Dyno2000 cam simulations.

[Chero77]

I tried three cams on Dyno2000 v. 3.10. They were a stock 401 cam as per '77 Jeep TSM specs (for a baseline comparison), a Comp Cams 260H and a Crane 260-2. Surprisingly very little difference between the Comp 260 and the Crane 260 even though the Comp is a 212/212 at .050 cam with a mild .447/.447 lift and the Crane is 204/216 with .448/.480 lift. I also tried a Clevite 1786 (the seemingly standard 204/214, .448/.472 grind) which showed no real difference from the Comp 260 or the Crane 260.

HP/Torque

RPM Stock 401 Comp 260 Crane 260

2000 85/223 141/370 138/262

2500 117/245 178/374 176/370

3000 153/268 218/381 217/380

3500 177/266 243/364 246/379

4000 201/264 252/330 259/341

4500 221/258 241/281 253/295

5000 230/241 210/220 227/238

An FSJ will never see 5000 rpm, but I did find it interesting that Dyno 2000 said the stock cam would make power out to 7000 rpm, whereas the Comp Cams 260H and Crane 260 were dead at 6000.

Seems like either the Crane or Comp 260 would work fine.

Don't have enough data on the K8600 to model it. Will call Summit and see if they have the info. But from the general specs, it would appear that the K8600 would push the power band to far up in the RPM range to be fully useful in an FSJ.

Will also call PAW and see if they have the data on the SSI 10300, though it appears to be identical to the Clevite cam which appears to be indentical to the Edelbrock cam.

[ June 30, 2003, 02:20 AM: Message edited by: Chero77 ]

[TexasJ10]

What do these cams do in a 360?

[Stuka]

I havent used DesktopDyno 2000, only the older version. But does 2000 actuallylet you choose and AMC 401, with all the specs of the engine? Or did you still have to manuall put in intake type, intake runner size and length, valve sizes, exhaust port size, etc etc?

[Cliff]

Chero - have you tried running the 401 factory hi-perf cam? I tried to find the specs on the web but couldn't find it. It is still highly regarded among AMC'ers, despite the 30 year old technology.

[netbear]

Cliff,
I have heard of the factory 401 High Perf cam
but cannot find one nor anyone who makes
a perfect copy of it or even the specs.
If you have leads to help with any of my many
questions please let me know.

I suspect AMC put some real effort into
the design and want to see what they came
up with.

Thanks!

[Chero77]

With Dyno2000 you have to enter all of the data yourself, but once you have done that you can save it as an AMC 401. So you only have to enter the block and head data once. I have run a number of cams now and one of the conculusions I have drawn is that the factory specs for the 401 cam are simply not useful for comparsion purposes to the specs for modern cams. For instance, the factory says a stock 401 makes peak torque at 2800 rpm and peak power at 4400 rpm. With all of the aftermarket cams having specs in the 204 to about 216 duration range Dyno2000 showed peak torque and power occurring at about 2800 and 4400 rpm respectively or just about where the TSM says it should be with the similer factory cam. However, if you put in the '77 TSM numbers for valve events for the factory cam, you get odd readings. Peak torque and power do not occurr where they should and torque is nowhere near as high as the factory says it should be. As I said, I think this occurs because the old factory cam specs are not comparable to the modern cam specs.

As for Dyno2000 as a program, its very good for comparing cams and cylinder head mods. Decent for comparing intake mods and carb sizing. However, its sorely lacking in the exhuast mod department giving you only a few default options. Considering that it costs only $40, I think its a good program. Better, than relying solely on guesswork, opinion, and hearsay. Not that these things don't have their place, but Dyno2000 makes it easier to figure out how to spend your $$$.

[Hammer]

Ramp speed on cams have increased over the years. Why you will see the difference between advertised duration and duration at .050" lift are getting closer and closer. I know most Comp Cams only have a spread of 50°, while others have around 60°. And the program wants to know when the lift starts and ends, but cannot truly take into effect the different ramp speeds and profiles. Newer cams are also designed better with a different ramp from the front and back of the lobe because closing the valve isn't the exact same as opening it. The older cams used the same ramp on both sides of each lobe.

I have played with desktopdyno before. Was some good fun to play with, but if you really want to get technical with it, you start having problems. Heck, that thing said my motor should have 500 HP and 550 ft/lbs. I think my HP is more like 450 or so in reality, but I haven't had it fully tuned and on a dyno yet either though.