Gears & Axles - power loss to expect?




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2000_SS
07-22-2007, 01:58 PM
i just bought a 9" Moser from EPP, it's not here yet, but i've heard a lot about rear ends robbing power. how much power exactly should i expect? i know a local guy here with a fox body 'stang lost almost a half second off his 1/4 mile ET due to the weight and such. are LS1 cars suffering similar losses, or do i not have any idea what i'm talking about? :confused:


GOaT Cheese
07-22-2007, 09:38 PM
If the ratio remains the same, and you lose .5 sec., from a rear end swap, then you have some super major geometry problems. Parasitic drag from one rear end design to another is negligeable, assuming the gearing is identical, the only thing you should experience is longevity.

PowerShift408
07-22-2007, 09:47 PM
Yes, your car will make less power. Mine made 466 rwhp through the 10 bolt. Through a 9'' and a much heavier twin dics clutch assembly, it made 432 rwhp.


blue98Z
07-23-2007, 12:42 AM
From what I've read on other threads you can expect about a 13-15hp loss just from the 9". That's not alot. That little bit for a rearend you can leave really hard on and not have to worry about it breaking is worth it to me.

Jimmard
07-23-2007, 01:38 AM
Yeah I'm sure I lost some power through the 9", but after taking it to the local 1/8th mile, I couldn't care less how much I lost as I dropped 7tenths off my previous best time.

EPP
07-23-2007, 04:57 AM
Yeah I'm sure I lost some power through the 9", but after taking it to the local 1/8th mile, I couldn't care less how much I lost as I dropped 7tenths off my previous best time.

Good analogy, I agree! Bob

candyblueta
07-23-2007, 01:18 PM
what about a 12 bolt???

2000_SS
07-23-2007, 04:26 PM
from what i understand, 12-bolts don't handle aftermarket torque arms very well and then to flex a bit more than a 9".

i got the alluminum center section on mine to help with weight redux, so that'll be a little help.

EITHER WAY, i've only ran the car once and went 13.1 @ 105 as it sits with mods in sig... :jest: :jest: :rotflmao: :rotflmao: :lol:

the tires spun for about 100-150 feet, then when i got 3rd gear the clutch let go at about 5800 rpms and i couldn't get it in 4th, then i crammed it in and the clutch completly let go, never grabbed any of 4th gear....

...so i'm sure i'll be doin' better. hopefully some sort of 11.xxx...even an 11.999 would suit me.

BlackScreaminMachine
07-24-2007, 02:58 PM
unless dyno'ed you wont know, ET trap speeds wont take into consideration the static weight added, but either way its more for a added insurance that the car wont break.

2000_SS
07-24-2007, 03:59 PM
the car has been dynoed, but the stock clutch slipped a lot. i've got a Textralia going in tonight/tomorrow...then the 9" thursday/friday....

similarly modded cars on here go into the 11's, so i'm pretty sure if i can make myself launch hard it will be there on a radial....