Open Inverter Takes on Hot Rod Drag Week

[P.S.Mangelsdorf]

Provided I get my BMS up and running and finish a few other repairs/adjustments, next week I will be taking Shocking Chevy on Hot Rod Magazine Drag Week. While not the first EV to take on the event (a stock Tesla Model S ran in 2019), I believe I'll be the first EV conversion.

Drag Week is an event to prove who has the ultimate streetable race car. Participants must race a total of 5 times at 4 race tracks and the race vehicle must be driven track to track along a specified route with no support vehicles, no trailering, no towing. Participants must carry all their gear, tools, luggage, etc in the race vehicle or in a small trailer towed by the race vehicle. Typically, the total route for the week is around 1000 miles.

This year, the stops are:
Darlington Dragway (South Carolina)
Rockingham Dragway (North Carolina)
Bristol Dragway (Tennessee)
Carolina Dragway (Aiken, South Carolina)
Darlington Dragway

If you want to know more, here's a link: https://www.motortrend.com/events/hot-r ... formation/

There will be a live stream on MotorTrend's Youtube channel, but my plan is only to make one run per day on days 1-4, so I can get right on the road. With a range of 60ish miles (maybe 70 but the new pack is untested) I'll be stopping to CHAdeMO fast charge often. I'm running in the Street Machine Eliminator class, which I have very little hope of placing well, but is the best fit for the car at this point. The real accomplishment is just finishing the week.

I'll try to update this thread throughout the week, and hopefully I won't end up stranded in the Blue Ridge Mountains somewhere.

[P.S.Mangelsdorf]

Well, we survived! If only by the skin of our teeth at times, but we did it; the second EV and first EV conversion to complete Hot Rod Drag Week.

Along the way, we had issues with Level 2 charging, lost an axle, had a water pump fail, had a different water pump catch fire, and got very, very, very little sleep.

Monday and Tuesday, I had the first run result in an OC trip, and then a clean but slow second run (both in the 13s). The first night drive was ok at first, then slow going due to lack of fast charging, and then the CV joint bolts backed out on the drivers side axle, leading to a roadside repair and a morning of properly repairing the issue.

The PCS charging issue (sees correct voltage and amps available, but only thinks it can pull 2kW) nearly ended my week in the NC/TN mountains between Rockingham and Bristol. The route did not have any fast charging for the last 70-100 miles in steep mountains (last CHAdeMO charge was in Hickory), but plenty of 7kW Level 2 chargers. The fact the car would not pull full power meant we limped into the track at the end of the day with a generator strapped to the roof, and took a 20-second timeslip. It then took nearly 5 hours to get to a fast charger; and I then had an uneventful 250-300 mile drive through the night (again) to Carolina Dragway, with plenty of fast charging.

At Carolina on Thursday, I had my best run of the week. Still rolling in to avoid tripping the OC issue, I went 12.6 @ 113, a personal best. The Hot Rod staff was ecstatic to see me make it there, and have a fairly good run.

After breaking the beams on a failed pass Friday (once again hit an OC error and shut off), I turned in my timeslip and completed the week, and then later in the day decided to make another tweak to the settings and attempt a hero pass. Unfortunately, when testing that change in the pits, two of 3 motor mounts failed, including one broken ear off the motor. Either I got the settings right, or the mounts had just had enough.

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I've got a long list of repairs and improvements based on this experience. First up will be remounting the motor, and possible switching to the Sport LDU I have, if that inverter turns out ok. If not, the base inverter will go into that case, and then back into the car. After that, fixing the PCS will be the next priority. I'm not sure the exact path forward on that, but I have a few ideas.

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I will certainly be taking on Drag Week again. For all the positive reaction I received, I'm sure there will be far more when the car can consistently lay down 11s or even 10s. The people of Drag Week are great. The Hot Rod staff loved the car, the other participants were fascinated by the car, and even the staffer/announcer that sells "gasoline forever" t-shirts had to admit that he liked my approach and how I put the car together.

Here's the lesson for everyone: Get out there and drive your stuff. It doesn't have to be perfect, hell it doesn't even need to be good. Take adventures. Push your and the car's limits. Stuff will go wrong, you'll have moments were you doubt every decision you've ever made, but the adventure is all worth it.

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PS: If anyone wants to join me on Drag Week 2024, I think it would be awesome to have another EV conversion to cruise with.

[RobCote]

Hell yeah!! What a legend! The first EV swap to complete Drag Week is a gargantuan accomplishment. Outstanding work!

2024 might be an aggressive timeline for myself, I'm not really sure yet. I'll say perhaps. I'd LOVE to, but I don't want to rush for an arbitrary deadline.

Is street machine eliminator the only class that an EV can enter? It seems like it, but it wasn't especially clear to me. I'm hoping to be under 10s, even low-9s, which brings into play all the necessary safety equipment, as well, which is also unclear with respect to EVs.

I need to spend more time reading around here and find your build to get caught up. But once again, nice work and congrats.

[P.S.Mangelsdorf]

Is street machine eliminator the only class that an EV can enter? It seems like it, but it wasn't especially clear to me. I'm hoping to be under 10s, even low-9s,

EVs can theoretically run in Unlimited or Ultimate Iron, if they meet the other criteria for those classes, which now includes a maximum ET requirement, to prevent them from being catch-all classes.

which brings into play all the necessary safety equipment, as well, which is also unclear with respect to EVs.

I need to spend more time reading around here and find your build to get caught up. But once again, nice work and congrats.

EVs need to meet NHRA safety rules, which just changed this summer. (https://www.nhraracer.com/Files/Tech/20 ... _08_23.pdf , section 4H) I had discussions with the race director after the change, and after discussion they ended up being ok with me meeting all of the old rules and some of the new rules for this year, especially as I was running in SME, where they really only look at roll cage/bar, helmet, and harness for typical cars.

There's a lot I would do differently if starting today, but I'm going to keep improving what I have for now. Where are you located? I'm happy to chat offline and help where I can.

[Aragorn]

This is great!

Have you got rough timestamps for the live feed?

edit

Scanned thru day1:

[Aragorn]

day 2:




day3, i couldnt see the run but there was some chat about your car at the start:



day 4:

[P.S.Mangelsdorf]

Thanks! I hadn't had a chance yet to go through the live stream, though I did have family members sending me clips.

[Aragorn]

Dave and Brian seemed pretty impressed with the car from their chat

A little technical inaccuracy ofcourse but the sentiment was overall positive i think!

I'm also impressed with your daring taking a car on drag week that both didnt charge properly and didnt accellerate properly

Something else i noticed one at least one of the clips, maybe your already aware, i dont know, but you drove thru the waterbox but then didnt do a burnout... If your going to skip the burnout, you can drive around the waterbox instead so your tyres dont get wet!

[P.S.Mangelsdorf]

Something else i noticed one at least one of the clips, maybe your already aware, i dont know, but you drove thru the waterbox but then didnt do a burnout... If your going to skip the burnout, you can drive around the waterbox instead so your tyres dont get wet!

It's still got an open diff so it was lightly spinning the right tire but not the left, it was also shutting off during the burnout. I've gotten some good ones before; and one of the planned upgrades for next year is an LSD.

[MattsAwesomeStuff]

Fantastic story and well done.

Is a generator legal per the rules?

The point of Drag Week is that you don't trailer your cars, you drive them to the next day's dragstrip. That to me says you have to be using the powerplant that you race with to do the transport. The point being to exclude race-only highly specialized un-streetable vehicles. So either you shouldn't be using a generator, or, you should be forced to bring your generator with you on the drag passes :p

Now of course you're only recharging the car with the genny, not propelling it directly, the motor is still doing all of that. But the battery and charger are basically getting a free ride out of it.

As a pioneer, just getting to the point of competing is a challenge enough, but eventually this'll have to be fleshed out.

Just spitballing here, suppose all EVs on drag week had lightweight hybrid batteries only, for their actual pulls, and otherwise all of them used gennies to transport. That's not fair to someone who would carry a large enough pack to accommodate the whole trip (what with the massive weight penalty of a travel battery), not is it really using their car (and stressing it appropriately) for transport considering that battery use is a huge portion of an EV's ability to travel long distances. It's a different challenge for the EV playing field.

That said, there isn't an ICE equivalent, no one worries about the ability of their gas tank to handle the drive. There's lots of dual-fuel setups and they probably drain the E91 out of the tanks when they run Meth for their passes to go lighter.

Interesting to see how things go.

Thanks for sharing the adventure!

[P.S.Mangelsdorf]

Fantastic story and well done.

Thanks for sharing the adventure!

Thank you! It was an awesome adventure.

Is a generator legal per the rules?

The point of Drag Week is that you don't trailer your cars, you drive them to the next day's dragstrip. That to me says you have to be using the powerplant that you race with to do the transport. The point being to exclude race-only highly specialized un-streetable vehicles. So either you shouldn't be using a generator, or, you should be forced to bring your generator with you on the drag passes :p

To the best of my knowledge, the generator was legal, and seeing as the race director saw it and didn't have a problem, its de facto allowed. The giant caveat here is that the generator was on the car, not a trailer. The rules specifically say nothing on the trailer can fuel, charge, or propel the vehicle during the drives.

The rules require you use the same long block all week, which while not exactly applicable, I take to mean the drive unit or motor for EVs.

Just spitballing here, suppose all EVs on drag week had lightweight hybrid batteries only, for their actual pulls, and otherwise all of them used gennies to transport. That's not fair to someone who would carry a large enough pack to accommodate the whole trip (what with the massive weight penalty of a travel battery), not is it really using their car (and stressing it appropriately) for transport considering that battery use is a huge portion of an EV's ability to travel long distances. It's a different challenge for the EV playing field.

My original plan for the car called for an additional battery pack that would be removed for the on track passes. I quickly realized the extra weight and logistics of not only the battery but also the hoist and equipment to safely remove and store the extra battery in the pits was not worth the challenge.

Until there's an EV specific class (which Sick Week does have, under the "Sick Freaks" class), parity between EVs will be less of a concern.

That said, there isn't an ICE equivalent, no one worries about the ability of their gas tank to handle the drive. There's lots of dual-fuel setups and they probably drain the E91 out of the tanks when they run Meth for their passes to go lighter.

Yeah, the best comparison is cars that switch from pump gas to E85, 116, or methanol. Some drain, some have trick valved fuel systems. There were cars in the past that changed entire doors and front ends, but that's mostly been done away with.

The other comparison would be ICE cars with only an E85 tune that have to carry many jugs of fuel with them to deal with very few gas stations carrying E85. I heard from a few people that it was a pain in the ass this year, especially because "E85" in the south is often far closer to E50.

I'd also point out, the generator was only providing 1kW of power. It couldn't move the car by itself, but it could help maintain momentum once it was moving, ever so slightly. I'd advise strongly against what I did - the right solution is to have an onboard charger that can use the full 7kW available at most Level 2 stations - but it worked in a pinch.

As a pioneer, just getting to the point of competing is a challenge enough, but eventually this'll have to be fleshed out.

Honestly, I am beyond excited for the day when there are other lunatics like me trying to do this. Fleshing out the rules package will be an interesting challenge, and I imagine the next several years as we get more conversions trying the event we'll build up a good group and enough experience to figure out what is needed and what isn't.

[MattsAwesomeStuff]

Ick, 1kw?

Jeez that only extends your range by like, 5% at highway speed. On its own your max speed would be, what... 5mph at most?

Ridiculous but I love it.

What's it cost to compete btw, event-wise?

[P.S.Mangelsdorf]

Jeez that only extends your range by like, 5% at highway speed. On its own your max speed would be, what... 5mph at most?

Oh it gets worse - right now the car is burning about 450Wh/mile. Which is why the PCS charging speed is such an issue. Charging at 2kW is only adding 4 miles/hr.

After fixing the motor mounts, tune, and PCS issue, the major upgrade for next year will be an attempt to lower that number. I need front coilovers to soften and lower the nose, and then I'm planning to add ducting in the former engine bay and likely louver the hood to let some air out, rather than have it hit the firewall and then make its way under the car. I have to make sure the radiators still get air, but that the air can get out. I'm also thinking about bringing a second set of rear wheels for on the street, so I'm not rolling on drag radials all the time. Save the track tires and reduce resistance.

Part of the motor mount repair will also include some adjustments to improve CV joint angles and let me lower the rear a little bit.

What's it cost to compete btw, event-wise?

I think the entry was $500? Registration was back in March or April, and as usual sold out in minutes.