RSK
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3.55 gears. Just had the fluid changed 3-4000 miles ago looked good no metal shavings or clutch material
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3.55 gears. Just had the fluid changed 3-4000 miles ago looked good no metal shavings or clutch material
johnp115
Active member
Even though my trans is completely fine starting to think that's what's holding my time back. It just won't shift hard/fast/efficient enough.
Probably the same situation for both of us man.
MrMike2010
New member
With a 1.70 60ft I'm pretty sure your not going to get much better without a good set of bars. I'm impressed you were able to launch at 20lbs without tremendous wheel hop.
I would do some monitoring and see if anything is out of the ordinary. Whether it be rail pressure or something trans related bc your mph is a little low. It could just be maybe you went on a real hot and humid day? Idk Without the 71 I was at 103 with it I'm around 105 maybe a little more. I just can't break 1.8s without lighting up my bald stock goodyears.
I would do some monitoring and see if anything is out of the ordinary. Whether it be rail pressure or something trans related bc your mph is a little low. It could just be maybe you went on a real hot and humid day? Idk Without the 71 I was at 103 with it I'm around 105 maybe a little more. I just can't break 1.8s without lighting up my bald stock goodyears.
RSK
Active member
I was gonna data log a few runs with my sct, see what they say. not sure how to read all of it but i'm sure with a little help i can figure it out. I had my nitto 420's air down to 38psi normally around 50 in 4 corners and the front of the truck is slammed riding on bump stops with 4400lb coils so i would guess that might be helping me be able to launch so hard. plus my front tires only have 5-6k rears are down to half tread from burnouts in the last 3 months but it doesn't matter they are gonna be dismounted at the end of the month and put in my buddies basement until next summer. going up with the truck...
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with 420s you should run 35 front 30 rear to start. rear should always be about 5psi less. keep upping the rpm/boost until it hops. if you're in the 1.60-1.69 range you're good. if not drop 5psi front and rear and try again. I HIGHLY doubt you will without traction bars. I cut a 1.66 with a tune only truck and ouo's . think it was 12.75 @ 104 with hanging shifts. had a better pass where the trans didn't hang a shift but jumped on the brakes to win a bracket race.
I think what a lot of you guys are missing, is that an actual race isn't the place to learn a whole lot. go to a test and tune night where you can make a good amount of passes , forget about reaction time, and find where your truck works. and honestly, if you're somewhat serious about getting fast , don't waste your time until you have taken ALL the steps to get traction. it sucks saying "maybe if I had traction bars it would hook better" .. start by knowing " if it had traction bars it WILL hook better" .
johnp115
Active member
I got down to 1.73 with 32front /28rear psi leaving at almost 2000 with no hop. Traction bars and 12.2wide terra graps
Think that's just cause I have a stock trans with some miles on it? I mean it really wouldn't do any better than that, though it was hot and decently humid.
drunk on diesel
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church
RSK
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I thought 1.6x 60's were being pulled off in crew cabs stock suspension, no traction bars or ALA's. I didn't realize you had traction bars. I went on a test and tune last saturday. so i wasn't focusing on racing, although jumping out on a 6000lb srt 8 jeep with "600"awhp and pulling on him for a part of the track was pretty cool to see a few times. I plan to go back this saturday hopefully its dead with it being 4th of july weekend. I don't plan to get serious getting fast, but through the different stages I do want make a few passes and see what I can run tune only which i'm in the process of, then with air upgrades only, then with dual fuelers and 60% nozzles then finally with some spray at the end of everything with the goal of breaking into 10.9x's after that it's done...probably detune the truck so it's around 700 in hot street. traction bars are in the plans, but I need to make up my damn mind on what height the truck will be first. probably throw a set of one up offroad ala's on before traction bars even though the traction bars probably help more.
RSK
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I did some praying that day....I was in the tech line and the girl was like how fast do you think this is going to run, I told her I don't know, she asked if it was gas or diesel? I said diesel she looked at the wheels/tires and said 16/maybe 15 seconds in the quarter mile. then she saw I had shorts on and not pants like are required and it was almost 90* out by 8:30am anyways I had to go find a pair of pants, she said sweat pants would work, so she told us about a dollar store 20 mins away which was the closest place. so i got there and i'm looking for some pants, anything at this point, and I see no mens pants at all...all they had were womens yoga pants which I was praying to god I was not gonna have to wear, but at least due to my aerodynamic and race ready figure I would have fit into...then my buddy is digging through a rack of shirts and find a pair black scrubs for men, so I prayed again bought them and left... I think my prayers were answered.....:tree: so this weekend I'm going back and wearing those black scrubs I bought, and with the go pro mounted on my helmet pointed at the gauge cluster, I'm gonna record my runs to see exactly where I'm leaving and make adjustments as needed. It's going 1.6x 60's and breaking into the 12's or i'll break it trying. i may do an fx4 package delete...those skid plates and spare tire are heavy!!!!
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wishful thinking, but nope! I think I cut a 1.75 on stock tires with no traction bars. but my 1.66 was with traction bars only and was constantly 1.66-1.69. my srt8 jeep cut low 1.70's and went 12.5 on a canned tune , so that dude was most likely leaving soft. and they only weigh 5200 full weight. that being said your trans could be slipping, converter could be tired , I didn't make too many passes with a stock trans so I have very little comparison.
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RSK
Active member
yah this jeep was leaving with traction control on...he didn't want to break his stock rear axle which i guess are the weak point in those, he had some fancy supercharger kit on it....he was running 12.20's-12.50's and all he wanted was high 11's....so my consistent 1.70's are about all this thing has in it without weight reduction which may or may not take place before this weekend. factory wheels and tires are actually heavier then 22x10.5 bmf's with the 420's on them. I did a before and after, and the cowl hood may be a little bit lighter then factory as well, not much that's for sure. It was only a 120lb difference. most of that is from weighing it with 3/4 tank of fuel and only having 1/4 tank when I went to the strip. does having a wider tire contact patch with the 12" wide tires hurt me or does the amount of traction gained from it out weigh the added resistance of the wider tire. I'd guess it only 2" wider then stock maybe 3...
RSK
Active member
I know why i didn't crack 12's.....it's because i was 603 feet above sea level.... It was also quite hot and humid out. Lol
bigaF250
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I was on stock transmission and 325/60r20s. That truck was also an fx4. Tune intake and exhaust at 5000 ft. I would look at your convertor
RSK
Active member
I was joking about the 603ft elevation. pretty sure the tires break loose in 2wd at around 1800-2000rpm i think its pretty tight. i'll check it today and report back.
RSK
Active member
Brake boosting in 2wd tires break loose at 2000-2200rpm depending on how hard i'm on the brakes and i can build 25psi in 2wd. Pretty sure that's right on with a stock stall converter, but not positive
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sootie
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i noticed my stock tc slipping more in the higher gears. it just wouldnt hold the power the same way. it seemed like it would rev up and kinda stay there while the truck caught up. with the RCD converter, the speed increases incrementally with the rpm.
curious what your trans temps are before and after a run?
curious what your trans temps are before and after a run?
RSK
Active member
I had a slipping converter in all 3 of my cummins i'm familiar with what a slipping converter. Mine hits 1st throught 5th perfect, trans temp gauge stays below the halfway point just like it does driving around. Not sure about the exact temps i'll datalog my runs this saturday and i plan to mount my go pro to my helmet pointing at the dash of the truck so i can see exactly where i am leaving. And make improvements
dsberman94
Well-known member
Just because you know what a cummins slipping felt like doesn't mean this feels the same way. It could be slipping less and you don't notice it. An upgraded converter isn't a bad thing and it's not all that crazy. Id do a converter before I even got tunes since that's what seems to go and destroy the rest if the trans with the shrapnel, atleast in some cases.
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lol dude. just stop .
I assume your truck was slow due to heat and humidity. my green truck was stuck in the 12.90's when it was over 80-85* out. all 60ft's were in the low 1.70's on a crappy track. heat and humidity make things slower. but drop tire pressure next time, if not you have no excuses.
madman1234509
New member
I agree. You'll be surprised if/when you go in the fall and be a bit quicker. Heat soak from sitting and also idling will kill times.
