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Discussion Starter · #1 ·
Just picked the car up from the dyno tuner. I've been working on the car myself, using the LM-1 tuner. That works pretty good. But there's just no replacement for the dyno.

Anyway, cars making 449 hp, and 448 ft/lbs. Torque curve is very flat. If you follow the 20% parasitic loss rule, that's about 539/538 at the crankshaft. Not bad.

Drove it a little before putting it on the trailer. This things a monster! I can't wait to get some more street time on it this week end.

Sometime this week end, I'll scan the graph and post it.
 

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Originally posted by John Card:
20% loss is way too much to assume - figure about 50-60hp max
Huh? A power steering pump eats 25HP all by itself. Depending on accessories and driveline, 20% is in the ballpark. Could even be low in some cases.
Frank
 

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a powersteering pump uses less the 1hp.
I don't know how you came up with 25.
The pump almost free spins when you are not turning.
20% is too much in your case 60hp is about right.

Grats Bob very nice numbers.

[ August 17, 2007, 05:54 PM: Message edited by: jamesfast ]
 

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Hey guys....

15-20%, what's the difference...all that really matters is how much is at the wheels and boB has some monster numbers. :eek:

Mark
 

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Discussion Starter · #7 ·
Mark is right. FWHP is just a calculated number. Not very accurate, good for comparisons only. The only number that really matters is the torque actually applied to the pavement. That's where the rubber meets the road.

I'm pretty happy with 448. And wait until you see the curve. It's almost table top flat. It's going to be fun at the track.
 

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I agree, 448 RWHP is great - It's just that there's a lot of misunderstandings out there regarding drivetrain loss. I work for a dyno company and have dealt with this subject every day for years now. 15-18% is about right for a Mustang drivetrain when you are talking about number that are close to stock or a little above. As the power goes up you have to scale that back or it gets ridiculous. Congrats on the good test!
 

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Discussion Starter · #9 ·
OK, here's the graph. The first set in Blue is from some tuning done a couple of weeks ago. As you can see, it was horrible. After much consultation (you know who you are, thanx) It was decided the camshaft was the culprit. It was a carry-over from my stock block based 427W. It performed amazingly well in that engine, and sucked in this one. Hmmm.

Anyway, last week end I swapped camshafts. I installed one from Coast High as recommended by Wayne Presley. That's the second set in red.



Now, a word about Dynos from a layman. I could test the car again next week and lose 10hp. Or gain 20 hp. I could test it on the same day using a differant dyno, and gain/lose 10hp. Some brands of dynos are considered "generous", and always seem to read a little high. However, the general curve should remain relativly stable from day to day, and machine to machine.

The point is that the shape of the curve, and the area under the curve is far more important than the total number. And the real power of the dyno is the ability to tune the car under a load at every single data point.

This car runs better now than it ever has. It's going to be a lot of fun.
 

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that torque curve is amazing, you wont have to shift at the track! Pop it in 4th and go!
 

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Discussion Starter · #12 ·
I do feel great! I drove the car just a little bit during my lunch hour. It really put a smile on my face. The weather's supposed to be nioce tomorrow, so I'll go out and burn up a tank of fuel.
 

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Bob, what valve springs and hardware do you have because it look like you have a few more HP at 6200 RPM. Beehive with the titanium retainers/keepers will net you a few hundred more RPMs before valve float. But considering you have over 400lb/ft of torque available from 2800 to 5900 RPM, you probably don't need it. If you start the pull at 1800 RPM you will see that the torque curve is higher that what is shown on the graph at 2500.
 

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Awesome torque curve.

As for the % loss thing. Using a percentage basis for FWHP is a bit rough. Losses are pretty much fixed at a given RPM as it's illogical to assume that that a tranny that burns 20hp bolted to a 200hp engine is suddenly going to burn 100hp bolted to a 1000hp engine.

Someone quoting 50-60hp is far more accurate. Your accessories don't become harder to turn on a more powerful engine.

For illustration, Honda bikes tend to lose around 15hp going to the wheel. That's pretty constant from a 60hp bike to a 200hp bike. My VFR puts about 90hp down at the wheel giving 100-105hp at the crank. Bang on Honda's numbers for a VFR 750.

Stew
 

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Discussion Starter · #15 ·
Originally posted by Wayne Presley:
Bob, what valve springs and hardware do you have because it look like you have a few more HP at 6200 RPM. Beehive with the titanium retainers/keepers will net you a few hundred more RPMs before valve float.
I'm using Comp Cams beehive springs designed for an LS1. Perfect fit on the Dart Pro-1 heads. But even I couldn't justify the expense of titanium keepers. I'm also using some Comp Cams magnum thick walled push rods to prevent the pogo effect.

I have the rev limiter set at 6,400. The engine will shoot to redline in a heartbeat. I'm not kidding you, it revs up so fast I can't believe it. I'm going to have to learn how not to bounce it off the rev limiter every time. I think I'll raise the redline a little higher and see what happens. I know the bottom end can take it (Dart and Eagle parts).
 

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Originally posted by jamesfast:
a powersteering pump uses less the 1hp.
I don't know how you came up with 25.
The pump almost free spins when you are not turning.
This is how. Just quoting the source.
Frank
 

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Discussion Starter · #18 ·
You're not kidding.

I was out yesterday pushing it a little hard. It will spin the tires in second gear while rolling. It now revs up so fast, that I'm constantly bouncing off the rev limiter. This is fun
 
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