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That dyno at Westech does not lie. When I changed the freeze plugs on my 351w in my 94 f-150, I decided to see how much power this motor made with a 160,000 miles on it. I took it over to Westech and made a few pulls. I could not believe it, it made 475hp at 5500rpm and 520ft lbs of torque at 3200rpm. Dyno's don't lie. I can,t wait to see what my grandma's Cadillac is going to make.
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Gee if I was going to spend the bucks to get my engine dyno'ed,I'd want to have the biggest H.P. numbers I could get (just for the bragging rights),I'd find the most liberal dyno I could, just like the magazine article guys. HMMMMM still never been passed by a dyno, even if they were all calibrated the same. I just want to know what the BOAT runs.....P.S. are the California RADAR guns calibrated by the dyno guys? Just some random thoughts,I could be wrong. I also realize that the gravity from the mountains might have somthing to do with it. Whatever.... I'm just mad because the only dyno I can afford says Dominator on it, I tune for the max R.P.M. and it runs what it runs.
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Others free to judge jibba jabba. No sense huh?
Think about it mister engine guru? The first crate 12:1 compared to your second crate 9.6:1 About 70 hp. The first crate 1095 cfm compared to your second crate 850 cfm, good for about 18 hp. The first crate .7 lift compared to your second crate .6 lift...good for about 10 hp. 70 + 18 + 10 = 98 hp... about 100 hp? Thus 720 vs 620. So the first crate 100 hp more. Easy enough to figure. But what does that prove?
Still no valid comparison to HB's head flow or cam profile.
Consider more cubic inches useless unless the engine breathes. Thus my comments on head flow and cam profile.
Nothing magic here just numbers.
jer
[ June 19, 2003, 11:57 PM: Message edited by: LVjetboy ]
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Well to this date there are only about 2.6 billion different combinations that make hp,but what really matters is when u get in the boat and u get to stand on it it performes the way u hoped it would as far as getting to dyno it well that is cool if u have acces to one near by.The only people that will be happy or even truly believe what it makes power wise is u and your engine builder so to hell with it go out and have fun. wink
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Timinator,
I doubt HBjet cares about dyno numbers for bragging rights, I know I don't. If you'd spend bucks for a lie, then a waste of bucks I'd say. I'm guessing most jetters care about top speed not engine rating...what's the point in bragging 700+ hp then only going 85 mph? None.
To me the dyno's all about measuring your engine's true power so you can predict performance...as in your jets top speed...anything else ($$ for engine hp braging rights) is bogus.
jer
[ June 19, 2003, 11:14 PM: Message edited by: LVjetboy ]
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Not that I want to get into the middle of this, but I decided to excercise my desktop dyno just for the heck of it and here's what it shows. 572 BBC with the CR, cam, valve, etc. specs shown in the post: 741 HP @6500 and 706 ft-lbf @ 4500, both a little optimistic. I ran HB's specs (what was listed anyway) 4.31 x 4.25, tunnel ram + 750 carb, assumed 10:1 CR, used same cam as in the 572, used fully ported rect port heads in both cases. The results; 696 HP @6500 and 613 ft-lbf @ 5000. If the 750 carb is replaced with a 1100 (I don't know if DD assumes dual carbs on tunnel rams or not) the numbers jump to 735 HP @ 6500 and 630 ft-lbf @ 5000.
So what does all this mean? If you believe desk top dyno for comparative purposes, HB's dyno numbers seam very reasonable. The big difference between the two motors is the much higher torque of the 572. It stays above 660 ft-lbf from 3500 to 5500 RPM, perfect for a car. HB's torque stays above 600 ft-lbf from 4500 to 6500 RPM, perfect for a jet boat (this is predicated on HB's cam being close to what was run in DD). Interesting results that show you cant alway just compare HP numbers. How much and where torque is made for the application is what is really important.
OK, I've sai enough, you can all flame me now!
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Congrats HB, you should be happy with those numbers. I'm sure you'll see mid 90's with that combo, hope you got a lifeline and some ballistic shorts. Also I'm sure the aluminum heads on those chevy crate engines flow pretty well, if you talk to most head guys I think they'll agree 990's are good heads (that's what we run), but even a good set of ported and polished 990's can't compete with a good set of today's aluminum heads
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40oz'nHO's:
That dyno at Westech does not lie. When I changed the freeze plugs on my 351w in my 94 f-150, I decided to see how much power this motor made with a 160,000 miles on it. I took it over to Westech and made a few pulls. I could not believe it, it made 475hp at 5500rpm and 520ft lbs of torque at 3200rpm. Dyno's don't lie. I can,t wait to see what my grandma's Cadillac is going to make. Thems some good ass numbers 40OZ. Let us know what Grandma's Caddy pulls will ya?
Congrats on the new power plant HB. I'm sure it'll haul the mail for ya just fine. If I remember right, you were running 80 something before all the pump stuff n new motor?
[ June 19, 2003, 11:48 PM: Message edited by: Squirtcha? ]
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No flames here Beaver. DTD like other analytical models a good tool if you use it right. I think one of DTD's strong points not so much absolute numbers, as showing relative changes. As you found, HBjets numbers certainly possible (according to DTD) depending on some key assumptions...my point above. If you don't know the flow specs, you can't say no way. DTD is just another tool, like real dynos, to predicting (or measuring) power. And if you know your power, you can predict performance.
The bottom line? What happens at the lake when you stand on it, like djdPC says.
Until then, a dyno can help tell me where I'm at and where I'm going. Just another tool, if used right can make a difference in how fast I go when I stand on it...the bottom line. So in my opinion, not a waste of money. And to me, debating dyno accuracy and why or why not a dyno gives true numbers is both interesting and worthwhile.
jer
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Beavertim, I have to agree! These are Jet Boat motors, we don't install RV cam's anymore (hello!), (thanks to the Real Jet Boat shops).
You guy's are thinking mid 90's. That would be great, but considering BN's SW runs 92ish in the 1/4 mile with 650 hp (dyno'd by MPD/DNE)....... What do ya's think 100 more ponies will do?
Just be careful HB, take it slow your going to be flyin!
PS: @75 - 85 your eye's water, @ 85+ your face starts to hurt.
Salute