What are your RPMs at 80? - Page 2 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

littlecammi · 06-21-2013, 03:55 PM

Quote:

Originally Posted by Scooter11

What are your RPMs at 80?

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

firedrop · 06-21-2013, 08:52 PM

like 2100-2300

BubbaSS · 06-21-2013, 09:48 PM

4.10 gears 2400-2500 rpm +/-

Dez · 06-21-2013, 10:42 PM

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

snymat68 · 06-21-2013, 11:31 PM

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

Scooter11 · 06-21-2013, 11:32 PM

Quote:

Originally Posted by littlecammi

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

Thanks everyone else

Scooter11 · 06-21-2013, 11:36 PM

Quote:

Originally Posted by snymat68

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/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

Wow, that's really useful! It reminds me of AP Physics though

Thanks

snymat68 · 06-21-2013, 11:59 PM

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.

Scooter11 · 06-22-2013, 09:20 AM

Quote:

Originally Posted by Comrando

If I was passing I wouldn't be in 6th.

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

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

)

pmandeep · 06-22-2013, 10:12 AM

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

two_wheel_mayhem · 06-22-2013, 10:17 AM

I have a 2012 SS with an LS3.

At 80 in 6th it is turning 1800 RPM.

meissen · 06-22-2013, 01:42 PM

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...?

Mikes SS · 06-22-2013, 02:02 PM

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!!

meissen · 06-22-2013, 02:07 PM

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...

06-21-2013, 08:52 PM	#16
firedrop Drives: 2012 2ss/l99 a6, victory red Join Date: Jun 2013 Location: philadelphia Posts: 387	like 2100-2300 __________________ 2012 2ss l99/a6 CAI, custom catback with flowmaster series 10s

06-21-2013, 09:48 PM	#17
BubbaSS WHAT RED LIGHT?! Drives: 2011 Black Camaro 2SS/RS M6 Join Date: Apr 2011 Location: Miami, Florida Posts: 1,115	4.10 gears 2400-2500 rpm +/- __________________ 2011 2SS/RS M6 BLACK - VARARAM NO TUNE INTAKE, MODDED AND PORTED TB, PORTED INTAKE MANIFOLD, VITESSE THROTTLE CONTROLLER, DOUG THORLEY LT'S, CATLESS, X-PIPE, 25" STAINLESS WORKS RETRO CHAMBERED MUFFLERS, CUSTOM 2.5" MANDREL BENT EXHAUST, RICHMOND 4.10 GEARS, CUSTOM CAM (231/242 @ 114LSA), MUSTANG DYNO TUNED BY TORQ, 20% CERAMIC TINTS, EIBACH PROKIT SPRINGS 1" DROP, HAWK PERFORMANCE CERAMIC BRAKES, NITTO INVO TIRES, HYDROCARBON TAIL LIGHT AND FOG LIGHT BEZELS BY EMBLEMPROS, METRA DASH KIT, JVC KW-AV71BT, PHOENIX GOLD iAMP GM1, PASSPORT QI45 - 450 RWHP 415 RWTQ

06-21-2013, 11:31 PM	#19
snymat68 Drives: 2013 Blue Ray 1LS M6 Join Date: Apr 2013 Location: Pittsburgh, PA Posts: 1,227 View My Garage	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 __________________ Performance Mods Elite Catch Can \| CAI Intake with Scoop & Washer Bottle Relocation \| MRT v2 Axle-Back Exhaust \| MagnaFlow Resonated X-Pipe \| Resonator Delete \| Vmax Ported Throttle Body \| GM Strut Tower Brace \| JDP Tow Hook \| Vitesse Throttle Controller Aesthetic Mods Chrome Peek-A-Boo Door Handles \| Interior Accessories Kit \| OEM RS HIDs w/ 6000k Bulbs & 5000k LED Fogs \| Tail Light, Marker Light, & Turn Signal Tint \| Tru-Sequence Sequential Turn Signals & Brake Lights \| Silver Fade Gill Stripes \| Carbon Fiber Bowties \| Various Chrome/Painted/Carbon Fiber Items Last edited by snymat68; 06-22-2013 at 12:32 AM.

06-21-2013, 11:59 PM	#22
snymat68 Drives: 2013 Blue Ray 1LS M6 Join Date: Apr 2013 Location: Pittsburgh, PA Posts: 1,227 View My Garage	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. __________________ Performance Mods Elite Catch Can \| CAI Intake with Scoop & Washer Bottle Relocation \| MRT v2 Axle-Back Exhaust \| MagnaFlow Resonated X-Pipe \| Resonator Delete \| Vmax Ported Throttle Body \| GM Strut Tower Brace \| JDP Tow Hook \| Vitesse Throttle Controller Aesthetic Mods Chrome Peek-A-Boo Door Handles \| Interior Accessories Kit \| OEM RS HIDs w/ 6000k Bulbs & 5000k LED Fogs \| Tail Light, Marker Light, & Turn Signal Tint \| Tru-Sequence Sequential Turn Signals & Brake Lights \| Silver Fade Gill Stripes \| Carbon Fiber Bowties \| Various Chrome/Painted/Carbon Fiber Items

06-22-2013, 10:12 AM	#24
pmandeep Drives: 2013 VR 2LT/RS Join Date: May 2013 Location: Michigan Posts: 266	I think I am right in between 2-2.1k @ 80mph. __________________ 2013 Victory Red 2LT/RS "I don't break rules. I just bend'em - a lot!" -Sideswipe

06-21-2013, 10:42 PM	#18
Dez Drives: 2010 CGM 2SS/RS Join Date: Jun 2013 Location: Mississippi Posts: 2	I'm pretty sure it's around 2000 RPM at 80

06-22-2013, 10:17 AM	#25
two_wheel_mayhem Would rather be riding Drives: No car no more Join Date: Jul 2009 Location: Indiana Posts: 2,750	I have a 2012 SS with an LS3. At 80 in 6th it is turning 1800 RPM. __________________ No dog in this fight anymore. 5th Gen owner 2009-2016.

06-22-2013, 01:42 PM	#26
meissen Founder - Michigan FBody Drives: 1994 Camaro LT1, 2012 Camaro 2SS/RS Join Date: Jun 2008 Location: New Haven, MI Posts: 2,599	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...? __________________ 2012 Camaro 2SS/RS L99 - *"Zooma"* 1994 Camaro LT1 A4 - *"Red Alert"* - v6-to-LT1 Swapped Cruiser; Cammed, Stalled, Enjoyed "Gone But Not Forgotten" 2016 Camaro 1LT A8 - "Elmo" 2014 Camaro 1LT M6 - "Cherry Bomb" 2012 Camaro 1LS M6 - "Clifford" Michigan FBody Association http://www.mifbody.com/

06-22-2013, 02:02 PM	#27
Mikes SS Drives: '10 CGM 2SS/RS 6M Join Date: Oct 2009 Location: North Central Florida Posts: 1,032 View My Garage	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!!

06-22-2013, 02:07 PM	#28
meissen Founder - Michigan FBody Drives: 1994 Camaro LT1, 2012 Camaro 2SS/RS Join Date: Jun 2008 Location: New Haven, MI Posts: 2,599	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... __________________ 2012 Camaro 2SS/RS L99 - *"Zooma"* 1994 Camaro LT1 A4 - *"Red Alert"* - v6-to-LT1 Swapped Cruiser; Cammed, Stalled, Enjoyed "Gone But Not Forgotten" 2016 Camaro 1LT A8 - "Elmo" 2014 Camaro 1LT M6 - "Cherry Bomb" 2012 Camaro 1LS M6 - "Clifford" Michigan FBody Association http://www.mifbody.com/