adding 3.91 gear to eforce supercharger good idea? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

10' Camaro SC · 10-07-2015, 06:09 AM

Is this a good mod to do for better acceleration/from a dig? Is the 3.91 gear and supercharger combo not a good idea?

Apex Motorsports · 10-07-2015, 09:31 AM

Gears are a great way to improve performance but with your set up I would go with 3.70.

williamp78 · 10-07-2015, 09:40 AM

see what RPM and what gear you trap in at the 1/4. Then figure out what gear you need to keep your RPM up in power range.

dreksnot · 10-07-2015, 01:29 PM

3.73's might be a better choice. The 3.91 will promote tire spin, big time!

fif_gen_powa · 10-07-2015, 01:43 PM

Quote:

Originally Posted by williamp78

see what RPM and what gear you trap in at the 1/4. Then figure out what gear you need to keep your RPM up in power range.

It's ideal to pass through the traps at the top of 4th gear in a manual transmission car. Does anyone know what mph stock redline in 4th gear with 3.91s or 3.73 would be on a ss m6?

10' Camaro SC · 10-07-2015, 02:05 PM

Quote:

Originally Posted by Apex Motorsports

Gears are a great way to improve performance but with your set up I would go with 3.70.

Quote:

Originally Posted by dreksnot

3.73's might be a better choice. The 3.91 will promote tire spin, big time!

Damn even with 520rwhp? I know there's plenty of bigger builds.

The pricing for the 3.91 kit is pretty good. Any 3.73 kits for around same price?

Thanks

DaFisch · 10-07-2015, 02:44 PM

To my knowledge their are no gm 3.70's gears. You would have to go richmond or another company which will be over 500 for just the gear and pinion while the gm 3.91's are around 380 for the pinion gear and install kit. It's a bummer but the 3.91's will retain a warranty. Honestly, it depends n your power band like everyone else is said. but, if you are looking to add power, don't care about a top speed top (250ish down to around 200) and you want to go fast get the 3.91's.

fif_gen_powa · 10-07-2015, 05:16 PM

Quote:

Originally Posted by DaFisch

To my knowledge their are no gm 3.70's gears. You would have to go richmond or another company which will be over 500 for just the gear and pinion while the gm 3.91's are around 380 for the pinion gear and install kit. It's a bummer but the 3.91's will retain a warranty. Honestly, it depends n your power band like everyone else is said. but, if you are looking to add power, don't care about a top speed top (250ish down to around 200) and you want to go fast get the 3.91's.

OK the top speed is irrelevant. No one here is going 200 let alone 250mph.

I also feel the traction issues with 3.91s get blown out of proportion . Yes on a street tire it's going to spin down low. But you're gonna have traction issues regardless on a street tire when you start making 5-600 whp. I don't see it being such a big deal on a car that should run drag radials when it races anyways

Apex Motorsports · 10-07-2015, 06:12 PM

Quote:

Originally Posted by 10' Camaro SC

Damn even with 520rwhp? I know there's plenty of bigger builds.

The pricing for the 3.91 kit is pretty good. Any 3.73 kits for around same price?

Thanks

520rwhp is pretty healthy. That is ZL1 power but with a more aggressively geared transmission.

3.73 is going to cost more but I think it would be the right choice.

10' Camaro SC · 10-07-2015, 09:24 PM

Quote:

Originally Posted by Apex Motorsports

520rwhp is pretty healthy. That is ZL1 power but with a more aggressively geared transmission.

3.73 is going to cost more but I think it would be the right choice.

I just fear going to something that's not from GM as far as gears go. Any downsides to going to different gear other then traction? Harder on tranny or axles?

Apex Motorsports · 10-08-2015, 06:35 PM

Quote:

Originally Posted by 10' Camaro SC

I just fear going to something that's not from GM as far as gears go. Any downsides to going to different gear other then traction? Harder on tranny or axles?

No, there are plenty of people putting down 600-700 rwhp with stock axles and sticky tires. The tranny is upstream on the gears so it doesn't know the difference.

Pro Stock John · 10-08-2015, 06:40 PM

There is a good 3.70 gear out there, but it's pricey.

What is your goal by doing 3.91s?

L99CAMA2011 · 10-08-2015, 08:57 PM

Quote:

Originally Posted by DaFisch

To my knowledge their are no gm 3.70's gears. You would have to go richmond or another company which will be over 500 for just the gear and pinion while the gm 3.91's are around 380 for the pinion gear and install kit. It's a bummer but the 3.91's will retain a warranty. Honestly, it depends n your power band like everyone else is said. but, if you are looking to add power, don't care about a top speed top (250ish down to around 200) and you want to go fast get the 3.91's.

ZL-1 rear end is 3.70 equipped.

Pro Stock John · 10-09-2015, 08:54 AM

ZL1 has a different carrier the gears don't interchange.

10-07-2015, 06:09 AM	#1
10' Camaro SC Drives: 2010 Camaro SS 5th Gen 6spd SC Join Date: Jun 2015 Location: Florida Posts: 614	adding 3.91 gear to eforce supercharger good idea? Is this a good mod to do for better acceleration/from a dig? Is the 3.91 gear and supercharger combo not a good idea? __________________ 10' LS3 Camaro 2SS (blacked out) - Edelbrock Supercharger, ZL1 rims, 275/315 tires, XS Power LT headers, 3" exhaust, twin tips, Edelbrock CAI, ZL1 fuel pump/ADM FPCM, VMax ported TB, JRE fuel mod, TR6ix plugs, ZL1 spoiler/splitter/grille, KW V1 coilovers, BMR sway bars, strut tower brace, trailing arms, toe links, Prothane radius arm & subframe bushings, Slotted rotors, Hawk pads, SS brake lines, HURST short throw shifter, Scosche dash kit, Pioneer 7" radio, backup camera, Dyno - 520 rwhp/tq

10-07-2015, 09:40 AM	#3
williamp78 Drives: 2011 2ss blk/wht strp Join Date: Oct 2014 Location: south of houston Posts: 446	see what RPM and what gear you trap in at the 1/4. Then figure out what gear you need to keep your RPM up in power range. __________________ 2011 2ss black/wht stripes "CAM only" https://www.instagram.com/w_j_p_boss/?hl=en

10-07-2015, 01:29 PM	#4
dreksnot Served USN - Atomic Chimp Drives: 2021 Camaro ZL1 1LE A10 (stock) Join Date: Jul 2012 Location: Fort Collins, CO Posts: 1,617 View My Garage	3.73's might be a better choice. The 3.91 will promote tire spin, big time! __________________ In excess of 1,000WHP LSX434 \| AGP 65/65 TT \| BTR Equalizer Intake \| Trickflow 245cc cathedral \| BTR custom cam \| Cortex EBC \| n2mb WOT \| ID-1700x \| Brisk GR12S \| RPM Lv 7 TR6060 \| AGP's Triple 525LPH Fore Fuel \| Monster LT1-S Triple \| 4.11 DSS Proform 9", CF driveshaft, 1400hp axles \| Hurst Line Lock \| MGW Retro Short Throw w/old skool Hurst T-handle \| ADM solid subframe mounts \| Prothane Motor Mounts \| Revshift Poly Trans insert \| Moreno camber/caster plates

10-08-2015, 06:40 PM	#12
Pro Stock John Writer Drives: 2010 SS / 1967 Camaro Join Date: May 2009 Location: Chicago, IL Posts: 7,216	There is a good 3.70 gear out there, but it's pricey. What is your goal by doing 3.91s? __________________ PROJECT HEAVY CHEVY Camaro Now: Mods for the Masses Part I \| Part II 13.15@106 1.95 \| 100% Stock 12.37@112 1.85 \| + Kooks Headers/Cats + 20" 555R + CAI + BW TB + UDP + Tune 12.06@113 1.70 \| + CD 3200 + 18" NT05R + RCR Intake + NE OTR + GPI Tune 11.84@115 1.59 \| + 3.91s + Race Star 17x7 Fronts 10.90@125 1.47 \| + GPI VVT Cam + BW Ported Heads + CD 3800

10-09-2015, 08:54 AM	#14
Pro Stock John Writer Drives: 2010 SS / 1967 Camaro Join Date: May 2009 Location: Chicago, IL Posts: 7,216	ZL1 has a different carrier the gears don't interchange. __________________ PROJECT HEAVY CHEVY Camaro Now: Mods for the Masses Part I \| Part II 13.15@106 1.95 \| 100% Stock 12.37@112 1.85 \| + Kooks Headers/Cats + 20" 555R + CAI + BW TB + UDP + Tune 12.06@113 1.70 \| + CD 3200 + 18" NT05R + RCR Intake + NE OTR + GPI Tune 11.84@115 1.59 \| + 3.91s + Race Star 17x7 Fronts 10.90@125 1.47 \| + GPI VVT Cam + BW Ported Heads + CD 3800

10-07-2015, 09:31 AM	#2
Apex Motorsports Drives: 2000 Camaro SS Join Date: Feb 2010 Location: Louisville, Ky. Posts: 25,179	Gears are a great way to improve performance but with your set up I would go with 3.70.

10-07-2015, 02:44 PM	#7
DaFisch Master Amateur Mechanic Drives: Victory Red 2011 2SS/RS Join Date: Jan 2013 Location: South Barrington, IL Posts: 1,720	To my knowledge their are no gm 3.70's gears. You would have to go richmond or another company which will be over 500 for just the gear and pinion while the gm 3.91's are around 380 for the pinion gear and install kit. It's a bummer but the 3.91's will retain a warranty. Honestly, it depends n your power band like everyone else is said. but, if you are looking to add power, don't care about a top speed top (250ish down to around 200) and you want to go fast get the 3.91's.