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fot80
Dodge Dakota
11/05/2001
13:45:52
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 Subject: 4.7 HO
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I tried doing a search, but couldn't really find what i was looking for. What is the difference between the base 4.7 and the 4.7 HO? And is it possible to do a HO conversion?
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Rockn blk dak
Dodge Dakota
11/05/2001
13:50:58
|  RE: 4.7 HO
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Well I know the power is a big difference they have 265hp and 335tq thats 30 more of each, thats pretty good, as far as the mechanics involved im not too sure, sorry. But maybe you can ask Bernd.
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fot80
Dodge Dakota
11/05/2001
14:02:08
| RE: 4.7 HO
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bernd, sorry to ask u, but do u know what they did differently? I'm guessing it's not exhaust, intake, and computer stuff, cuz i doubt all that stuff will add 30hp and 30 torque. Plus it's in the new cherokee, so the yuppies won't want to be offended by a louder exhaust and intake.
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Duner
Dodge Dakota
11/05/2001
14:23:20
|  RE: 4.7 HO
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I got this info from a very reliable source:
The 4.7 HO has a forged crankshaft, is now at 9.7:1 compression, hotter cam, new intake manifold with shorter runners and new heads that are slightly different in the combustion chamber. At this point I don't know if the additional compression ratio is because of different pistons or just the difference in the combustion chambers.
You could probably get some performance improvements from just the intake manifold and cams. Replacing the crankshaft would be a very expensive and labor intensive change that would probably never actually show up as a performance gain. The heads might actually make a big difference, but are bound to be pricey also.
I still also believe that most of the supposed 30 hp and torque could be achieved with a custom PCM alone.
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MikeW
Dodge Dakota
11/05/2001
20:37:06
| RE: 4.7 HO
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The cast iron crankshaft was replaced with a forged one. Gaining strength while reducing reciprocating mass. They also added a unique (to the HO 4.7) crankshaft damper and special main bearings. The compression is bumped from 9.0 to 9.7 to 1 by using a domed piston. The HO gets two knock sensors were the standard 4.7 has no knock sensors.
Horsepower goes up from 235 @4800 to 265 @5200rpm.
Torque is up from 295 @3200 to 325 @3600rpm.
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Jeffster
Dodge Dakota
11/05/2001
20:51:31
| RE: 4.7 HO
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Great info on the HO guys. Doesn't it seem to you however that with those kind of mods they should be doing a little better than +30 HP?
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CW
Dodge Dakota
11/05/2001
20:57:31
| RE: 4.7 HO
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They have to leave something for us to improve.
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Duner
Dodge Dakota
11/05/2001
21:25:35
| RE: 4.7 HO
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Hmmmmmm..... something to think about.
Does anybody else think it sounds kinda odd that they would bother to add a forged crankshaft and two knock sensors to a naturally aspirated engine? They certainly didn't think that 30 extra horses was gonna put the standard crank in jeopardy.
You know.... a forged crank and knock sensors would sure be handy on a forced induction engine.
Hmmmmmmmm
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Kyle M.
Dodge Dakota
11/05/2001
22:42:23
| RE: 4.7 HO
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Hmmm. that does sound a little interesting. Maybe Dodge has seen all the turbos and supercharged vehicles on the road. Maybe they thought it would be a nice thing to do for the owners so that we can mod them up nicely. Thanks Dodge! I need my an HO.
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Duner
Dodge Dakota
11/05/2001
22:54:08
| From the factory?
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I was thinking more long the line of what might be needed to make a 4.7 Dakota run as good as a Lightning - from the factory....
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Kyle M.
Dodge Dakota
11/05/2001
23:09:59
| RE: 4.7 HO
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Where can I get me detailed info on this little treat? I looked on Dodge's website but found nothing.
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Duner
Dodge Dakota
11/05/2001
23:23:15
| RE: 4.7 HO
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I think MikeW has the inside track on the hard info. I got my info 2nd hand from my favorite parts guru at my local Mopar dealership. I did however get him to price out the parts required to make my engine into the HO version. I can't seem to find the prices right now as I type..... but it was definately cost prohibitive. All that cost for just an additional 30 hp made the cost of the turbo install look like it was almost free in comparison!
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Will
Dodge Dakota
11/06/2001
08:59:29
| RE: 4.7 HO
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Does the HO version require the use of high octain fuel?
Duner-when you get the total est. for the conversion, let us know just for kicks.
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Hersbird
Dodge Dakota
11/06/2001
11:32:02
| RE: 4.7 HO
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The cams are definately different as said before, this and more comperssion is probably what makes the most power. The knock sensors are needed for the hight compression to prevent, uh, knocking. And the best thing is if Dodge does it from the get go it's only like a $400 option on a Grand Cherokee over the normal 4.7. Problem Is if you go buy the parts form Dodge, not even counting anything like heads, or crank, just pistons, cams, and custom PCM, then you'd have just spent a ton for a mere 30 HP. You're better off just renting a Jeep Overland for a week and doing the motor swap in your garage. Even stealing one like that would be expensive!
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Todd
Dodge Dakota
JOIN HERE
2/05/2003
17:21:33
| RE: 4.7 HO
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Here is the link to all the info you need comparing the 4.7 and 4.7HO
http://www.wjjeeps.com/engine.htm#PINS
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Thinker
Dodge Dakota
JOIN HERE
2/11/2003
14:48:18
| RE: 4.7 HO
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Peak HP at 5200 RPM? Peak torque at 3600? These are pretty high numbers for an SUV full of soccer balls aren't they? Not like you're gonna be flipping the thing back & forth up mountain roads, or blasting down the 405 at 100 mph through traffic jams every day after work. (Maybe towing a boat all the way down the Interstate in second gear?) It's a weird engine to be putting in a vehicle like that. Make more sense to use a pushrod hemi or ol' 5.9.
Just like having a working truck. Better to get a 3/4-ton with a nice new Cummins to do everything you need it to. -And not squeezing your business by buying a new truck every 2 years together with lots of expensive gasoline to drive the thing from site to site.
A Dak on the other hand is made to be a quick fun truck driven by people that don't mind hitting 6000rpm a couple of times a week. A SOHC HO engine, with lots of high end or even the 5.7 would be a Good Thing.
So why the weird packaging? What does DC save by not putting hot cams or a 5.7 into the Dak? Probably to suck people 'up' from a Dak into either a higher margin SUV or a large working truck, right?
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DC
Dodge Dakota
JOIN HERE
2/11/2003
15:13:23
| RE: 4.7 HO
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We'll never tell!
Big brother is watching!
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