Camshaft Selection --- Software?

[Stan Weiss]

Has anyone tried the Comp cams CamQuest6 software package? If so is there away to enter rod length? Is there away to enter rocker arm ratio? I believe these get set when you select and engine family and in most cases this is fine. I am trying to use the program on a Pontiac 455 ci engine (400 block with a stroker). The default is 1.5:1 ratio rocker arm, But the Ram Air IV heads came with 1.65:1 rockers, and the Edelbrock heads we are using were designed based on the Ram Air IV head.

[FlowSpecialist]

Hmmm. Just downloaded it to have a look. The calculation engine looks suspiciously similar to Desktop Dyno 2003 which came out with complete gibberish when I tried it on a couple of sample engines. The closest it could get to an actual 210 bhp engine we'd just dynoed was 150 bhp and that was only by dint of selecting the biggest carb it had on offer and which bore no resemblence to the fuel injection throttle bodies we were actually using.

This raises the topic of engine simulation software in general. I've also tried Engine Analyzer Pro which is more complex but still fairly useless. Is there actually a software package out there that works?

The one I'd really like to try is the Bosch Lapsim effort but that costs several thousand euros. The demo version doesn't actually let you enter an engine spec.

Dave

[Stan Weiss]

I was trying to model a create engine that my nephew had bought. The program showed the best fit cam as the one in the engine. But torque was down about 35 and HP was down about 75 and both were are at a lower RPM. But the engine has 1.65:1 rockers and the program will only use 1.5:1. So at higher lifts it does not see the increase in duration.

I have not had any time to really play around with this. Have you looked at the Freeware version of the Lotus Engine Simulation? it is limited to single cylinder models.

[FlowSpecialist]

Originally Posted by Stan Weiss

Have you looked at the Freeware version of the Lotus Engine Simulation? it is limited to single cylinder models.

I downloaded it and had a look for about 5 minutes. I got as far as deciding this was something I definitely needed to download the instructions to first

Seriously complex bit of kit that. Definitely not designed for tinkerers wanting to play at engine builder on their pc. On that basis it looks very promising. I'll have to devote some proper time to it later and see what it can do.

Thanks for the heads up.

Dave

[Packard V8]

FWIW, I have used the Dyno Sim/Camquest software and find it easy to use and pretty accurate. It does use rod length, but does not use rocker arm ratio. The cam duration, intensity and net valve lift approximates the rocker arm ratio.

thnx, jack vines

[Stan Weiss]

Hi Jack,
The engine is a SBC 383 ci Bore = 4.03, Stroke = 3.75" Rod = 6.0" CR = 10.5:1
Heads are DART 200 cc out of the Box
Intake is Edelbrock Performer Air Gap -- Holley 820 CFM
HEI -- Street Driven.

After this text is a screen print from CamQuest6 and from the Master Lobe Profile Catalog. Maybe if I play with the program so more I would get close to what the tech person told me.

I talked to Comp Cams
12-000-5 5203/5208h 110+4 small base circle
050 duration 230 236
1.5:1 Lift 480 491
will like 1.6:1 rockers lift 512 523

The program only uses off the shelve cams while their tech department will mix and match from the Master Lobe Profile Catalog.
Stan

[Stan Weiss]

Jack,
Have you ever had this happen to you. When you reload the file at a later time it changes the order of the great fit cams that are listed?
When I reload the saved file I get this as the number 1 great fit. It shows 460.8 HP @ 6500 and 438.1 ftlb @ 4500
7 - Auto - Max Street, Good Track Power, Rough To Very Rough Idle
295TH7
295 313
243 257
0.500 0.486
LSA 107 ICL 102
The original cam which is now number 6 for great fit, shows 486.3 HP @ 6000 and 472.1 ftlb @ 4500 (This is shown in the screen in my above post)
Stan

[rookie]

It looks like it was designed to pick the proper Comp cam for your motor, not the proper cam for your motor.
I would say the 110 is far too wide for that combo.

[Lasse]

This is one on my christmas present list: Gamma Technologies - Engine simulation
I think it is also very pricey software/software package.

Maybe I will try Dynomation. It is only one I can afford. I have old Dynomation version, so I can get cheap upgrade. Motion Software, Inc. Automotive Engine And Vehicle Simulation Software

Lotus Engine Simulation also looks very interesting. Freeware version simulates only one cylinder, but that is not big deal if it is free.

[MAP]

Greetings,

For my 383 small-block Chevy re-design effort, I compared three highly disparate sources: first and foremost, the consultation advice of Mr. Vizard himself, then Engine Analyzer Pro, and then this CompCams software that you can download as freeware.

The goal metrics were: peak torque; peak hp, torque bandwidth between low-rpm limit of 80% peak torque, and high-rpm limit of 80% peak torque (the difference between the two, divided by the high-rpm limit, is what I call the torque bandwidth ratio. I usually strive for 0.75 or better for a "daily driver" street motor, where economy and performance are both important.)

I expected large differences between the three, and to quantify what I mean by "large," I mean optimized camshafts differing by more than about 8 degrees in 0.050" lift duration, and by more than a few degrees in LSA's.

Amazingly, at least for me, the differences were moderate or small according to the above criteria, with a maximum difference across the set of 5% for predicted HP and torque.

Nevertheless, close agreement between three sources in one isolated instance does not a rigorous comparison make, so do take caution.

Having said that, of course I put my highest confidence in Mr. Vizard's recommendations, since his opinions are finely nuanced, and based on considerations of all kinds of minutiae which no FEA or CAD package I've ever seen even has inputs for!

Best,
Mark