Need "crawler help" for a drag racing 4x4!

[MAXLLY]

Gents!

My name is James, I built a 4x4 Diesel drag truck and i need help with the CV's/lockers. I am not a crawler but the stuff i have problems with is the stuff you guy's know about, so i figured i needed to talk to the Guy's who have the experience. There is only 1 other lowered GMC Diesel 4x4 drag truck on the planet (IIRC), it's in Australia, he recently gave up on 4x4. I don't have many to talk with!

Here's the issue, I have a front locker and stock rear AAM 11.50. I have lowered the truck in the front. The axles are just past level, usually they are pointed down a bit but when i lowered the truck the angle was "inverted", they point up slightly. I broke two sets, who makes a stronger front axle for this thing? Is it a bad angle? How can i stop the angle from entering the "bad zone". It happens on the street when the front wheels travel through the range entering and exiting parking lots

Sorry for the opened ended questions but this is not my area of expertise, please ask me the questions you need to know to help.. Please help

 

[mbryson]

Gents!

My name is James, I built a 4x4 Diesel drag truck and i need help with the CV's/lockers. I am not a crawler but the stuff i have problems with is the stuff you guy's know about, so i figured i needed to talk to the Guy's who have the experience. There is only 1 other lowered GMC Diesel 4x4 drag truck on the planet (IIRC), it's in Australia, he recently gave up on 4x4. I don't have many to talk with!

Here's the issue, I have a front locker and stock rear AAM 11.50. I have lowered the truck in the front. The axles are just past level, usually they are pointed down a bit but when i lowered the truck the angle was "inverted", they point up slightly. I broke two sets, who makes a stronger front axle for this thing? Is it a bad angle? How can i stop the angle from entering the "bad zone". It happens on the street when the front wheels travel through the range entering and exiting parking lots

Sorry for the opened ended questions but this is not my area of expertise, please ask me the questions you need to know to help.. Please help

There's a reason we swap in solid axles. You've found it. The IFS stuff is EXPENSIVE and has proven to be a little more on the fragile side than it's worth.

There was an article in Petersens a while back that might help you? I'm not sure if the parts would crossover to your truck platform, though?
http://www.4wheeloffroad.com/projec...fs_silverado_truck_wheeling/build_photos.html
(that's the project, but I can't find the latest article)
Executive Summary: They bought some $2000 CV shafts but broke the IFS centersection in half and decided to call it a build and cut their losses.

I'd bet you could check out the desert trucks with their bling Porsche CVs and such and they might have a better option for you?

 

[MAXLLY]

There's a reason we swap in solid axles. You've found it. The IFS stuff is EXPENSIVE and has proven to be a little more on the fragile side than it's worth.

There was an article in Petersens a while back that might help you? I'm not sure if the parts would crossover to your truck platform, though?
http://www.4wheeloffroad.com/projec...fs_silverado_truck_wheeling/build_photos.html
(that's the project, but I can't find the latest article)
They bought some $2000 CV shafts but broke the IFS centersection in half and decided to call it a build and cut their losses.

I'd bet you could check out the desert trucks with their bling Porsche CVs and such and they might have a better option for you?

Bryson, thanks for the response.

Bummer, they fixed the CV issue and broke the next part down the link.... discouraging and costly.

Why are they breaking? I don't swing a big wheel "arc" like you guy's do, they aren't breaking under hard acceleration at the drag strip, I am not slipping and hooking suddenly. Is it a bad angle? I have heard a CV doesn't like to be straight? Is this correct? Could i attach a limiting strap keeping the CV at the inverted angle? Not allowing it to cross the level point/line?

Can anybody suggest where to find a manufacturer of the solid axle and reccomend any other features i should consider in a replacement purchase?

Thank in advance Guy's.

 

[pELYgroso]

do you have any pics of this truck? sounds pretty cool.

 

[notajeep]

On the solid axle front, I think that Currie is in your neak of the woods and would be willing to help you.
For the CV stuff.. good luck. Have you thought about using hubs, so that you can totally disconnect the front axle when you don't need 4wd?
Dan

 

[Jeremy]

how low is the front end? do you have room to put a solid axle and still keep it as low as you want it?

 

[mbryson]

Bryson, thanks for the response.

Bummer, they fixed the CV issue and broke the next part down the link.... discouraging and costly.

Why are they breaking? I don't swing a big wheel "arc" like you guy's do, they aren't breaking under hard acceleration at the drag strip, I am not slipping and hooking suddenly. Is it a bad angle? I have heard a CV doesn't like to be straight? Is this correct? Could i attach a limiting strap keeping the CV at the inverted angle? Not allowing it to cross the level point/line?

Can anybody suggest where to find a manufacturer of the solid axle and reccomend any other features i should consider in a replacement purchase?

Thank in advance Guy's.

I really don't know the real answer to why the IFS isn't holding up. Very few of us even have an IFS rig that gets 'used'. I was a big fan of it until I got into this hobby. Now all the rigs in my house have solid axles.

I'm not sure why the CV is breaking (is that what's breaking?--you indicated your 'front axle' and that could be a general term or specific ). The only knowledge I have about CV is related to drivelines and they're fine if they're within their operating range from what I know. There's some smart guys on the board. Post up the pics of the carnage and I'm sure you'll get some opinions. You are dropping some SERIOUS torque to the drivetrain having a modded diesel. I'm not sure that was in the engineer's specs as it was designed at GM (I do get a kick out of my Powerjoke with chip/exhaust/intake, but I'm sure I'm not 'using' it like you are. Mine hauls stuff. Yours sounds like it just hauls)

A limiting strap could solve some problems but... I have no idea? You've got a LOT of things going a lot of different ways upon accelleration with a lot of moving parts. IFS totally defeats the KISS method. I'm sure there's some solution, but it might cost a lot of time and money to come up with it?

OffRoadDesign and Dynatrac should be able to help you out with an axle swap (unless you want to fab your own with junkyard parts).

 

[MAXLLY]

I don't have much at the office that is current and meaningful.

But I'll share what i have, this is street trim and some parts pict's. All very old but you can see it's a purdy serious street/strip effort. I did the guages in the hood for a little bling-bling

I spun the charger sideways (they are usually WAY smaller and sit in the valley) for several different reasons, I think i may be the first to do it? Regardless, it's in the shop again for more work and i wanna get the CV thing worked out. Sorry for the old pictures.

Don't ask why i chose a 7000lb 4x4 for a drag truck... I ask myself the same question all the time.... WHY

 

[MAXLLY]

On the solid axle front, I think that Currie is in your neak of the woods and would be willing to help you.
For the CV stuff.. good luck. Have you thought about using hubs, so that you can totally disconnect the front axle when you don't need 4wd?
Dan

Solid axle? Hmmm stronger and i prolly save some weight?

If i used hubs i would have to get out of the truck to lock it on the street, this thing is a monster on the streets i need 4 wheel to keep it off the curbs and the K-rails. In other words, I have traction issues.

 

[Jeremy]

this looks pretty strong. but i dont know how it would help in your application.

 

[Jinx]

Sounds like an awesome project.

as far as your problems go, we probably sounds like an echo as we all say "solid front axle"

Everyone here has probably been around or owned a ifs rig that has had problem. That is why the majority of people who crawl change it out.

From the description of where you are breaking things (non drag strip), it sounds like you have a "bad" or improperly installed lowering kit. Is it a do it yourself or some brand?

 

[MAXLLY]

how low is the front end? do you have room to put a solid axle and still keep it as low as you want it?

The pictures i posted are without the 850 lb motor in it. It sits a measly 3-4 inches lower than stock in the front, loaded and rolling.

I don't know about solid axles and if it would fit, I can say the oil pans are somewhat wrapped around the crossmember attaching the A arms.

 

[gripguru]

well here is the progression in CV shafts - basically building a short enough driveshaft instead of a CV:

http://highangledriveline.com/sandrails.html

The problem IMHO is that you have lift from the torque pushing the front of the rig away from the ground. I have in no way near the amount of torque that you have, but can feel the front lift with my measly 660ft/lbs tq. That travel, regardless of your stance does set you up for all kinds of oddities.

So your IFS is not designed to have torque applied as it makes its travel curve whether it is raised/lowered/widened/narrowed etc. I see that you have done everything right building a drag 4 link for the rear...time to focus on the front. A solid axle would be a simple fix, so would putting on slicks and deleting the 4x4 ( a more reasonable way to lose weight and go faster ). I have done a TON of research on http://thedieselplace.com and have since stopped visiting there because it was going to escalate to what you have there. Nice lilly.

 

[MAXLLY]

Sounds like an awesome project.

as far as your problems go, we probably sounds like an echo as we all say "solid front axle"

Everyone here has probably been around or owned a ifs rig that has had problem. That is why the majority of people who crawl change it out.

From the description of where you are breaking things (non drag strip), it sounds like you have a "bad" or improperly installed lowering kit. Is it a do it yourself or some brand?

I used Mcaughys 2" spindles in an effort to retain some semblance of stock geometry. I need to go find a solid axle truck and take a peak at it, see if i can fab it in. Do they make conversion kits or is that a build it yer self deal?

 

[Greg]

well here is the progression in CV shafts - basically building a short enough driveshaft instead of a CV:

http://highangledriveline.com/sandrails.html

x2, you really need to call Jesse at High Angle Driveline. He has been building bullet-proof CV's for Baja trucks & buggies. At the least, he could give you some great ideas as to part costs, limitations, etc.

IMO getting a solid axle under that truck and keeping it low will be next to impossible. I won't say impossible, because with enough money anything is possible.

 

[MAXLLY]

this looks pretty strong. but i dont know how it would help in your application.

BEEF! What is that in between the axles/CV's? It looks like a diff only different? Those look hand made, may i ask who made 'em?

 

[MAXLLY]

x2, you really need to call Jesse at High Angle Driveline. He has been building bullet-proof CV's for Baja trucks & buggies. At the least, he could give you some great ideas as to part costs, limitations, etc.

IMO getting a solid axle under that truck and keeping it low will be next to impossible. I won't say impossible, because with enough money anything is possible.

Thanks to all of you, I am grateful. I will pick up the tele and call Jesse, I went to his website and checked it out. He builds the stuff i break. I think he can turn my half shaft/CV/ whatever you guru's call it into a shorty driveshaft with knuckles at both ends I have to assume i have a kink somewhere and have exceeded the angles allowed with one knuckle?

 

[78mitsu]

BEEF! What is that in between the axles/CV's? It looks like a diff only different? Those look hand made, may i ask who made 'em?

I'm pretty sure that's Walker Evans rig.

 

[BlackDog]

Where it is already lowered, and doesn't articulate like a crawler, couldn't he steal rear susp lowrider tech, and run a thin stiff spring pack, and c-notch the fram, that may cause some weird stuff with the oil pan, but that is bypassable, ya would think, remote reservoir's come to mind, never paid enuff attention to the technology to start a decent discussion myself, but that should be enuff for a smarter guy than me to jump on.

I know the Spring pack on a Dodge half ton is almost level.. that could be amplified to support the diesel, or even inverted like on a ttb F250, those already support a 6.9/7.3 IDI, then c notch the frame, mount the axle right level with where the bottom of the fram used to be, springs extending up towards the wheelwell, in the casee of the TTB springs. they moutn to the outside of the frame rails, I believe, I dunno, my truck is broke 200 miles from me, or I 'd go look, then you would have the c-notch for travel......

 

[waynehartwig]

BEEF! What is that in between the axles/CV's? It looks like a diff only different? Those look hand made, may i ask who made 'em?

Looks like a Dynatrac 60 center section? The shop looks like the Campbells' shop? With Walker Evans rig in there being worked on. Maybe they can be of better service to you?
http://www.campbellent.com/
480-782-JEEP