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fast80cc
Dodge Dakota
7/13/2001
15:13:33
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 Subject: 4.7 vs 3.9 = 9%
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The 4.7L looks like a great motor (no flames please) - just some interesting observations:
The 3.9L produces 45HP/Liter (58 ft-lbs/L) and the 4.7L about 49HP/Liter (63 ft-lbs/L). This represents only about a 9% improvement for the new, high-tech. 4.7L. I'm surprised that all that new tech. (OHC, near hemi CC, ultra-light rods., etc.) only resulted in a 9% gain! Seems like DC is being VERY conservative for the first few years with the 4.7 (to gauge long-term reliability).
BTW: What was the big change that made the 3.9L jump from 120HP in 1993 to 175HP in 1994??? Could it really have been just the MFI (vs. TBI) alone???
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CyberWolf
Dodge Dakota
7/13/2001
16:18:01
|  RE: 4.7 vs 3.9 = 9%
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They have a 4.7 HO that will show up in the next couple years that pushes 270 hp.
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Anthony G
Dodge Dakota
7/13/2001
16:37:19
| RE: 4.7 vs 3.9 = 9%
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Where did you see this 270hp 4.7 HO? I did hear that the next 4.7L update will be in the New Ram! It will produce 240hp! vs the 230hp right now.
Now the new 3.7L V6 will be nice! 210hp
3.7L 210hp
4.7L 240hp
4.7L HO 270hp<--per CyberWolf(Possible gap filler)
5.7L 330hp
I wonder how much weight these new engines will have to push? I think the 2002's will be the last year for the current GenIII Daks.
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fast80cc
Dodge Dakota
7/13/2001
19:09:31
|  RE: 4.7 vs 3.9 = 9%
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It's interesting to look at the current Liberty specs. for the new 3.7L (only vehicle it's installed in today, far as I know). Yeah, 210HP but only a measly 235ft-lbs of torque?!? DC is clearly playing the "my HP number is higher than yours" marketing game here. Maybe I'm strange, but I want TORQUE in my truck motor! The V6, 5-spd. combo is barely adequate in my light RC Dak. No WAY anybody's gonna be happy with that pushing a big 2002 RAM!!!
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Hersbird
Dodge Dakota
7/13/2001
20:14:31
| RE: 4.7 vs 3.9 = 9%
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according to www.car-truck.com they are currently building the 270 HP 4.7 HO for installation in the 2002 Jeep Grand Cherokee sport, (which was reported to be able to run 14.7 in the 1/4 mile)
There is a big difference between a motor that makes say 250 HP at 5000 rpm and one that makes the same power at 3000 rpm. Usually that 3000 RPM peak motor will be making much more torque and will be a faster motor, especially if it has to move some weight. Do you think if you bolted the stock Honda S2000 motor and 6-speed in a Dakota it would be anywhere near as fast as the stock R/T? They both make about the same HP, but I bet that vtech motor couldn't even manage a 17 sec 1/4 mile pushing 4000 pounds with a 153 ft/lbs. So I agree, torque is the number you should really be looking at, as an old drag racer said, "Horsepower sells cars, but torque wins races."
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Dan Gruber
Gen III
7/13/2001
22:13:00
| RE: 4.7 vs 3.9 = 9%
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True, the new 3.7 may only make 235 lb-ft, but that's 10 more than the 3.9, the motor it replaces. And the 3.7 makes an extra 35 hp over the 3.9. Admittedly all this happens at a higher rpm, but that can be taken care of through tighter gearing either from the factory or through the aftermarket. As far as the 3.7 in the upcoming Ram, remember that the 3.9 has been offered in the Ram for years as the base engine. So I'm glad to see the 3.7 and maybe a HO version of the 4.7...maybe the introduction of those will push the aftermarket into making more stuff available for this engine family.
Dan
2000 CC SLT 4.7 4X4 Auto 3.55 LSD
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cbsdakota
Dodge Dakota
7/14/2001
04:33:01
| RE: 4.7 vs 3.9 = 9%
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Most of that HP increase is merely from the displacement. The high reving cam helps too I'm sure. I decided against the 4.7 because it was so new (in the Dak's) and I've owned 3 3.9's prior to the one I have now. They have always done me good.
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