I bought a copy of Pro Racing Sim's DynoSim Advanced software and have been playing with it to simulate the LS1 engine. I'm thinking of doing a heads and cam package on my car, so I thought this software could help me decide what size cam to get. So far it looks pretty good. I've been able to replicate the torque and power curves of the stock LS1 pretty closely. I've also been able to fairly closely replicate the current set of mods on my car with LT headers.

So now I'm working on modeling heads from GMPP and AFR based on flow numbers that I've found on the web. I've also modeled several cam shafts again based on info on the web or at Comp Cams web site. Its interesting to note that as the cams get over 220/220, they start decreasing the torque in the range below 3000 rpms. They also generate big HP numbers that move higher and higher in the rpm band the bigger the cam gets. I suppose that's not news to many of you, but it really is interesting to see with graphical overlays.

As of right now, I'm thinking of getting a set of AFR 205 heads with a custom ground Comp Cams cam shaft that's 212/218 .552/.563 112 LSA using XE lobes. It doesn't lose any torque across the rpm band and it generates +85 HP up around 6000 rpm with the heads. I'll continue to play with different cams in this software and see what I like.

Has anybody else used this software? If so, do you have any experiences to share? I'm not sure how far to trust what this software is telling me.

- Mark

 

Does it allow you to enter component weights? If it does, I'd like to play around with it to see what lighter parts does to move the redline.

 

Nope it doesn't take component weights into account. It's primarily based on pressure, airflow, and friction models. I bought a book that explains how it works which is also very interesting in teaching about engine theory.

I've not heard of component weights making much difference in power output, aside from the fact that lower weight means you could possibly spin the engine higher. This software doesn't calculate what a "safe" redline would be. It will show torque and power much higher than you could possibly spin the engine safely.

- Mark

 

I have this and Engine Analyzer Pro v3.3 from Performance Trends. One thing to be very careful about with these engine simulation programs is that you can't use them to determine an absolute HP increase/decrease with specific parts. It should be used to see 'trends' associated with different parts. One of the most difficult aspects of these software packages are the data points needed for each part that you want to test. Each part has a different set of data points required to accurately simulate it and many times you have to physically test/measure the actual part to get these data points. Guessing on these data points can really skew the output.

Simulating heads and cams is the most difficult. Heads have a few aspects that really make a difference, i.e. swirl, port length, port volume, material, etc. The aspects of cams are lobe profile and timing.

My personal preference is Engine Analyzer, but Dyno Sim has some neat features.

Leftye neither will simulate mass. Engine analyzer does a good job of simulating friction characteristics associated with piston and bearing surface sizes. Performance Trends has a program called 'Rotating Intertia Calculator' that will simulate the weight of parts for the engine and chassis. It doesn't give absolute horsepower outputs like Engine Analyzer, but it shows the impact of a part to the weight of the car. I've found it to be very enlightening.

Good luck!

 

I was worried about that. I think I'll have to try to cross reference real dyno graphs from other people's cars with this software. I still think I'm going to stay on the "small" side of the cams out there. Thanks!

- Mark

 

I bought it when it first came out, I was shopping for a cam to compliment my Magnacharger. When I entered in everything that I had at the time, it gave me a dyno number that was pretty darn close to what my car was actually making. Then I started adding different cams and heads and found that the numbers were pretty well maxed out as far as the program was concerned, so at that point I lost confidence in the software and sold it to another forum member.

BTW - according to the dyno-sim software a 5.7 litre engine with a Mag supercharger maxed out right around 430 hp

 

This is the issue that I talked about earlier. When you start adding heads with different port work, cams with different lobe profiles, superchargers, turbos, and intakes with different runner lengths and volumes and plenum specs, the software becomes very complex to work with. You need a lot data that is difficult to obtain to correctly model these engines. Garbage in = garbage out.