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i have a question on a lightweight flywheel. Does it affect gas mileage? If so, which way. Since the weight is reduced from the crankshaft spinning it, would it makes the car better on gas mileage? I'm thinking of the 8lbs (something around there) flywheel (if any problem on it, any opinions are welcomed), plz correct me if i'm wrong with anything i'm saying on.
 

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99'civic 4D
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Running a 8lbs fidanza boosting 11psi d16y8 lsd tranny
 

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i have a question on a lightweight flywheel. Does it affect gas mileage? If so, which way. Since the weight is reduced from the crankshaft spinning it, would it makes the car better on gas mileage? I'm thinking of the 8lbs (something around there) flywheel (if any problem on it, any opinions are welcomed), plz correct me if i'm wrong with anything i'm saying on.
Not enough to matter. Definately not enough to justify cost just on fuel savings.
 

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You probably won't see your mileage change unless your driving habits change because of it for whatever reason.

Boosted cars and flywheels:
Fact, turbos spool faster the more load the engine has (a turbo spools at an earlier RPM is 4th. then in 1st or second)
Fact, the heavier the flywheel, the more load on the engine.

You can figure the rest out. Then it really becomes what you want, a bit quicker spool, or better heal/toe etc. I wouldnt go out and pickup a fidanza with boost (actually, nor would I with NA, but thats a different discussion) but maybe a 12 pd street FW would be decent. Stock will spool the earliest.
 

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Brokedick Millionaire
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lighter flywheel = worse gas mileage since you have to rev the engine higher to get moving, and shift quicker.

SMOOOOOTH = better mileage.....
 

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EG
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From what I've read, a lot of people like to run ~12lb flywheels with boost to help keep the turbo spooled, but still get the shifting advantage of the lighter flywheel.

@tranzex:
You have to rev the engine higher? Explain that, I'm not sure what you mean.
 

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Worst Mechanic Ever!
EG
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From what I've read, a lot of people like to run ~12lb flywheels with boost to help keep the turbo spooled, but still get the shifting advantage of the lighter flywheel.

@tranzex:
You have to rev the engine higher? Explain that, I'm not sure what you mean.
 

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this topic is so touchy. i think its more a point of personal preference. i had a 7.5lb fidanza flywheel on the first car i ever drove and now i have a fidanza on the car that i have now. so, it doesnt bother me that i have to give it more gas to "go" and to tell you the truth, i HAAAAAAAAAAAATE driving cars with stock flywheels. and its one of the cheapest flywheels you can get. quality, its fine. your never going to break it. if you do, you must be doing something stupid or be throwing out some ungodly ammount of power... but its just an opinion of personal choice. i also use my car for autox, so the lighter flywheel benefits me even more because of the type of racing i do. as for gas mileage, you dont really notice any difference. its all about how you drive.

you gotta rev the engine a little higher by like.. idk, 500rpm with the lighter flywheel and let off the clutch faster... its not that difficult. but then again, i grew up driving a car with a lighter flywheel... you just gotta ask yourself what type of driving you will be doing with the car, and how much you wana spend... after you figure that out, youll make the right decision
 

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EG
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I think I understand what he meant by rev higher now. Thanks! Also, good info, I've heard some people complain about the streetability of 8lb flywheels, but its probably because it didn't fit the way they drive more than it being "a bad idea".
 

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civic coupe
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hmmm well i may pick up the lsd motorsprots 12 lb then? i know the search button owns me on that question but still
 

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Worst Mechanic Ever!
EG
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hmmm well i may pick up the lsd motorsprots 12 lb then? i know the search button owns me on that question but still
I'd say go for it. When I was doing research about building my own turbo kit on here, a 12-12.5 lb FW was on my list. I read anything less than that and it can be hard to keep the turbo spooled right for track use (autox, not drag). By all means, don't trust my opinion over that search button, but you should be good.
 

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civic coupe
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yea im going to be setup for track (drag) not (i may try autoX once?)
but none the less the new lsd motorsports 12lb f.w should be a nice up grade for a stock one with 130k+
 

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88 ED6
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lighter flywheel = worse gas mileage since you have to rev the engine higher to get moving, and shift quicker.

SMOOOOOTH = better mileage.....

As long as you're not using some super grippy clutch and still have some low end(thank god for VTEC :p ) you don't have to rev it higher.
 

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Not to bring this back from the dead, but a lighter flywheel will equal worse gas mileage because most of us let go of the gas whenever we know that we are going to stop (I.E. coming up to a stop sign or red light, etc...) but we dont press on the clutch, with a stock flywheel you will go further because of the interial energy stored in the flywheel. The lighter flywheel wont go as far resulting in either adding fuel to keep going. Newer cars such as hybrids use very heavy flywheels in order to store this inertial energy proving that lighter flywheel=worse gas mileage (but not by much)
 

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Not to bring this back from the dead, but a lighter flywheel will equal worse gas mileage because most of us let go of the gas whenever we know that we are going to stop (I.E. coming up to a stop sign or red light, etc...) but we dont press on the clutch, with a stock flywheel you will go further because of the interial energy stored in the flywheel. The lighter flywheel wont go as far resulting in either adding fuel to keep going. Newer cars such as hybrids use very heavy flywheels in order to store this inertial energy proving that lighter flywheel=worse gas mileage (but not by much)
thats exactly what i was thinking
 
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