RLJ10X
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4.56, better still.
Forced Induction
- Thread starter 15RamEXP
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charonblk07
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If that was your question then it wasn't worded very well, my answer was for two trucks with comparable mods and the only difference being the gearing. A supercharged 3.21 will be faster and quicker than a N/A engine with 3.92s, it also depends on what kind of supercharger you go with. There are many variables you need to consider and gearing is only part of the equation. Power to weight ratio, tire diameter vs gearing (final drive ratio), centrifugal vs positive displacement supercharger, etc. If you think just having 3.92s will make you quicker than a supercharged 3.21 then you have a lot of learning to do and I'm happy to help if you're serious about going faster.
My buddy with a N/A bolt-on 5.7L w/ 8-speed, 3.55s, w/ a 28" tire is holding the fastest Ram record at our drag strip on a small 75 shot; he's running a 12.6 in 3500DA. The one time I took my D1SC powered quad cab 4x4 with 3.92s and a 5-speed to the strip I ran a 13.2, admittedly not on a great tune and I couldn't hook for anything, but my truck could do 273km/hr on the way home. As you can see, there are a lot of differences in power and gearing and he's still quicker.
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charonblk07
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Not with an 8-speed, or even the 5/6 speed, you run out of gearing real quick and are shifting continuously down the track, especially if you're running shorter tires like drag radials. It's the whole combo you need to pay attention to.
Everyone told me 4.56s was a bad idea when I was putting them in my truck, now I'm dropping the 4L80 into it and they all understand why I went 4.56 now. 3.00 first gear in the 545 to the 2.48 first gear in the 4L80: 11.76 fdr compared to 11.3fdr with the 5 speed/3.92 vs the 4L80/4.56 combo.
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Wild one
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12.55 at 4200 ft Kurtis,lol. First gear in your 4l80E should be 2.48 not 2.68 if I remember right from my old GM days.
charonblk07
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you're right, I keep saying 2.68, not sure why that ratio sticks in my head.
RLJ10X
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My reply was in reguards to the OP's question concerning 35s. Smaller dia tires would in effect, lower the final drive.
Yah that's my question, sorry english is my 15th language.I was talking about same truck just different ratio 3.21 and 3.92. Sadly I have 3.21. I don't go to race track but I want a quick truck tha I can reliably use daily. I'm planning to buy procharger but not sure yet if it's safe for my stock transmission. I've read mixed opinions. Thanks for the reply.
Wild one
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Wade Mosley is working on a bolt on turbo set-ups for the later 4th Gen trucks,might be something you'd want to look into to.You can find him on a few facebook pages,not sure if he's on here anymore.Your 8 speed will be okay behind most forced induction set-ups.I've been putting nitrous threw mine and drag racing it every week-end for the last 3 years and the trannies the last thing I worry about.Mine puts down 435 hp and 455 lb-ft at the tires on a small 75 shot. The weak link will be your stock rear-end and it's clutch posi unit,it doesn't like horsepower. The best thing I did was put a tru trac posi in mine,so far it's been holding up good,lol.
BEAST19
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How much did it run to put Ur tru trac posi in? Parts and labor and where did u get it
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charonblk07
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If you have the 8 speed then any of the superchargers are safe to use as the 8-speed has proven to be a very strong transmission that can safely handle between 550-600 horsepower. Don't be scared by only having a 3.21, the first gear in the 8 speed is 4.71 which still gives you a 15.11 final drive ratio which is still higher than the 5/6 speed with a 4.56 rear end (13.68 ratio) and people have been preaching the 6 speed/4.56 combo for years.
Wild one
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I'm in Canada,so the costs aren't really applicable to somebody south of the border,lol. The tru trac came through Matt at Moes,and I have a buddy who's a Chryco tech so labour didn't cost me anything,and he got the axle/gears and rebuild kits at dealer cost for me.But plan on probably somewhere around 1500 bucks or more to put a tru trac in the later ZF diff.You have to swap to the earlier 9.25 gears to put a tru trac in,and you need one pass side axle to do the swap. I got tired of blowing up the stock clutch limited slip,and was getting worried the dealer wouldn't warrenty another one for me,lol
