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Discussion Starter · #1 ·
Has anyone heard of the "Desktop Dyno" software?

Details here

They say that it can estimate engine performance for any engine, with any amount of modifications, including cams, porting, turbo, supercharged, N2o, and even different fuel types.

Has anyone tried this with a CIH? I am sure that this works well for benchracing your Chevy Small-Block, wonder how close it could get you with the unique Opels.
 

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Tried it many years ago. Worked well, in fact every engine I 'built' on the desktop was within 4 hp of the actual dyno numbers when those engines were actually later built, with one sole exception. And that engine somehow made 22 hp more than the desktop's estimate. ??

BUT, as with any computer, garbage in= garbage out. So the information you input must be honest and accurate. If you guesstimate or exaggerate the airflow/compression/etc, the numbers will be way off base. Just FWIW....
 

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Discussion Starter · #3 ·
Thanks for the vote of confidence. I picked up a copy for, mostly for giggles, but I figure that it might be helpful with benchracing various ideas that rattle around inside my head.

Did you use the software to simulate any Opel motors? Did you use another mfg. or set everything manually?

I did a mild build using a chevy 2.2L 4cyl, and came up with about 180 HP. Kind of surprised that it was that high. More research, less guessing will probably get me closer.

Garbage in... garbage out.
 

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I have one on my PC. I used all the info for a stock 73 opel 1.9 and It tells me the engine makes 73 HP at 6000 RPM. Does this sound about right to you Bob?
 

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Stock hp should be closer to 62-65 hp at 5200-5400 rpms. This is for a late model 'smog' engine with Solex.

Earlier engines will be closer to 85 hp.

When I 'built' the Opel engines, I plugged in all my own data I had accumulated, such as port dimensions, port airflow, manifold flow (intake and exhaust), specific cam specs, true compression (Opels are over-rated), carburetor flow, etc.

As with real Opel engines, getting over 150 honest hp requires a lot more modifications than just bolt-ons, which you'll find out as you experiment with the program.
 

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Discussion Starter · #6 ·
Anyone have any saved profiles for any of the possible Opel CIH builds?

I have been experimenting a little, but they are SWAG at best (Scientific-Wild-Ass-Guess). Anyone have any ideas on ways to build a flow bench on-the-cheap?

For example, I got 180 hp at 6000 RPM and 195 ft-lbs. at 4500 out of a 2.2 with a .488 lift cam, 10.5:1 pistons, and 44/35mm valves, and assumed 500 cfm from individual runners @ 1.5 mmHg (SWAG for dual 45 DCOE).

Perhaps I should have called it WAG (same minus the scientific part).

Here is a good thread on flow numbers for anyone that is interested.
http://www.opelgt.com/forums/showthread.php?s=&threadid=997&highlight=flow+bench
 
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