Desktop Dyno?

[Ned S]

Do any of you guys have one of these simulators ? I had a SBC stroker motor built last fall. In my area it was way to expensive to gain access to an actual engine dyno. I am trying to determine what prop to run. I had the motor balanced so I can wind it up high, but so far from the props I was able to borrow it seems I need to know where the torque is.
I would be happy to compensate if someone was willing to take the time to help me out.
If so what info do you need?
Thanks,
Ned

[Jetaholic]

I have desktop dyno. Here's what I need from you for specs:
Block Type
Bore (how much overbore)
What heads you're running
Valve sizes
Compression Ratio
Carb CFM
Manifold Type
Type Exhaust
Which cam do you run? (Make/Part Number)
Hyd Roller, Hyd Flat Tappet, Solid Roller, Solid Flat Tappet ???

[pw_Tony]

Desktop dyno's fun to dik with but it's not really accurate. I think there was a Car Craft issue that built motors on the dyno and then built them on desktop dyno. It was relatively close, off by about 10% and the power bands were different. But if you want to download it yourself anything like Kazaa or Limewire should have it.

[Ned S]

Thanks,here we go
Block: 5.7L SBC Bored +.040 Stroke 3.750
Heads: Canfield SBC Large Runner 23-600-65
Valves: IN 2.08 EX 1.60 Intake port VOL 220 Chamber VOL 65
Comp ratio was to be around 9-1 -18cc dished pistons were used (marina fuel)
Carb: 750 Edlebrock
Manifold: Single plane Pro Products (out of money)
Exhaust: Revolution Marine 4" Thru Hull (no mufflers)
Cam: (got this set-up at a bargain) Hyd Roller cam + Roller Lifters
Lobe Center Sep= 110.4
Valve Overlap= 3.8 Crank Deg
Intake:
Valve Opening= 1.9 BTDC
Lobe Center= 105.4 ATDC
Duration= 210.1 Crank DEG
Max Cam Lift= .31429
Net Valve Lift= .47144
Lobe Area= 23.27
Exhaust:
Valve Opening= 44.8 BBDC
Lobe Center= 115.4 BTDC
Valve Closure= 1.9 ATDC
Duration= 222.9 Crank DEG
Max Cam Lift=.33799
Net Valve Lift= .50699
Lobe Area= 26.45
Then we have our bargain roller rockers:
Intake + 1.6
Exhaust + 1.55
Thanks And If I owe you or if you have any suggestions let me know.
Ned

[Ned S]

Desktop dyno's fun to dik with but it's not really accurate. I think there was a Car Craft issue that built motors on the dyno and then built them on desktop dyno. It was relatively close, off by about 10% and the power bands were different. But if you want to download it yourself anything like Kazaa or Limewire should have it.
For my purpose 10% would be close enough. It wold have cost me more than the price of 2 props to get a real dyno test. Thanks for the info
Ned

[lilrick]

WHERE is SSLOWRIDER????????

[GofastRacer]

I mess with Dyno from time to time for something to do, and I can tell you it is darn accurate, "BUT" just like anything else it don't know anything else but what information you feed it that's what it goes by!. I did a friend's motor once that he had dynoed and I came in within 1hp and the torque was right there with the dyno sheet he had!..
Ned, that is great information the only thing you need to complete it is the head fow numbers, otherwise it will be a guess from the list in the program and that will throw it off big time!..

[Oldsquirt]

Here's the flow numbers From Canfield's site for the 23-600-65 heads
VALVE LIFT....Intake.....Exhaust
.100_________72______53
.200________145_____107
.300________201_____143
.400________247_____175
.500________258_____190
.600________259_____200
.700________259_____203

[GofastRacer]

Here's the flow numbers From Canfield's site for the 23-600-65 heads
VALVE LIFT....Intake.....Exhaust
.100_________72______53
.200________145_____107
.300________201_____143
.400________247_____175
.500________258_____190
.600________259_____200
.700________259_____203
Thanks, I'll have to play with it over the weekend!..

[SmokinLowriderSS]

WHERE is SSLOWRIDER????????
He was in bed, asleep (unfortunately). The fun of 5AM alarm clocks.
I'll run it tonight and post up.
If you want, I can e-mail the prog to ya to play with as well. PM me an address or post one up.

[SmokinLowriderSS]

I printer off al the specs and will let the laptop tinker with it at work on breaks, post up results and thoughts by 6PM. :)

[cfm]

This will be an interesting one since there is no where in DD to put in the CSA of the cyl head runners, or even cc for that matter.
I'll leave you with this - the 220cc 2.08 valve Canfield Head was not designed for a grunt (210 at .050 cam) 9:1 low compression 383.
Ned S - this is not jabbing at you for combo. It should still make decent power, however DD is not going to account for this .
I'll put down $50 that DD will show near 30ft/lbs torque higher from approx 2500-4500 or so than reality.

[cfm]

Woh, just drank more coffee for more brain blood flow.
These 220 heads are the one's with the offset intake rocker arms correct ?
Okay, I may throw in another $25 and say actuall (not DD) torque output may be less than what I was thinking above.
I do business with the person who designed these heads for Canfield - I'll see if I can get more info on top of what I've seen with these heads.
Did we buy these heads used or did we have them on a strip motor set on kill ?

[Ned S]

I bought them new cheap. They were not much more than the chinese stuff. If there are others that would work better please let me know.

[Ned S]

My e-mail is hdtvned@yahoo.com Thanks

[cfm]

Here's the flow numbers From Canfield's site for the 23-600-65 heads
VALVE LIFT....Intake.....Exhaust
.100_________72______53
.200________145_____107
.300________201_____143
.400________247_____175
.500________258_____190
.600________259_____200
.700________259_____203
No, those are for the 195cc 23-500-65.
This 195cc would be a much better cyl head for even a stout 383,406 marine engine.
Since you mentioned "Bargain roller rockers" Do I dare ask who's offset rocker package you got ?
The posted flow #'s for the 23-600-65 heads are :
These flow numbers are reflective of mildly bowl blended ports.
VALVE LIFT .100 .200 .300 .400 .500 .600 .700
Intake Port 71.7 144.9 206.4 252.4 288.0 301.7 306.1
Exhaust Port* 52.2 104.9 146.2 184.0 203.2 219.2 227.2
These are typical flow numbers at 28 inches of water measured on a SF 600 bench by an independent shop.
*Exhaust flow numbers are without a pipe
===================================
Is it possible we actually have the 195cc heads and just mistakenly read the part# wrong ?

[Oldsquirt]

No, those are for the 195cc 23-500-65.
You are correct. I guess I was up past my bedtime......:)
Here are the numbers in an easier to read format.......
VALVE LIFT____Intake____Exhaust
.100__________71.7______52.2
.200__________144.9_____104.9
.300__________206.4_____146.2
.400__________252.4_____184.0
.500__________288.0_____203.2
.600__________301.7_____219.2
.700__________306.1_____227.2

[Ned S]

The heads are the 220s. The rockers are Crower. I got them used.

[cfm]

Where are the desk top dyno results ? I thought they'd be interesting ?
Ned S -
None of us have any info for these heads on a very mild 383. Sorry. So, just gut instinct here. So take this with a grain of salt. These heads where designed for large cubic inch, high compression, high rpm all out drag motors. It's one of the largest 23° heads available for the sbc. Thus, why not chosen for and used on lesser motors.
Very good chance that with your cid, compression, and cam that your engine will be lower on torque output than with a better chosen more conventional 170-195cc 23° head.
But, sometimes it is what it is. If you enjoy the motor as it is, then don't worry about it.
BTW: Crower rockers are fantastic. I was just worried you bought an e-bay special low $$$ chinese type Pro Comp or Cat rocker system.

[Ned S]

With that said what would be the best heads to use? If I could find some that would use the same valves and springs I may be able to flip these on ebay while they still shine and not be out much.
Thanks for the advice

[maddad]

Hi Ned S. I don't know which heads are best, but here's some info to think about as you decide on intake volume.
Just built a 413 ci SBC(400+.060) to spin an older Volvo drive in a fairly heavy v-bottom. With Dart Iron Eagle 2 180cc heads it made 490lbft @4100 and 432HP @5300, where I ended the dyno pulls. The curves indicate peak HP was still a few hundred rpm away. So with 413 ci, I could have made more power where I wanted it with even smaller, maybe 165cc, heads. Or vortecs.
Cam is comps 4x270h.

[Ryan00TJ]

Punched in all your info on my DD program. Used HP manifolds for exhaust and single plane intake. 750 carb, 9-1, your head flow numbers and camshaft.
2000 155 407
2500 203 426
3000 256 449
3500 300 450
4000 337 443
4500 364 425
5000 371 389
5500 363 346
6000 339 296
Just an idea.. The motor is begging for a larger camshaft. A 224/230 Comp XM276HR bumped the hp up to 425 and produced a much flatter torque curve that held close to peak torque up to 5000rpms.
I would opt for a high velocity 195cc port head for your setup. AFR Eliminators are very sweet, they flow close to the 220 Canfields but with a smaller port with much higher velocity.

[pw_Tony]

R.P.M HP TORQUE
2000---------155------------407
2500---------202------------425
3000---------256------------448
3500---------301------------451
4000---------339------------445
4500---------368------------430
5000---------383------------402
5500---------378------------361
6000---------357------------312
6500---------329------------265
7000---------283------------212
This is according to desktop dyno with the numbers you gave out. Pretty much mostly torque and little horsepower. But then again who knows how close the torque is when desktop Dyno does have input for Port size to help with velocity

[pw_Tony]

Opp I guess I did something wrong

[GofastRacer]

Intake:
Valve Opening= 1.9 BTDC
Lobe Center= 105.4 ATDC
Duration= 210.1 Crank DEG
Max Cam Lift= .31429
Net Valve Lift= .47144
Lobe Area= 23.27
Exhaust:
Valve Opening= 44.8 BBDC
Lobe Center= 115.4 BTDC
Valve Closure= 1.9 ATDC
Duration= 222.9 Crank DEG
Max Cam Lift=.33799
Net Valve Lift= .50699
Lobe Area= 26.45
A couple things missing here, intake closing and what are the timing events at, .050???..

[cfm]

I apologize if it looks like I responded to this thread to tell you that your combo is "off." I was responding to you asking for a desktop dyno report so you can get a better idea of where to prop your boat. I truly feel desktop dyno is not going to accurately give you what you are looking for.
If you are happy with the performance of your engine, leave it alone. If you want to better it, well, that is a different story. I'll help if that's the case. If you want to pursue this 'sidetrack' that I guess I started then please tellu us everything about the boat and what your ultimate goal is and what your preferences are.

[Ned S]

cfm, No need to apologize and actually the results others posted are what I feel in the seat of my pants when I am running it. She pulls hard down low and thru the midrange and runs out of steam at the top. Actually this is my first American iron build. My hobbies in the past were sports cars and shifterkarts so the only engines I have experience with are the Mazda rotary and 125cc Honda 2 stroke. Im getting too old for the shifterkart and tired of the money pissing contest in all forms of motorsports so I decided to get back into boating. The $250-$500 I used to spend on race weekends can buy a lot of gas and beer.
My boat is a 85 21' Scarab 1 When I got it it had a 350 that probably had 300 hp and it would run about 50 with a 19p prop at 5000rpm. I did not have a GPS at that time. It broke down every other time I took it out so I decided to rebuild, repaint and rewire everything. That was with an Alpha drive. We now have a Bravo 1.5 As it is right now with a 21p prop and GPS in hand I got 63.8 at 5400 rpm. That was upstream on a river on a windy day. My goal is 70-75 NA on regular fuel. I ski occasionally but dont mind changing props. Being somewhat reliable is an issue as we can get as far from the dock on the Kaskaskia and then on to the Mississippi rivers as we want as long as fuel is available. No premium fuel is available unless one wants to tote cans. One thing I noticed my last time out is that if I cross another boats wake or hit just a bit of rough water anything that will bounce the bow up she will pick up speed for a bit but the engine cant keep it up for long. To me it seems and the dyno simulator shows that I have no power on top. I would prefer not to change cams this season but heads would be easy.
I did however blow my cam specs because I did not have my specs on.
Intake & Exhaust
Lobe Center Sep= 110.4 Cam Deg
Valve Overlap= -3.8 Crank Deg
Intake
Valve Opening= -1.9 BTDC
Lobe Center= 105.4 ATDC
Valve Closure= 32 ABDC
Duration= 210.1 Crank Deg
Max Cam Lift= .31429 in.
Net Valve lift= .47144 in.
Lobe Area= 23.27 in. deg.
Exhaust
Valve Opening= 44.8 BBDC
Lobe Center= 115.4 BTDC
Valve Closure= -1.9 ATDC
Duration= 22.9 Crank Deg
Max Cam Lift= .33799 in.
Net Valve Lift= .50699 in.
Lobe Area= 26.45 in. deg.
GofastRacer asked for the timing evens at .050 I dont have these specs.
I dont want to be a moocher. What is the best DD program to use?
Thanks, Ned

[Ned S]

Here is a pic of the boat when I was fabricating a windshield.

[jmherbert]

I cant give you dyno #'s, but my non-expert opinion is you need more cam, especially for those heads. Its a 383 running 200cc Dart Iron Eagle platinums, and a crane 284H (228@050) cam. Tyler Crockett (look him up if you don't know who he is) spec'd out this cam and a brodix dual plane intake. This motor pulls hard from idle 'till about 5500, which is my personal RPM limit. Of course, I am also 10.3:1, which has run on 92 octane so far.
I would build this motor again, with the only change being machined pistons to get the compression down to around 9.5:1 for piece of mind.

[GofastRacer]

Intake & Exhaust
Lobe Center Sep= 110.4 Cam Deg
Valve Overlap= -3.8 Crank Deg
Intake
Valve Opening= -1.9 BTDC
Lobe Center= 105.4 ATDC
Valve Closure= 32 ABDC
Duration= 210.1 Crank Deg
Max Cam Lift= .31429 in.
Net Valve lift= .47144 in.
Lobe Area= 23.27 in. deg.
Exhaust
Valve Opening= 44.8 BBDC
Lobe Center= 115.4 BTDC
Valve Closure= -1.9 ATDC
Duration= 22.9 Crank Deg
Max Cam Lift= .33799 in.
Net Valve Lift= .50699 in.
Lobe Area= 26.45 in. deg.
GofastRacer asked for the timing evens at .050 I dont have these specs.
I dont want to be a moocher. What is the best DD program to use?
Thanks, Ned
So what are these timing events taken at??, The best DD right now as far as I know is the 2003 with Pro Tools version, haven't checked lately to see if they'rs a newer version though!... Engine Analizer is even better yet!..

[cfm]

She pulls hard down low and thru the midrange and runs out of steam at the top.
Your are feeling/witnessing operating range of the cam. Ryan00TJ + JmHerbert are right on pointing this out. Both of them have also built some strong runners for themselves, so they present very factual info also - not just ideas.
What exhaust system do you have ? If any mods to it please list.
BTW: with reading your goals and expectations above I 100% would address the camshaft first before swapping out the heads. The cam will have to go either way - even if heads are swapped. So, let's tackle this first and if your goal is reached or 'close enough' then you won't have to go thru that part.

[Ned S]

My exhaust is Revolution Marine 4" thru hull. I ported it to match the heads. How long is a SBC cam. I think I can saw a hole thru the fiberglass under the back seat get a buddy and slip it in without pulling the engine.

[Ryan00TJ]

Going from memory it's close to 3' long. Let us know if you need any help picking out new cam specs.

[maddad]

L.O.A. of a SBC cam shaft is 21.75". That includes the timeing gear stud.

[Ned S]

Thanks for all the advice. We now have a cam access hole. Please help me pick a cam. I should have never bought the GPS.

[Ryan00TJ]

Thanks for all the advice. We now have a cam access hole. Please help me pick a cam. I should have never bought the GPS.
A GPS will humble you quickly! I was using a crap Faria speedo years back and it was showing 84-86 mph. When I switched to a Gaffrig GPS setup I went down to 73-77mph depending on load and weather conditions.
Here are a few 383 spec cams that would work pretty well....
Crane 222/230 .509/.528 112LSA
Comp XM270HR 218/224 .495/.503 112LSA
Comp XM276HR 224/230 .503/.510 112LSA
I'm running a modified XM276HR in my 355 and it's a awesome cam. I'm still breaking in a new outdrive so I haven't went WOT yet but I have a feeling the boat is going to fly. 4500rpms was getting me 62gps and it has alot more to go. Idles great, 800rpm neutral w 10* vac, and 650-700 in gear.
My main concern with your engine combo is adding a larger cam but still keeping the 9-1 compression. The larger the cam you go the more your DCR drops softening up the midrange and power curve. I also believe you would be better suited with a Peformer RPM or RPM Airgap intake manifold vs a single plane intake staying around 5500rpms.
Shoot a PM to cstraub69 on the board. He's the man in designing cams and can cut a custom one tailored to your engine specs.
HTH

[pw_Tony]

So what are these timing events taken at??, The best DD right now as far as I know is the 2003 with Pro Tools version, haven't checked lately to see if they'rs a newer version though!... Engine Analizer is even better yet!..
Finaly starting to get the hang of engine analyzer. It was a biatch at first but now I'm commin around to it. You just need alot more specs! But it is definetly more technical/accurate compared to desktop dyno. I built two crate motors on DDD and on Engine Analyzer and EA was within 10 hp at the smae RPM, as for desktop dyno was off about 30-40hp and off on rpm. And then I tried a motor I built a while ago, and the torque was right on the money and the hp was 7 hp off, but still rpm was correct. I gotta buy this program:) :)

[GofastRacer]

Finaly starting to get the hang of engine analyzer. It was a biatch at first but now I'm commin around to it. You just need alot more specs! But it is definetly more technical/accurate compared to desktop dyno. I built two crate motors on DDD and on Engine Analyzer and EA was within 10 hp at the smae RPM, as for desktop dyno was off about 30-40hp and off on rpm. And then I tried a motor I built a while ago, and the torque was right on the money and the hp was 7 hp off, but still rpm was correct. I gotta buy this program:) :)
Yes it is a lot more in depth but once you get used to it, you'll find you can do a lot more with it, and it's not really any harder than DD, just more parameters!..

[cfm]

Ned S:
We also need to know what valvespring package you have in there. What springs and what height installed ? Seat psi, open psi, and what lift they can take.
A bunch of these modern hyd rollers have fast enough rates that even with the cam manufacturers recomendation (couh, Comp, cough,cough) won't sustain proper control over float even as early as 5k. Seen it many times.
To spin to past 5k + of course beyond with modern 'good power' cams we need somehwere between 135-150lbs on seat and 350-375lbs open. Or we can pony up and go with beehives that will typically end all worries.
We can't 'cam it' if your springs won't work with it. If it turns out you are good to go then we can finalize cam choices.

[Ned S]

The installed spring height was to be 1.9" per Canfields specs. I wont be able to find out what springs were used till Mon. I think they were Manley. I know they were expensive and im sure the builder was thinking more cam than one could put in a marine engine at that point. The only parts I skimped on were the cam and the intake.