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  #1 (permalink)  
Old 09-15-2001, 08:24 AM
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Default Dyno 2000 results

OK. I said I'd print the results of my research with the Windsor engine on the Dyno 2000 software so here it is. Basically I was looking for something in the 450 to 500 hp area with about the same or slightly less torque. It's going to be hard keeping this much hp anchored without going to a pro-street setup so I saw no need to go bigger. I did find a significant difference in the amount of hp and torque with the stroker kit as well as how long it was maintained, so I believe the stroker kit is well worth the extra bucks. The decision I haven't made yet is whether or not the roller cam valve train is worth the extra bucks ($700 for cam and rollers). I've heard a lot of stories about lifters turning sideways and screwing up some good engines. Any opinions?
This is what I used for my baseline engine: 351 Windsor block bored .030, stroked to 3.85 in., Ford N351 sportsman heads, 9.50 compression ratio, 750 cfm carb., large tube headers with mufflers.

The first setup is using a Crane 443941 hydraulic cam and lifters. Intake dur. 272, lift .484, exhaust dur. 284, lift .512.
2000 rpm 157hp 411lb/ft
2500 199 418
3000 243 426
3500 295 442
4000 347 455
4500 396 462
5000 436 457
5500 465 443
6000 482 422
6500 486 393
7000 476 357

The second setup is using the Crane 449541 roller cam and lifters. Intake dur. 278, lift .520, Exhaust dur. 286 lift .542.
2000 rpm 167hp 437 lb/ft
2500 208 438
3000 252 440
3500 308 461
4000 366 481
4500 427 498
5000 470 493
5500 516 493
6000 532 465
6500 539 435
7000 539 405

The horsepower and torque curves are pretty flat on top using the roller cam, but what about reliability? Plenty of good ol' horsepower though!
H Dog
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Old 09-17-2001, 06:53 AM
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hound dog,

how accurate do you consider the software?
and what hp is this software calculating?
old, pre 1972 SAE hp? guess so.

my engine delivered about the same numbers as your second setup, although with 496 cui ...

and don't tell that's so because mine was a chevy

seriously:
your hp ratings in the US confuse me. when punching in my numbers into the Dyno software the result was 650 hp for my engine instead of 550 as found on the dyno.

if you have the money, i would recommend the roller cam. we never had any problems, even with 10500 rpm 373 cui small blocks, or with 6900 rpm 565 cui big blocks for the Can-Am cars.

Ford cams shouldn't be weaker at any point - it's only steel.

dominik
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Old 09-17-2001, 10:17 AM
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Dominik;
In the US we generally list horsepower in two different ways, flywheel hp and brake hp. The old way of doing it is by flywheel hp which is the same way that the Dyno 2000 does it. Here in the southeast, around NASCAR country, there are plenty of engine dynos available to run up and tune just your engine (very expensive). A more common type of dyno, and less expensive, is the rear wheel dyno which you simply drive your car onto, strap it down, and do a run up. This, of course only gives you the rear wheel hp which is about 25% less than flywheel hp because of the drivetrain drag. A close friend of mine who builds drag racing engines says that the Dyno 2000 software is within about + or - 5% of what he actually gets on an engine dyno. This isn't good enough for a professional racing program, but for us guys who just want to compare some engine changes and different cams, compression, heads, carbs., etc. it seems to do all we need through good comparative numbers. They tell you up front that the biggest unknown in the program is cylinder heads and the flow numbers because the biggest flow may not give you the most hp. There are some large hp gains and losses to be had in cylinder head design as far as airflow and burn rates and I guess their software isn't capable of handling all of the possible combinations.
I have no problem with Chevy's. Certainly the most horsepower for the dollar here in the US. I just couldn't bring myself to put one in a Cobra.
My question relating to the rollers kind of got back to the fact that the 5.0 HO came with rollers from the factory which worked real well and were reliable as far as I know, but the block was designed for rollers. The aftermarket rollers have to work in blocks which aren't designed for them and That's where I don't have enough experience. My friend who builds the drag engines says "no problem". But he does his driving a 1/4 mile at the time.
H Dog
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Old 09-17-2001, 11:43 AM
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Hound dog,
Your right heads make a big difference with Fords. You did not specify the ones you used. Could you please list all items you entered into Dyno2000?
Thanks,
frankg
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Old 09-17-2001, 11:56 AM
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Darn it, I must be going blind.
Still I don't see the intake listed. Also try Airflowresearch heads. They have flows listed on their site, and are much better then Ford heads out of the box. If you try them you will probably have to search for cams that work with them since they change the airflow so dramatically

frankg
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Old 09-17-2001, 01:12 PM
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Frank;
The heads I used were the cast iron N351 Ford Sportsman heads. I'm told that the cast iron heads work better with lower compression engines (under 10:1). I'd like to try to run this thing on pump gas. I tried the AFR heads with the 185cc intake ports, 2.02 valves, 1.60 exhaust valves as well as Brodix heads with the 2.08 intake valves and 1.6 exhaust valves. They both gave slightly more horsepower but at higher RPM. I didn't try the Ford GT40 heads. The intake used is a dual plane. Single plane gives more horsepower but again at higher RPM.
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H Dog
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Old 09-17-2001, 01:40 PM
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The stock 351W with it's 3" main bearings may not live long running to 7000rpm. I've heard that 6000 is safe or use the sportsman block with the smaller Cleaveland mains.

Good Luck
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Old 09-17-2001, 02:19 PM
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Rose;
I don't disagree and likewise with the longer stroke. I wanted to get something that was basically done by 6,000 rpm. Maybe 6,500 in a pinch.

H Dog
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Old 09-17-2001, 02:31 PM
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hounddog,

I am in the same process, building a motor with the aid of Dyno 2000. There was a magazine, I believe Hot Rod that compared data that they actually saw at the dyno with what the got from Dyno 2000. Dyno 2000 was pretty accurate, within about 5-10 HP, but on the optimistic side. I trust the results as engine building really is a series of mathmatical processes.

Regarding your cam conundrum. You can build lots of power with a hydraulic roller cam. The 351W did not have one as stock, but Comp Cams builds a number of retrofit cams. They also have the retrofit hydraulic roller lifters (PN 851-16) and the 'spider' retainer needed to keep them from twisting in their bores (PN 31-1000). Cam, lifters, and retainer will run you around $520, but you'll be hard pressed to equal the same kind of performance gain for the same money. However, any hydraulic lifter is going to start having problems after 6500 rpm's or so, so play with the Dyno to get your peak HP around 5500.

Unless you are on a tight budget, consider aluminum heads. You can run a higher compression ratio on pump gas. You should be able to run 10:1 without problems. Here in California octane peaks at 91-92 and these motors run OK. I understand in some states you can still get close to 100 octane. In most cases the aluminum heads breathe better too.

Lastly, the main journal diameter is not the limitng factor in the stability of the engine - it is the fact that the 351W generally have 2-bolt mains. You can get a 351W from Ford Racing that has 4-bolt mains, but given your other requirements I don't think it would be cost-effective. At 3.00", the Ford crank is beefier than the Chevy crank, so before you break the crank you would probably destroy the mains.

Brad
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Old 09-17-2001, 03:31 PM
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I have been playing with the Desktop Dyno since it came out and I have had the chance to "run" two motors on the Desktop Dyno that had been run on real dynos. One was a 600 cu in Ford Pro Stock style motor that made 1,000 hp and the other was a 383 Chevy stroker putting out 475 hp. The big block came in at 8% over actual dyno numbers and the 383 came in at 5% over actual dyno numbers.

The biggest "unkown" so to speak is the head flow and also things such as rods are not taken into account and really can not with the software.There are other things that you can not account for either such as your bearing clearances and piston to cylinder tolerances and such that will make a difference in hp readings.

All in all,I think it is good for us "armchair" racers to fool around with and pretty close for the type of stuff we usually do with our engines. Around here, actuall dyno time goes for about $50-75 bucks an hour with a $200.00 min. which is really not bad for a dyno tune...

David
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Old 09-18-2001, 03:06 AM
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H dog,

thanks. of course the real hp are a question of head porting.
dyno lists: full port and polish ,which is a little rough definition.

anyway, my engine builders in Florida agree with the 5-10% variation for the flywheel rating.

That in turn now results in 650 hp for my engine - great!

david,

dyno hours are on a daily basis in germany. about USD 800 per day, which isn't foo bad either. but we have only few dynos capable of handling big engines.

dominik
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