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Statistically Speaking, Fuel Capacity


Black Magic
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I wanted to examine this topic with some statistics, since emotionally this dead horse has taken a beating. Fuel comes up every year in petitions, but it seems like the ideas lack details on execution, proof or consistency. I am only looking at proof of a correlation, not trying to fix anything yet. This could be a good guideline for new teams, on what cars are pretty helpless and better left to another series, if nothing else.

 

The idea is to try and keep this to "does it take x amount of fuel to be competitive" or "is having below x amount of fuel a handicap", from a statically backed standpoint. This is gonna be a little tough, cause several cars use all of the grey to dark grey area's of the rules (maybe an integra in the for sale section :) ), and the math will be based on the assumption the capacity is somehow linked to the oem capacity. 

 

Weight was grabbed from Edmunds or automobile catalog using the lowest weight the best engine package had (what you would race). The typical "champcar % weight reduction" factor was then multiplied (use 90%). Smaller non luxury cars get screwed in this, but we have to pick some number since I don't have a good list of race weights.  Fuel to weight, FWR, is this 90% curb weight divided by oem tank capacity.

 

I was able to get ahold of the race results for 2017 to current. I took the podium results, and just excluded cars that were EC. If an EC car finished 2nd, then I only used the 1st and 3rd place cars. The data was already immense, and with 88 races missing one or two isn't gonna destroy the trends. I made sure the highest podium was moved up to winner, to make sure the winner stats were at least accurate.

 

Moving on, There are 110 teams who scored a podium since 17'. These teams used 32 different chassis makes, which shows some diversity despite 3 cars (NA miata + E30 + E36) being 59 of the 110 wins. Plotting a histogram of the FWR for these types of cars looks like what you would expect, a clump around the e30\e36 range

 

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Looking at all the races, you see a big clump in the mid 160s or better. 

 

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Looking at all the races can be a bit deceiving, since we have some west coast races with very low turnout. Not sure how much fuel economy matters if there are less than a dozen cars still running at the end (at any pace). If we limit the conversation to races with at least 40 cars, we still have 47 races of data, potentially 141 podium spots, all with more people and hopefully good cars fighting for it.

 

These results look more bleak for cars with poor fuel to weight. In the past 2 years with races that have over 40 people only 3 cars with a FWR over 170 have won a race. 3 out of 47.  

 

image.png.a73025b6dbaa465ae501d8a6ea98efc5.pngimage.png.7d35e09e2ee14bf384d642c88f1ed214.png

 

Of the races with over 40 cars, only 9 teams with worst than 170 lbs\gal have scored a podium. They scored 18 podiums of the roughly 140 possible chances.

 

The 9 teams used 6 types of cars, Integra Gen 2 (10X), Civic Gen 5 (2X) and 6 (1X), Neon (2X), Gen 4 Mustang (2X) and SC2 Saturn (1X). Besides the mustang, these cars are in the high 170s, off the pace but perhaps close enough if lots of cautions, 7 hour races or off sequence racing.  Several of these cars do not use a cell, which you can sort of figure out why if you stroll through the classified and buy one of these cars that happens to be for sale.....

 

So does fuel capacity really represent this large of a performance detriment? Not that some stroke of luck, a good call, or some other act can't result in a win, but do you think the numbers represent or approximate the real odds of winning outside of the 160-170 lbs per gallon "wall"? I wish I had sorted out tracks with really low or high fuel burn, which wouldn't change the # of stops for a good vs bad fuel capacity car. Assuming these non typical races would make life easier for a bad capacity car, they still don't appear to be winning much anywhere......

 

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Edited by Black Magic
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Weights are already being manipulated in the current swap calculator.  Are you suggesting another type of fuel capacity calculator based on weight?   We will just have teams cry until their weight is adjusted down to what they want and not what the rules state.  

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2 minutes ago, Snake said:

Weights are already being manipulated in the current swap calculator.  Are you suggesting another type of fuel capacity calculator based on weight?   We will just have teams cry until their weight is adjusted down to what they want and not what the rules state.  

 

I have heard tons of proposals to change this, so far only trying to figure out, prove\disprove that fuel really matters all that much. 

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51 minutes ago, Snake said:

Weights are already being manipulated in the current swap calculator.  Are you suggesting another type of fuel capacity calculator based on weight?   We will just have teams cry until their weight is adjusted down up to what they want and not what the rules state.  

More weight = more fuel allowed.

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You’ve taken a guess at weight,  what you don’t have ( I don’t think). Is how much fuel they actually have.  How many have cells? How many have modified vents on stock tanks ?  How much does that gain?   If they couldn’t do that would the results shift?   How much additional is being added with long 3” fill necks?    

 

What your working toward has merit,  but may have some unintended consequences too

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3 hours ago, JDChristianson said:

You’ve taken a guess at weight,  what you don’t have ( I don’t think). Is how much fuel they actually have.  How many have cells? How many have modified vents on stock tanks ?  How much does that gain?   If they couldn’t do that would the results shift?   How much additional is being added with long 3” fill necks?    

 

What your working toward has merit,  but may have some unintended consequences too

 

Totally agree, and don't really have a way to do it besides list the 9 trams that podiumed at races with over 40 cars. I don't recall any of the gen 2 integras having a cell (like the one for sale) and that model accounts for half of all podiums for over 170 FWR at races over 40 cars.

 

 I have heard suggestions of pumpouts, which would probably put the nail in the coffin for several of the "magic 9" teams. If nothing else it should help you know that if cars at 160 FWR win with a cell and little work, you know how much you need to "work" on your capacity. 

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9 hours ago, karman1970 said:

Maybe separate by region?  West of the Mississippi I think there is a lot less reliance on FCY for strategy and pit stop planning simply because they happen much less often - in my limited experience. 

 

I tried to do this in a "nicer" way by making the races > 40 cars.....

 

Only 2 races, one weekend at Laguna, of the 47 races with > 40 cars was west of Mississippi.  If you remove another weekend at COTA, 43 races were what I consider "in extended range" for central east coast teams (gingerman\sebring\ glen about the limits of travel from north carolina). 

 

So over 40 cars basically = East region.

Edited by Black Magic
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Specifically with the Saturn, they are a good team with a slow car.  This was a podium at the nelsons 24.  High attrition and they were dozens of laps back.

 

Their accomplishment is amazing, but fuel had nothing to do with the podium.

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2 hours ago, Black Magic said:

I have heard suggestions of pumpouts, which would probably put the nail in the coffin for several of the "magic 9" teams. If nothing else it should help you know that if cars at 160 FWR win with a cell and little work, you know how much you need to "work" on your capacity. 

Since we are talking about actual races and the consequences of the limitations of fuel, I think it would be more relevant to use as accurate data as possible to define any trends that may appear. That means using actual race weights and fuel amounts if possible, despite the wringing of hands that surfaces whenever the topic of actual race weights comes up. Since I already have a reputation for discussing things that some would rather not see the light of day, I'll start with some of the more obvious cars that have already been mentioned.

 

E30: typical race weight is about 2300 lbs, +/- 50. Fuel tank size is 16.4 or 16.6 gallons depending on what source you use. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2300/18 or 128 lbs/gallon.

 

E36: typical race weight is about 2500 lbs, +/- 50. Fuel tank size is 16.4 or 16.6 gallons depending on what source you use. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2500/18 or 139 lbs/gallon.

 

Integra: typical race weight is about 2300 lbs, +/- 50.  Fuel tank size is 13.2 gallons. Allow 2.3 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2300/15.5 or 148 lbs/gallon.

 

Civic: typical race weight is about 2100 lbs, +/- 50.  Fuel tank size is 11.9 gallons. Allow 2.3 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2100/14.2 or 148 lbs/gallon.

 

Neon: typical race weight is about 2100 lbs, +/- 50.  Fuel tank size is 12.5 gallons. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2100/14 or 150 lbs/gallon.

 

Miata: typical race weight is about 2100 lbs, +/- 50. Fuel tank size is 12.4 gallons. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2100/14 or 150 lbs/gallon.

 

Mustang: typical race weight is about 2700 lbs, +/- 50. Fuel tank size is 15.4 gallons. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2700/17 or 159 lbs/gallon.

 

It would be interesting to see where this data for these cars appears on the graph.

 

 

Edit: entered Drew's numbers for the Neon.

Edited by mender
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26 minutes ago, mender said:

Okay, before the rhetoric dials up, I think it can be said that Drew's thread will be, as much as is possible, about the cars rather than the teams. 

 

Henceforth the mantra of this thread will be, "We didn't pick your team."  :lol:

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8 minutes ago, ABR-Glen said:

Sorry I chose an example specific enough to be linked to a single team. It's still valid to question the success of a platform as a proportion of wins/podiums to number of entries as opposed to just the total number of wins/podiums.

I agree, and as long as the examples are brought up to help clarify the issues by taking out stats that may muddy the water, it's beneficial.

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26 minutes ago, mender said:

Since we are talking about actual races and the consequences of the limitations of fuel, I think it would be more relevant to use as accurate data as possible to define any trends that may appear. That means using actual race weights and fuel amounts if possible, despite the wringing of hands that surfaces whenever the topic of actual race weights comes up. Since I already have a reputation for discussing things that some would rather not see the light of day, I'll start with some of the more obvious cars that have already been mentioned.

 

E30: typical race weight is about 2300 lbs, +/- 50. Fuel tank size is 16.4 or 16.6 gallons depending on what source you use. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2300/18 or 128 lbs/gallon.

 

E36: typical race weight is about 2500 lbs, +/- 50. Fuel tank size is 16.4 or 16.6 gallons depending on what source you use. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2500/18 or 139 lbs/gallon.

 

Integra: typical race weight is about 2300 lbs, +/- 50.  Fuel tank size is 13.2 gallons. Allow 2.3 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2300/15.5 or 148 lbs/gallon.

 

Neon: I'll let Drew fill this in.

 

Civic: typical race weight is about 2100 lbs, +/- 50.  Fuel tank size is 11.9 gallons. Allow 2.3 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2100/14.2 or 148 lbs/gallon.

 

Miata: typical race weight is about 2100 lbs, +/- 50. Fuel tank size is 12.4 gallons. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2100/14 or 150 lbs/gallon.

 

Mustang: typical race weight is about 2700 lbs, +/- 50. Fuel tank size is 15.4 gallons. Allow 1.5 gallons for the surge tank, vents, filter, hoses, etc;  that gives a FWR of 2700/17 or 159 lbs/gallon.

 

It would be interesting to see where this data for these cars appears on the graph.

 

I would think miatas are slightly lower when trying hard, say maybe 50 lbs. Same for the integra. Neons with a 2.4 swap and full fuel load are gonna be in the 2150 range, mine was 2100 full of everything (full fuel) needed to race besides driver gear and driver. Neon will be between civic and Integra in weight and fuel. 

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4 minutes ago, Black Magic said:

 

I would think miatas are slightly lower when trying hard, say maybe 50 lbs. Same for the integra. Neons with a 2.4 swap and full fuel load are gonna be in the 2150 range, mine was 2100 full of everything (full fuel) needed to race besides driver gear and driver. Neon will be between civic and Integra in weight and fuel. 

Entered.

 

That's why I put +/- 50 lbs, there will be variance from team to team. 

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The way I read this thread, and I may be wrong, is that it's a thinly veiled attempt to try and put limits on anybody's ability to increase fuel capacity within the current rule set. It appears to insinuate that the "magic 9" teams are cheating, which is insulting to those teams.

Basically if you aren't racing a Miata or a BMW, then eff off. 

Edited by Snorman
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1 hour ago, ABR-Glen said:

Since you have the data... how does the number of podiums/wins correlate to the number of entries for these outliers? I.e. one podium for the Saturn SC2, but is it the only one being raced? 

 

It will take a little more work to get the precisely, because people don't fill out the model or put a chassis name in their car info to tech. Oh and some of you cannot spell your own car make\model :)  ......

 

Rough data, of the almost 1000 teams total 202 are BMW 3 series, 187 miata. If you add up all the teams to podium at events over 40 cars and worst than 170 lbs per gal (my math), Civic teams (37), Integra teams (20), Neon teams (16), Mustangs (38) and all Saturns (3) you get 114, or half the BMW field. 

 

At over 40 car field races 3 series BMW scored 14 wins to the rest of those cars total of 3, much more than the 50% difference you would expect. 

 

It could also be a significant factor further made big because good teams have the money to build new cars and follow the trend. Looking at the 5 SC300 teams, only one has failed to win (but was just a different car # to a team that has won, maybe the same car). Assuming you have the cash to take on that part shortage\limited production run of the model of car raced (5 speed), etc....you are pretty much guaranteed to win (if you believe the numbers) . 

 

I don't know how to better separate team quality\team wealth(and resources) out of this, but am all ears. 

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28 minutes ago, Snorman said:

The way I read this thread, and I may be wrong, is that it's a thinly veiled attempt to try and put limits on anybody's ability to increase fuel capacity within the current rule set. It appears to insinuate that the "magic 9" teams are cheating, which is insulting to those teams.

Basically if you aren't racing a Miata or a BMW, then eff off. 

 

Opposite,

 

If you are one of the magic 9 teams, are you statically hampered by your capacity and would make a better "race" if you weren't. Punched above your weight.

 

Or is your performance not linked to your fuel, and you had an equal chance of winning.  

 

 

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15 hours ago, karman1970 said:

You also might want to look at podiums or winners as a percentage of each weight:fuel bucket you are looking at.

@Black Magic I don't think you have addressed the question that karman1970 poses.

 

Your graphs might just be showing that cars commonly center around 155 lbs / gallon from the factory. It makes sense, nobody wants to refuel every 100 miles and carrying 1000 miles of fuel would just be inefficient! (exaggerations of course). 

 

Cars in the winningest FWR brackets may not be more likely to win, they may just be far more common. Please do something about this in your data.

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48 minutes ago, enginerd said:

@Black Magic I don't think you have addressed the question that karman1970 poses.

 

Your graphs might just be showing that cars commonly center around 155 lbs / gallon from the factory. It makes sense, nobody wants to refuel every 100 miles and carrying 1000 miles of fuel would just be inefficient! (exaggerations of course). 

 

Cars in the winningest FWR brackets may not be more likely to win, they may just be far more common. Please do something about this in your data.

 How would you do this?  Since the weights and fuel listed for each model of car is the standard weights and fuels, the numbers would be exactly the same as the average of those cars as well.

 

In other words, if you just looked at 1 e30, 1 e36, and 1 miata, the results would be exactly the same.  You would just have less data points.  Arguably, the data would show exactly the same.

 

The fuel limited cars would be just as fuel limited compared to the less fuel limited cars.  Which, is all I think you can take away from this.

 

In other words, most of the podium cars are not *really* fuel limited.  Mostly due to the high number of entries of non fuel limited cars.

 

Unless I am misunderstanding something.

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