First Ever (AFAIK) Carbon Fiber Radiator Support

[bigjae46]

A carbon fiber radiator support! 2lbs lighter and stiffer. There is a vertical piece that I deleted, not really needed. The carbon pieces could be lighter but I need some strength and stiffness in the bottom piece to support my splitter struts.





The bad…I can’t screw in the rubber hood bump stops. I made the part too thick. If there is a next time, don’t lay core around that opening. Not a big deal since I use hood pins which have a rubber stop on them. So now I can delete the OE stops and save some more weight! 🤣

The good. Stiffer, lighter and stronger. May not be as crash worthy but YOLO. The stock part has a bracket riveted where the radiator support screws go. I was able to replace that part so the radiator mounts like OE. Really happy that worked out.

Why? Because I can. And I am trying to get down to 2525 lbs (no driver/no fuel) so I can put in a new roll cage with 1.5”x.095 tubing - would put me at 2475 which might make it the lightest E46 M3 in the world. Right now I’m right at 2600 with a weight distribution of 51.58%. I’m 40lbs over on the axle. I really need to find most of the weight loss over the front axle. I can move my seat back another 1”-2” but the cage won’t allow. Something I will need to account for when I build the new cage. Figure I need to lose 50 lbs over the front…I have a plan!

Infusion completed...




Hand laminated and then vacuum bagged the small panels for the radiator mounts



As it came out of the molds.



Here's the detail on the radiator mount brackets

[SQ13]

Awesome work! Re losing more weight up front..I imagine a Karbonius Race airbox would help you shed a few lbs. Maybe CF brackets/mounts for the strut tower brace?

[old///MFanatic]

Innovative bigjae 👍🏻

[bigjae46]

Awesome work! Re losing more weight up front..I imagine a Karbonius Race airbox would help you shed a few lbs. Maybe CF brackets/mounts for the strut tower brace?

I already have a carbon front reinforcement plate. I'd like to stay close to stock on the motor, just makes things easier long-term. I'll go with a carbon airbox if I have to. I've been brainstorming a carbon strut bar to ties into the firewall and radiator support.

[toy4to]

Good job!

[Gt4]

Do you have composite doors? Roof?

With custom engine mounts, you could shift the engine backward and a bit lower too?? Shorter driveshaft too than

Still have headlights?

[Gt4]

And if you go with 4130 Chromoly, you can get 1.375’’x0.095’’ tube. Might worth checking weight per linear feet of both option

[bigjae46]

Do you have composite doors? Roof?

With custom engine mounts, you could shift the engine backward and a bit lower too?? Shorter driveshaft too than

Still have headlights?

I do have the BW engine mounts and my headlights are gutted. I'm pretty sure I've done all that I can without spending money. My body wiring harness (minus engine & DSC harnesses) weighs less than 10lbs.

I'm making a mold for a carbon hood right now. Waiting on more resin and FG cloth. I have a front bumper, left door and trunk to make a mold from. I have a new roof skin on order, waiting for it to come from Germany. It's going to be awhile.

I'm only doing the left door to get a better left-right balance. Likely will end up doing fenders as well.

I will use a spread tow fabric for most of the panels. This helps to reduce weight by reducing epoxy consumption at the expense of cosmetics - tends to have more pin holes and small surface voids.

[SQ13]

I already have a carbon front reinforcement plate. I'd like to stay close to stock on the motor, just makes things easier long-term. I'll go with a carbon airbox if I have to. I've been brainstorming a carbon strut bar to ties into the firewall and radiator support.

CSL intake is stock on a CSL 😅 Don’t forget about the weight reduction!! 😅😅

[Cronenberged]

Could just modify the door the and add a cf panel.

[Gt4]

Could just modify the door the and add a cf panel.

It’s a full race car, he doesn’t has door cards and his doors are fully gutted

[Gt4]

I don’t think 2475lbs makes it the lightest E46 M3 in the world. I think you will need to be sub 2400lbs.

A guy here in Ontario, Canada has an E46 M3 race car with Karbonius CF rear quarter panel and his friend told me his car was sub 2400lbs (don’t remember the exact number).

[Gt4]

You can also do a built K24 swap to lower weight and get better corner balance

[bigjae46]

I don’t think 2475lbs makes it the lightest E46 M3 in the world. I think you will need to be sub 2400lbs.

A guy here in Ontario, Canada has an E46 M3 race car with Karbonius CF rear quarter panel and his friend told me his car was sub 2400lbs (don’t remember the exact number).

With a cage?

[bigjae46]

Could just modify the door the and add a cf panel.

I’ve already gutted the doors. I could probably cut a little more but would like to avoid cutting my leg open when I get in and out of the car.

I’ve drilled out or cut off every bracket, stud, and various stuff from the interior. It’s literally a tin can. I’ve done stuff like slicing the intake manifold bracket in half, take out nuts and bolts that really aren’t needed. No wipers, ground off useless stuff on the valve cover…I’ve even tried deleting the power steering…then tried to run PS with no expansion loop or cooler. I need the cooler…