Thread: Dyno-Sim combinations

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I enjoy putting virtual dyno engine combinations together, particularly for street-driver applications where a fellow needs good torque right off idle and good power to 5,500. I was able to rescue my desktop HP from my ex-wife's house, so I have the Dyno-Sim with Pro Tools software again.

This is an excellent way to get in the ballpark with a build before you ever buy the first piece. I'm not saying that it will rival a hard dynomometer, but the stuff I publish has shown to be within about 2% of the figures obtained from a hard dyno pull. I use the head manufacturers flow numbers, but discount them by 5% to 10%, depending on how much I think they're fudging on their numbers.

Here is the basic information that I will need to run a virtual pull....

Bore
Stroke
Rod Length
Cylinder head flow, intake and exhaust 0.100" through 0.700" or whatever the mfg gives for range. The flow of thousands of heads is given on this site....
Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software
Intake valve diameter
Exhaust valve diameter

Static compression ratio. To figure SCR, you will need 5 values:
1. cylinder volume in cc's
2. chamber volume in cc's
3. piston deck height volume in cc's
4. piston crown dish volume or pop-up volume in cc's
5. head gasket volume in cc's
I'll can figure the volumes for you is you'll supply me with some measurements.

CFM, type of induction (2-bbl, 4-bbl, TBI, TPI)
Intake manifold type, mfg (single 4-bbl, two 4-bbl, one 2-bbl, three 2-bbl, individual runner Weber, mechanical fuel injection, low-rise, high-rise, tunnel ram, dual-plane, single-plane, part number if you have it. Be advised that after doing scores of these sims, I have determined that the Edelbrock RPM, Holley 300-36 or Weiand 8016 (out of production but available used) will work best for a spirited SBC street motor. These manifolds are knock-off copies of the original Winters Foundry aluminum Chevy 302 Z-28 manifold and will work well on a 355 and really well on a 383 or 406.
Exhaust system (be specific, primary tube size if long-tube headers).
Camshaft
Part number, grind number.
Type (flat, roller, solid, hydraulic).
Intake valve lift, exhaust valve lift.
Timing info and at what tappet lift the info is valid, i.e. 0.006", 0.050", etc.

yep run number s threw mine all the time for custom cams last engine was on paper making 1200hp on a real dyno it was about 1180 .i run all my custom grind cam numbers threw a sim s dyno and years of knowing what works helps as well .very handy tool .were its handy is seeing were power is getting held back . right now in the shop i building a 498.10to1 one 598 11to1 . 598 13to1 . one 302 out to 347 4.125x3.250.. hi rpm screamer .. and a 548 blower engine i run all them on the sim.s the 347 was a eye opener on cam by moving the intake center was good for 30 hp really pulling all the stops out on the 347 ford

Richard,
What timing. I was just thinking of contacting you to run some numbers now that my engine build specs are close to finalized.

Bore: 4.020"
Stroke: 3.48"
Rod Length: 5.7"
Cylinder Heads: GM Vortec 906, factory except for new valve springs. (not sure what line item to choose in your linked data page)
Intake valve dia: 1.940"
Exhaust valve dia: 1.500"

Static Compression Ratio: 9.013
Dynamic Compression Ratio: 8.187 (my own calculation)

cyl volume:723.806cc
chamber vol: 63.981cc (after milling head)
piston deck height vol: 2.288cc
piston dish vol: 18.0cc (not sure if dished is shown as negative or positive)
head gasket vol: 6.058cc (0.028" by 4.100 dia)

Carb: 650cfm single 4-bbl (Proform 67207)
Intake manifold: dual plane, (Edelbrock performer EPS 2716)
Exhaust: Hooker 1-5/8" full length headers w/ 2-1/4" Maxflow mufflers
Camshaft: Compcam magnum, pn 08-410-8, grind 260HR
Hydraulic Roller,
Intake valve lift 0.500, Exhaust valve lift 0.500
Timing copied from cam page, forgot what they all mean)
Duration(0.050) Intake:206.0, Exhaust:206.0
Timing (0.050-inch) IVO:-3.0, IVC:29.0, EVO:37.0, EVC:-11.0

Let me know what ever I forgot and I will re edit this page.
Results of this sim will be very interesting to me.
Thanks
Rollie

Richard, is there provisions in your software for adding in a supercharger or turbo?????

The way you've built it, here are the results....
SCR 9.01:1
DCR on KB calc 8.187:1
You didn't list the squish and I didn't reverse engineer it, but if you're around 0.040", this DCR will work fine on junk pump gas, but is a little light. I'd rather see 8.250-8.750 on the KB calc.
RPM HP TQ
1000 59 310
1500 103 360
2000 155 406
2500 200 420
3000 237 416
3500 274 411
4000 304 398
4500 317 370
5000 312 328
Peak volumetric efficiency 80.4% @3500
Peak BMEP pressure 178.8 @2500
I'm seeing this as the perfect daily driver motor. Excellent torque for moving that Camaro away from stop signs and lights and should make excellent manifold vacuum for accessories such as power brakes and operate detonation-free on crap pump gas. The hp follows the specs given by Comp for the cam, RPM range 1200-4500.
08-410-8 - Magnum

I'm going to bump the compression up one notch, retard the same cam 4 degrees and still be able to operate on pump gas with iron heads.
Substitute 12cc pistons instead of the 18cc units, making a SCR of 9.58:1 and a DCR of 8.527:1 on the KB calc, smack in the middle of the range that I like to see.
Cam timing is IO-7, IC33, EO33, EC-7
RPM HP TQ
1000 60 315
1500 104 365
2000 157 413
2500 204 430
3000 243 426
3500 283 424
4000 317 416
4500 338 394
5000 343 361
5500 318 304
Peak volumetric efficiency 81.4% @4000
Peak BMEP pressure 183.0 @2500
Intake duration 206
Exhaust duration 206
Intake centerline 106
Exhaust centerline 114
Lobe separation angle 110
Valve overlap @0.050 -14
Picked up 26 hp and 10 ft/lbs of torque with a "flat as a pool table" torque curve. I resisted using more cam in this tweaked version because the short cam is just right for a daily driver with stock converter and gears. It just needed some tweaking. Practically no change was noted when changing to 1.6 rockers and the combination lost power using an RPM intake manifold. More carb will make more power, but I'd rather have the small primary throttle bores for off-idle response and driveability and possibly a little more fuel mileage.

Richard,
As usual, you have provided great information that is much appreciated. Thank you.

I was a little surprised to see the HP numbers that low, but very pleased to see the torque numbers in the rpm range you show. My goal was to build an engine with good torque and run on cheap gas and I think this will fit that goal. For a street driven car, I think I would be very happy with that kind of performance. In fact, now that I look at the numbers, I would guess the torque numbers are comparable to many of the 400+ hp engine builds out there, as they usually get their high hp numbers in the upper rpm range. At 420 ft lbs of torque, my car on the street should be very impessive. My other goal was to get good fuel mileage, but I don't think I will know for sure how that goes until I can actually drive it.

Squish/quench on the engine was calculated to be about .040 but I won't know for sure until Everything is assembled after the final decking and I do the final measurements. I have held off ordering a head gasket until after I determine the final "in the hole" measurements. So far I was planning for a .028 thick gasket to get the .040 quench, but we will see.

I also appreciate you doing a "what if" to show potential results with a few upgrades. I should be getting my block and heads back from the machine shop in the next couple days after the final decking ang milling, and I've already had the rotating assembly balanced and piston pressed on rods, so I will likely continue as previously specced, but I am having so much fun, that part of me wants to start on another build after this one and possibly go for a much more aggressive build, maybe something like a 383. We will see.

Overall, I have really learned a lot. Presently I'm getting ready to assemble the heads and am learning about, installed spring height, pressures and forces, and what causes valve float. It continues to be a great ride.

Originally Posted by Dave Severson

Richard, is there provisions in your software for adding in a supercharger or turbo?????

There is Dave, but I have never been able to make any sense out of the results. Maybe I just need to study it further.

Originally Posted by rollie715

Richard, Thank you. I was a little surprised to see the HP numbers that low, but very pleased to see the torque numbers in the rpm range you show. My goal was to build an engine with good torque and run on cheap gas and I think this will fit that goal. For a street driven car, I think I would be very happy with that kind of performance.

You have to remember that the L31 heads have only a 170cc intake runner, so they're more of a torque head than they are a horsepower head. We could have made more horsepower with more SCR and more cam, but I sensed that you wanted an easy street-driver. Don't worry, it'll nail you back in the seat.

Be very, very careful checking the interface between the heads and the intake manifold to insure that they are parallel in both X and Y axes. If the port is gapped open at the top, you will have a vacuum leak that you can normally find with ether or other flammable spray, but if the port is gapped open on the bottom, the cylinders will be pulling oily vapors into the cylinder from the crankcase and you'll never find the leak with ether. I suggest sacrificing a set of intake gaskets on the mock-up build and closely inspecting them for being "pinched" all the way around each and every port. If not, further machine work will be necessary to make them parallel in X and Y.

on post #6 before i deck a block. i really know were the deck is that the part were building real engines you must know how your parts stack up

Originally Posted by pat mccarthy

on post #6 before i deck a block. i really know were the deck is that the part were building real engines you must know how your parts stack up

Pat, I assembled a rod and piston and measured all 4 corners before I sent the block back to the shop for final decking, so my design should be on track, but I would still like to confirm everything again as they are final assembled. I supplied the cut depths for each corner to the shop. The machinest is very experienced at building engines and squaring the deck to the crank.

Originally Posted by rollie715

Pat, I assembled a rod and piston and measured all 4 corners before I sent the block back to the shop for final decking, so my design should be on track, but I would still like to confirm everything again as they are final assembled.

yes and if your the guy doing the math and the guy decking the block then your odd.s could be better ?? that and the rods your using all 8 are the same over all distance . stroke is not off or CH of the pistons getting the deck true is more then a deck job the deck is the first thing that i will machine every thing is base off this less the block needs a line bore then thats first then deck then bored . the deck is the foundation of the block many time block will not clean up square up threw crank and cam center line were a tin shim gasket is going to work this get back to what CH the pistons you have

Let's do a down and dirty 360 build with a lopey cam. (350 block bored 0.060" with 882 heads, Comp Thumpr cam, stock cast iron intake manifold with 600 carb, stock cast iron exhaust manifolds and mufflers.
This head gasket...
Fel-Pro Head Gaskets Q7733PT2 - SummitRacing.com
These pistons...
Summit Racing® Hypereutectic Pistons SUM-17350-60 - SummitRacing.com
Cut the block decks to 9.000". The stack will be 9.000" for a zero deck.
We'll use stock cast iron SBC production heads, casting 882, 76cc chambers, 1.94"/1.50" valves, Comp 981-16 springs.
Use this cam, install advanced 4 degrees....
12-600-4 - Thumpr
Actually, the K12-600-4 kit with cam, lifters, springs, retainers, keepers, seals and timing set might be a better deal than buying individual parts.
Static compression ratio will be 9.16:1, dynamic compression ratio will be 8.22:1. Squish will be 0.039". Idle will be choppy/thumping.

RPM HP TQ
1000 37 194
1500 85 296
2000 125 328
2500 162 340
3000 201 352
3500 240 360
4000 261 342
4500 275 320
5000 275 287
5500 259 247

Max volumetric efficiency 84.6% @4000
Max BMEP pressure 150.5 @3500
Not bad for a low-buck, mostly junkyard parts motor in my opinion.

I was asked to do this sim on a PM.....

428 Ford FE, bored 0.030" to 4.165". Stroke 3.980", 433 CID.
Edelbrock 60069 heads. I used the flow numbers that Edelbrock publishes for this head.
Tunnel Ram single plane intake mounting two 660 carbs.
Zoomie headers.
CompCams 33-781-9 solid roller cam, installed straight up at 106 ICL.
33-781-9 - Magnum
Advancing or retarding the cam lost power over installing straight up.
9.97:1 static compression ratio. 7.96:1 dynamic compression ratio on the KB calculator.

RPM HP TQ
2000 105 277
2500 198 417
3000 272 476
3500 344 516
4000 424 557
4500 502 586
5000 567 595
5500 606 579
6000 630 551
6500 619 500

Peak volumetric efficiency 111.2% @5500
Peak BMEP 207.0 psi @5000

This cam would prefer another full point of static compression ratio, from 9.97:1 to 10.97:1. It would make 655 HP @6000 and 615 FT/LBS @5000, with a dynamic compression ratio of 8.7:1. The builder should observe that the Edelbrock springs, if he uses the Edelbrock springs, are good to 0.600", while valve lift is 0.645" with the Comp cam. Check closely for piston to valve, retainer to guide clearance as well as checking for stacking solid of the spring coils. This is a solid cam and you have the margin of valve lash, so it might be ok.

Originally Posted by techinspector1

I was asked to do this sim on a PM.....

428 Ford FE, bored 0.030" to 4.165". Stroke 3.980", 433 CID.
Edelbrock 60069 heads. I used the flow numbers that Edelbrock publishes for this head.
Tunnel Ram single plane intake mounting two 660 carbs.
Zoomie headers.
CompCams 33-781-9 solid roller cam, installed straight up at 106 ICL.
33-781-9 - Magnum
Advancing or retarding the cam lost power over installing straight up.
9.97:1 static compression ratio. 7.96:1 dynamic compression ratio on the KB calculator.

RPM HP TQ
2000 105 277
2500 198 417
3000 272 476
3500 344 516
4000 424 557
4500 502 586
5000 567 595
5500 606 579
6000 630 551
6500 619 500

Peak volumetric efficiency 111.2% @5500
Peak BMEP 207.0 psi @5000

This cam would prefer another full point of static compression ratio, from 9.97:1 to 10.97:1. It would make 655 HP @6000 and 615 FT/LBS @5000, with a dynamic compression ratio of 8.7:1. The builder should observe that the Edelbrock springs, if he uses the Edelbrock springs, are good to 0.600", while valve lift is 0.645" with the Comp cam. Check closely for piston to valve, retainer to guide clearance as well as checking for stacking solid of the spring coils. This is a solid cam and you have the margin of valve lash, so it might be ok.

Richard,
Wow i'm impressed. I was told I would be in the 650 range so it's right there.
I do have an improved spring and retainer package for the build.
I was thinking I was closer to 11:3:1 on the compression ratio with the .051 head gasket.
I trust your numbers more than mine
Looks like if I go 4.230" and .040 on the head gasket I can get to the 655 hp @6000 615ft/lbs TQ ?
Cant thank you enough for running the numbers !
I will post actual Dyno numbers to compare when I'm done with the build.
Hope all is well,
Brian

Any others ?