Grit66

05 stock w/auto tran 4sp what rpm can I expect at hiway speed
65-75
Tks

Vette_DD

I thought I had a chart for the 05 A4 automatic tranny, but the only chart I've got is for the later years A6 tranny. That tranny would be at about 1500 to 1600 rpm at 65 to 75 mph.

I'm guessing the A4 would be close to that.

4SUMERZ

I would venture to say around 1500 RPM. That's what I get on my 2006 A6.

RobLo

Same car...IIRC at 70 I'm at about 1800 RPM's...

Edited...after looking at the comments I realize I didn't mention mine is a Z51, that would make a difference!

Bruze

If one really wanted to know without actually driving it, check the A4 hi-gear ratio compared to an A6. If they're the same, then the RPM would be the same *IF* the diff ratio (and tire diameter) is the same.

But screw all that math, I do math for a living. It would be a lot easier to just drive it. What difference does it make anyway?

fireparamed

windyC6

Well i'd feel a lot better knowing mine was only turning 1400 instead of 1450.....

LowRyter

just look at the tach (?)

Bruze

irok

70 mph with 3:15 gear is approx. 2,000 rpm in 4L65E

Vette_DD

3:15 gear was available only if purchased as an option or came with the Z51 option package. Standard was 2:73.

RocketDawg

I'm guessing he's getting about the right rpm's (1500-1600 at those speeds) but thought it was way too low. Probably he's not familiar with V-8 engines. Most cars these days turn much higher at "highway" speeds.

ruxvette

That's a big factor...Z51 or no?

Bruze

Actually they turn much lower. They outlawed overdrives (late '50s?) from the danger posed because they free-wheeled when you let off the gas, possibly overloading the brakes.

Then the environmentalists and safety tyrants infiltrated Washington and fuel economy became mandatory so overdrives came back, although now not free-wheeling. I noticed in my A6 Vette that 4th is very close to 1:1; 5th and 6th are both overdrive. (On an old style stick, in high gear the input and output shafts were locked at 1:1. In high gear, the only reduction between the crankshaft and rear wheels was via the diff ratio).

My best friend was driving my Vette a couple of summers ago and he noted how low the RPMs were at highway speeds (12-1400?). I told him that to compare RPMs with "old" cars, you would have to check the C6 RPMs in 4th -- it being the closest to 1:1.

Ha, I had a '70 Roadrunner 4-speed with 4:10s. As I recall, in 4th I think it cranked about 3,000 at 60 MPH (4th gear was 1:1).

Something like that anyway. I'm on my 4th (5th?) drink (no guarantee on that) so I could be off.

windyC6

Oh yea...I remember those days. My 67 Nova had a pretty stout mouse in it with 5.13's. Can't remember the R's @ 60, but I remember not wanting to go on the highway too often. Thank goodness I got the motor balanced and printed cause the "safe" red line was close to 9000.....YEE - HI that was fun !!!!........

phileaglesfan

Off topic somewhat, I thought all 4 bangers were high revvers on the highway. Even my 12 300C Hemi was around 2500 RPM at 80mph. Bought a 16 Malibu with the 2.0T and 80mph is about 2000rpm and it has enough grunt to make it over small hills even in 8th gear.

Z51 or not is the key for 2005 as that is about a 15% difference in gear ratio. I think 4th gear in the A4 is the overdrive gear where in the A6 it is 1:1. I think A6 gearing in 6th gear is about .5:1.

irok

thats exactly what I stated.my stock MSR car came with the optional 3:15 gear.the 3:15 gear was available on all 05 C6 auto cars

Vette_DD

OP needs a way to find out which one he's got. He should be able to look at his RPO list in the glove box.

G90 is the RPO code for 3:15, or Z51 for the Z51 performance package.

roboticjunky

In my non-Z51 auto 2005 Corvette with stock tires, turns 1500 at 60 mph. So 65 mph is around 1600 rpm. 70 would be 1730 rpm.

Also here is a calculator. http://spicerparts.com/calculators/t...rpm-calculator