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Should I spend $10,000 to further improve my hybrid Corolla’s gas mileage?


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I have a 2021 Toyota Corolla Hybrid just shy under 1000 miles. I get great gas mileage at around 55MPG. I been having some curious thoughts. 

Now I know I can maintain great MPG by keeping up with air in my tires, reasonable highway speed, so on so forth. 

I been planning for a few days on investing around $10000 to improve the mileage. How so you might wonder? I been thinking of reducing the weight on the car to hollow it out to make it a two seater with carbon fiber seats. 

As for the hood I been looking at a Seibon carbon fiber hood with vents to have the engine expel any excess heat in the summer. 

I been thinking a combination of K&N engine filter, Injen cold air intake, Amsoil and Amsoil filter, Borla exhaust, and carbon fiber rims.

Now the million dollar question: Is this all worth it? Am I just spending money to get little in return, or am I making upgrades that will truly increase my MPG? All answers from pros and cons would be great to help me come to a conclusion. 

This topic was modified 1 week ago by LSLD
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10 Answers
Posted by: @lsld

I been planning for a few days on investing around $10000 to improve the mileage.

Laughter To Tears


This is the funniest thing I've seen all day

Posted by: @lsld

I been having some curious thoughts.


Posted by: @lsld

I been thinking a combination of K&N engine filter, Injen cold air intake, Amsoil and Amsoil filter, Borla exhaust, and carbon fiber rims.

How could you forget the holy grail?! Go slap on that turbocharger, too! That should bump the mileage figure to atleast 100 mpg, if not more..?

That is one insane image not gonna lie. Lol


Do the math. Find out how much MPG you get as stock as compared to the weight reduction.

While doing the exact math may be difficult, you may be able to estimate. 

Take for example the Hybrid versions of the Highlander, the Venza, the RAV4. All are basically the same shape, and have about the same ground clearance. And they all basically have the same engine. Yet some are bigger than the other and heavier, which contributes to the better or worse MPG.


I should get me a journal for this. The least I can do is document the progress for one year. That journal would be better than just spending my money away or tearing up my interior.




Don’t think anyone could truly know the answer to your $10,000 question because  it is unknown how much you will improve the fuel efficiency of your car by making the modifications that you mentioned. You need to remember that a great percentage of the energy used is to spin the engine and drivetrain, expel the exhaust, overcome rolling resistance and air drag, etc.  And your proposed modifications do not improve your vehicle’s aerodynamic performance in any way. 
Anyhoo, let’s say that you increase your gas mileage from 55 mpg to 70 mpg (a generous supposition). And you plan to drive this baby another 200,000 miles. The 55 mpg car would consume 3,636 gallons while the 70 mpg model would consume 2,857 gallons. At the current national average price for one gallon of gas being approximately $5 per gallon, you would spend $18,180 vs $14,285. A savings of $3,895. 
Only $6,105 more to recover in order to break even. 😉
Of course the price of gas will most likely increase under the current powers that be, and no one knows the future. Maybe under future powers that be, fuel prices would be lower as they were two years ago. 
All things being equal otherwise,  to justify the $10,000 expenditure, the average price you paid for gasoline to drive 200,000 miles would need to average $12.84 per gallon. And if you only kept the Corolla another 100,000 miles, the average price would need to be double to $25.68 per gallon in order to justify(break even) on your $10,000 project. And so on, and so on. But hey, you may have fun making the mods and that little Corolla may scoot around a little quicker. That’s always a good time. 😁

This is possibly the best advise I have read. With this I am really thinking on just keeping it stock for the most part. Weight reduction seems like the only reasonable thing and save a lot of that money I mentioned. Hell, why mess up a good thing right?


Save all that money and use the $10,000 towards repair funds that will eventually be required when the batteries and rest of the hybrid system need replacing.


The way you phrase your question, it seems to me you think of this more as a hobby than a financial investment.  So, sure, have fun.  Hypermiling is a perfectly good, benign hobby.


Spend that $10K on an old diesel and run it on used french-fry oil if you need a earth-friendly hobby. Scotty just did a video on somebody who did that.


Topic starter

I really thank users Avalon04 and Kaizen. Definitely gonna document my MPG stock Also truly reconsider dropping that kind of money on a car I just barely have. Maybe weight reduction is as far as I will go but I will see how my documentation goes. 


No and no and no and no. i have a hybrid so let me tell you, Rule #1- drive at 25 miles and hour slowly, then if you need to speed it up, slowly increase to 35 and keep your driving habits like that. Rule #2, replace your PVC valve, mines was stuck closed, after i replaced it, i went from 24 to 38 mpg, and thats even after having replaced a lot of parts that I "thought would help", # Rule number 3 - charger your hybrid battery with a grid charger and DO NOT buy a "new battery wich in reality they dont make them new they actually rebuil the used ones and will only last you 4 years strong after that youre back to square 1. and buy your grid charger from maxx volts . com , they are design specific to your battery, no cheap chinese crap, they are the real deal, this is around 300 bucks, save money bro. Rule #5!!!- stop putting that cheap gas, i put in my life avout 120,000 car miles, i know good gas when i drive it, right now how things are because of covid you will not get good gas mixtures!! they will give you more ethanol than gasoline! noooo!! i been using chevron and so far it has given me the perfect fuel mixture and last me 3 times longer than all the other cheap crap, so keep an eye to see wich is the best one for your car, every car is different but for me in my 2008 honda civic hybrid 4 cylinders i found chevron to be the best in performance and miles per gallon

gas mixtures are different throughout the year. Right now they are switching to summer blend.