center 108,int Dur@.050 224 ex Dur @.050 232, in.lift .312 ex lift .313 adv@1.76= in .549 ex .550 2500-6000 RPM

I was able to find a timing chart on Crower's website and get the timing events....then calculate the intake centerline and exhaust centerline from that information.
http://crower.com/misc/valve_timing_chart.html#108
Crower 16255 hydraulic flat tappet, 280/288 degrees advertised, 224/232 degrees @ 0.050", Intake Centerline 104 degrees ATDC, Exhaust Centerline 112 degrees BTDC, Lobe Separation Angle (Lobe Center) 108, Theoretical valve lift intake 0.549", exhaust 0.560". Overlap 12 degrees @ 0.050". Timing events are: Intake opens 8 degrees BTDC, closes 36 ABDC, Exhaust opens 48 BBDC, closes 4 ATDC. Dynamic compression ratio with this cam and 9.9 static compression ratio is 8.647:1, so tighten up the squish if you are planning on running on pump gas without detonation.

Everything is the same as the other DynoSim, just the cam was changed. This cam is shorter and clicks off at 5550, but makes a nice torque curve from 3500 to 5200. It also makes more torque down low which would be better for a heavy vehicle or tall gear.

RPM HP TQ
2000 170 446
2500 214 449
3000 273 477
3500 337 506
4000 399 524
4500 449 524
5000 491 516
5500 505 483
6000 457 395
6500 404 326

Here's the first DynoSim so you can see 'em together....
RPM HP TQ
2000 160 419
2500 196 412
3000 248 434
3500 319 478
4000 388 509
4500 460 536
5000 512 538
5500 535 510
6000 550 481
6500 514 415