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Matt Barret
Dodge Dakota
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5/24/2002
23:45:44
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 Subject: Pulled the dyno today, 4.7L..
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I rented the dyno for an hour today with 2 objectives. 1. to get a good baseline prior to installing the HO cams, HO intake and Leach PCM. 2. to see if there would be any difference in RWHP between the Sport 15x8 rims, and my new RT rims. I really thought there would be. As I posted previously the RT rims weighed 10 lbs more per wheel and tire. My results were as follows:
First 3 pulls were with the RT wheels and tires. I averaged 213.5 RWHP and 291 RWTQ.
The HP peaked at about 4300 rpm and was flat from 3800 to 4800 rpm were it began to drop off hitting 200 hp at 5000 rpm. The TQ peaked at 3300 and leveled out at 285 TQ until 3900 were it began to drop steadily to 215 TQ at 5000 rpm
The next 2 pulls were with the 15x8 Sport wheels and tires. I averaged 215.5 RWHP and 288 RWTQ.
The HP peaked at about 4000 rpm and was flat from 3800 to 5000 rpm were it began to drop off to 200 HP at 5100. The TQ peaked at 3300 and leveled out at 285 TQ until 3900 were it began to drop steadily to 220 TQ at 5000 rpm
Specs/Mods: '00 RC 4.7L 5spd 3.92 LSD 48K miles
72mm TB, airintake W/filter removed, Flowmaster cat back, Gutted 3rd cat, Mobil 1, IAT box.
So everyone take note, the RT wheels and tires made no significant difference in power or torque compared to the Sport rims and tires. One less excuse that can be used ? LOL
All 5 pulls showed that power starts to drop off after 5000-5200 rpms. At 5300 rpms HP is below 200 hp.
Hope you all can make sense of all this! I'll have more dyno info after I install everything.
Matt Y2K-HEMI
'00 RC 4.7L 5spd
14.23 @ 94.49
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jj
Dodge Dakota
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5/25/2002
00:02:25
|  RE: Pulled the dyno today, 4.7L..
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Wow a very good start Matt ! Please keep us informed , jj
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Hersbird
Dodge Dakota
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5/25/2002
00:38:15
|  RE: Pulled the dyno today, 4.7L..
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I'm not completely sure about how this would work, but the added weight wouldn't show up so much on the dyno as it would on the track. I realize rotating mass is 10 times more effective then static mass so you think you would see it on the dyno. But the dyno cannot take into account the extra weight on the front wheels as they just sit there, and yet weight on the front wheels has the exact same effect as the rears. The fronts just end up getting driven by the rears through the road. If you put 300 pounds in the bed, it wouldn't effect they dyno either. I think that the dyno cannot see the extra wheel weight even on the back because it's effect is to slow the rate of acceleration down, not the actual torque applied to the dyno, and all a dyno can measure is the torque applied to it. So the effect is just within error of analysis on the dyno, but on the track I bet there would be a bigger difference then indicated, a good .1 for every 10 pounds.
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cadetdak
Dodge Dakota
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5/25/2002
00:50:34
| RE: Pulled the dyno today, 4.7L..
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this is a little off topic but check this out it's a post on a viper forum about a 2003 viper beating an F-16 with afterburners in a 1/2 mile drag. of course the F-16 does weigh in at 35,000lbs but still that's inpressive.
http://vca1.viperclub.org/ubb/Forum21/HTML/000335.html
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kota on 20s
GenIII
5/25/2002
01:13:32
| RE: Pulled the dyno today, 4.7L..
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matt, isnt that what a stock R/T dyno's at? or a R/T with a gen II at most. except i beleve the R/T has more torque.
since hersbird is right about the weight on the dyno, i guess if you has a 5 speed R/T, with sport rims, one would be faster than your 14.23. being a 5speed owner myself, i know 3500 rpm clutch dumps are fun, and so it speedshifting through the gears.
why dont you try this the next time you are on the strip. dump the clutch at about 1300 rpm, and dont bang the gears so hard, and see what you run. this will kind of simulate the auto trans of the R/T, and see how compair.
Eric, 98 5.2 5speed, K&N gen II, 50mm TB, 2bbl M-1, 1.7RR's, JBA ciramic headers, carsound cat, dumped gibson, and a lot more
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MW
Dodge Dakota
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5/25/2002
18:38:53
| RE: Pulled the dyno today, 4.7L..
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Thanks for the info on the dyno results. Just make sure your next pull is at the same dyno machine.You forgot to state the diameter of the tires that you were using. If I am not wrong the higher TQ is with the smaller dia tire and higher HP is with the larger tire.GOOD LUCK with the next pull.
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Josh
Dodge Dakota
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5/25/2002
22:04:01
| RE: Pulled the dyno today, 4.7L..
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Hersbird, I don't think that rotating mass times ten thing is very accurate - I am by no means a car guru but I do have a very strong physics background. The amount of torque needed to accelerate a rotating mass is directly proportianal to its moment of inertia. The higher moment of inertia, the more torque needed to equally accelerate the rotating object. The moment of inertia is a calculated value that depends on the distribution of the mass of the object. The closer mass is to the center of rotation, the less the moment of inertia will be. What really seems to matter in the case with the wheels is how the mass is distributed. You could add ten pounds to the center of the wheel and hardly see an effect, but ten added pounds to the outside of a wheel will give you a lot higher moment of inertia.
I have no clue on how the mass is distributed on any of these wheels and tires, so I can't give a solution to how the wheels should react; however, I do know ice skaters spin faster with their arms folded in rather than sticking out.
Sorry for the long boring mumbo jumbo
Josh
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kota on 20s
GenIII
5/25/2002
22:19:40
| RE: Pulled the dyno today, 4.7L..
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the R/T wheels are 9" wide, and have a larger diameter by 1", thus putting more of the mass out even further.
Eric, 98 5.2 5speed, K&N gen II, 50mm TB, 2bbl M-1, 1.7RR's, JBA ciramic headers, carsound cat, dumped gibson, and a lot more
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Dr0p0ff
GenIII
5/25/2002
22:39:33
|  figured you'd pull more hp
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Matt, what's the altitude where you are?
Keep On Truckin!
Sgt G
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bfs426
Dodge Dakota
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5/26/2002
15:01:01
| RE: Pulled the dyno today, 4.7L..
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The R/T rims are also wider and will cause more wind resistance, but that is getting really picky.
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Matt Barret
Dodge Dakota
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5/26/2002
17:36:31
| RE: Pulled the dyno today, 4.7L..
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I'll see if I can clear up a few questions.
Hersbird, I can't argue the point you make about acceleration. It was clear on the dyno sheet the power came a little quicker with the lighter wheel. But it was all within a few HP. I won't argue the fact that on the street acceleration would be effected more with a heavier rim/wheel. How much, we don't know. Josh has very good point, we really don't know how the extra weight is distributed. Maybe the tires are heavier??
My test was to see the effect on rear wheel power. Measuring acceleration on the street has too many variables, Weather, Tires, etc...
I've seen stock RT's dyno anywhere from 190 to 210 hp stock. TQ is generaly in the 300 range.
The Diameter of my 275/50/17's and the 275/60/50 are both 28"... so there is no difference in the two.
Altitude is approx. 100' ;) Richmond VA
I'll keep this thread updated as I get more info
Matt Y2K-HEMI
'00 RC 4.7L 5spd
14.23 @ 94.49
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Jeffster
Dodge Dakota
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5/26/2002
19:20:01
| RE: Pulled the dyno today, 4.7L..
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Hey Mat. When you ran on the Sport wheels was your engine hotter than your first run on the R/T wheels? If your first run was on a cold engine you would have also show a better pull.
Hey Eirc don't forget that a 5.9 engine also weighs in a few hundred pounds heavier than a 4.7 engine so that would make it slower even if the dyno numbers are identical. Also the 4.7 probably produces it's maximum HP over a broader range since it revs out higher. Not really certain on how the power curves compare however.
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Matt Barret
Dodge Dakota
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5/26/2002
22:03:23
| RE: Pulled the dyno today, 4.7L..
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Jeffster, great question. The answer is, I dropped off the truck at lunch time and it sat for 5 hrs in the shop prior to my first run (with the RT wheels) I made 3 pulls (all within 1 hp) by the time I made that 3rd pull the engine was hot), then I swapped the rims. If I had only made one pull with the RT wheels and a cold engine, maybe we could question the results. 3 pulls with the RT rims was enough to reach operating temp, certainly.
Matt
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kota on 20s
GenIII
5/26/2002
22:12:05
| RE: Pulled the dyno today, 4.7L..
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jeffster, where do you get your #'s??
even though the 4.7 has aluminum heads, and plastic intake, it is phyisicaly bigger so this brings the weight back to what the 360/318 weighs.
where do i get my info from?? i have heard duner say this in another thread... im sure he will be reading this, and he can throw in his .02 too.
Eric, 98 5.2 5speed, K&N gen II, 50mm TB, 2bbl M-1, 1.7RR's, JBA ciramic headers, carsound cat, dumped gibson, and a lot more
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Hersbird
Dodge Dakota
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5/27/2002
00:26:29
| RE: Pulled the dyno today, 4.7L..
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The 4.7 with a 5-speed is probably a little less because of things like the 5-speed should weigh less. Although the clutch and pressure plate, with the bellhousing do weigh a lot, so does a torque converter full of fluid. The actual motor may be about the same. The R/T wheels and tires add some weight. Even so you can order a 4.7 5-speed more stripped down the the R/T so they may weigh less because of differences in accessories. It used to be possible to order a R/T w/o A/C, but now even a sport comes standard with A/C. I bet a 2002 cc 4.7 auto with wheels and tire package, is about the same weight as a cc R/T with the same extras. I really need to get my truck down to the scales and see what I'm working with. My R/T is pretty stripped down and still basically stock. It has the cooling package, and A/C as the only options on a RC 2000.
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Sam
Dodge Dakota
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5/27/2002
03:44:16
| RE: Pulled the dyno today, 4.7L..
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"Aluminum cylinder heads, a hollow camshaft with sintered steel lobes, magnesium valve covers and a molded composite intake manifold contribute to an overall weight reduction of 54 pounds (24 kg) compared to the previous 5.2-liter engine." ALLPAR.COM
Which means the 4.7L ENGINE is lighter.
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kota on 20s
GenIII
5/27/2002
14:14:22
| RE: Pulled the dyno today, 4.7L..
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well 54 lbs is not a lot of weight. 100lbs = .1 in the 1/4, so 54 = .05. the differance in driver weight can more than compensate for that!
im 6' weighing 175, so if i go up against some fat ass in a 4.7, ill have the advantage ;-)
Eric, 98 5.2 5speed, K&N gen II, 50mm TB, 2bbl M-1, 1.7RR's, JBA ciramic headers, carsound cat, dumped gibson, and a lot more
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Jeffster
Dodge Dakota
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5/27/2002
20:43:34
| RE: Pulled the dyno today, 4.7L..
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And how much lighter is the 5.2 than the 5.9L?
Ya I am off still but I know that my truck weighs just under 3,800lb's so I guess it's the tranny,fender flares and auto that ballon the R/T's weight up to over 4,200lb's. My apologies Eric.
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Jeffster
Dodge Dakota
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5/27/2002
20:45:55
| RE: Pulled the dyno today, 4.7L..
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Sorry that's engine,fender flares, and auto.
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Sam
Dodge Dakota
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5/27/2002
22:07:00
| RE: Pulled the dyno today, 4.7L..
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Eric I'm not saying that it will make a big difference. I was mainly clearing up what was meant by the 4.7L engine is lighter. Hersbird was saying that it might not be the engine. Thats all my post was for. Jeffster was right about the engine being lighter.
As for the whole truck weight, yes it depends on the options and whats been done to it.
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Hersbird
Dodge Dakota
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5/27/2002
22:17:24
| RE: Pulled the dyno today, 4.7L..
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No way 4200 on a regualar cab, I've heard some R/t's are also 3800 pounds. Is that weight with you in the truck? and how much gas? Don't forget the rear sway bar, that might be as heavy as additional motor weight. The 5.2 and 5.9 should weight almost the same, the crank might be a little heavier on the 5.9 and it might hold more oil in the pan but that would be the extent. Fender flairs weigh maybe 10 pounds (the 2002 sports with tire package get fender flairs anyway), and like I said the entire transmission assemby might be closer then you would think. So 200 pounds tops, maybe only 100 pounds between a 4.7 5-speed and a R/T, less difference on the CC as it has the rear bar, and the percentage difference would be less significant. I'll get my Truck weighed when my parents finish "borrowing" it for moving.
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Matt Barret
Dodge Dakota
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5/27/2002
22:42:00
| RE: Pulled the dyno today, 4.7L..
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2000 RC 4.7L 2x4 (stock trim) with spare etc.. A/C,cruise, tilt, sliding rear window and 1/2 tank of gas weighed 3670. Removing the spare and tailgate will knock it down to 3570.
4 fender flares weigh about 3 lbs, total. They're plastic.
BTW, I installed the HO cams and intake today. Had no problems with the install. Was actually a very simple install. Fired it up this evening but had an injector that was'nt seated properly and was leaking like crazy. It'll be tomorrow before I can get that straight. Should be on the road tomorrow evening.
"Hollow camshafts", thats what they say, but I can tell you these cams are just as heavy as a normal V-8 camshaft. You can't tell they're hollow, you can't see through them.
The Magnesium covers are VERY light.. as is the plastic intake. The heads are very large, so even though they're aluminum, there is A lot of aluminum there.
Matt
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CW
GenIII
5/27/2002
23:08:54
|  RE: Pulled the dyno today, 4.7L..
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I have weighed mine many times and it is right on about 4000lbs with a full tank, me and all parts in place. That is with a few extra things in the cab. Shouldn't have gotten the sport plus fully loaded.
2001 4.7HO RC 5sp 3.92 LSD
Click on thumbnail for mods.
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1Flamed92Dak
Gen I
5/28/2002
00:47:14
| RE: Pulled the dyno today, 4.7L..
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True the R/T wheels weigh a whole lot more than the 16x8 Sport wheels,You should try the Gen II steel wheel thats 15x7 Less rotating weight more POWER I know there is about 15 pounds per wheel between the 17x9 R/T wheels and my 15X7 Steelies maybe more so that less rotational weight means quicker acceleration. My ole butt dyno tells me that. But i wouldn't give up my R/T wheels for the world in looks
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B1llyw
GenIII
5/28/2002
07:20:24
| RE: Pulled the dyno today, 4.7L..
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FWIW, I have the build sheet on my truck. It weighs 4398, bone dry, with nobody in it and no mods.
Bill White - 2002 QC 4x4, SLT , 4.7, 5 spd, 3.92's w/LSD, Airaid, MBRP Super Single, Hurst T-Handle, BFG A/T's, IAS Shocks, 180 T-Stat, Jet Chip - Stage II
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EyeTrip
Dodge Dakota
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5/28/2002
19:14:25
| RE: Pulled the dyno today, 4.7L..
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I have a 2000 CC R/T It scales in at 4340 with 1/4 tank of gas and without me.
My dad has a 2001 CC MotorSport It scales in at 4100 with a 1/4 tank and without him.
The MotorSport has the same package (swayaways, suregrip rear end, electronic crap... all the same as an R/T) It's A 4.7 with an RFE trans.
His ran a 14.6 in the 1/4 with 3:55 gears
the average times for a stock R/T is about 15sec stock with 3:92 gears
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Hersbird
Dodge Dakota
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5/28/2002
21:11:57
| RE: Pulled the dyno today, 4.7L..
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Actually when the motorsport package came out all contained was the tire and handling group, some Nascar stuff (like bag and cooler), the yellow lettered goodyears, a chrome grill, and some lettering. It could actually be ordered with any motor besides the 5.9, and could have an automatic or manual. It was only about a $500 option. You had add all the extras you wanted separately, mainly the 4.7. It's sad to think there are probably a few 4 cylinder motorsport trucks running around out there.
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aden
Dodge Dakota
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8/24/2002
23:20:31
| RE: Pulled the dyno today, 4.7L..
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surely 100or200 ibs is negated by the fact that
a auto loses about 20% more power than the stick
so thats why a 4,7 can run with a 59 rt evan though it makes slightly less horsepower
q can a rt run with them old lightnigs before they were charged
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