LOL!

 

Here's the thing on gear ratios. In first gear, your driveshaft will turn one revolution for every 3.54 (1st gear ratio) engine revs. The driveshaft must turn 3.358 (final drive ratio) times to turn your rear wheels once. So that means to turn your rear tires once, the engine must go through 11.887 revs.

Now, let's take it a bit further. I know this is a coupe thread, but I don't know the tire size of the stock coupe. My stock tires were 235/45/18. That means one tire was 235 millimeters wide, the sidewalls were 45% as tall as the tire was wide, and the inner diameter was 18 inches. 45% of 235 millimeters is 105.75 millimeters. Convert millimeters to inches(25.4 millimeters an inch) yields 4.16 inches. That means the total diameter of the tire is 26.3 inches(inner diameter + [sidewall height * 2 ]). With a diameter of 26.3 inches, that means the total tire circumference is 82.74 inches.

In first gear, this means that every 11.887 revolutions the car will move 82.69 inches. At 6600rpms(still first gear), the rear axle turns only 555.213 times. That means the car travels 45,939 inches in one minute. Which is 3,828 feet per minute, which is 43.5 mph. That means the redline in the 5AT is 43.5mph(ish) in 1st gear.

Now, if you change out to a 3.54 final drive ratio, 1st gear will only wind out to 41.2mph, 2nd will top out at 64.52, 3rd will finish at 99.3, 4th 146, and 5th at 175(not that you'll have the power to get there).

Basically, a shorter final drive means the engine has to turn more times to travel the same distance. It's the same reason 1st gear accelerates faster than any other gear, 2nd faster than anything after, and on and on.

 

if ur losing after 50 to a wrx there is something wrong, i can keep up with sti's on the freeway, you should be able to take a wrx above 50 easily, u should make him look like hes standing still...

maybe ur 5AT is broken, trade it in for a 6mt and put the mods on that =)

 

damn, suprisingly enough i kept up with that.. but DAMN!!!! what do u do for a living???

 

I don't know what he does for a living, and I'm sure he's a very intelligent solitary schizophrenic...

but as far as the things he broke down for you goes, can all be learned at wikipedia and about.com with a little bit of reading. So, with some grade school level math and english skills under your belt, you too can astound mechanical noobies!

 

im taken my car to the mechanic/friend on sunday if he says its my tranny then i will bring my car to inifiniti the following week. If i find a 6mt i like then ill trade in the lease for that car instead. cuz i love the g35 and with my mods i should be doen alot more. i dish so much money into my car because with every mod i do i feel nothen so i keep maken excuses to get diff bolt ons saying ohh if i get this then that will work better and i already bought that so i just have to get this! lol if i got a decent 6mt i prob would have been finished with my car by now. but this was my first new car besides my lexus es 300 and this is my first car that i modded so im new and i learned alot about cars in general and really with modding cars time, patience, and knowledge are key to having a beautiful and powerful car.

 

1. pull head out of ***

2. listen

3. it's your combination of mods (i'd guess the y-pipe is killing it since my plenum/headers/hfcs/pullies r0x0rs my s0x0rs) plus the fact you're probably really runnign lean.

 

so should i sell my y pipe? if i bought a fujitsboro exhaust that comes with a y pipe. what am supposed to do in that scenario?

 

your y-pipe is killing you man. your mods are conflicting with each other. Im a stock 06 5AT coupe and i dont got that problem racing my friends with the 6mt

 

if you have a catback keep it; but chances are u need a tune at this point and are [robably running very llean uptop

 

gear ratio..

6MT > then AT on 3rd gear.. closer ratio.. but he probably let off but not completly off throttle..

 

you should not buy an automatic.

I'm confused what everyone is so confused about here? there is nothing wrong with your car. Two reasons you lost, you have less power and worse ratios not to mention automatic transmission are much less efficient than manuals.

 

Automatics have come a long way since the days you're talking about. Nowadays, most autos are only behind by 1mpg on efficiency, and not a whole lot more on power. If anything, a lot of people prefer them for FI'ing since they're so much more robust than our time-bomb MTs.

I agree with the conclusion about the gear ratios (brought up before), but the auto is not robbing him to the point of being "much less efficient". If anything, it's helping him by not being so slow with the shifting in MM mode.

Countless threads comparing AT versus MT performances show that the auto is no slouch, and his crooked-*** mods are messing with his AF, and lord knows what the ecu is doing because of that.

stop being a MT fanboy, and look at what's really happening.

 

^^^

with proper driving and conditions an auto today is just as fast as a manual....maybe .1 slower in the 1/4.

 

What traditionally made automatics worse was the # of gears. For a long time, autos only had 3 forward gears and one of them might have been overdrive. That = terrible gear selection.

With the advent of 5sp,6sp and now 7sp automatics w/ 4,5,6 non-overdrive forward gears, the gears can be spaced way better.