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

[redpoint5]

Originally Posted by Regenerit

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 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?

When I was in the market for a car, I looked at all of the aspects that you mentioned, but overlooked the drive ratio. Since my car is a 6-speed, I just assumed it has a tall 6th gear. Unfortunately it's rather short, as is your ratio. I'm sure 6th gear would never be used on a race track anyhow, so I'm disappointed the engineers didn't just make the last gear tall. Since I have a close-ratio manual gearbox, I find that stop and go driving yields the same MPG as steady freeway cruising.

For my manual gearbox, I can swap out the final drive with a different ratio. The RSX has a taller ratio, but only marginally so and the cost of the part is $300. No idea how hard it is to install. Then there is a $1000 custom part with a good ratio, but that is a lot of money and I have no idea what it would do to my speedometer, cruise control, odometer, stability control, ABS, etc.

I don't know what the cost or complexity would be to change your ratios, but it would likely have a negative impact on performance and possibly mess with other systems that rely on having a stock ratio. This would be a better question for a Genesis forum.

EDIT: From what I have read on other forums, the best value for dollar you can spend in the performance department will be lightweight wheels/tires.

[UltArc]

Umm. Okay. Lol, I don't know where to start...

Gearing will be more valuable than everything else you planned to do. And most likely cost less. Close to half the price, if not less.

Aero mods are your friend. A belly pan, not visible unless you drive over someone, would be more helpful than what you are planning to spend. As others have said, upper grille block. I believe the "hurt" on power is overcome by the help in aero. But, I weigh 200 more pounds than you and run 300-325 hp. So if I lose 5% power, I am still pushing high 2s, you may feel it more with less power. Really, aero mods and gearing are by far the most valuable. You could easily upgrade rims/tires to bigger diameter and do total invisble aeromods for the money in the carbon fiber.

[Regenerit]

So gearing is something I'm definitely interested in however I have absolutely no idea where to start. Where would I look, what kind of shops would be able to install such gearing? And what % fuel gains could I expect?

Also, I was able to measure the rpms at varying speeds tonight at 28degF.
Keep in mind this is a 2.0L engine so rpms are expected to a bit higher. So that Tsx of yours with the 2.4L having 3000rpm at 70mph makes my 3250rpm at 70 more understandable.

40mph 1800rpm
45mph 2000rpm
50mph 2275rpm
55mph 2500rpm
60mph 2750rpm
65mph 3000rpm
70mph 3250rpm

[HypermilerAX]

Provided the parts exist for your type of gearbox, you can either change the differential ratio, every gear will be higher meaning worse accelerations or only the 5th gear, you keep good accelerations but have a bigger gap between 4th and 5th. It's up to you to deicide according to your usual trips which option will be the best.
For example, if you drive on smaller/hilly roads with speed variations, changing the rear end might be better. If your old 5th gear was good but limit, only changing this gear might force you to drive in 4th which won't have the wanted result.
If you drive mostly on the highway at constant speed, any will help.
You can expect a gain of about 60% of the gearing change. If you increase your 5th gear by 10%, you get around 6% better FE.

[niky]

A lot of manufacturers are going with 6-speed boxes with overdrive ratios that are similar to older 5-speeds. They don't need longer 6th gears because fuel economy is tested within very limited speed windows, so why bother?

I'd look and see if the Genesis sedan has longer gearing and whether surplus differentials or gears are available, because no way is a new custom gear going to be cheap... and I doubt you'll find a longer final drive from performance parts makers. To get longer gearing, you may have to go for taller tires.

The longer gears that I know that are available on the market for common cars are simply repackaged gears from Euro- or Japanese-spec cars with different engine choices from US cars. Far as I can recall, the Genesis gearbox is the same wherever you are.

[jakobnev]

Why in heavens name did you go with the auto?

[niky]

Is it an AT? Scratch the flywheel idea, then.

There are some good reasons to go AT with the pre-facelift Genesis. The ZF box is prerty smooth and snappy, and makes for relaxed cruising. The stock box for the pre-facelift models had a pretty stiff clutch and a crunchy 2nd to 3rd shift.

[Xist]

Originally Posted by Regenerit

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).[/U][/B]

I have had some interesting conversations on here regarding leg room. I am 6'2" and have driven very few cars comfortably, while there have been many stories of men much taller than me loving small cars.

Many people on here have done grill blocks. I always think that I need to wait to try one until I am less busy with school and then get distracted.

Oh, right. I am supposed to stay away from this forum!

Some people have done very nice-looking grill blocks and while one behind the grill would be less effective, it is also less noticeable. Additionally, you could do a partial one.

I think that you have a point about your engine getting enough air, but that should be easy to check. Guys, what would be the best way to do that?

The usual concern with grill blocks is engines overheating. Here http://ecomodder.com/forum/showthrea...tml#post349862 is a thread about finding out when your radiator fan turns on.

Good luck!