So i was up early this morning and decided to time my 0-60 runs. I was driving her yesterday pretty hard and it felt slow. I figured it was just heatsoak kicking in thanks to the 90+ heat here in Parker Colorado.

So i did my runs(3 total) and i couldnt manage to break 8.00 second Sprints! I just changed the spark plugs to NGK IX recommended to me by forum members.

My car has no oil cosumption issues(checked the 5 and 6th plug when i changed them) but still its really slow accelerating from what every1 else is doing. Ive looked at the car alot too and i dont see anything loose or leaking.

The Temp was about 77 degrees and altitude was 6000ft here in parker.

 

Also its a 2005 5AT with 245/45/18 rears and 225/45/18 fronts on stock wheels.

Everything else is stock too, just bought it in april with 77,000 miles.

 

Acceleration lag? I think it's normal. My 2010 Sedan loaner feels the same way. People on here are telling me it's because I don't know how to drive an automatic. lol

 

try resetting ECU

 

You really think your stock 6MT is faster then a G37 7AT........


OP, if I remember correctly your at a 6,000+ feet elevation in 90 degree temperatures and you have a stock automatic. Your 0-60 is not going to be that good to begin with. When was the last time you replaced the fluids? (oil, tranny, differential) If there's no codes present I don't think the dealership will be able to help you out.

 

I've changed the oil and transmission fluid so far. Haven't touched the differential yet is that a reason? It's got 79xxx miles on it and idk when it was changed last. Elevation is a huge factor but would it slow me down to 8 second accerlation to 60?

Thank alot for the help guys.

 

I doubt it, but I would change the fluid regardless since your at 79K miles. Heat and elevation will definitely kill the performance, I don't know by how much but I'm pretty sure thats your problem.

 

It just seems really slow. Even for my high elevation. This car is seriously my baby I jus lt wanna make sure she's not in need of something lol

 

Sounds like she's in need of a turbocharger or supercharger.

I used to fly a couple of different types of twin-engine airplanes for a company I worked for. One was a Beechcraft Baron 58 with two 285 horsepower engines. Loved that airplane...it handled like a G35, and there weren't many piston twins out there that could outrun it - so long as one was below 7000 feet above sea level.

The other airplane type was a Piper Chieftain - with two 350 horsepower turbocharged engines. The turbochargers would allow the engines to produce the full rated 350 horsepower all the way up to and beyond the altitudes I was flying at. Flying this airplane was not nearly as much fun as the Baron because it lumbered along like a school bus.

When it came to flight in icing conditions though, the Chieftain was my choice hands down. Beginning at about 7000 feet, the altitude induced power drop off in the Baron would allow the Chieftain, which was still capable of producing 700 horsepower thanks to the turbochargers, to begin to pull away. And climb rate at 8000 feet and above was more than twice as much with the Chieftain - again thanks to the turbochargers allowing the engines to produce full rated power while the normally aspirated Baron could only pump out about 70% of that 570 total rated horsepower at that altitude.

When one is dependent on climb rate to get through a layer of ice-laden clouds quickly, normally aspirated engines can be a significant handicap.

So the moral of the story, if you've read this far, is your G is probably only producing 80% or less of the 280 - 300 horsepower it would otherwise produce at sea level.

 

You drive a almost 80K mile G35 and you're concerned about your 0-60 MPH times with 90 degree temps? At 6K feet I'd be slow too with that many miles on my clock! Differential fluid is supposed to be changed at 30 mile intervals so you're way past due and no, that's not why your G is slow. What other services have you failed to do, has your mass airflow sensor ever been cleaned? Little things like that can make a huge difference along with synthetic fluids. Try giving your G some TLC and quit beating up on the old girl!
Gary

 

When or where did I ever say that? I know damn well the G37 sedan and even the G35 Sedan is FASTER than my 6mt G Coupe. The Sedan is lighter.

All I am saying is the acceleration lag at the very beginning sucks.

 

Altitude plays a heavy role on your times you would need to correct for DA (density altitude) to get an idea of what your times would be at sea level. Based on you info your DA is about 9500 feet so multiply your times by 0.9835 to correct for elevation. Its not the car but the altitude and weather causing the lack of power. Here are a few links for ya.

http://www.wunderground.com/ (get the weather info here)
http://wahiduddin.net/calc/calc_hp_dp.htm (input weather data here to get DA)
http://www.greatlakesdragaway.com/co...onfactors.html (use chart to get the correction factor)

 

I like that second link. It shows the percentage of engine power produced on a standard day with 75% humidity and 90 degrees F to be a little over 75% of maximum rated horsepower...pretty close to my generous 80% estimate.

Where did you come up with that .9835 correction factor though? That doesn't make sense to me considering the OP's engine is only putting out 75% of rated horsepower. Seems that correction factor should be much more aggressive.

Thatattguy there's 20% less air pressure at 6000 feet than what there is at sea level. That means there's 20% less "stuff" to burn in your 13.7:1 or so air/fuel mixture. This, coupled with high temperature - which again decreases the amount of air molecules in a given volume, explains your lack of performance. You paid for G performance, but at your altitude and current high temperature, you're getting Honda Civic performance.

The only way to fix this is to make your intake charge more dense...and the only effective way to do that is with forced induction - or move to a lower elevation.

I hope this makes sense.

 

Irrelevant: Well thats very interesting. I can relate and i feel what your saying. Thanks for the input, your advice is great/confirms what i feel.

GaryC: I dont beat up the car, i take as best of care for her as i can. I was told that the differntial oil change was 70,000. Maybe wrong but im getting it changed to synthetic Sept 3rd. Thats my payday.. So far ive had the brakes done, belts look great, oil has been changed to syn every 3000 miles, Transmission flush done at 70,000, spark plugs replaced last week and all the fuids are level.

Im excited to find though that my car is not consuming oil like most. Zero oil in my coil packs!

Okay so heres what ive researched. The car puts 286HP to the crank, because my drivetrain loss(5AT) that puts me at roughly 224 whp(based on other similar cars that have dyno'd at sea level). I ran some Density Altitude tests using Drag times DA calculator, and for the time, day, place, temp, etc... My DA is about 8515FT above sea level. I read on many many websites that for every 1000FT you go above sea level its a .3% power loss.

- SO: 224 * 24% = 170.24WHP

And if i reverse that math and apply it to my 0-60 times:
- SO: 8.3s * 76 = 6.308s at sea level

6.308 sounds about right for the amount of miles my car has.

 

I did the calculation wrong I added when I should have subtracted the correction factor should be .8795. The chart in the 3rd link only goes to 5500' and each 100' =.0013 so (.0013*40)-.9315=.8795. I used to race my maxima a lot and here on the east coast is where you find that the DAs are usually negative making the cars produce more power than normal due to high pressure, low temps/humidity and low altitude. The last time I raced my DA was -2800' and the calculator showed my car to be making 128% power and was my fastest run ever.