Build Broken4 Racing 4500 Class Build

[broken4_racing]

Hey Guys, thought I would get my new build started with a thread. My name is Mitch and I've been racing in the 4500 class for the last roughly 6 years up in Canuk land along with some of the YORR stuff in Montana. I built my current car with a university budget and limited knowledge of what it takes to build a fast car. Through many revisions, modifications and changes I am finally ready for a new chassis. After racing Hammers as apart of the Rookie program this year, I am excited to see where I can take a new car.

While I would love to build a completely new car, the budget is thin, and this will mostly be a new chassis build with most of the parts from my current car moving over.

Some Specs on the new car:
115" WB
19" Belly Height
56" Tube Width
6'2" Roof Line

Rough Parts List:
Engine - rebuilt GM 525 LS3
Trans - rebuilt 6L80e
TCase - Current Plan is the NP205 in the current car, but would love to put in a SCS Case.
Shocks - 2.5" Radflo CO/BP F/R spec'd and tuned by Phil
Front Axle - 05+ Superduty 60
Rear Axle - TBD

After finishing the shop build at my new place (Broken4 Racing Compound) I finally have a building to do it.

And of course this wouldnt be possible without the help from some of our sponsors:

Holley Performance
Nexen Tires
Raceline Wheels
Radflo Shocks
Mevotech
Kartek
Vivid Lumen LED
Stage 8 Fasteners

 

[broken4_racing]

The car is being fully 3D designed by myself in Fusion 360 so hopefully that will help with less revisions and changes come time to build.
Tubing is ordered and should be in next week!! I will be building the chassis entirely myself with some help from friends. One of these great friends has a langmuir CNC plasma table that I will be borrowing for most of the plate work, and I will also be building a rotary attachment to CNC notch all the tubing.

 

[mobil1syn]

looks good.

i thought you needed factory frame for 4500

 

[Tryloff]

looks good.

i thought you needed factory frame for 4500

Or, 2x3 from stock motor mount to idk where in the rear.

 

[broken4_racing]

looks good.

i thought you needed factory frame for 4500

Kind of! lol here is a portion of rule from the Ultra4 Rulebook:

"4.1.1 The frame is considered to be the primary frame rails used to mount the drive train and body. It shall run from the OEM motor mount location to behind the rearmost portion of the occupants' seats. The balance of the frame shall remain whole however allowances will be made for suspension mounting.

4.1.2 The stock frame should be retained, however aftermarket and custom frames are allowed. Aftermarket and custom frames must be of a boxed design with minimum dimensions of 1.5” (38mm) x 3” (75mm) x 0.120” (3.0mm)."

If you look at the second last photo you can see that I have box tubing between the front and rear lower link mounts and it carries up to the motor mount. Here is a better photo

A lot of 4500 class cars have put the tube on the outer rub rail ( Like John Matthews new car), but I like the idea of keeping it at the bottom of the subframe for a few reasons. Makes mounting and supporting the skid plate very easy. I can also incorporate the link mounts in a way that keep the bottom and outside faces of the frame smooth for sliding over rocks.

 

[JR4X]

looks good.

i thought you needed factory frame for 4500

Not since 2012. The “factory” requirement got modified to be box tube in the rule book. You can use 100% new material if you want, doesn’t even have to use any actual production vehicle dimensions

 

[mobil1syn]

interesting i guess i should read the rules before running my mouth

 

[broken4_racing]

interesting i guess i should read the rules before running my mouth

Someone needed to get the first reply in so i appreciate you getting it started

 

[snivilous]

Very cool! I want to see what you come up with for the rotary CNC since I've wanted to do the same thing.

 

[broken4_racing]

Very cool! I want to see what you come up with for the rotary CNC since I've wanted to do the same thing.

My plan is to do a very close version to this:

They sell them to fit their table.

The draw to this style for me is not needing a lathe chuck at the end and I think it will just be overall easier. Everything is adjusted right at thee machine vs walking to the other end etc. The only downside to a rotary on this small of a table is most of the tubes will need to be cut, rotated, and cut again so there will be a little more room for error.

 

[broken4_racing]

While waiting for tubing I am tackling a couple quick projects I figured I would share. First is a filter cabinet. I used a furnace filter on a box fan for a few years so figured it was time for an upgrade.

Being the complete hoarder that I am, the only things I needed to purchase were the filters and a cover plate for the switch. Furnace fan I had laying around for this.

The whole filter assembly is going under the cart that it is sitting on. This will make it easy to wheel wherever I am working, and also keep it as a workbench or weld table. I decided to use a plug end rather than chop up an extension cord. I will have a dedicated cord that will stay with the cart, but no point in mangling a cord for no reason.

Used tape for proof on concept and then made some plywood retainers for the filters to slide into. It honestly works amazing. I love that I can get it real close to where I am working and limit the dust/smoke before it gets too far away. I looked at installing one of the industrial wood shop systems, but didn't like that it would be mounted in 1 location. Filters are MERV 13 which should filter out alot of fine dust and even the welding smoke. Total of about $75 CAD into the project. Ill give some updates for how long the filters last.

 

[GiS]

I really like the look of the swept back C pillars .. will be watching Mitch!

Will you be running a dedicated trans cooler (didn't see one modelled) or do you hope to get away with just a heat exchange/radiator combo?

If there was one thing I could do or change to make superduty axles more "racey" (and before you figure out master cylinders, pedals etc) it would be to ditch the monstrous/heavy factory brakes.

 

[broken4_racing]

I really like the look of the swept back C pillars .. will be watching Mitch!

Will you be running a dedicated trans cooler (didn't see one modelled) or do you hope to get away with just a heat exchange/radiator combo?

If there was one thing I could do or change to make superduty axles more "racey" (and before you figure out master cylinders, pedals etc) it would be to ditch the monstrous/heavy factory brakes.

I appreciate it! One of my favorite cars is Jason Scherer's so the swept back C is taken a bit from his.

Yup! I have a Large single fan CBR trans cooler. It will likely be going in the space between the grille and the X brace for the bumpstops

Ya that's a great point. I will likely try and swap out to some lightly stuff. On my current car i ran through 3-4 different manual brake systems and finally ended up with hydroboost. Plan is to run it again as its an absolute dream.

 

[Bebop]

Ya that's a great point. I will likely try and swap out to some lightly stuff. On my current car i ran through 3-4 different manual brake systems and finally ended up with hydroboost. Plan is to run it again as its an absolute dream.

For a racecar, may I suggest looking into the ibooster?
I'm a hydroboost guy as well, but that's another potential failure point that I wouldn't want.

Kind of! lol here is a portion of rule from the Ultra4 Rulebook:

"4.1.1 The frame is considered to be the primary frame rails used to mount the drive train and body. It shall run from the OEM motor mount location to behind the rearmost portion of the occupants' seats. The balance of the frame shall remain whole however allowances will be made for suspension mounting.

4.1.2 The stock frame should be retained, however aftermarket and custom frames are allowed. Aftermarket and custom frames must be of a boxed design with minimum dimensions of 1.5” (38mm) x 3” (75mm) x 0.120” (3.0mm)."

If you look at the second last photo you can see that I have box tubing between the front and rear lower link mounts and it carries up to the motor mount. Here is a better photo

A lot of 4500 class cars have put the tube on the outer rub rail ( Like John Matthews new car), but I like the idea of keeping it at the bottom of the subframe for a few reasons. Makes mounting and supporting the skid plate very easy. I can also incorporate the link mounts in a way that keep the bottom and outside faces of the frame smooth for sliding over rocks.

Welcome to 2005, that's how my Bent Fab chassis is built.
Make it thick down there, if you're anything like me it'll take a few hits.

 

[broken4_racing]

For a racecar, may I suggest looking into the ibooster?
I'm a hydroboost guy as well, but that's another potential failure point that I wouldn't want.

I read that thread awhile ago and was seriously considering it. I’ll go back and check it out. Meh, I don’t think the chances of hydroboost failure are all that high. But I do like the idea of taking any strain off the PS system.

Welcome to 2005, that's how my Bent Fab chassis is built.
Make it thick down there, if you're anything like me it'll take a few hits.

lol, yup. Most were like that back then. I am using 2x3 3/16 wall. All the DOM on the skid will also be 3/16, and then I have some 1/4” 7075 that will be the skid plate with some UHMW, thickness TBD.

 

[broken4_racing]

Had a very productive weekend in the shop. Spent most of the time building the chassis/frame table.

Table Details:
Overall 5'x10' and 24" tall.
Frame tubing is mostly 3x3x1/8 and 3x2x1/8.

The two large plates are 8'x2' and are 3/4" thick and the smaller end plate is 5'x2' and 1/2" thick. Since I really dont have the space to keep a frame table and honestly I dont plan on building another car anytime soon, I wont be drilling any fixture holes. Once the chassis is done, I will be pulling this apart and building a couple 3x5 tables that can bolt together and will have nice layout and fixture holes.

While it isn't the nicest or the fanciest, I spent a lot of time making sure it was flat, square and level. I have the squareness around 1/32 and the flatness within 1/16. I only had my 4' level laying around so i will borrow my dads laser level and dial it in even better.

 

[broken4_racing]

Also took some time to finally mount up my cord reel to the central most post of the lift. I am bad for leaving cords out on the floor so this should help with that. The plan is to bring air down and put a hose reel up beside it as well.

This looks like its hanging low... but the cord end is about 7 ft off the ground. Out of head hitting distance, within reach.

 

[broken4_racing]

Need some input:

I have two transmission pans shown here. The stock pan is the deeper one and holds 7 liters. The shallower pan only holds 6 liters.

This shallower pan would allow me to drop the whole drivetrain over 1" in the chassis. With a stock 6L80 holding over 12 liters plus the large @cbrperformanceproducts cooler adding another 1-2, would you be worried about the loss of 1 liter?

In general we always move to more fluid but I am thinking the gain in center of gravity would be worth it.

 

[Gumbybronco]

This is not my expertise. I would use the configuration that fits the chassis best and make up the volume in the cooler or with a remote filter. 1 liter doesn’t sound like much if you’re running a high performance cooler.

 

[gt1guy]

Is the shallower one a G8 pan?

 

[broken4_racing]

Is the shallower one a G8 pan?

Yup! It would be the G8 pan with the respective GM filter

 

[broken4_racing]

This is not my expertise. I would use the configuration that fits the chassis best and make up the volume in the cooler or with a remote filter. 1 liter doesn’t sound like much if you’re running a high performance cooler.

Thanks, that's definitely what I was thinking as well.

 

[WiscoF100]

1” +/- is the same as your fluid volume quandary. Don’t skimp on pan protection or buffer zone. Also don’t use a cast pan. Your space age low cog buggy won’t finish the race if you busted the trans pan. Not picking on your design and build process. You’ve got to build like a tank where it counts most.

My second iteration for KOH is converting the drivetrain to an automatic. My pan will clear as-is in the subframe but with 1/8” clearance. One rock and it’s done. Most likely be lifting the drive train 1” in my case.

For keyboard racing purposes, what’s the anticipated height for the crankshaft at ride?

 

[JR4X]

I think we have 1/2” between the skid plate and trans pan on the 4531 car. We have caved the skid in far enough to dent the pan. Have also had a Little Rock get in between the two and rub a hole in the trans pan

 

[mobil1syn]

I think we have 1/2” between the skid plate and trans pan on the 4531 car. We have caved the skid in far enough to dent the pan. Have also had a Little Rock get in between the two and rub a hole in the trans pan

putting foam in between pans and skid plates is a good way to prevent large debris ruining your race when you land on a skid.

 

[WiscoF100]

When he mentioned the rock, I was immediately thinking of ways to keep garbage out of tight spaces. Foams a great idea

 

[JR4X]

putting foam in between pans and skid plates is a good way to prevent large debris ruining your race when you land on a skid.

The things I wish I knew before

 

[broken4_racing]

1” +/- is the same as your fluid volume quandary. Don’t skimp on pan protection or buffer zone. Also don’t use a cast pan. Your space age low cog buggy won’t finish the race if you busted the trans pan. Not picking on your design and build process. You’ve got to build like a tank where it counts most.

My second iteration for KOH is converting the drivetrain to an automatic. My pan will clear as-is in the subframe but with 1/8” clearance. One rock and it’s done. Most likely be lifting the drive train 1” in my case.

For keyboard racing purposes, what’s the anticipated height for the crankshaft at ride?

Yup, totally agree, Everything on the bottom of the car is 3/16" steel and the skid will be 1/4" 7075 with probably 3/8 UHMW.

In the model the crank height is right at 30" at ride height.

 

[broken4_racing]

I think we have 1/2” between the skid plate and trans pan on the 4531 car. We have caved the skid in far enough to dent the pan. Have also had a Little Rock get in between the two and rub a hole in the trans pan

I was actually going to post and get some info on this when i got to mounting the drivetrain. I think 1/2" is a good number. How thick was your skid plate when you were able to dent it up that high?

 

[broken4_racing]

putting foam in between pans and skid plates is a good way to prevent large debris ruining your race when you land on a skid.

Thats a fantastic idea.. definitely stealing this. If i can remember once i get there