Ram50

Hey, I may have missed this in all your pages, but how are you compensating for the gearing tire size differences in the front and rear? Seems like you keep changing them.
 
Seems like you keep changing them.
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lol, no seems about it. We've changed gears a total of four times since we started running this thing and were not even close.

We were getting there once we got the converter to start biting a bit harder, but, the last pass we made was sort of an unexpected glimmer of what she might do once a lock up converter is actually used. For these 300' and shorter runs, we need to gear down (numerically up) a bunch. I have three separate third members for each application (street, 1/8 mile, mud). We also figured out at Antrim that we could be running a bit lower (numerically higher) gear to get it to top out in the 1/8th.

We like to do wheelies and so far all it does is jerk 'em up. Either the converter is giving way and unloading the chassis or we are overcoming the engine power with to much gear.

Russ (RPM Motorsports) hooked us up with Pete at Hughes Transmissions. We are working a deal as we speak. Once I get a converter in the thing that repeats and doesn't melt itself, we'll do a better job of finding the correct final.

As far as the front gear goes, the general rule is 20% overdriven on the front. This insures the front keeps you straight and the larger rear tire growth is compensated for.

It's a simple direct proportion calculation using tire rollout. The 9" makes this all easy with so many gear choices. You can't always hit the magic 20% so you get as close as you can. The Toyota front also has numerous gear choices although we've only changed those once. We went from a 3.90 to a 4.56. I've been adding tire height either through air pressure or buying more tires. We were just a bit underdriven (less than 1%) at the Lee Hill race as we had only borrowed the 44 cuts for a test. We liked 'em and will soon have a set of our own and get the gearing corrected.

Front roll out/gear ratio*.2=rear roll out/gear ratio
 
Bodacious said:
lol, no seems about it. We've changed gears a total of four times since we started running this thing and were not even close.

We were getting there once we got the converter to start biting a bit harder, but, the last pass we made was sort of an unexpected glimmer of what she might do once a lock up converter is actually used. For these 300' and shorter runs, we need to gear down (numerically up) a bunch. I have three separate third members for each application (street, 1/8 mile, mud). We also figured out at Antrim that we could be running a bit lower (numerically higher) gear to get it to top out in the 1/8th.

We like to do wheelies and so far all it does is jerk 'em up. Either the converter is giving way and unloading the chassis or we are overcoming the engine power with to much gear.

Russ (RPM Motorsports) hooked us up with Pete at Hughes Transmissions. We are working a deal as we speak. Once I get a converter in the thing that repeats and doesn't melt itself, we'll do a better job of finding the correct final.

As far as the front gear goes, the general rule is 20% overdriven on the front. This insures the front keeps you straight and the larger rear tire growth is compensated for.

It's a simple direct proportion calculation using tire rollout. The 9" makes this all easy with so many gear choices. You can't always hit the magic 20% so you get as close as you can. The Toyota front also has numerous gear choices although we've only changed those once. We went from a 3.90 to a 4.56. I've been adding tire height either through air pressure or buying more tires. We were just a bit underdriven (less than 1%) at the Lee Hill race as we had only borrowed the 44 cuts for a test. We liked 'em and will soon have a set of our own and get the gearing corrected.

Front roll out/gear ratio*.2=rear roll out/gear ratio
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As long as you're doing math, I support it. I'll leave the details up to you :Cheer:
 
Front roll out/gear ratio*.2=rear roll out/gear ratio
Click to expand...

I messed this up. It is actually

Front roll out *1.2/gear ratio=rear roll out/gear ratio

Sorry for any confusion.

I put a hold on the xp5 powerglide. I'd say the Pete fella with Hughes is getting a little aggravated with me. I can't seem to make up my mind. We tore the FTI unit down and found the input shaft twisted pretty bad. I tried to post up some pics but photobucket was down for maintenance.

I also pulled out an executive decision and forced my hand on the BMW power plant. Fear not fellow cummins lovers, Craig has decided to use our existing engine and build a dedicated mud racing vehicle with it. Now we'll see which combo is the fastest. Craig should be able to lose at least 200lbs over what Bodacious weighs if not more. I ordered some hanging scales so we can determine just how much weight will be cut by installing the BMW engine.

Oh boy, the winter is getting busy!!!!
 
Ok, looks like photobucket is up and running.

This is the part of the input shaft that splines in to the converter.

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This is the part of the input shaft that splines in to the reverse planetaries.

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I think this happened while spooling up on the trans brake. Craig liked to get to 60psi before launching so if you do some hypothetical figuring at 60psi she will be approaching 600HP and roughly 1200lb ft of torque twisting on this shaft. This is why we wanted a higher stall. The problem was, when the stall was high enough, the converter was not tight enough with the limited RPM of 5000 to quit slipping.
 
In my experience with twisted input shafts on Dodge transmissions, twisting usually happens from shock loading where rotational momentum is added to the torque output of the motor itself. For example, a wheel hop at the drag strip, a locked gear shift with a heavy truck racing in 4x4, or a bind-up in the transmission on a gear shift.

Most billet input shafts Dodge A618 (47rh, 47re, 48re) are rated at or above 2,200 ft-lbs of torque, yet many have been broken with trucks only making 1000-1500 ft-lbs.
 
So what's this BMW engine you're switching to? Other people are hotrodding them in other applications? Diesel or gas???
 
So what's this BMW engine you're switching to?
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Well, I don't know a whole lot about it. The earliest I've found is an '09 and it is still used today. It is a 3.0L, 24 valve, all aluminum L6. It has the common rail injection.

I've been on a few websites where folks are deleting and ramping up the fuel. As far as I know, no hard hot rod parts are available such as rods, cams, etc.. One fella was in the high 10's in the 1/4 at over 4000lbs with just tuning.

We drove a 335d a couple weeks ago and I was flat amazed at the power this thing had. I'm currently bidding on a totaled '09 and hopefully can pick it up cheap enough to allow for an additional totaled purchase. This way, we can personally find its limits and go from there.

Other than doing the head gasket and CP3 swap on the wife's '09 dodge 6.7, I have no real experience with the common rail stuff. Therefore, I will have to rely heavily upon the CompD experts to get this thing on its ear.

Right off the bat (hypothetical reasoning at this point) I am thinking the best alternative to extreme modification is to convert the engine to run with '03-'07.5 cummins ECM. This way, at least the programming is readily available.

I want to get it here and apart before thinking too much on it at this point.

Hey Big Blue24, yea I guess the twist could have happened on our last run up at Lee Hill. I'm not sure if you have watched the video, but, just after launch you can here the converter lock and the truck takes a hard bounce.
 
You were at maybe half power with your Cummins, it seems that it's a bummer that you'd throw in the towel now. The truck has so much potential with a p-pump 12v. With the BMW you'll be blazing new ground and it'll be cool, but you'll never proceed forward, performance wise. You're a cool dude and it's your truck, those are just my $.02
 
Don't worry guys. I'm putting the Cummins in a little jeep. It'll still be in the family.
 
How much weight savings are you projecting with the BMW motor? I'll bet you'll struggle to exceed 600 HP for a long time and at great expense blazing that new trail. It will be fun to observe and you might end up being one of the most knowledgeable in the country on that specific motor, but at the end of the day, sticking with the "small block chevy" Cummins 6bt will be cheaper, faster, and more reliable. You're already unique in the fact that you mud race, drag race, etc. with a D50. Give it one more season with a proven motor setup from one of the best in the business and you'll be putting a hurting on many blown alcohol big blocks. Step back into a Dodge 47rh or 47/48re setup with a transbrake and you'll have a bullet proof tranny in that light weight setup, I mean 0% failure.
 
why not a nira or something along those lines?
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I haven't the slightest clue what you're talking about unless you mean Northern Illinois Rocketry Association????

you'll never proceed forward, performance wise.
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You may be correct JQ. A fella has to look at the whole package. Those Thailand boys sure know how to get it done with 3L's. We were at the next level of building the 12v which unless I forked out $18,000+ for the aluminum block, I would no longer be able to street drive the package. Therefore, since Craig likes the mud, we'll go the next step with the 12 valve and put it in a purpose built mud/dirt drag vehicle.

At least I'll have another diesel to run against. lol I'm hoping to see a few more of these types of vehicles built with diesel power. The diesel dirt drag deal is catching on pretty good in OH & IN. You can have a big diesel event and not have to worry about having a drag strip near by.

you'll be blazing new ground
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Not really...though I have a feeling I be blazing the wallet!! lol
 
Big Blue24, I wont quote any of what you said cause I can simply say I agree with ya.

We raced against some really lite and powerful rides. Craig is going to do his best to keep the new project somewhere around 2800lbs race weight. More weight is going to be added to the 12v as well. With his purpose built ride, we can hopefully get the mighty 50/50 weight distribution.

We won't know the weight savings of the BMW until I get one here and get it on the scales.

I met the Wolf racing team today in Morgantown, WV and bought this to put behind the BMW.

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100_7422_zps5359c972.jpg
 
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nira is a standalone common rail ecm. completely controllable, and full standalone. no factory hacking...
 
lol, I thought the poster was poking at me. lol amazing what comes up when you just google 'nira' lol. I'm such a dip ****!!!! lol

Ok, I'm done laughing at myself. Thanks crackerman. It appears I have several options with stand alone ecm's. The nira may work with all the BMW sensors.
 
Craig and I rolled out to Knoxville, TN yesterday and picked up a B&J 3-speed tranny. It came with a crower triple 10". I'll need to have a flywheel made so we can bolt this combo to the cummins. I'm actually contemplating keeping this 10" for the BMW and having an 11" built to go behind the cummins. If I knew for sure it would hold, I'd rather keep the 10" for the cummins and have an 8" built for the BMW.

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