Frame mods & Custom A-arms

[Dusty B]

How much can you mod/change the frame? Was thinking of building an old C10 Blazer. Is it Class 3 legal to make a custom front frame and long travel A-arms?

[Blanco]

Even though Its not finished, here are the current SCORE rule's right from the book.
http://www.class3racing.com/showthread.php?t=1

[gunit]

How much can you mod/change the frame? Was thinking of building an old C10 Blazer. Is it Class 3 legal to make a custom front frame and long travel A-arms?

Frame cannot be altered except for an angle may be cut from the bottom of the frame 8" back to allow for additional approach clearance , the top of the frame rail must remain unaltered. You may add material or strengthen where required but you cannot remove material or alter the shape of the stock frame.

No A Arms on a early Straight axle Blazer, you must maintain the stock concept.

[Blanco]

No A Arms on a early Straight axle Blazer, you must maintain the stock concept.

I assumed he was considering one of the smaller Blazers that came with an IFS "A" arm front end. http://www.thewebwheeler.com/forums/images/smilies/shrug.gif
http://www.americandreamcars.com/1985chevyblazers10020105.jpg

[gunit]

He actually said he was building an "old C 10 Blazer" A C 10 was a 2wd 1/2 ton pick up. But from that era, a Blazer would have been a K 5 and I assumed that is what he meant. They made some C5 blazers that were 2wd and were A arm, but of course that would not be C3 legal.

[Blanco]

He actually said he was building an "old C 10 Blazer" A C 10 was a 2wd 1/2 ton pick up. But from that ere a Blazer would have been a K 5 and I assumed that is what he meant. They made some C5 blazers that were 2wd and were A arm, but of course that would not be C3 legal.

Looking back I see that now. :o
I do at times speed read through these post & miss some details..

I generally assume most of the talk here is all Class 3 legal :confused:

[Dusty B]

I am reading my SCORE book, and I missed the fact that it must be 4x4 to be class 3. I was thinking short wheelbase sport utility.

I would like build something V8 powered, unique and competitive without building just another Bronco. I think the coil springs in the front give it a distinct advantage over building a K5 Blazer, Jeep Wagoneer etc. I am NOT a Ford guy, but I have to say the Bronco is probably one of the best starting platforms out there for minimal cost.

[BajaBronco13]

Is the Grand Cherokee's wheel base too long for Class 3? Some had V8s in them and coil sprung front and back.

Chris

[gunit]

Maybe a Land Rover Discovery

[Dusty B]

Currently, I run a Jeepspeed and would really like to get away from the unibody. So, Grand Cherokee would not be my first choice. Although I have to admit the thought of building a 98 limited with the 5.9 does sound pretty fast.

I currently own a 95 Discover I with the 3.9 V8. Although cheap to purchase used- I'm not impressed. It is guttless, expensive to maintain, and overengineered. I am going to sell it real soon.

I have an old Scrambler CJ8 tub and frame that I planned to make a crawler with, but it may just become a race car. I've also thought about building a retro Jeepster Commando. Last couple years of the Commando actually had a V8. How competive have the full leaf sprung vehicles been in the last couple years? I could run 1/4 elliptical in the back, but the front would probably have to remain a full leaf.

[Blanco]

I have an old Scrambler CJ8 tub and frame that I planned to make a crawler with, but it may just become a race car.

You mean like Mike Duncans?

[Dusty B]

I have not seen that car before, but that is the type of tub & frame I have. How does Duncan's CJ8 do?

[Blanco]

I have not seen that car before, but that is the type of tub & frame I have. How does Duncan's CJ8 do?

He's not raced it in years...:rolleyes:
I'm trying to talk him back into it but, he dot seem very interested.

He use to race it back in the days of La Rana.

[Broncodawg]

Small world, I went to a few La Rana races with Mike duncan and his CJ 8 back in the day. Used to work down the street from him in burbank.

[Blanco]

Small world, I went to a few La Rana races with Mike duncan and his CJ 8 back in the day. Used to work down the street from him in burbank.

So you know him & actually went with him?
Or you saw him at the race's & knew who he was?

[Broncodawg]

Statement was pretty clear, went with him, pitted his jeep and got a ride in it prerunning. Might have only done one race with him, but why the third degree questions? Just curious.:confused::rolleyes:

[Blanco]

Statement was pretty clear, went with him, pitted his jeep and got a ride in it prerunning. Might have only done one race with him, but why the third degree questions? Just curious.:confused::rolleyes:

http://www.thewebwheeler.com/forums/images/smilies/WTF.gif

Whoa Dude! why so defensive :confused:
I only asked one queston about how close to Mike you are?

[Broncodawg]

Your questions had a challenging tone to them, especially w/out any clarification as to where you were going with them.
I got the impression you thought I was trying to one up you knowing Mike, which is not the case. You've got a great thing going here and just trying to add to the conversation with my posts and it would be great to get Mike back into racing. Peace out, we've hijacked this thread long enough.

[Blanco]

we've hijacked this thread long enough.

Yeah your right. http://www.thewebwheeler.com/forums/images/smilies/3.gif

[dannyroark89]

hey everyone totally new to all of this but as stoked as they come to start racing, one thing i was reading... the frame or in my case the unibody cannot be altered from its original shape on the top? is that how i am interpruting all this? so would building any type of gusset to run to my frame (unibody) rails be illigeal in anyway to strengthen them? like i said sorry im new! but im glad i found this forum because ive been working on my rig for a while now and had no idea there were guidlines i had to abide by to actually race it. hope some of my other stuff is legit!

[gunit]

You can add material to the frame to strengthen, here is a copy of the rule:

CR48 CHASSIS & BODY

"Frame may be strengthened by adding material but must retain stock configuration, size and shape. Frame must retain stock length but may be notched 8" at front for ground clearance as long as the top frame rail is not modified."

[retroblazer]

I am reading my SCORE book, and I missed the fact that it must be 4x4 to be class 3. I was thinking short wheelbase sport utility.

I would like build something V8 powered, unique and competitive without building just another Bronco. I think the coil springs in the front give it a distinct advantage over building a K5 Blazer, Jeep Wagoneer etc. I am NOT a Ford guy, but I have to say the Bronco is probably one of the best starting platforms out there for minimal cost.

Welcome to the debate. This is exactly the reason why some of us have been pushing for a rules change. Allowing coil-overs for everyone would increase the number of potentially competitive vehicles.
You asked how competitive the the leaf spring trucks have been. There are only two that have actively competed recently. Myself and the Pikes. Pike's truck is brand new. I'd call it a modern version of mine, standard leafs up front and quarter elliptics in the back. I think it is a competitive truck, but we haven't seen it run at it potential yet.
We have been modestly competitive with our Blazer. Suspension has only been one component of the equation, but it is has had largest effect both in cost to maintain and breakage. In a spring under front end, it is not possible to reinforce the housing nearly as well as a coil set-up. The spring gets in the way of being able to tie the housing together. We have broken the housing and have been taken out of four races on this alone. We have concluded that we need to do a new front axle housing each season. We have broken leaf springs in another three or four including being taken out of a 1000 when the front left spring broke and took out the trans after the driveshaft was shoved into the t-case. Although we only have 11" of front wheel travel, it generates five inches of plunge on the front driveshaft. We have lost numerous front driveshafts. Most of the time we were lucky that it didn't take out the trans, but that happened at one of the Primm races while leading. We think that we have taken care of this problem by pushing the tcase further back in the car.
If one looks at the history of off road racing, it is clear that a coil over car will dominate over leaf springs. A perfect example is back in the late eighties or early nineties when Rod Hall was campaigning his Dodge in Class 4. When Savage built a Nissan with coilovers, there was nothing Rod could do to beat it unless it broke. He even went so far as to put quarter ellipitic springs on all four corners, but to no avail. Part of this was an issue of straight axle versus ifs, but a lot of it was because of the springs.
A properly built ttb Bronco is the standard of the class. With all due respect to Mosses and their team, there isn't any other 4wd that compares in the class. In fact when people used to race ttb's in the class, before Mosses started running, they imposed a front travel limit. Somebody suggested that they thought the new FJ would pose a threat, but that is a joke. Five or six hundred easy horsepower and 15-19" of front wheel travel in the Bronco at the max wheelbase of the rules puts it at the top of the pile by far.

[dannyroark89]

excuse me again im new! but after reading the ruler pretty much what i have come up with is that the top of the frame rail may not be modified but the sides can have support via gussets or struts?
and commenting on what retro said... does your suspension have to remain a spring under? is that part of the rules? and why not build a truss for it over the top of it then. like i said im new dont bite my head off just trying to figure out the jist of it all.

[straightaxle]

*89, I did not see what kind of vehicle you are starting with. It is just about impossible to put a truss on the top of a front axle because it would take away all the clearance with the engine and oil pan. We snuck in a piece of 1/4" flat strap on the top just to tie it together, but it is still very tight at full bump. Springs over or under are allowed, but they go under for the same reason mentioned above.

Did I read that right? Retro contradicted himself in the same post saying that coilovers for all is the answer to level the playing field in the class, and then a couple lines later said a ttb Bronco is really the only competitive class 3 vehicle?????

[straightaxle]

OK, since I have the pictures as an example and the discussion is regarding frame mods, take a look at the sequence below and let's have some opinions on whether it is allowable under the Class 3 rules.

[Grimm]

1. The frame was modified for the bump stops- so that would not be legal
2. The rear cross member was cut off the frame - debatable, but technically illegal
3. The added upslope is adding material to the frame - which would be legal

[steves118]

Get the popcorn

[dannyroark89]

axle, maybe weld the axle tubes to the housing? or a truss around the front maybe? anything is better than nothing! im starting with a 95 jeep cherokee, not the most desireable rig for a desert racer but none the less, i believe once i finish the stroker it will be half way competitve, who knows though its all about the driver during the technical stuff ;) so the general rule of thumb then is you can add material to the frame to strengthen it as long as nothing is removed or changed to a different location during the fab work?

[3amigo]

Those frame mods are not legal.

I would love to mount my bump cans like that, but even if I squint really hard I can't make the rules wrap around that one!

[gunit]

2. The rear cross member was cut off the frame - debatable, but technically illegal


The cross members are not considered as part of the frame and may be modified, strengthened or removed. The frame for the sake of the rules is the two main rails only.

[Grimm]

Yes, i agree, but it is hard to tell in the picture how much of the frame rail was cut off along with the crossmember. He did not just cut the crossmember off between the rails he took the rail section with it.?? I don't see it as a big issue either way.

[retroblazer]

I don't think I contradicted myself by saying that a ttb Bronco is the highwater mark in the class. Most wheel travel, big horsepower, longest and widest footprint.
Again, there was a reason why the class had a 15" front wheel travel limit. I'm not saying the ttb set-up is perfect, but all things being equal, it should have the advantage. I know the radius arm fsb has most of the advantages of the ttb with a trade off of less travel versus simplicity. The only other drawback would be motor, but that hasn't stopped anybody from putting in a Windsor where there wasn't one from the factory.

[retroblazer]

Back to the Jeep with the bump cans in the frame. The relative position of the frame remains unchanged and it doesn't change the potential up wheel travel. It works for me.

[Broncodawg]

Altho the frame position may be unchanged, the upper and lower frame rail can not be modified according to the rule. Seems to me the important benefit of putting the bumps in-frame is the extra room it allows you to mount up COs and bypasses. Is that an unfair advantage? Fabbers out there can answer that better than I.
I've heard that other classes requiring a stock frame do allow in-frame bumps.
If true, that would shed some new light on the issue, but can anyone confirm that?

[straightaxle]

axle, maybe weld the axle tubes to the housing? or a truss around the front maybe? anything is better than nothing! im starting with a 95 jeep cherokee, not the most desireable rig for a desert racer but none the less, i believe once i finish the stroker it will be half way competitve, who knows though its all about the driver during the technical stuff ;) so the general rule of thumb then is you can add material to the frame to strengthen it as long as nothing is removed or changed to a different location during the fab work?

We have seen some pretty capable Cherokees in the past. The Jeepspeed program is providing more competition and other incentives that have been drawing the type away from Class 3.

The link below will get you to some pics that is version 3.0 and the one that we are currently using. Note that the pictures show the axle upside down in the jig.

http://www.thewebwheeler.com/forums/showthread.php?t=220&highlight=axle+truss

Welding the cast iron center housing to the tubes will do nothing for you. The weld will crack at the casting. I believe the outer C's are cast steel because the weld seems to stick pretty well to them and the tubes are welded to them at the factory, not just pressed in. The idea is to tie the two ends of the axle together. There are cable trusses out there that do the same thing, but it is impossible to keep them under the truck in the rock bashing environment of racing.

[Tazz]

When we were building ours, we looked into mounting the bump cans that way. It definitely would have made it easier to get everything in place if we did do it. I chose not to, because of the part of the rule that says “long as the top frame rail is not modified". As opposed to the part of the same frame rule that says “must retain stock configuration”. I read that as a literal statement about the top frame rail. If we had chose to do it that way it would have been a lot easier to get the bumps to work, there is nothing on the axel or in the way in that location. As it is they are side mounted on the outside of the frame rail and I had to build a secondary pad, for a flush landing surface over the u-bolt nuts. My fuel cell takes up the area between the frame rails there, so inset wasn’t an option.

If the rule only had the "stock configuration, size and shape" statement and did not contain the other statement. Then I would not have done it that way.

[dannyroark89]

hmm is this just for the front axle that draws the most concern because i recently built one for my 8.8 is this going to just get beat up and broke off in a race? im really curious now... and for the matter different axles are accetible right and lockers and new gears? because i did it all. i know it is in jeepspeed in the xj classes. but baja is my ultimate goal and it makes no sense to put in wrench time on a vehicle i cant race there. do you think a truss on top would be a big concern with a strait axle?

[straightaxle]

hmm is this just for the front axle that draws the most concern because i recently built one for my 8.8 is this going to just get beat up and broke off in a race? im really curious now... and for the matter different axles are accetible right and lockers and new gears? because i did it all. i know it is in jeepspeed in the xj classes. but baja is my ultimate goal and it makes no sense to put in wrench time on a vehicle i cant race there. do you think a truss on top would be a big concern with a strait axle?

If you're asking if different axles and parts can be used, they are wide open, just says it has to be an "automotive" type. Guess you can't use an axle out of a John Deere? Front axles are more critical because there are a whole lot more moving parts and they run closer to the engine and steering - clearance issues. From the factory they tend to be a little lighter than the factory rear axle because they assume they won't get used as much of the time.

[dannyroark89]

ok no tractor axles got it! haha well do you think the clearence issue could be due to ttb? atleast i believe thats what the fullsizes have? because i have honestly never had an issue nor thought about it with my strait axle...granted i have yet to do any epic jumps in the desert with it. so much to think about and overcome, i am envious of those of you who are competitive in this class. im trying to get there!

[dannyroark89]

another question.... what is the most desirable kind of air intake for racing in the desert? i was thinking some type of cowl induction... would this be a good choice. i have kind of slowed down the process on my build as i am saving up for the material to build my cage but i still want to be productive so ill start hitting the little stuff.

[straightaxle]

ok no tractor axles got it! haha well do you think the clearence issue could be due to ttb? atleast i believe thats what the fullsizes have? because i have honestly never had an issue nor thought about it with my strait axle...granted i have yet to do any epic jumps in the desert with it. so much to think about and overcome, i am envious of those of you who are competitive in this class. im trying to get there!

Basically to check the clearance you take the springs out and jack the axle up until it hits. You need all the travel you can get, so you start moving or cutting stuff to get it to suck up as far as it will go. Doesn't matter if its ttb, straight axle or swing arms, its the same story. If you can't cut the frame, then that is your ultimate clearance limit.

[straightaxle]

another question.... what is the most desirable kind of air intake for racing in the desert? i was thinking some type of cowl induction... would this be a good choice. i have kind of slowed down the process on my build as i am saving up for the material to build my cage but i still want to be productive so ill start hitting the little stuff.

I don't mean to drag your thread off the original subject (even though I already have earlier) but they are reasonable questions. I thought it was better to move the intake to the inside of the cab and to use an air cleaner designed for industrial construction equipment that works in this kind of environment every day. This has worked well for us, but we still managed to plug it up at the Vegas to Reno race last year. There is a YouTube video out there of the Bronco powering through the silt near Tonopah. It plugged up shortly after that. UMP makes a very popular aluminum version of the Donaldson type industrial air cleaner, uses the same paper filter element and everything. If you think about it, it would be the most logical to mount the air intake as high as possible to keep it above the dust assuming it tends to stay and settle low, just remember there is low hanging trees, sagebrush and cactus out there!

[dannyroark89]

man axle you are man of wisdom i hope you know that! well i know what my project for the weekend is now... check axle clearence, i can see how the truss would be in the way now. and ya putting it in the cab wouldnt that reduce the amount of air greatly though? well i guess if your windshield is gone it wont haha and cactuses and the desert is something ive been dreaming of for a while now, its slowly becoming a reality!

[Blanco]

man axle you are man of wisdom i hope you know that!
Well, you dont get to be Class Champ over & over & over & over again without knowing a bit about what your doing.. :D

[jkrell]

OK, since I have the pictures as an example and the discussion is regarding frame mods, take a look at the sequence below and let's have some opinions on whether it is allowable under the Class 3 rules.

The frame material at the rear was untouched. The tin rear cap/cross member was removed so i could add material back in order to mount the fuel cell properly.

Can a hole be drilled in the frame in class 3? Because that is a frame modifications. I say that partly in jest, but partly to continue that debate that straightaxle has proposed. There is nothing on the wrangler that has increased wheel travel or extended wheelbase which would give an advantage. Like i have said before...we are at a disadvantage with a straight axle and 6cyl...at an advantage with coils in the rear.

Thanks for the support gunit and retroblazer.

[jkrell]

I don't think I contradicted myself by saying that a ttb Bronco is the highwater mark in the class. Most wheel travel, big horsepower, longest and widest footprint.
Again, there was a reason why the class had a 15" front wheel travel limit. I'm not saying the ttb set-up is perfect, but all things being equal, it should have the advantage. I know the radius arm fsb has most of the advantages of the ttb with a trade off of less travel versus simplicity. The only other drawback would be motor, but that hasn't stopped anybody from putting in a Windsor where there wasn't one from the factory.

2008 jeep grand cherokee (wk i think they call it) would be a solid match for ttb bronco if built properly....link/coil spring rear, a arm front...big hemi power...perfect wheel base.

[Broncodawg]

"Can a hole be drilled in the frame in class 3? Because that is a frame modification. I say that partly in jest, but partly to continue that debate that straightaxle has proposed."

The rule refers to mods to the top rail of the frame specifically and says nothing about mods to the side of the frame. Given that, drilling a hole in the side of the frame would not be an illegal mod.

While you're here Jon, what other stock frame classes were you referring to a while back that have accepted in-frame bump cans? Just for the sake of discussion?

[dannyroark89]

2008 jeep grand cherokee (wk i think they call it) would be a solid match for ttb bronco if built properly....link/coil spring rear, a arm front...big hemi power...perfect wheel base.

which would be about the equivalent of a jeep cherokee minus the v8 power. but everything else minus the body are about the same. but with a 4.7 L stroked straight 6 i think it would stay right in the running. and theyre called zj's just for future refrence

[Grimm]

ZJ's have Independent front susp. compared to a straight axle on a cherokee.

[dannyroark89]

ZJ's have Independent front susp. compared to a straight axle on a cherokee.
i stand corrected, im sorry, zj's were pre 98, an 08 is a wk

[jkrell]

ZJ's have Independent front susp. compared to a straight axle on a cherokee.

ZJ's (93-98 grand cherokee's) are straight axle as well....same front end as cherokee pretty much. The WK (05 and up) is the first independent front suspension Cherokee/Grand Cherokee.

[Grimm]

Ahhh. I too stand corrected. Thanks

[63chevyll]

back to the orig question??? kind of,

what about the 2wd blazer? should be legal

[Blanco]

back to the orig question??? kind of,

what about the 2wd blazer? should be legal

Legal?
Not for Class 3.
Class 3 is the 4x4 SUV class.

[63chevyll]

i see now, just read the rules closer.

Heck ive been reading rules for weeks

[straightaxle]

Get yourself to some races out here and that will give you an idea of what it takes in a vehicle. As the available desert shrinks, the courses get more and more chewed up, and it takes a lot more suspension then it used to when they were using essentially existing roads. Even Mexico has funneled the courses down to the same sections year after year. The ultra high horsepower classes make it worse with even deeper ruts.