Saturday, July 18, 2020

DIY - Under Panel Drain (Speed) Holes

I read about Model 3s losing their bumpers due to filling up with water. When I look underneath at the rear diffuser and I see that there are some small holes where it meets the undertray for drainage, so I decided to make some enlarged holes along the slope. Drilling holes in cars always reminds me of this clip from the Simpsons.

"Speed holes"

I decided to perform this modification without having to remove the diffuser from the rear bumper as that was way too much work. This is where my "speed" holes are position and they do not interfere with the rear deep trunk section.

Friday, July 17, 2020

DIY - Eibach Lower Springs - Positive Wh/mi results

I specifically bought a P3D- because I wanted to make my own version P3D, by putting in better parts the Performance Upgrade Package aka PUP. Or even perhaps a P3D+ but with a twist such that I don't want a fully track dedicated car (as I have my GT-R) but I want it to be comfortable and fact if possible more efficient than an LR AWD model. So the journey started by looking at brakes, aero parts, suspension components and eventually tires + wheels. I want it to come in under the cost of the Tesla PUP but with better parts.

Two piece rotors shave of approximately 14-16lb depending on front rotor size option. This is both sprung and unsprung weight. Sprung weight is not enough to make a considerable efficiency difference and the problem with the unsprung weight is that it is too close to the rotational axis i.e. lighter rotor hats not lighter rotors themselves. Therefore, maybe a last choice more for better braking and not efficiency, specially considering a $2,000-$2,200 cost, but I will first consider better brake fluids and lines.

One sure way to make a positive impact is aero. I first look at front splitters and rear spoiler. Anyone who watches any form of racing will know that the Model 3 "carbon" spoilers stuck on with 3M tape do absolutely nothing for considerable downforce. If my assumption is not correct, I should be able to put about 30-50lb of pressure on a spoiler stuck to a trunk with 3M tape and not have it snap off. 😅Therefore, it purely cosmetic unless bolted on and not worth the $1000 IMHO. A better rear under diffuser would take care of eddy currents behind the car. 

The front splitter is also a crock. Studying the front aero changes over 4 iterations of the current generation GT-R for the last 12 years has revealed what works and does not work in terms of aero. I don't care what a self funded CFD study states, the speeds at which you need to go to achieve ~5% efficiency simply by putting some additional plastic is not practical even for every day highway driving speeds. Visual inspection of the front of a Model 3 shows its pretty damn good aero design, if anything aftermarket products simply seem to cover the wheel opening slightly more, pushing the air out sideways. Perhaps sharing raw CFD data for a peer review would be one sure way for a vendor to stand behind product claims by manufacturers. Instead I believe that a more aero front under diffuser would help reduce the gap between the car and ground more cost effectively. This is what Nissan did to the GT-R after lap upon lap of Nürburgring testing.

So I next looked at lowering springs and for $324 the Eibach E10-87-001-02-22 PRO-KIT Performance Springs is one of the most cost effective ways to improve aero. Indeed my GT-R is lower and I can barely fit 2 fingers compared to my Model 3 in which I can fit 4 fingers between the tire and body. Lowering the car over an inch reduces drag, all around...period. Anyone an F1 tech fans? You know exactly what I am talking about. It also improves handling and could enhance ride quality. Bonus was that the springs are available on Amazon which means I can use gift cards to pay for it.

First off, I am extremely happy with the way the car looks with these springs on. This is how it should have been from the factory, IMHO.

Visual Comparison of before and after springs

Secondly, it is much more compliant on bumps due to the dual rate springs. The best way I can describe this improvement is that I can hear the tires hit road imperfections, but not feel them anymore. Before, I could immediately feel them as well as hear them. Handling is same to only slightly better, steering is very neutral as it was before. As you can see from my post about track mode, I do beat it up on back roads and these are not always the smoothest surfaces so compliance was important for me, I don't want it so stiff that it is unstable.

As for the Wh/mi, huge improvements here...

Wednesday, July 15, 2020

DIY - Changing Front Springs

Changing the front spring requires a little more precision and some special tools compared to the rear spring. In addition to the tools needed for the rear springs, this will require

  • A 13mm thin wall deep socket, and you may still need to grid the outer walls of the socket extra to have it fit through the mount to unbolt the struts. I used 1/4" drive socket which is the thinnest wall I can find and still had to grind the outside a few 10th of a mm using a Dremel.
  • TT50 and T40 Torx sockets
  • Long Hex Wrench (4.5 mm or 5 mm)
  • Strut socket
  • Straight edge & marker
  • Spring compressor (This can be rented from a parts store such as O'Reilly and is usually free after the deposit is refunded upon return
Changing front springs.

Start by removing the front trunk (frunk) as per these instructions.

Tuesday, July 14, 2020

DIY - Removal of Front Trunk

The Model 3 front trunk or (frunk, as its known on the streets) is fairly easy to remove.

Definitely needs to be removed to access things such as strut mounts for spring changes, front alignment and other service work.

To remove the frunk, first open the frunk lid. Remove the vent shield close to the wind shield. It is held by several plastic clips and simply pops up. The down arrows show the mounting points and the entire piece just pops up.

Cover removal.

Next remove the vent inlet. Again, it is held by the white plastic clips as illustrated and so it simply pops up. 

Monday, July 13, 2020

DIY - Eibach Lower Performance Springs - Rear Spring Install

Fair warning: If you are not mechanically inclined and have no experience working on cars, just don't do this. If the car is jacked unsafely or the torque is set wrong on suspension components and wheels, it can leave you dead. Just hire a shop to do it. This DIY is at your own risk.

Arguably doing the rear is easier because of the lack of need for specialized tools such as Torx bits and spring compressors. However, I did learn half way that removal of the rear diffuser is important to release the springs and to set the torque of bolts properly, so be prepared for that and see the approparite instruction here.
Eibach and Stock Springs side by side

Let's get started. The tools that will be needed are shown below.

Sunday, July 12, 2020

DIY - Removal of the Rear Diffuser for spring change or cleaning or extra drain holes

This is a lot easier to do with the car jacked up even on one side. Remove the 3 pop fasteners using a flat screw driver. Remove the small nut that hold the fabric in the wheel well behind the well, this will give easy access to other bolts. 

Note I have aftermarket splash guard so my setup looks different. Repeat this for the other rear wheel.  The wheel does not need to be removed, a short flat screwdriver will work just fine or come in from under the car.

Remove pop fasteners

Remove the two bolts from under the bumper behind each wheel. This needs to be repeated on each side.