What affect will this have on my rpms on the highway and around town. And how bad will it affect my gas milage. The truck will have 20's on it
What affect will this have on my rpms on the highway and around town. And how bad will it affect my gas milage. The truck will have 20's on it
My truck gets 14 aound town and 18-19 on the hiway....with a very lite foot
Vortec Performance Tuned
LQ9 built 4L60 LTs and a billion miles on the speedo!
Uh...it WILL affect it! Going from (3.42 I assume) your gears to 4.56 would absolutely KILL your highway MPG. Good luck getting anything over 16 MPG on the highway...Originally Posted by GenIII_4Ever
2000 ECSB 6.0L
TORQUER V2 CAM ● COMP 918's ● 7.4 HARDENED PUSHRODS ● K&N SERIES 77 CAI ● 80mm BBK ●PACESETTER LT HEADERS AND 3'' ORY ● SUPER 40 FLOW ● 3000 STALL ● 4.10s ● BUILT 80e ● VORTEC PERFORMANCE TUNE ● MSD 8.5mm PLUG WIRES● ELEC. CUTOUT ● UD & ALT PULLEYS ● FLEX-A-LITE E-FANS ● 22" CENTERLINE STINGRAY III's ● LUND FIBERGLASS TONNEAU ● 2" LEVELING SHACKLES ● 12K HID LOWS & FOGS ● LEDs ● DEBADGED ● WHITE-FACED ESCALADE GAUGES ● KICKER 450.1 ● 2-CVR 10's ● DS60's ● K693's
What gears do you have right now? Because that could be a bit much...
With heavy wheels/tires, the 4.56 gears might help city mileage and will definately kill hwy mileage. And if you have a loud exhaust, it will be even louder since it'll be at a higher RPM all the time.
Then again, I think most folks that are going to throw on 4.56's or higher have already given up on their vehicle being "practical."
lol im running 4.56's but ill have 6 gears... so hopefully it wont be to bad
09 CREWCAB LTZ SILVERADO, 6.2, SIX SPEED, CAI,
Yeah, you should be fine--but for us hopeless A4 people, 4.56 gears would help a little in town, but the highway would be killer on the MPG...
2000 ECSB 6.0L
TORQUER V2 CAM ● COMP 918's ● 7.4 HARDENED PUSHRODS ● K&N SERIES 77 CAI ● 80mm BBK ●PACESETTER LT HEADERS AND 3'' ORY ● SUPER 40 FLOW ● 3000 STALL ● 4.10s ● BUILT 80e ● VORTEC PERFORMANCE TUNE ● MSD 8.5mm PLUG WIRES● ELEC. CUTOUT ● UD & ALT PULLEYS ● FLEX-A-LITE E-FANS ● 22" CENTERLINE STINGRAY III's ● LUND FIBERGLASS TONNEAU ● 2" LEVELING SHACKLES ● 12K HID LOWS & FOGS ● LEDs ● DEBADGED ● WHITE-FACED ESCALADE GAUGES ● KICKER 450.1 ● 2-CVR 10's ● DS60's ● K693's
what brand gears do people reccomend? i have heard some whine...
09 CREWCAB LTZ SILVERADO, 6.2, SIX SPEED, CAI,
Expect to loose 23% - 27% of your MPG (Originally 20mpg, now 15mpg) but gain 45% in *oomph*
*If you're making 350 Ft/Lb at the flywheel with a 3.42 gear, the force you tires apply to the road surface in 4th (1:1) is going to be 982 lbs of "thrust".
With a 4.56 that number will be something like 1,300 lbs.
Last edited by SS Killer; 03-26-2008 at 03:51 PM.
Eric "The" Pyles
14.06 @ 96mph / 9.02 @ 79mph
302 RWHP/298 RWTQ
With your 275/40-20 tires, the tire height is calculated to be 29.74 inches. With a 4.56 gear, 4l60E with a 0.70 overdrive, and 29.74 inch tire height, your engine will be turning approximately 2167 RPM @ 60MPH, 2528 RPM @ 70MPH, 2889 RPM @ 80MPH, and 3611 RPM @ 100MPH.
Hopefully these figures will help you with your decision.
Mixing alcohol and Prozac...
i say do it
02 Sierra... motorless for now.
02 SS.. stock bottom 4.8, 241's, 224-220/116+4, 918's and pushrods, front mount turbonetics 78mm, HKS GTII, TiAL, eBoost2, Yank PT3600, Performabuilt 60e, solid motor mounts. Tuned by me with HP Pro and LM2/AFX
Posting Permissions
Reply With Quote
