Ran the 1/8th tonight and posted up two runs at 10.06 and 10.07. It was mid eighties and very muggy and humid. 5/8's of a tank of gas and the girlfriend's purse.... 60 ft was 2.36 and MPH was 71.9. Not terrible runs and seemingly better than the magazines...but I wanted more! This was on my red truck which is bone stock except the 18" wheels and Nitto Terragraplers. Odometer read 3,021 on the first pass.
Vmax225
05-09-2009, 12:55 PM
and the gf's purse lol.
v8440
05-09-2009, 03:00 PM
Did you use 2nd prime? Also, how does the tire height of your wheel/tire combo compare to the stock wheels?
Bubba_Hemi
05-09-2009, 03:19 PM
2nd prime would have made no difference in running the 1/8th, would it? He'd still be running in 2nd.
Also a couple big factors... the warm weather and humidty will kill you.
i'll have to find my slips and see where I ran the 1/8th at.
biggestdiesel
05-09-2009, 05:40 PM
The tires are 31.38" on 18s vs stock of 31.7" on 17s. The new wheels/tires are much heavier than the stock wheels/tires so I'm sure even though it is a shorter tire it is hindering me slightly. I'm ready for some mods....seems like it is taking forever to get anything....
I ran the truck in drive with the traction control off.
emsdad
05-09-2009, 06:48 PM
What is 2nd prime?
Lead Head
05-10-2009, 12:00 PM
The 545RFE has "two" second gears. 2nd is 1.67:1, and 2nd prime is 1.5:1.
A little back ground helps, the 545RFE started life as the 45RFE, which was a 4 speed transmission, but also had "two" second gears. The RFE design has 3 planetary gear sets, which allows for a theoretical 8 forward speeds depending on which clutch packs the computer commands the transmission to lock up. Chrysler only originally decided to use 4.
What they found was that do to how they designed the transmission, a down shift from 4th into 2nd required an extra step in the shift process actually momentarily stopping power transmission to the wheels, making the shift rough. So they looked at all their 8 available ratios, and found 1.5:1. A 4-2 down shift to this ratio did not require that extra step in the shift process, making for a smooth shift.
In normal acceleration from a stop, it goes 1st, 2nd(1.67:1) 3rd, 4th. When going to pass on a highway, it goes from 4 to 2nd Prime, or the 1.5:1 ratio. Later Dodge programmed in a "5th" gear to bring the revs down lower on highway travel, but it still uses the 2nd Prime ratio for down shifts.
Now it seems that for the 09 Rams, if you are using the manual shift option, it allows you to use 2nd prime for normal acceleration
antman182
05-10-2009, 03:39 PM
i hate to be the bearer of bad news...but if you wanted to go fast easily, a truck probably wasnt the best decision
v8440
05-10-2009, 04:22 PM
In that case, rejoice-you aren't the bearer of bad news. The "news" part of it is what saves you there, as I'm sure the original poster was aware that many lighter cars will be quicker than his truck.
biggestdiesel
05-10-2009, 05:19 PM
If I wanted to go fast I would have purchased a bike....I get that.... I have another car that is relatively fast, although it still has 4 doors...but runs 12s in the quarter. The simple fact here is that I wanted to be at 9.8 or better. That's my expectation of this truck. Better weather and more miles I'll be there for sure and with some mods I'll be at ~9.4 which is what I'd like to see post-mod. So, in the end I know this truck isn't fast, but having goals and expectations are ok in my book.
v8440
05-10-2009, 05:52 PM
Whenever you have a thread about how to get your truck to go faster, there's almost always somebody that feels the need to point out the blindingly obvious, as though you're retarded or something. I have a mustang that has gone 9's with the smallblock in it. Yet for some reason, I feel the desire to see how quick of a pass I can get out of my stock '09 hemi truck. In other words, we're in exactly the same boat.
biggestdiesel
05-10-2009, 07:03 PM
Yep, we're on the same page. I've never had a vehicle that I didn't want to optimize performance!
chirp08
05-11-2009, 09:59 AM
The 545RFE has "two" second gears. 2nd is 1.67:1, and 2nd prime is 1.5:1.
A little back ground helps, the 545RFE started life as the 45RFE, which was a 4 speed transmission, but also had "two" second gears. The RFE design has 3 planetary gear sets, which allows for a theoretical 8 forward speeds depending on which clutch packs the computer commands the transmission to lock up. Chrysler only originally decided to use 4.
What they found was that do to how they designed the transmission, a down shift from 4th into 2nd required an extra step in the shift process actually momentarily stopping power transmission to the wheels, making the shift rough. So they looked at all their 8 available ratios, and found 1.5:1. A 4-2 down shift to this ratio did not require that extra step in the shift process, making for a smooth shift.
In normal acceleration from a stop, it goes 1st, 2nd(1.67:1) 3rd, 4th. When going to pass on a highway, it goes from 4 to 2nd Prime, or the 1.5:1 ratio. Later Dodge programmed in a "5th" gear to bring the revs down lower on highway travel, but it still uses the 2nd Prime ratio for down shifts.
Now it seems that for the 09 Rams, if you are using the manual shift option, it allows you to use 2nd prime for normal acceleration
Doesn't the 1.5:1 accelerate slower then the 1.67:1? I can see how it would be useful on a downshift because you'd be right in the powerband in 2nd while the 1.67 would most likely cause the computer to just put you in third instead of winding the truck out in 2nd for a brief instant. But that's only for downshifting for accelerating on the highway, from a dead stop wouldn't you want the 1.67 to maximize your acceleration?
Bubba_Hemi
05-11-2009, 11:11 AM
The way I used it at the track... I put the shifter into 1st, then shifted to second then at the end of the track, shifted to 3rd (2nd prime).
Also I look at my slip, my best 1/8 was 9.889... so it was definitely your weather that slowed you down because I have 3.55's.
mopowar
05-11-2009, 11:14 AM
Doesn't the 1.5:1 accelerate slower then the 1.67:1? I can see how it would be useful on a downshift because you'd be right in the powerband in 2nd while the 1.67 would most likely cause the computer to just put you in third instead of winding the truck out in 2nd for a brief instant. But that's only for downshifting for accelerating on the highway, from a dead stop wouldn't you want the 1.67 to maximize your acceleration?
He's talking about using both 2nd and 2nd prime when you make a pass. I've been playing around with it. 2nd prime doesn't last very long at all.
Lead Head
05-11-2009, 02:54 PM
Yes, 2nd is 1.67:1, while 2nd prime is 1.5:1, the difference is quite small
biggestdiesel
05-11-2009, 07:02 PM
Next time I'll try different settings and see if anything improves ET... Thanks for everyone's input!
Ed Mullen
05-14-2009, 11:49 AM
Right - 2nd prime is only good for another 6-7 MPH over 2nd. In my truck (with short wheels), 2nd maxes out at 71 MPH and 2nd prime is 77 MPH.
At least in my 3rd gen truck, 2nd prime is never available as an option when accelerating from a dead stop at full throttle - it always shifts from 2nd (1.67:1) to 3rd (which is 1.00:1).
I have heard horror stories of some Ram owners whose trucks shift out of 2nd and into 3rd, and then downshift to 2nd prime, and then upshift to 3rd again, but thankfully that never happens to my truck.
A 10 flat in the 1/8 is pretty slow, actually - you're on the way to a 15.70-15.80 second pass. A night with good air (50s and dry with high pressure) and some weight reduction (lose the gas, the GF purse and your spare/tailgate) and lighter/shorter wheels/tires should have you seeing 9.50s @ 73 in the 1/8.
biggestdiesel
05-14-2009, 08:44 PM
Respectable for a truck but yes, could be faster! The conversion I used had the 1/4 at 15.60. (http://www.eldemoniorojo.com/calculator.htm) and that's where I've seen the stock trucks running according to mags/web. I am confident that with good weather and less weight I could be at least 9.75. A few mods and hopefully sub 9.50.
Ed Mullen
05-15-2009, 06:36 AM
Respectable for a truck but yes, could be faster! The conversion I used had the 1/4 at 15.60. (http://www.eldemoniorojo.com/calculator.htm) and that's where I've seen the stock trucks running according to mags/web. I am confident that with good weather and less weight I could be at least 9.75. A few mods and hopefully sub 9.50.
10.07 in bad air and you're closer to 15.7x - the Rams fall flat in 3rd and you're probably at the 2-3 shift at ~1100 feet. That truck really should be running closer to 15.2x - did you calculate the DA corrected time?
nickb304
05-15-2009, 08:46 AM
2nd prime uses one of the overdrive clutches which is why it makes a smoth shift from 4th to 2ndp for a quick pass on the highway. the problem is the overdive clutches are not as strong as the lower ratios and thats how the 3rd gen guys burn up their transmissions. I would not want to be doing any any wide open shifts into 2nd prime because its just like doing a wide open shift into overdrive.
dodgeramit99
05-15-2009, 11:05 PM
Took my truck to the track tonight and I ran a 10.16@70.64mph. It is completely stock with the crewcab. No mods what so ever. I have a 3.21 gear though which I hate. Cant wait to change the gears to 3.90 or 4.10.
biggestdiesel
05-16-2009, 11:16 AM
I didn't run the DA Corrected. I know there is value in doing so but I just take my times as they are.....like em or not! :)
Ed Mullen
05-16-2009, 05:28 PM
I didn't run the DA Corrected. I know there is value in doing so but I just take my times as they are.....like em or not! :)
I keep a log of both. It's the only way to keep my sanity when the truck runs a 14.90 one night in good air (i.e., the actual and DA corrected are almost identical), and then the next trip back runs a 15.15 in bad air and that's even with 100 pounds less weight on board. Turns out the DA corrected time on that particular run was about 14.82. So then it all made sense.
Hell, the other night I ran against a '90 5.0 Stang and led him even out to the 1000' mark and he nipped me by a tenth at the traps. He normally runs 14.7x and we both ran 15.1x in really bad air.
So DA corrected time can easily explain what appears to be an abnormally slow time, and can also allow you to compare against magazine times (they usually run at the track, just like we do). All the major magazines post DA corrected times, and the 2009 Crew Cab 4x4 with 3.92 and 20" wheels should be running somewhere around 15.20 @ 88 (corrected) and that puts them at 9.7x in the 1/8, and I'd bet $$ that's where your corrected time would be.
biggestdiesel
05-16-2009, 08:30 PM
Ed, I hope that's what it is! I like to see it with my own eyes so hopefully I'll have some favorable weather before we get into the Texas Summer! I have to think some more miles will pick up a tenth or two...
