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MoparDave
Dodge Dakota
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11/30/2004
13:51:03
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 Subject: 4.7 beating an R/T
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I need help, I have a problem. It's a good one to have,I just want to know why. I have a 2000 QC 4x4 4.7. The only mods I have are 40series flowmaster,K&N fipk, and a snugtop fiberglass bedcover(I only mention this because of improved airflow). Everything else is stock for my bought new SLT+ that I know of. My buddy and I cant understand why my truck runs a now consistant 15.2@92mph (of about 6 runs,last 2 runs were 15.2,3 were mid 15's, and the first run was the worst-16.1@85-I think due to my reaction time). The tires I used for all 6 of the 1/4 runs that day were the goodyear wrangler R/TS size31x10.50x15. My friend had a stock 2001 R/T CC and his 1/4 times were around 15.6-9@86mph(avg.-???? neither of us can figure this one out??? Was something wrong with his R/T, or is there something really good with mine? Other stock 4.7 QC's that I know of run 2-3secs slower than mine. Can somebody tell me what the deal is. I want mods but dont want to change whatever it is that is causing me to run good.
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JC
Dodge Dakota
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11/30/2004
16:28:41
| RE: 4.7 beating an R/T
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Hmmmm, the answer to your question can be many things but unfortunately your guess is as good as mine. What I can tell you is that a friend of mine has a truck very similar to yours (K&N fipk, 4x4, QC, 4.7L) with the only exceptions being a Gibson exhaust and a LeBra cover out back. Being blunt, on his best day, he couldn't beat me on my worst! Now I have a regular cab 99 R/T with simple mods such as a flowmaster exhaust, K&N fipk, Mopar Performance PCM, plugs, wires, coil, etc.., and believe me, his is a good 4x4 but in terms of speed and performance, nopers. I have watched his truck get anhilated by his fathers' 2003 Silverado 1500 (K&N and gibson exhaust) and now by his newly aquired bone stock 04 Silverado LS. They both had the 5.3L
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prple-gaseatr
Dodge Dakota
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11/30/2004
16:31:06
| RE: 4.7 beating an R/T
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maybe you have a factory freak...
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r/t
Dodge Dakota
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11/30/2004
17:03:54
| RE: 4.7 beating an R/T
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a stock cc r/t will only run 15.6-15.9
and your reaction time is not counted in your et.
your reaction may have affected your launch though...different launch rpms, etc.
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RaZoR1
Dodge Dakota
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11/30/2004
18:40:52
| RE: 4.7 beating an R/T
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What gears you got??
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GraphiteDak
GenIII
11/30/2004
23:54:33
| RE: 4.7 beating an R/T
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Yeah. What gears.
My tires are about the same as yours now. They are 255-65 16's. Which makes them just under 31's. Same as my stock height, but a good inch or so wider than stock.
I've got 3.55's. My truck romps like hell but I'd like to take it to the track to see how fast (or slow) mine sits.
4.10's are coming for me, but looks like not until after the holidays now :-(
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Mikes99Dakota
GenIII
12/01/2004
10:41:33
| RE: 4.7 beating an R/T
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Well my truck is pretty dam quick too for a 99 RC 318 auto. I made two passes both with very little tire spin due to VHT. My first pass was a 15.8 @ 87 mph and my second pass is shown below. If I get a good launch and a good 60' I can be in a 15.2 and maybe a 14.9 with the upcoming Mopar PCM. The other day I was messing around with a CC R/T We did a little 40-45 punch on a side road and by the time i hit third at about 65 he was about a half a truck behind. The guy was pissed and said that my 318 was no where near stock!!
Mike
1999 RC Auto 5.2L
Flowmaster 40 series, Homemade CAI, Shift Kit
Track Times: 60' - 2.188
1/8 - 9.75 @72 mph
1/4 -15.42 @ 89 mph
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01Motorsport
Dodge Dakota
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12/01/2004
20:23:54
| RE: 4.7 beating an R/T
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GraphiteDak, a 255/65/16, in Goodyear LS at least, is almost exactly 29" diameter. You can feel a performance change by reducing the tire diameter. I went from the stock 255/65/16 on my 2001 RC 4.7 5spd 3:92 to the R/T setup of 255/55/17 at 28" diameter. City mpg improved at the expense of highway mpg. The PCM should be flashed with each 1" diameter change to keep your speedometer correct.
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David Moore
Dodge Dakota
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12/02/2004
11:56:09
|  RE: 4.7 beating an R/T
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Razor1 and Graphite...I have 3.92gears. Would changing them be an improvement?
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RaZoR1
Dodge Dakota
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12/02/2004
18:29:15
| RE: 4.7 beating an R/T
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THose are good track gears. I have the 355 which are a good all around gear but not the best for towing or racing.
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as usual
Dodge Dakota
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12/02/2004
20:08:18
|  RE: 4.7 beating an R/T
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the near stock 360's are dogs
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88 SC DAK
Dodge Dakota
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12/02/2004
22:35:57
| RE: 4.7 beating an R/T
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A friend of mine had a 01 reg cab 2wd with a 4.7 5 speed with a flowmaster muffler and thats it. This truck wass basically a stripper has ac and thats about it on the options, even had a rubber mat. I have seen him take out R/T's with no problem (talk about some mad competitors). The only good reason we've come up with for this is the fact that it has no options, less weight. Wish I could remember his times but it was about 2 years ago. Only a thought about the diference.
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Kowalski
GenIII
12/03/2004
06:08:58
| RE: 4.7 beating an R/T
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Message:
There are more differences. Your friend has a manual transmission, which has less power loss than the R/T's automatic. He may also have 3.92 gears. It is well known that a Dak with this combination can beat R/Ts.
Lead, follow, or get out of the way
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Demon Dakota
DakotaEnthusiast
12/03/2004
14:55:13
| RE: 4.7 beating an R/T
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Message:
255/65/16's are 29.1" diameter, and 275/60-16's are 29.0" diameter.
3.55's for me are perfect, but I still use street tires at the track personally. I have a set of 3.92's available, but have never installed them (as yet)...
True Dual exhaust and removed third cat
HO Cams & HO Intake
FASTMAN 70mm TB
Autolite 3923 Plugs
TPS @ .76 VDC
IAT Adjuster Mod
Custom tranny VB Mod
Demon long tube headers
Ported/polished heads w/ 1.92" Intake/1.60" Exhaust Valves
One dead stock LSD unit (POS...)
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01Motorsport
Dodge Dakota
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12/05/2004
22:00:20
| RE: 4.7 beating an R/T
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Power-to-weight ratio is a factor, also. A RC 4.7 5-spd weighs 3759 pounds; a RC R/T 3880. Most of the weight difference is in the engine and rear end. Dyno results have shown that the rear wheel horsepower difference between the two above mentioned combinations is only 5HP or less.
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sniper
Dodge Dakota
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12/13/2004
20:16:58
| RE: 4.7 beating an R/T
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my truck is a 2000 4.7 auto cc and i was beating r/ts when i was stock. now i stomp them and all i have done is fipk, flowmaster, .75 tps, and no torque limiter. the guy krc told me that the best thing to do is go with 4.10 gears. he said they would knock off like .4-.5 of a second on my time, and that it wont throw off my speedo cause the computer is smart enough to adjust. only tire sizes throw it off. i'm happy to say that i already ordered the gears and the 208 cams.
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TexasTodd
Dodge Dakota
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12/13/2004
22:46:23
|  RE: 4.7 beating an R/T
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01motorsport,
Not to argue but,
If my 4.7, manual, QC, etc., has the same rear end as the r/t, 91/2, Hows that part of the weight difference?
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FLDak
Dodge Dakota
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12/14/2004
08:44:37
| RE: 4.7 beating an R/T
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Demon Dakota,
Great to see you back on the boards!!
I'm not trying to steal this thread but whatever become of those longtube headers for the 4.7L? Are you still running them?
Can I buy a pair?
Later...
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N56629
Dodge Dakota
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12/14/2004
13:33:59
| RE: 4.7 beating an R/T
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"he said they [4.10 gears] would knock off like .4-.5 of a second on my time, and that it wont throw off my speedo cause the computer is smart enough to adjust."
If some idiot told you that, I wouldn't believe anything else he says. The computer doesn't have a clue what size tires or what gear ratio you are running.
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TexasTodd
Dodge Dakota
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12/14/2004
20:00:17
| RE: 4.7 beating an R/T
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N.....,
NO, he's right!
For the gear change that is. The sensor is after the rear end gears, so channing gears only, you don't throw anything on the speedo off.
The tire diameter change will however.
Someone else back me up on this one?
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FLDak
Dodge Dakota
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12/15/2004
08:31:45
| RE: 4.7 beating an R/T
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Your right.
I went from 3.55 gears to 4.10s and the speedo is right on. Checked it with my GPS.
If you change tire height it will change speedo.
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