What are your RPMs at 80?
 

So on my latest road trip, I found myself at a bit over 2,000 RPMs when at 80 in 6th (only when passing of course :D)

Just wondering what you guys are all seeing at that speed? I know gearing is the main factor here, so I think my 2.73 gears have something to do with this low number. What about SS, ZL1 guys?

i think like 1800

Ok, so you have 2 more cylinders and 3.45 gears (correct me if I'm wrong) so that seems to make sense at the moment

3.93

OK, so 1LE has 3.93, LS has 2.73, what does a stock SS and ZL1 have?

3.27 and I see just over 2,000

Manual ZL1 has 3.73, I believe the auto is 3.23

Sorry, my bad, i missed what i thought i read:facepalm:my gears are actually 3.91

That's cool, I don't know why that # popped in my head :noidea:

1LS, manual trans, about 2200-2500 at 80mph

Pretty sure I'm around 2K (I know @ 60 I'm around 1400, so I'm just guess here lol)

Wheel size also comes into play here.

A bit over 2k I think.

I'm somewhere in the 2K range at 80mph, probably at least 2300 or more. I have 3.70 gears.

I'm not that old yet, but I don't expect to move very fast when I am that age.

like 2100-2300

4.10 gears 2400-2500 rpm +/-

I'm pretty sure it's around 2000 RPM at 80

These numbers are for my '13 1LS M6 with 18" wheels. Change out the bold numbers for your own and recalculate.

The math...

KNOWNS
A = Vehicle Speed (in mph)
B = Wheel Radius (in inches) measured from the wheel center to the ground
C = Rear Differential Ratio (ie 3.27)
D = Transmission Gear Ratio (ie .84)

VEHICLE - Convert MPH to in/min
(80mi/1hr) x (5280ft/1mi) x (12in/1ft) x (1hr/60min) = 84,480 in/min

WHEEL - Convert radius to circumference
C = 2πr = (2) x (π) x (13.75in) = 86.39 in = 86.39 in/1 rev

WHEEL - Convert in/rev to RPM
(84,480in/1rev) x (1rev/86.39in) = 977.89 RPM (at the wheel)

RPMs - Work it backwards through the drivetrain
(Wheel RPM) x (Differential Ratio) x (Transmission Gear Ratio) = Engine RPM
(977.89) x (3.27) x (.84) = 2,686 RPM

:facepalm: :sm0:
Thanks everyone else :thumbup:

Wow, that's really useful! It reminds me of AP Physics though :fear:
Thanks :w00t:

Yeah, no prob. I also have a spreadsheet that I whipped up one day when I was bored that tells me the vehicle speed for any given combination of engine rpm and gear. :headbang:

Wow! What program is this, or did you make it completely yourself? Very neat :w00t:

(Oh and I only said the passing thing so I wouldn't get flak from people for cruising at that speed, but I do :smiling1:)

I think I am right in between 2-2.1k @ 80mph.

I have a 2012 SS with an LS3.

At 80 in 6th it is turning 1800 RPM.

What I don't understand is I thought the LS Camaros had a tall gear for fuel economy... I thought that taller gears would get lower RPMs when cruising on the freeway?

I tested to make sure - at 80mph I'm at 2300-2400 rpms.

So wouldn't that mean I have a shorter gear? I really thought an economy geared v6 would have lower RPMs at 80mph than the SS...?

I think on the V6 the rpms are that high to compensate for the power compared to the SS. You have 2 less cylinders to feed @2300 rpms so it still gets better MPGs..if it could do it, it would get crazy MPGs @1800!!

Yeah I guess so - when I was driving a Corvette 427 a month ago I was shocked when I shifted into 6th gear and took it to 80mph and saw I was sub 2000 rpms... :lol:

Do you have one for the 2013 2LS? That has 2.73 gears

Around 2K+, last time I was on I-10 in West Texas speed limit was 85mph. Numerous cars pulled over by DPS.