2011 Hyundai Genesis Coupe Build (aiming for lighter parts and engine efficiency)

[Regenerit]

Hello Everyone, I purchased by 2011 Genesis Coupe 2.0T (2 Liter inline 4 cylinder turbocharged engine with 5 speed close ratio automatic transmission) this past December 2012. I've been running itnow for the last month and a half in somewhat chilly 25-45deg F weather in Chicago and have been getting 21-22mpg per tank on average with combined city/hwy driving. The EPA combined is 23 mpg; 20city, 30hwy. I'm essentially hitting the EPA numbers if you take out cold starts that net 4-8mpg for the first couple of minutes.

With my build, I am going to be aiming for engine efficiency and lighter parts, specifically a custom ECU tune on a dyno, a carbon fiber hood and trunk, lightweight wheels, and a lighter battery.

I wont be adding a boattail, making higher gearing, covering up the exterior of the car to lower its Cd, or any modification that will easily make it obvious the car has been modified with often rather ugly (if I may so so) aerodynamic mods.Nor will I be ripping out any of the interior, removing any seats, or even removing my spare wheel and Jack.

I may put on a lighter street legal more open single exhaust with a muffler(the vehicle is dual exhaust stock), upgrade to lighter pulleys, and more as it comes about.

At this time, with the the mods I will be doing, I will be looking at about $3210 altogether and may be able to recoup some of that money by selling the stock parts.

Weight savings for all of the mods together will be about 95lbs (43.1kg).

I will be purchasing a carbon fiber hood and trunk from Carbon Creations, both OEM style. The hood will not have any holes for breathing in it.
stock hood weight: 38lbs (17.2kg)
Carbon fiber hood weight: ~13.3lbs (6kg)
weight savings: ~24.7lbs (11.2kg). Cost: ~$700

stock trunk weight: 18lbs (8.2kg)
Carbon fiber trunk weight: ~6.5lbs (3kg)
weight savings: ~11.5lbs (5.2kg). Cost: ~$600

For wheels, I will be getting 18" Enkei RPF1's 18x8
Stock front wheel weight: 26lbs(11.8kg) x 2wheels= 52lbs (23.6kg)
stock rear wheel weight: 27.5lbs (12.5kg) x 2 wheels = 55lbs (25kg)
Enkei RPF1 wheel weight: 17.8lbs (8.07kg) x 4 wheels = 71.2lbs (32.3kg)
total weight all stock wheels: 107lbs (48.5kg)
weight savings: ~35.8lbs (16.2kg). Cost: ~$1200

Stock battery weight: 38lbs (17.2kg)
Braille AGM B2015 battery weight: 15lbs (6.8kg)
weight savings: 23lbs (10.4kg). Cost: ~$160

TOTAL WEIGHT savings: 95lbs (43.1kg)

Total cost of mods: ~$2660. + $550 ECU tune: ~$3210.

Expected summer fuel economy with all mods and ECU tune and typical hypermiling driving without engine off coasting or driving in neutral: 30mpg city, 40mpg highway.
EPA estimates: 20 city, 30highway. That is a 33% improvement.

[UltArc]

Originally Posted by Regenerit

Hello Everyone, I purchased by 2011 Genesis Coupe 2.0T (2 Liter inline 4 cylinder turbocharged engine with 5 speed close ratio automatic transmission) this past December 2012. I've been running itnow for the last month and a half in somewhat chilly 25-45deg F weather in Chicago and have been getting 21-22mpg per tank on average with combined city/hwy driving. The EPA combined is 23 mpg; 20city, 30hwy. I'm essentially hitting the EPA numbers if you take out cold starts that net 4-8mpg for the first couple of minutes.

With my build, I am going to be aiming for engine efficiency and lighter parts, specifically a custom ECU tune on a dyno, a carbon fiber hood and trunk, lightweight wheels, and a lighter battery.

I wont be adding a boattail, making higher gearing, covering up the exterior of the car to lower its Cd, or any modification that will easily make it obvious the car has been modified with often rather ugly (if I may so so) aerodynamic mods.Nor will I be ripping out any of the interior, removing any seats, or even removing my spare wheel and Jack.

I may put on a lighter street legal more open single exhaust with a muffler(the vehicle is dual exhaust stock), upgrade to lighter pulleys, and more as it comes about.

At this time, with the the mods I will be doing, I will be looking at about $3210 altogether and may be able to recoup some of that money by selling the stock parts.

Weight savings for all of the mods together will be about 95lbs (43.1kg).

I will be purchasing a carbon fiber hood and trunk from Carbon Creations, both OEM style. The hood will not have any holes for breathing in it.
stock hood weight: 38lbs (17.2kg)
Carbon fiber hood weight: ~13.3lbs (6kg)
weight savings: ~24.7lbs (11.2kg). Cost: ~$700

stock trunk weight: 18lbs (8.2kg)
Carbon fiber trunk weight: ~6.5lbs (3kg)
weight savings: ~11.5lbs (5.2kg). Cost: ~$600

For wheels, I will be getting 18" Enkei RPF1's 18x8
Stock front wheel weight: 26lbs(11.8kg) x 2wheels= 52lbs (23.6kg)
stock rear wheel weight: 27.5lbs (12.5kg) x 2 wheels = 55lbs (25kg)
Enkei RPF1 wheel weight: 17.8lbs (8.07kg) x 4 wheels = 71.2lbs (32.3kg)
total weight all stock wheels: 107lbs (48.5kg)
weight savings: ~35.8lbs (16.2kg). Cost: ~$1200

Stock battery weight: 38lbs (17.2kg)
Braille AGM B2015 battery weight: 15lbs (6.8kg)
weight savings: 23lbs (10.4kg). Cost: ~$160

TOTAL WEIGHT savings: 95lbs (43.1kg)

Total cost of mods: ~$2660. + $550 ECU tune: ~$3210.

Expected summer fuel economy with all mods and ECU tune and typical hypermiling driving without engine off coasting or driving in neutral: 30mpg city, 40mpg highway.
EPA estimates: 20 city, 30highway. That is a 33% improvement.

You are welcome to do whatever you want, and I look forward to seeing results, but 3210 dollars for 95 lbs of saving does not seem very efficient. Especially if you are not going to increase your gearing.

And with just those mods, I do not know how feasible your goals are. I think in a standard, any vehicle should be able to get highway mpg in the city. I see 32 mpg in the city depending on distance, but 6 speed standard. Maybe the tuning will help, but it does seem a bit unlikely :/

[niky]

You could probably more cost-effectively lose weight by stripping out the rear seats and the safety spare (if the 2011 still has a safety spare). Essentially free would be to remove the steel beam underneath the plastic front bumper. Or replace it with a lighter nerf bar for not much money.

Aero and engine mapping will help you a lot more than a mere 95 lbs of lightening.

Rather than a carbon hood, I'd put that money in a flywheel upgrade, to free up a little more power.

[redpoint5]

You have chosen to replace components that have a high cost to performance ratio. There are tons of things you could do for much less money that would yield better results. The CF hood and trunk goes against what you say here; "or any modification that will easily make it obvious the car has been modified with often rather ugly", and at a very high cost without any performance benefit that will be noticeable to you. You won't notice the difference with the lightweight battery either.

From the list of your planned mods, the wheels will likely be the thing you notice the biggest difference from. But holy smokes, $1200! That said, I am considering Kosei K4R wheels at $800 for my car, really would rather find a used set.

If you're driving efficiently already, weight won't really make much of a difference in MPG.

With your cold weather, start with an upper grill block and paint it black so that it isn't obvious. Your car will warm up quicker, maintain heat longer, and be a little more aerodynamically efficient.

[Regenerit]

Originally Posted by UltArc

You are welcome to do whatever you want, and I look forward to seeing results, but 3210 dollars for 95 lbs of saving does not seem very efficient. Especially if you are not going to increase your gearing.

And with just those mods, I do not know how feasible your goals are. I think in a standard, any vehicle should be able to get highway mpg in the city. I see 32 mpg in the city depending on distance, but 6 speed standard. Maybe the tuning will help, but it does seem a bit unlikely :/

Thank you for the support. I admit, the numbers are a bit high but not as much as you may think. When traveling at 45mph at 35deg F I was and with my 250lb cousin in the passenger seat, I was able to net 34mpg. At 50mph, I get about 32-33mpg, at 55-60mph I get about 30-31mpg at about the same temperatures. Lastly, at 65-70 I get about 28-29mpg.

Check out these fuel economy figures from Metrompg.com for the Honda Civic Hybrid at 60mph at varying temperatures.

At 60mph at 35degF I get 30mpg. If the temperature went up to 85deg F which is realistic for chicago's summer weather, my fuel economy would jump by 22% to 36.6mpg at 60mph.

Also, the ECU tune which will be done by BTRcc can be tuned according to which fuel I am using, in this case 93 octane. People on the forums at gencoupe.com who have gotten tunes from SFR and BTRcc have noted fuel economy improvements on top of the improved power. One said he noticed right away a good 2-4mpg improvement. Other's noticed a better fuel economy on trip back home from the tuning later that day as well as further after that. So being conservative and saying maybe 1mpg extra in city and 3 in the highway, I would be looking at about 39mpg highway at 60mph at 85deg F. Add in the weight loss at the wheels plus the other 60 some lbs and I think 40mpg is very doable.

Originally Posted by niky

Rather than a carbon hood, I'd put that money in a flywheel upgrade, to free up a little more power.

I really like this idea. I'll look into it and see what I can get and at what cost.

Originally Posted by redpoint5

You have chosen to replace components that have a high cost to performance ratio. There are tons of things you could do for much less money that would yield better results. The CF hood and trunk goes against what you say here; "or any modification that will easily make it obvious the car has been modified with often rather ugly", and at a very high cost without any performance benefit that will be noticeable to you. You won't notice the difference with the lightweight battery either.

From the list of your planned mods, the wheels will likely be the thing you notice the biggest difference from. But holy smokes, $1200! That said, I am considering Kosei K4R wheels at $800 for my car, really would rather find a used set.

If you're driving efficiently already, weight won't really make much of a difference in MPG.

With your cold weather, start with an upper grill block and paint it black so that it isn't obvious. Your car will warm up quicker, maintain heat longer, and be a little more aerodynamically efficient.

I like the look of the carbon fiber hood and trunk and they also give a performance aspect to the car. Also, when removing weight off a car, every little bit counts but I do not want to make it to the point where I am removing items that deteriorate the quality and look of the ride (removing rear seats, I occasionally have more than one passenger in the car without notice) or reduces the emergency readiness of the car (having the spare and jack removed). I understand I will probably never recoup the $3200 spent on items to improve fuel economy but the whole point of it all is to make this an enjoyable good looking ride that I can enjoy driving like gramps and achieving great fuel economy but at a moment's notice make it roar as someone challenges me or I have to bust balls to evade a potential acccident, etc.

I've used a grill block on my old 1993 chevrolet Lumina back when it was my beater and I didnt give a damn how ugly it looked. I'm kind of thinking about getting a grill block but then I remembered that the grill is the only area where fresh air comes into the air intake (the intake itself is sealed an has a tube which leads to a widened vent at the grill. I would not want to starve my engine of air at full throttle (although highly unlikely). I'll have to look into a material for the grill block (maybe an abs plastic dyed black or something and perfectly cut to fit the grill perfectly).

[cRiPpLe_rOoStEr]

I believe fuel-economy doesn't have to make the car look ugly or boring. Carbon fiber is not cheap, but I also like its race-oriented aspect. Anyway, some interior trim mods can be also a good point to take dead weight away, such as replacing soundproofing and thermal insulator blankets for lighter ones, and nothing prevents you to get all the comfort features fully functional.

[redpoint5]

Originally Posted by Regenerit

At 60mph at 35degF I get 30mpg. If the temperature went up to 85deg F which is realistic for chicago's summer weather, my fuel economy would jump by 22% to 36.6mpg at 60mph...

...I would not want to starve my engine of air at full throttle (although highly unlikely).

Given the high octane fuel with tuning to take advantage of it and the summer temps, perhaps you can achieve the fuel economy figures you are after. I don't believe the weight reduction will play much into this and will have almost nothing to do with highway fuel economy.

However, the real hindrance to your highway fuel economy goals is your gearing. I don't know what ratio your top gear is, but you mentioned it is a close-ratio gearbox. You're going to be wasting a lot of fuel just spinning the motor at such a high speed. My 6-speed TSX turns 3000 RPM at 70 MPH, which is way to high.

You can't starve an engine of air even running a full grill block, but it might be pulling in warmer air which could marginally reduce full power. Some people on this forum install warm air intakes to increase their fuel economy though. I get the sense that performance is your primary interest, with fuel economy as a secondary bragging right. Please, correct me if I'm wrong.

I choose a balance of performance, economy, and price by sticking with a 4-cylinder TSX.

[Regenerit]

Originally Posted by cRiPpLe_rOoStEr

I believe fuel-economy doesn't have to make the car look ugly or boring. Carbon fiber is not cheap, but I also like its race-oriented aspect. Anyway, some interior trim mods can be also a good point to take dead weight away, such as replacing soundproofing and thermal insulator blankets for lighter ones, and nothing prevents you to get all the comfort features fully functional.

Excellent points but would I still be able to retain the stock look if I changed out some materials such as the sound deadening stuff?

Originally Posted by redpoint5

Given the high octane fuel with tuning to take advantage of it and the summer temps, perhaps you can achieve the fuel economy figures you are after. I don't believe the weight reduction will play much into this and will have almost nothing to do with highway fuel economy.

Thats perfectly ok if the weight reduction doesnt improve my highway by much. What I'm really after is the city fuel economy since I currently do about 50% city driving (or greater) for work and general errands and also prefer to avoid the often longer distance (although faster) tollroads to work (I drive 28 miles one way) due to the expensiveness and overall greater length at higher speeds. I only use the tollroads if I'm in a hurry. (It's $1.50 one way to work if I use the tollroads).

Originally Posted by redpoint5

However, the real hindrance to your highway fuel economy goals is your gearing. I don't know what ratio your top gear is, but you mentioned it is a close-ratio gearbox. You're going to be wasting a lot of fuel just spinning the motor at such a high speed. My 6-speed TSX turns 3000 RPM at 70 MPH, which is way to high.

My final drive axle ratio is 4.81, my 5th(last) gear ratio is .83:1
I dont remember my rpms at set speeds at this point but I will retest and jot down the figures. In an earlier post when I first got the car, i listed 2700-3000rpms from 55-60mph but that doesnt make sense Since I clearly remember at every 5mph increase, my rpm's going up by 250.

Originally Posted by redpoint5

You can't starve an engine of air even running a full grill block, but it might be pulling in warmer air which could marginally reduce full power. Some people on this forum install warm air intakes to increase their fuel economy though. I get the sense that performance is your primary interest, with fuel economy as a secondary bragging right. Please, correct me if I'm wrong.

I choose a balance of performance, economy, and price by sticking with a 4-cylinder TSX.

You hit it right on the head with performance as my primary interest, followed by fuel economy. However, fuel economy is a close second as noted by me getting a 2 cylinder turbo charged engine over typical V6 of the other competitors and in addition, I researched the Cd's and fuel economies of all of the competitors as well as cabin sizes (since I'm 6'3") for the front and back (for passenger comfort).

Originally Posted by Frank Lee

It would be easy enough to test the weight reduction theory on your car without buying a thing- you have already mapped out the potential weight savings with your proposed parts; TEMPORARILY pull the seats, spare, etc. to match that and see if there is a demonstratable effect. This would be most accurate for the hwy figure, as it doesn't take into account rotating/unsprung weight of lighter rolling stock that has more effect in stop-n-go city driving.

Excellent point although we know for sure that such mods will improve fuel economy even if slightly and If I'm going to spend this much money regardless due to the looks and bragging rights, I feel the effort put into taking out the seats, spare, jack, etc and putting them back in after testing is an unnecessary burden when it is gauranteed for fuel economy to improve with weight reduction.

As a final important note, if I decided to install higher gearing (which I'm a bit skiddish about due to the fear of it costing too much), would I have to have my transmission replaced or would it simply be literally installing an extra tall gear and how much money would I expect to pay with the parts and professional installation?

[Miller88]

Wow! 4.81:1 rear end is going to be screaming when going down the highway! My Focus has 3.51 (or so) "rear end" with similarly sized tires and I feel that's spinning way too fast going down the highway.

4.81 are dumptruck gears - the only vehicles I've ever seen with that type of gearing are trucks for pulling or trucks/jeeps with large tires.

It'll get you a good 0-60 time, get you out of the corners on the track ... but not help FE that much.

[Regenerit]

Originally Posted by Miller88

Wow! 4.81:1 rear end is going to be screaming when going down the highway! My Focus has 3.51 (or so) "rear end" with similarly sized tires and I feel that's spinning way too fast going down the highway.

4.81 are dumptruck gears - the only vehicles I've ever seen with that type of gearing are trucks for pulling or trucks/jeeps with large tires.

It'll get you a good 0-60 time, get you out of the corners on the track ... but not help FE that much.

Ha yeah. This thing gets 0-60 in 6.9 seconds. Fast no doubt. lol Due to the close gear ratio, it actually goes into third gear around 53 mph at full throttle.