Crazy question: Gear up the entire transmission?

[AlanLGuy]

My suggestion would be to stop skipping gears, especially going 1 to 3 and skipping 2nd. you really aren't saving any gas that way because you have to run 1st out more in order to not bog the engine down when shifting to third. Either that or your shifting too early and bogging the crap out of it and wasting even more fuel. The only time skipping a gear makes sense is when getting on the highway and running third out then Shifting directly to 5.

You're money would be much better served getting a smaller and thinner set of wheels as someone mentioned above than dumping money into something that will make the care slower.

To each his own, but I can't help but think the FR-S is a silly choice of car for someone so concerned with hyper-mileage.

[radroach]

I think that the money spent on this would be a greater cost than the extra gallon of gas you might save with this every once in awhile. This stock stup on this car car is already at a pretty peak eco setup while providing enough grip and handling.

If you want to save gas, it's mostly about driver mod. Which means going slow, not accelerating unless necessary or you get an opportunity to gather speed. Unfortunately you guys in the midwest don't have as many hills to coast downhill to gather some free acceleration. Here I can vary 25-50mph and get 50mpg all the way down the road.

[Turdinator]

Taller, skinnier, low rolling resistance tyres are a great idea. A taller sidewall will also make the car more comfortable. The JDM underpanels and the factory spoiler both drop the cD and may help on longhauls at freeway speeds. You could also look into a tune for economy rather than power. I suspect these options individually would be cheaper than changing your final drive and definitely cheaper than modifying the gearbox.

[Dephective]

Not worth any of that. Buying parts to save pennies on fuel makes zero sense. you'll spend 2500 on parts and labor for a new R&P gear/labor. Purchasing the other parts mentioned, while giving you potentially better fuel economy, all add up to spending more than you will save. Sure, buy them, but not because they are saving you money. Underbody aero makes the car more stable on the highway and less prone to wind buffeting at speeds, taller tires are more comfortable and the 16" makes them cheaper to purchase than the 17".

I wouldn't recommend skipping gears all the time commuting either. You'll save more fuel by babying the throttle going through the normal upshift pattern than you will running a gear out then bogging the engine while trying to accelerate in too tall of a gear. You are also not doing your synchros any favors either. You are literally forcing them to accelerate from a stop twice as fast in order to match the speed of the gear that you are coming from. Lots of guys will argue that it doesn't have much of an effect but there's tons of other transmissions that have synchro issues because of this very reason at low miles. Plus, with all the 5th gear synchro failures and plethora of transmission issues with this car, I wouldn't chance it.

Stop being afraid to rev the car. The internals are literally designed for high revving capacity. There is a reason we have a 7500 rpm redline; it's not an arbitrarily set number. If it were in any way unsafe, they wouldn't have done it. In fact, by never taking it past a few thousand rpms I'd even say you're doing more harm than good.

[jshadeck]

Try this: pick a familiar stretch of highway (preferably not perfectly flat or straight), 6th gear, set cruise control, at a specific point (sign/mile marker/etc) reset your avg mpg, then at another marker several miles further, check the mpg. Repeat this, the same direction shortly after (to eliminate as many variables as possible, weather etc) but leave it in 5th gear. See how many mpg u lose based on the ratio difference, u might be surprised.


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[Dephective]

Originally Posted by jshadeck

Try this: pick a familiar stretch of highway (preferably not perfectly flat or straight), 6th gear, set cruise control, at a specific point (sign/mile marker/etc) reset your avg mpg, then at another marker several miles further, check the mpg. Repeat this, the same direction shortly after (to eliminate as many variables as possible, weather etc) but leave it in 5th gear. See how many mpg u lose based on the ratio difference, u might be surprised.


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Assuming the OP is doing mostly highway, the taller final drive would be a slight boon to fuel economy. However, driving around town it would take more fuel to accelerate with a taller final drive through ALL gears, and would probably negate the benefits of having the increase fuel economy at steady state speeds, if not make it LESS efficient.

The reason why all the "economic" cars like the jetta, golfs, audi 4cyl, other turbo 4 cyclinders have crazy low end torque and drop off like a rock at higher RPM's is because low end torque is what makes city driving more economical. Getting up to speed in the least amount of time possible while using the least amount of fuel possible is what does this. This is part of the reason why diesel is so economical for city driving as well (among other reasons). The turbos while cruising aid efficiency through air atomization when not in boost, and the diesels rev low and produce gobs of torque adequate enough to steady state cruise with minimal fuel use, as well as it's ridiculous compression ratio.

Increasing the time and effort it takes to reach cruising speed is only going to lessen efficiency. You'll be playing catch up with that taller gear at that point.

[DC2R]

Have to agree with what's said here...just not the hostility. People hyper mile corvettes so why not a 2.0?
A long sixth would be ideal. Don't know why we can't have one. Maybe aftermarket? I know people would swap the LS Integra fifth into the GSR transmission to get a proper cruising gear(longer)

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[Poodles]

Originally Posted by DC2R

Have to agree with what's said here...just not the hostility. People hyper mile corvettes so why not a 2.0?
A long sixth would be ideal. Don't know why we can't have one. Maybe aftermarket? I know people would swap the LS Integra fifth into the GSR transmission to get a proper cruising gear(longer)

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Except the vette has the torque to run low RPM's on the highway, plus it has a double overdrive transmission while this car doesn't.

[glorydays]

To the op... you can't simply gear up a transmission as this isn't gran turismo. I believe fbm made a bellhousing to link the fa20 to a supra v160 which should have taller gears but that's extreme too. Best thing to do is better driving habits. You COULD go turbo if you can resist boosting, especially on the hwy, but it's hard to do.

[Reaper]

Originally Posted by jshadeck

Try this: pick a familiar stretch of highway (preferably not perfectly flat or straight), 6th gear, set cruise control, at a specific point (sign/mile marker/etc) reset your avg mpg, then at another marker several miles further, check the mpg. Repeat this, the same direction shortly after (to eliminate as many variables as possible, weather etc) but leave it in 5th gear. See how many mpg u lose based on the ratio difference, u might be surprised.


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I get better gas mileage the closer i can get to peak torque while staying out of boost. I get better gas mileage at a higher RPM. SCIENCE!

[unsurety]

You have to be careful with this. There's the chance that whatever money you spend on trying to make the car more efficient may not be recouped for a long time.

I use this calculator to determine the cost difference for running E85. But you can just plug in the same gas price for both gas and E85 while varying the mpg figures.

http://toflexornottoflex.com/

Assuming a 30 mpg average before and 35 after, and 12k annual mileage, you'd save $240 a year. It is much harder to gain mpgs than you expect, so keep that in mine.

[jshadeck]

Originally Posted by Dephective

Assuming the OP is doing mostly highway, the taller final drive would be a slight boon to fuel economy. However, driving around town it would take more fuel to accelerate with a taller final drive through ALL gears, and would probably negate the benefits of having the increase fuel economy at steady state speeds, if not make it LESS efficient.

The reason why all the "economic" cars like the jetta, golfs, audi 4cyl, other turbo 4 cyclinders have crazy low end torque and drop off like a rock at higher RPM's is because low end torque is what makes city driving more economical. Getting up to speed in the least amount of time possible while using the least amount of fuel possible is what does this. This is part of the reason why diesel is so economical for city driving as well (among other reasons). The turbos while cruising aid efficiency through air atomization when not in boost, and the diesels rev low and produce gobs of torque adequate enough to steady state cruise with minimal fuel use, as well as it's ridiculous compression ratio.

Increasing the time and effort it takes to reach cruising speed is only going to lessen efficiency. You'll be playing catch up with that taller gear at that point.

I think you missed my point, i dont think the increase he would see under my scenario would be deemed worth the cost/hassle/negatives (such as yours) that would be needed to achieve the ratio change, my suggestion would show that w out costing him anything but a few gallons of gas at most.


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[wparsons]

Originally Posted by wheelhaus

Taller tires will have the same effect as taller gearing, that's a good point. Just remember that anything changed after the transmission will make the speedometer inaccurate.

Just a slight correction... changing the final drive won't effect the speedometer either, the car uses the wheel speed sensors and not a sensor in the gearbox to determine vehicle speed.

Taller tires will definitely throw the speedo off though.

[JasperNoone]

Gear up the trans, add V8 = win.