Smaller and Lighter wheels make you faster, more efficient, and offer better road hazard protection.

[mpgxsvcd]

I was looking at your charts and doing some analysis of my own and noticed an interesting trend. It does appear that Tesla may limiting the initial launch (~0-10mph range). It hits the "1.0G limit" that many mention and acceleration rapidly drops. You can actually see the rear motor torque output drop in this range, despite sufficient battery power. It looks like Tesla may be dropping the battery amps and/or phase amps here. They then ramp the battery current up progressively from there. It doesn't appear to be a battery limitation as it's clearly capable of more amps. The front motor doesn't appear to experience this dip.

View attachment 875591

Drop in rear motor torque, but not front motor:

View attachment 875588

Drop in battery current (amps):

View attachment 875610

That is probably the car cutting power because it is at the traction limit as opposed to an artificial acceleration limit.

I seriously doubt it measures acceleration and artificially says “cut power despite having traction”. It is much more likely that it senses wheel slip and cuts power.

If I am right then a sub 3.10(without subtracting rollout) should be possible simply by removing weight, which I have done now.

 

[EVolv3d]

That is probably the car cutting power because it is at the traction limit as opposed to an artificial acceleration limit.

I seriously doubt it measures acceleration and artificially says “cut power despite having traction”. It is much more likely that it senses wheel slip and cuts power.

If I am right then a sub 3.10(without subtracting rollout) should be possible simply by removing weight, which I have done now.

That's something that could be tested pretty easily if someone has access to a good set of sticky tires and a well prepped drag strip. Granted, wider/stickier tires wouldn't be ideal for the best 1/4 mile time.

 

[mpgxsvcd]

That's something that could be tested pretty easily if someone has access to a good set of sticky tires and a well prepped drag strip. Granted, wider/stickier tires wouldn't be ideal for the best 1/4 mile time.

I will have plenty of grip on Saturday. I have good PS4S tires and they are charging us double the normal price to have the ultimate track prep for a Test and Tune. The only thing that would make my 0-60 mph time faster this weekend would be if I got my daughter to drive it.

I can do a rolling burnout before each run so that should get my tires warm enough.

 

[mpgxsvcd]

Here is a bit more data that demonstrates how consistent my car is at running 11.399 or faster with the 18" T Sportline wheels. This is FORTY FIVE separate 1/4 mile passes at the Rockingham Dragway from this summer. Every single one of them is 11.399 or faster. I think 4 or 5 of them are 11.30 or faster.

Pretty insane to have this kind of consistency. Charging at the track makes this possible. If I couldn't charge in-between runs the car begins to fade after 3 passes. By the 5th pass it will be in the 11.4s.

Also, I can run 11.30 and then within 10 minutes have the car maxing out at 11.59 even with 95+% SOC by running Track Mode. Cooling the battery obliterates straight-line acceleration very quickly. However, that also means I can do 11.3 passes and then dial in an 11.501 pretty easily if the class calls for that. This car is an absolute beast for bracket racing or 11.50 and slower racing.

 

[SantaCruzOMB]

I decided to go with lighter wheels since that's really the only "mod" available for drag racing. I settled on the 19x8.5 and I wanted your feedback on tires. Do you think 235/40-19 will have any less traction then the 245/40-19 for straight line racing? The 245 width would look better but I'm assuming there's at least a little weight savings from the 235 width.

My best 1/8 miles is a 7.28 but most are in the low 7.30's. I'll report back after trying the new setup.

 

[mpgxsvcd]

I decided to go with lighter wheels since that's really the only "mod" available for drag racing. I settled on the 19x8.5 and I wanted your feedback on tires. Do you think 235/40-19 will have any less traction then the 245/40-19 for straight line racing? The 245 width would look better but I'm assuming there's at least a little weight savings from the 235 width.

My best 1/8 miles is a 7.28 but most are in the low 7.30's. I'll report back after trying the new setup.

Honestly, I would go as small in diameter and width as possible for pure straight line acceleration. Traction in a straight line just isn’t an issue for this car with reasonable summer tires and warm temps.

I think I will go to 225/45/18 when my current PS4S tires wear out. Those will still stick in a straight line with the correct pressures. They are crazy cheap even for decent summer tires.

Weight reduction helps for sure. I had a pretty epic day at the track yesterday.

 

[SantaCruzOMB]

Honestly, I would go as small in diameter and width as possible for pure straight line acceleration. Traction in a straight line just isn’t an issue for this car with reasonable summer tires and warm temps.

I think I will go to 225/45/18 when my current PS4S tires wear out. Those will still stick in a straight line with the correct pressures. They are crazy cheap even for decent summer tires.

Weight reduction helps for sure. I had a pretty epic day at the track yesterday.

View attachment 876567

What was your avg gain from the weight reduction? I saw your prior 0-60 was almost 0.2 higher than that run. Did you change anything else?

I'll likely go with the 235 width. It sucks the PS4's are cheaper in the 245's but I guess that's a more popular size.

 

[mpgxsvcd]

What was your avg gain from the weight reduction? I saw your prior 0-60 was almost 0.2 higher than that run. Did you change anything else?

I'll likely go with the 235 width. It sucks the PS4's are cheaper in the 245's but I guess that's a more popular size.

I had some 3.11 and 3.13 runs before weight reduction but they were marked invalid so I didn’t post them.

It appears that 150 lbs of static weight gives me .1 seconds from 0-60 mph through the 1/4 mile. 40 lbs of rotational weight gave me about .08 seconds for 0-60 mph through the 1/4 mile. About a 3x factor for rotational weight vs. static weight.

 

[Lindenwood]

It is interesting how this topic died right as you got to that 3.01 natural 0-60, @mpgxsvcd .

My wife shot it down but a friend and I were spitballing about replacing the entire roof and rear glass with a single custom molding of carbon fiber… it should only cost maybe $500 to do two iterations (one practice and one real), and save a good 50-60lb off the roof.

 

[tm1v2]

It is interesting how this topic died right as you got to that 3.01 natural 0-60, @mpgxsvcd .

My wife shot it down but a friend and I were spitballing about replacing the entire roof and rear glass with a single custom molding of carbon fiber… it should only cost maybe $500 to do two iterations (one practice and one real), and save a good 50-60lb off the roof.

<evil conscious voice> CF roof M3P...do it...

Seriously that would be pretty sweet. Glass is very heavy as we all know. Even on a 4k lbs M3P I bet replacing that glass roof with all that weight up high would be a detectable benefit. Plus it could look sweet, potentially, if done cleanly.

Have you done any CF work yourself yet? I haven't, but friends who have found it pretty challenging to make things look good. Making a functional piece that fits and serves its purpose might take two tries, but getting to the point of it looking like a nice professional product is/was another story. Maybe you'll do better!

Most of these CF pieces were for hobbyist race cars though so functional was all that was needed.

 

[Lindenwood]

<evil conscious voice> CF roof M3P...do it...

Seriously that would be pretty sweet. Glass is very heavy as we all know. Even on a 4k lbs M3P I bet replacing that glass roof with all that weight up high would be a detectable benefit. Plus it could look sweet, potentially, if done cleanly.

Have you done any CF work yourself yet? I haven't, but friends who have found it pretty challenging to make things look good. Making a functional piece that fits and serves its purpose might take two tries, but getting to the point of it looking like a nice professional product is/was another story. Maybe you'll do better!

Most of these CF pieces were for hobbyist race cars though so functional was all that was needed.

Never once done CF, but I’ve worked with epoxy in general a good bit (both structural as a matrix and for layered things like hand grips) and like to think I am pretty smart and technically savvy. In any case, I have never been one to let people tell me I can’t do something, so I am very willing to try.

I would honestly be okay if it looked good from 15 feet away haha.

More generally, by my math one could theoretically hit a 10.99 on an M3P with a 100% full, hot battery AND about 350lb in weight reduction.

-125lb (equivalent) comes from lightweight, undersized wheels and tires
-50lb comes from removing the passenger seat, -75lb comes from removing the rear bench, frunk tray, etc (maybe an hour worth of work)

-50 comes from the CF roof, taking us to 300lb under stock.

If one wanted a real cheap solution, removing the front and rear anti-sway bars and links would probably save about 50lb and only take another hour or so of work.

Otherwise, without spending $5-7k on CF trunk and doors, there isn’t really a way to reduce weight to that threshold and still keep the car comfortable for daily use.

 

[rayrevolver]

Good data in this thread.

If you searched the internet for "sprung vs unsprung weight" you would find lots of information to back your findings.

Unsprung = What you call rotational
Sprung = What you call static

There are rules of thumb like 1lb removed from unsprung weight = 4lbs or more of sprung weight. You say 3 lbs and that is real data for a Tesla, which is awesome.

How Do Lightweight Wheels Affect Your Car's Performance?

Why does wheel weight matter? Lightweight wheels can have a huge effect on any vehicle's acceleration, braking, and cornering abilities.

news.classicindustries.com

There are rules of thumb with respect to power to the ground but the numbers I recall apply to motorcycles.

I had a hot hatch that I removed 6.25lbs per corner. No hard data but it spun up faster (170 raging HP), handling/braking was better, but also I think the lack of unsprung mass made the car harsher over bumps.

 

[gearchruncher]

More data for this thread.
While I have advocated that the car may be software limited in acceleration, it appears that's not true.
B is for build stripped a whole M3P. As in took off the whole roof.
They did a 0-60 before and after. 3.8 before, 2.8 after. Weight does matter and improve performance. (Time test is @20:00)

 

[Lindenwood]

More data for this thread.
While I have advocated that the car may be software limited in acceleration, it appears that's not true.
B is for build stripped a whole M3P. As in took off the whole roof.
They did a 0-60 before and after. 3.8 before, 2.8 after. Weight does matter and improve performance. (Time test is @20:00)

I rarely reminisce about the “good old days” (because we wouldn’t have our badass cars cars in said days), but man do I miss not having to watch 20 minutes of rambling to get to actual data . Long live discussion forums!

 

[Unclepaul]

Smaller wheels & tires are more efficient, however larger looks better and can fit larger brakes.

More buyers want the better looking tires, while fewer will opt for the more efficient ones.

Everybody wants both better looking and more efficient, but that is not the way it works

 

[Sam1]

More data for this thread.
While I have advocated that the car may be software limited in acceleration, it appears that's not true.
B is for build stripped a whole M3P. As in took off the whole roof.
They did a 0-60 before and after. 3.8 before, 2.8 after. Weight does matter and improve performance. (Time test is @20:00)

Yeah, that video is a bad example. they say it goes from 3.8 seconds down to 2.8 seconds by using a clock and speedometer. that's an M3P it looks like, it was never getting a slow 3.8 second time, and then they say they think it's faster than a plaid 0-60 now at 2.8, and then even corrected it with text saying the plaid is only 2.3 seconds 0-60 in the video.

Whole thing is full of wrong info. If they can't even spend $150 on a dragy to get accurate data, after ruining a car, nothing else they are doing is going to be remotely correct either.

 

[CKwik240]

More data for this thread.
While I have advocated that the car may be software limited in acceleration, it appears that's not true.
B is for build stripped a whole M3P. As in took off the whole roof.
They did a 0-60 before and after. 3.8 before, 2.8 after. Weight does matter and improve performance. (Time test is @20:00)

Reminds me of a Sport Compact Car article many years ago where they took a Sentra SE-R and did something like this and ended up with a significantly faster car. Something on the order of a 16 second car down to 13s or 14s IIRC.

 

[gearchruncher]

Yeah, that video is a bad example. they say it goes from 3.8 seconds down to 2.8 seconds by using a clock and speedometer. that's an M3P it looks like, it was never getting a slow 3.8 second time, and then they say they think it's faster than a plaid 0-60 now at 2.8, and then even corrected it with text saying the plaid is only 2.3 seconds 0-60 in the video.

There are lots of inconsistencies in this video. They are at a much higher SoC in the quicker run than the slower one also. The quick one was with a cold battery though (notice the limited regen icon despite a ~70% SoC)

However, they do manage to get a model 3 to go from 0MPH on the speedometer to 60 MPH on the speedometer in 2.8 seconds. Which is clearly faster than a full weight car can do it because nobody has ever pulled off a 2.8 0-60 in a Model 3.

The only proof we have here is that the car will accelerate faster if it weighs less. The computer is not holding the car to a specific acceleration number. That's still interesting data, despite not being as perfect as we'd hope.

If you watch the whole video series, you'll see he specifically says he knows almost nothing about Teslas, so picking over not knowing a Plaid 0-60 off the top of his head isn't really relevant. The fact is, he did cut up a whole Tesla, kept it driving with almost no errors, and pulled off a killer 0-60 that may actually represent a low 2 second 0-60 when measured the way other processes measure it.

 

[Lindenwood]

Yeah, that video is a bad example. they say it goes from 3.8 seconds down to 2.8 seconds by using a clock and speedometer. that's an M3P it looks like, it was never getting a slow 3.8 second time, and then they say they think it's faster than a plaid 0-60 now at 2.8, and then even corrected it with text saying the plaid is only 2.3 seconds 0-60 in the video.

Whole thing is full of wrong info. If they can't even spend $150 on a dragy to get accurate data, after ruining a car, nothing else they are doing is going to be remotely correct either.

In any case, @Zerosport ran a 2.96 natural 0-60 and reportedly 10.7x 1/4s with 450lb removed.

 

[Sam1]

In any case, @Zerosport ran a 2.96 natural 0-60 and reportedly 10.7x 1/4s with 450lb removed.

That's not very fast because with a completely stock (not a single thing removed) M3P stealth I have a 2.98 0-60 on dragy. The 10.7 is good though.