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blk
Dodge Dakota
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8/18/2005
23:12:31
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 Subject: 4.7s suck
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All you guys that are disappointed with the performance of the 4.7 litre v8, should know that the reason for the lack of power is that the bore of the engine is small in relation to the stroke.The valves and cylinder heads are fine, but the bore is small, therefore won't allow efficient airflow.It has a long stroke for low end torque which is o.k but it seems to die at the top end.Cams won't change much.So opening up the bore to match the incoming air volume would work and make a diffrence, but costs and time is the factor.The way to do this and make it cost effective, force air into the engine, i.e. Supercharger.High cost initially, but in the long run, it's a one time investment,providing you can keep your foot off the gas.
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4.7onNO2
Dodge Dakota
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8/19/2005
00:15:00
|  RE: 4.7s suck
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Cams wont change much. LOL
KRC 206s are worth 30 hp in 5 hrs labor.
I dont think too many people are disappointed with their 4.7s. Im def not. Especially for the price. 4.7 Daks are cheap you cant expect to run 12s in a truck that only costs 18 Gs. Well not without a crap load of work anyway.
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FLDak
Dodge Dakota
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8/19/2005
08:56:50
| RE: 4.7s suck
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Who's disappointed?
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ObieWonDakota
Dodge Dakota
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8/19/2005
09:53:12
|  RE: 4.7s suck
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I used to own a '95 Neon, now I own a 4.7 Dak. I'm not disappointed but my neck hurts from the added power. Keeps slamming into the back of my headrest upon acceleration. Neon said "Hi", Dakota says "Bye"
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GraphiteDak
GenIII
8/19/2005
13:07:24
| RE: 4.7s suck
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The 4.7 makes MORE power all around and then some over the 5.2 and can even rival the 5.9 in some cases.
And he said the 4.7 sucks???
I raced a Chevy 4.8 2WD RC a few weekends ago (at a track) with my 4X4 4WD and my simple mods so far and BEAT HIM.
I'm not disappointed. Maybe you have one that just has "bad tuning" or something. Or did you move to high altitude where everything N/A is slow?
Also. KRC has a all motor 4.7 build up that does 450 HP
Has Forged 11:1 pistons. But bore and stroke are stock!
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blk
Dodge Dakota
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8/19/2005
13:51:17
| RE: 4.7s suck
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O.k guys don't get your hackles up, I do own a
dakota with a 4.7 litre in it, and it is
pretty much stock except for a K&N and 3 inch
flowmaster cat back. I have a truck that is
supposed to be able to tow up to 6600 lbs.
It was working to tow 5000 lbs. Dealer told me
anything the 1/2 ton Ram can do, it can do as well.I'm not so sure.So I looked into it with
a mechanic that has done his fare share of performance engine building.He had a look at the engine specs of my truck and recommended the supercharge as a reliable and cost effective solution.
So I apologize if you guys are offended,but I found out about the unhappy 4.7 owners from this very site.
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blk
Dodge Dakota
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8/19/2005
13:55:59
| RE: 4.7s suck
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to Graphite dak
Stock pistons are 9:1 in stock bore and stroke.
to fit 11:1 forged pistons,one of those has to change.
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no
Dodge Dakota
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8/19/2005
13:59:42
| RE: 4.7s suck
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blk, neither bore or stroke has to change to go from 9:1 to 11:1 compression.
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IntenseDak39
*GenIII*
8/19/2005
14:45:21
| RE: 4.7s suck
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"The 4.7 makes MORE power all around and then some over the 5.2 and can even rival the 5.9 in some cases."
not any of the dyno's i have seen.
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Kowalski
GenIII
8/19/2005
15:35:46
|  RE: 4.7s suck
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It'll make more power than the 5.2 on the big end - keeps making power where the 5.2 is dropping off - and thats because of the stock cam design. Several upgraded levels of cam are available - and they will make a difference. "no" is correct blk, you seem to have some misconceptions here. I didn't feel my 4.7 was working too hard towing 5000 lbs, and that was with the 3.55 gears. The heads were designed for the size of the bore, the bore size is not a problem. Motors with a longer stroke than bore are known as "oversquare" - typical characteristics are that they might be slightly slower reving than an undersquare motor with the same reciprocating weight (another positive trait of the 4.7 is its lighter reciprcating weight than the 5.2 or 5.9) but rings are piston walls will wear more slowly due to the geometry. My Dak will out tow a similar half ton since total weight will be less, and it'll fit into a tighter parking spot too. Mine will also out plow a half ton - Fisher said a plow was fine on my truck, but they wouldn't put it on hte same year half ton. Go ahead and supercharge if you desire a drastic increase, but there are plenty of other hop ups that will work just fine with the Dak's bore.
Lead, follow, or get out of the way
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IntenseDak39
*GenIII*
8/19/2005
16:08:32
| RE: 4.7s suck
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no offense, but i'm gonna take what you say with a grain of salt as we had a local dyno day and it proved just how much the 5.2 is underrated... hell, it may just be my 5.2, but it sure beat some modded 4.7's that day.
i'm not saying the 5.2 is underrated meaning it makes more than the advertised power, but it's underrated compared to the 4.7.
bone stock numbers for my 2000 5.2 auto are as follows;
184 rwhp
261 rwtq
that beat my buddies 2000 4.7 auto w/ aftermarket exhaust, headers, home brew intake and viper fan.
179 rwhp
240 rwtq
My other buddy dynoed his 2002 4.7 auto, k&n, superchips and got the following;
185 rwhp
240 rwtq
another buddy has a 2003 4.7 5 speed, exhaust, cold air intake and F&B 70mm TB:
203 rwhp
261 rwtq.
all dynoed the same day... only thing that got a considerable amount of more horsepower was the one with less drivetrain loss (five speed compared to auto).
ya can preach it all ya want, but those are the real world numbers down here in Dallas-Forth Worth, Texas.
... and yes, my 5.2 gets 20 mpg and has a torque curve like you wouldnt believe... made more than 200 rwtq from 1500-4500 rpms. Yeah it makes it's max horsepower at 4000 rpms, but hey, it's a 5500 lb durango!!
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Kowalski
GenIII
8/19/2005
17:50:00
| RE: 4.7s suck
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Well those are peak #s, don't show the whole curve which you have to see to know what I mean about power at higher revs - but isn't this thread really more about bore versus stroke relationship to power than comparing the 4.7 to the larger 5.2 & 5.9 ? There's nothing about the design itself of a longer stroke engine that limits the power - take stroker A engines for example - they get a longer stroke and still make great power.
Sure larger displacement is a time honored recipe for power, but blk specifically blamed the bore size.
Lead, follow, or get out of the way
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IntenseDak39
*GenIII*
8/19/2005
19:22:09
| RE: 4.7s suck
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that's true about blk... bore size has nothing to do with it.
but if i had a scanner, i'd show you the graphs. IMO, the only thing that makes the 4.7 better than the other two motors is the transmission behind the 4.7. It has a much shorter first two gears in it and has a variable second gear. All this allows for quicker accelleration.. but not power.
traditionally, OHC motors have a smaller bore and longer stroke.. there's no magical number on which one is better. People say mopar fudged up when they got a 383 and opened the bore up to 4.342 and crapped out a 400. To me, i've got a 320 rwhp/ 400 rwtq torque monster that runs on factory short block and heads. It's getting the right relationship of the moving parts is all that matters.
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facts
Dodge Dakota
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8/19/2005
22:54:43
| RE: 4.7s suck
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4.7's don't "suck", they're fine for their intended purpose - modernized cost-cut replacement of the 40 year old LA V8. I have one and it's got plenty of jam when I need it.
A 360 dwarfs the 4.7 from the start, and both the 318 and 360 can be safely bored and stroked to 400+ cid. All of them are easily capable of 1.2 hp/cid:
More displacement = more hp + more torque
Stock 4.7's will only put up with so much abuse, unlike a stock 5.2 or 5.9. Start modifying them, and the LA will make more power in the end. 4.7's blow up when you expect too much out of them - just ask Duner. Big blocks are a totally different animal altogether and it wouldn't be fair to throw a non-factory motor in the mix...
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GraphiteDak
GenIII
8/20/2005
01:12:23
| RE: 4.7s suck
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A 5.2/5.9 would have blown up too if it saw over 20PSI of boost!!!!!!!!!!
Supposedly, i hear the 4.7 is a GOOD engine to boost. It has some technolodgy built into the bottom end that performance shops would otherwise have to do to a LA.
I like LA engines, don't get me wrong.
And intense, I guess the tranny could have something to do with why a 4.7 Dakota would out run a 5.2
My bro in law actually wants to get rid of his 5.2 RAM and get something with a 4.7 because he likes how responsive it is. I guess again some could be that the electronic tranny with the 4.7 just seems more responsive than his 46RE behind the 5.2
Speaking of bore vs stroke
I was always a Ford 302 fan. 4" bore x 3" stoke. High revs are fairly easy on it. But now I'm reving my 4.7 to 6500 so that aint to bad!
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allpar
Dodge Dakota
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8/20/2005
02:07:04
| RE: 4.7s suck
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The 4.7 will never live up to the 318. I wouldnt believe there is another motor out there that will put up with as much abuse as the 318. Hech the 4.7's havent even been out long enough for the guys who own them to rack up a usual 300,000 mile run as a 318 normally gets. This goes for the whole block 3.9/5.2/5.9
3.91 and 3.31 bore in stroke on 3.9 and 5.2, you cannot kill those motors for nothin, reliability doesnt get any better!
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ecdak
Dodge Dakota
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8/20/2005
02:54:35
| RE: 4.7s suck
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sucks having the fastest stock truck. maybe i will trade mine for an s10 or ranger that is no where near as fast or powerful. hate my truck. why did i buy such a peice of crap?
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Kowalski
GenIII
8/20/2005
07:36:50
| RE: 4.7s suck
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That the 4.7 makes as close to the power of an engine that is a full half liter larger is a testimonial to its design.
This thread seems to be going way off the original topic. As side notes to what some are saying; the auto tranny behind the 4.7 is also more efficient than the others, passing more of the power through to the rear; and if you're looking for a motor that will take more abuse than the 318, look at mopar's old slant six. But this thread really wasn't supposed to be a 5.2 or 5.9 versus 4.7 debate.
Lead, follow, or get out of the way
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mopower
Dodge Dakota
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8/20/2005
09:00:30
| RE: 4.7s suck
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I love my 4.7 in my '02 QC 4x4. I have 3.92 gears and it's got all the get up and go I would ever want.
I used to have a 94 ram 318 and it was pretty good too though, but I think I like the 4.7 better.
To me the 4.7 is the perfect sized motor for the Dakota. I wouldn't want a bigger motor or a smaller one in it.
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blk
Dodge Dakota
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8/20/2005
09:29:57
| RE: 4.7s suck
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to NO:
I agree with you about the bore and stroke size to a certain degree.you can modify the heads, change the cams,but how is the same bore going to handle that?It is going to take in the same
volume regardless, unless you can force more into
that space.So how do you do that?
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no
Dodge Dakota
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8/20/2005
11:03:41
| RE: 4.7s suck
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the volume doesn't need to change. you just have to compress it more. you don't have to force anything into it. the motor is one big pump. sucks in air & fuel and pumps out exhaust. raised top pistons alone will bump comp from whatever to whatever. not to mention heads with smaller combustion chambers.
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