The Red Drift ///Machine - 2026 NASA TT4 adventures

[332]

nothing changed since e46fanatics, carry on!

[bigjae46]

Pretty sure Titanium will be stronger than Aluminum with thinner wall so probably lighter too and can handle heat better than alu too. But will be more expensive.

I think for our level of preparation and driving skills (we are building cars at home and doing track days for fun, not for a living), you will be able to feel weight reduction more than weight distribution. So if you are able to remove 100lbs, you should be able to feel it a little bit during acceleration, cornering and braking vs the difference from 52.5/47.5 f/r to 50/50 f/r.

Also, you are talking about carbon fiber parts. Don’t get fool by carbon fiber parts, a lot of those parts are made for look only and aren’t that light at all. I had a single side Vorsteiner hood 10 years ago and it was heavy. I am trying to work with the guy who’s doing the Mile End composite parts to do E46 M3 track/race specific parts in the future. He has the knowledge to do crazy lightweight parts.

Couldn’t tell a big difference when the car was around 3000lbs dry. Funny thing was I’d used to forget I had a passenger. Now that it’s around 2600lbs dry with aero...you can feel 50lbs. The car is far more sensitive.

Improving the weight from 53.75 on the front to 52.5 has made a significant difference. I want to keep going that direction for now.

As for carbon fiber...true. Many parts are FG chop mat underneath. I’m making my own CF parts so I can control weight and strength...or at least to the best of my limited abilities.

Target weights -

Left front door - 10lbs
Fenders - 7lbs
Roof - 4lbs
Hood - 8lbs


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[Gt4]

I’d like to see what you did with the A and B pillars.

I want to get weight off the left front corner. I am considering a carbon fender and door on the left side only.

I’m at 52.5 fr weight distribution. I don’t want to do the side exit right now because it would take more weight off the rear. It’s on the list though.

What about using aluminum for the exhaust?


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Pretty sure Titanium will be stronger than Aluminum with thinner wall so probably lighter too and can handle heat better than alu too. But will be more expensive.

I think for our level of preparation and driving skills (we are building cars at home and doing track days for fun, not for a living), you will be able to feel weight reduction more than weight distribution. So if you are able to remove 100lbs, you should be able to feel it a little bit during acceleration, cornering and braking vs the difference from 52.5/47.5 f/r to 50/50 f/r.

Also, you are talking about carbon fiber parts. Don’t get fool by carbon fiber parts, a lot of those parts are made for look only and aren’t that light at all. I had a single side Vorsteiner hood 10 years ago and it was heavy. I am trying to work with the guy who’s doing the Mile End composite parts to do E46 M3 track/race specific parts in the future. He has the knowledge to do crazy lightweight parts.

[bigjae46]

Here are some advices to remove weight.

-You can get composite doors. Even if you gutted the OEM doors they are still heavier than composite doors.

-you can remove all the undercoating under the car and stitch weld all body joints. I did that on my last track car build. It’s a lot of work but help to get a stiffer chassis

-if you are going to redo the cage, you can cut all the sheet metals inside the A-B-C pillars and quarter panels. Car will be like a semi-tube frame car. And to get rigidity back you make gussets from cage to A-B pillars. I did that too on my last race car build. I was able to get the tubes touching the inside of the A pillars /the visible sheet metal visible from outside.


-you can relocate the battery in the passanger side footwell area and eliminate 1 big wire.

-you can do a custom side exit exhaust and save some length of exhaust piping and probably get better exhaust flow.

-while doing the side exit exhaust setup, you can redo the exhaust setup with Titanium parts from Vibrant to save even more weight

I have pictures of all of this if you want

I’d like to see what you did with the A and B pillars.

I want to get weight off the left front corner. I am considering a carbon fender and door on the left side only.

I’m at 52.5 fr weight distribution. I don’t want to do the side exit right now because it would take more weight off the rear. It’s on the list though.

What about using aluminum for the exhaust?


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[Gt4]

Here are some advices to remove weight.

-You can get composite doors. Even if you gutted the OEM doors they are still heavier than composite doors.

-you can remove all the undercoating under the car and stitch weld all body joints. I did that on my last track car build. It’s a lot of work but help to get a stiffer chassis

-if you are going to redo the cage, you can cut all the sheet metals inside the A-B-C pillars and quarter panels. Car will be like a semi-tube frame car. And to get rigidity back you make gussets from cage to A-B pillars. I did that too on my last race car build. I was able to get the tubes touching the inside of the A pillars /the visible sheet metal visible from outside.


-you can relocate the battery in the passanger side footwell area and eliminate 1 big wire.

-you can do a custom side exit exhaust and save some length of exhaust piping and probably get better exhaust flow.

-while doing the side exit exhaust setup, you can redo the exhaust setup with Titanium parts from Vibrant to save even more weight

I have pictures of all of this if you want

[bigjae46]

I have a 2021 goal of getting into the 1:40s on NT01s on my home track, MSR Houston. PR so far is 1:43.9.

I'm at about 2900 lbs with 275/40R17 NT01s. Ran a 1:41.269 and consistent 1:42s to 1:43s. I also measure my best lap against my virtual best to get an idea of how consistent I am. On Sat, I was .1 sec off my VB and .4 sec on Sun. Very happy with that! I put in fairly consistent sector times lap over lap, with .5 sec per sector (about .5-.75 miles). I have 5 things I can improve with my driving which I think can net me 1 more second. My next effort is to reduce drag, especially in the front wheel wells. And as always...more weight reduction.

[bigjae46]

Finished the splitter up. Riveted some aluminum T bars as a reinforcement and UHMW blocks on the bottom as skid plates.



Installed Turner monoball RTAB and FCABs.



Performed a corner balance and alignment. Perfect 50/50 cross weights and a 52.5/47.5 F-R weight distribution. Then I dialed out some toe on the rear tires (.11 each side which is about .03 from min spec.


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[bigjae46]

One last video from COTA. Its an interesting power vs handling battle.

MSR Cresson 3.1 in Nov. Best lap of the weekend was a 2:22.9 which I'm really happy with. I hope with some weight loss, aero improvement and a little more midrange power coupled with better driving I can be in the 2:20's.

[bigjae46]

Looking good! Sucks about the engine problems, hopefully that won't be an issue now.

It does suck but its not THAT bad. At least I know what to do now. The engine has been running pretty well.

UPDATE:

The bad news...not going to be ready for the first event of the year. Seat, brake rotors, and harnesses did not arrive in time to get a tech inspection for the NASA event. The upside is I'm going to be playing lots of ice hockey this weekend

The goal - get to 2550 lbs dry so I can install a 1.5' dia x .095 wall roll cage which meets NASA and BMWCCA rules (SCCA too...I think) and a carbon roof with some margin of safety. Both should cut out another 70lbs.

I got my scales back...lots of people like borrowing them. Helped out a team get 5th overall in a WRL race!

Here are the corner weights with me in the car, no pass seat, AGM battery and 38L of fuel.



First off...I'm fat right now. I'm adding 220lbs incl helmet and hybrid device. Should be closer to 180-190. Got some work to do there. Happy about the 50.3 cross weight. Still 51.2/48.8 front to rear. The goal is to get to 50/50 which is going to be tough.



2761lbs
65lbs of fuel (38l * 1.71lb/L)

2696 dry - that is more than I expected. 46 lbs is the battery, I can install a lithium battery which saves 42 lbs. If I run Hoosiers instead of NT01s - saves another 16 lbs

2638 lbs post battery w/ hoosiers. So 88 lbs to go, have to lose almost all of it over the front axle. I've spent very little money in weight loss parts but now its time to open the wallet

Carbon fiber hood, headlight blanks, seat floor mount adaptors, and front reinforcement plate - 27 lbs
CSL/carbon air box - 9lbs
Hotchkis Sway to replace the OE bar - 4 lbs
Containment seat - 4 lbs
Muffler delete - 8 lbs
Tilton clutch/flywheel - 5lbs

That's 57 lbs, still have 31lbs to go.

Probably should have did this in the first place but it going to make the most sense to use the BMW C&R oil cooler which saves me about 6 lbs.

Now 25 lbs to go and the options are getting less and less...

Carbon fenders - 6 lbs
Rear coilover/convert upper control arm to link - 5 lbs
Carbon trunk lid - 5 lbs
Carbon rear floor brace - 3 lbs
Carbon muffler hanger mount/cross brace - 1 lbs
ECU relocate/Dash Trim - 3 lbs

Its not going to easy. I figure that I'll have to find another 10-15lbs in the end to account for little things that get added back (paint, hardware, etc) and adds weight. This should make it the lightest E46 M3 in existence!

I had Paul Claude update my tune to account for the headers. The AFRs were high and I had a 30hp dip between 4k to 5.5k rpm during my last dyno in 2018 which I think hurts me quite a bit. The engine is in this range when I start to turn into most turns. It feels like the engine is lugging through the corner and then the VTEC kicks in. It gets worse as the IATs climb. I hope that I get a more linear power delivery as I roll back onto the throttle to exit. I need a little more power...I keep getting run down on the straights.

[liam821]

Looking good! Sucks about the engine problems, hopefully that won't be an issue now.

[M3dragon]

nice build

[bigjae46]

This damned front splitter...think I have it figured out. I was trying to stay away from using steel to mount the splitter but aluminum is too soft.

I welded some threaded inserts onto a steel plate. The mounts are height adjustable.



I attached the brake ducts to the front reinforcement bar. I used some L brackets from home depot and bolted them on using riveted nut-serts.



First two attempts at the carbon splitter...let's say I learned a lot. Biggest issue was the top had a lot of air trapped in the finish so the carbon didn't get completely wet out. I punched holes in the foam core and got much better results...







Better mounting. Using some binding posts and a urethane 2 part adhesive to mount the hardware to the splitter. Here it is! Comes on and off much easier.

[bigjae46]

The front lip looks great! Im planning on doing the same thing over the winter but just with a wet layup. Do you have a oven big enough for that splitter?

I was going to try a vacuum infusion but wasn't sure if my vacuum pump could handle it. I did a wet lay up and then pulled a vacuum through a bleeder cloth.

The epoxy resin I use cures at room temp. You get some more impact resistance and strength with an oven but it is not necessary.

[SandeepM3]

The front lip looks great! Im planning on doing the same thing over the winter but just with a wet layup. Do you have a oven big enough for that splitter?

[bigjae46]

Wow, lots of great work with this build! Also liking the composites work.

For the splitter are you going to be implementing steel or aluminum inserts into the layup for fasteners? It would make the mounting points a lot stronger, and a lot less prone to tearout.

For now I’m still going to run a bolt through the panel.

I’d like to attach a stud to the splitter so I can just spin a couple of nuts off to remove the splitter. I think I know what adhesive to use and it should be plenty strong. Just don’t have enough time to mess around with it right now.


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