Rear diff ratio improving cam surge question - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

jaysrippen · 09-21-2022, 12:12 AM

Hey guys, just looking for your opinion, my LSD diff failed and also wrecked my gears, sticker on my diff show 3.45 for my 2010 ss with m6.
My question is: i have cam and get cam surge/bucking at LIGHT throttle around 1300rpm (school zones/parking lots…), so i wonder if a lower rear ratio like 3.73 or 3.9 would improve or worsen cam surge?? I assume improve but thought id ask.
And looks like 3.73 are Alot more $, not sure why??

larry_g · 09-21-2022, 05:47 AM

I'm sure it depends on the cam but I have a PDS stage 3 cam with a 3.91 and don't have an issue with surge.

The 3.73 might be from a ZL1, which is a completely different setup and not a direct swap.

Sent from my Pixel 5 using Tapatalk

morepowerjoe · 09-21-2022, 05:47 AM

Well I'm no expert when it comes to this but I believe that lowering your rear gear would raise the rpm in any given gear so, with that being said it should help you out a little by raising that rpm point from 1300 rpm to ??? You'll have to plug transmission gear ratio, rear end ratio, and tire size into one of the calculators online to see where your rpm will land in that particular gear with the proposed new rear end ratio.

CamaroCracka · 09-21-2022, 07:14 AM

Putting a 3.91 in after upgrading the cam on the vert improved low speed drivability. Of course, it hurt mileage.

09-21-2022, 12:12 AM	#1
jaysrippen Drives: 2010ss M6 LS3 Join Date: Jun 2018 Location: Alberta Canafa Posts: 38	Rear diff ratio improving cam surge question Hey guys, just looking for your opinion, my LSD diff failed and also wrecked my gears, sticker on my diff show 3.45 for my 2010 ss with m6. My question is: i have cam and get cam surge/bucking at LIGHT throttle around 1300rpm (school zones/parking lots…), so i wonder if a lower rear ratio like 3.73 or 3.9 would improve or worsen cam surge?? I assume improve but thought id ask. And looks like 3.73 are Alot more $, not sure why?? __________________ 2010 SS M6, stage 2 summit cam, CAI Intake/long tube cat delete with flow master/ZEX NOS at 150RWHP/ custom tune/MSD wires/short throw shifter/ crank vent catchcan/ SS braided brake lines/ 1.5” lower springs/bigger rear sway bar/fully poly bushings everywhere/toe arms/trail arms/front caster plates/factory shocks/steering poly inserts

09-21-2022, 05:47 AM	#2
larry_g Drives: 2014 1SS/1LE Join Date: Nov 2015 Location: Louisville, KY Posts: 826	I'm sure it depends on the cam but I have a PDS stage 3 cam with a 3.91 and don't have an issue with surge. The 3.73 might be from a ZL1, which is a completely different setup and not a direct swap. Sent from my Pixel 5 using Tapatalk __________________ 830 WHP 700 WTQ, Whipple 2.9 @ 13lbs Boost, Flex Fuel Tune by Blevins Tuning, LSA SBE, 3.5 GripTec, ATI LS3 Damper, AFR 260cc Mongoose, ARP Studs, Yella Terra Ultralites, Johnson 2110R, BTR PDS Stage 3, Melling 10355, Improved Racing Baffle, ID1050X, DSX Triple Fuel Pump, RotoFab CAI, NW 103mm TB, Stainless Works 1-7/8" LTH to 3" Speed Eng w/ X-pipe to NPP, Powermaster 9509 XS, Detroit Speed Motor Mounts, MGW, Monster LT1-S, ZL1 Calipers, DBA Rotors & Pads, Bilstein B6 Struts & Shocks, BMR 1.25" Drop Springs & Adj Rear Bar, Pegasus Solid Bushings, Z/28 Wheels, other misc parts.

09-21-2022, 05:47 AM	#3
morepowerjoe Drives: 2012 Chevrolet Camaro l99 Join Date: Aug 2020 Location: Austin, TX Posts: 2,105	Well I'm no expert when it comes to this but I believe that lowering your rear gear would raise the rpm in any given gear so, with that being said it should help you out a little by raising that rpm point from 1300 rpm to ??? You'll have to plug transmission gear ratio, rear end ratio, and tire size into one of the calculators online to see where your rpm will land in that particular gear with the proposed new rear end ratio. __________________ DSS FX Forged Pistons, Eagle ESP L19 Forged Rods, ARP Head and Main Studs, TSP PRC 260 CNC Ported Heads milled .030, Cometic .040 Head Gaskets, GPI SS3 VVT Camshaft, GM Performance Racing Lifters, CHE Trunnions , Molly Pushrods, Melling 10355HV Oil Pump, Cold Air Inductions CAI, Fast LSXR Intake Manifold, Nick Williams 103 TB, TSP 1 7/8" Longtubes with 3" TSP Exhaust, ZL1 Fuel Pump, Mishimoto Radiator, Mishimoto Oil Cooler, Tru Cool 40k Tranny Cooler, 3600 Circle D Converter, Fluid Dynamics Balancer Build Thread https://www.camaro5.com/forums/showthread.php?t=609817

09-21-2022, 07:14 AM	#4
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 2,735	Putting a 3.91 in after upgrading the cam on the vert improved low speed drivability. Of course, it hurt mileage. __________________ 2010 SS - On3 kit with downpipe cutout, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1/1LE brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. ZL1 brakes.