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Relocating the Battery? ...Why or why not?

Posted by NewTurboTuner, Nov 8, 2006

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  1. NewTurboTuner

    NewTurboTuner Proven Member

    385
    19
    Joined Jul 21, 2006
    Rslv, Arkansas
    I'd like to discuss the Benefits, and Drawbacks of relocating the Battery to the rear of a DSM.
    ~~(( I'm not trying to start an argument here, so please keep it cool. ))~~

    I've been thinking alot about the weight of my car lately, and I've been considering relocating my battery to the rear of the car.
    Domestic drivers move their batteries to the rear to add weight over the driving wheels, but that's for a RWD car.

    The more I think about relocating the battery in a DSM's.... I think it won't do much to add performance. And I'm starting to think there will be more drawbacks, than there will be benefits. BUT I'd like to hear what you other DSM'ers think about it, because there could be something I'm overlooking.........

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Here are the benefits, and drawbacks that I can think of so far.....

    Benefits:
    **Relocating the battery to the back of a FWD or AWD car might help with cornering ability, by giving the car a slightly better front/rear weight balance.
    **If you've got a Full blown, or fast race car, you might have to relocate the Batt for race regulations.

    Drawbacks:
    **For a FWD car; Moving the weight of the battery from the front (off of the driving tires), to the rear of the car would hurt traction.
    **For a AWD car; Moving the weight of the battery from the front to the back, could hurt traction by transferring too much weight to the back of the car, causing the front tires to lift, and loose traction; making the AWD less effective. Like a FWD car... A AWD car needs weight up front for hard launches. It helps the car stay flat so that all 4 tires will put power to the ground. (you don't want a AWD car to pop wheelies off the start like a RWD car does)
    **Relocating the battery to the rear of the car will easily add 20-25.lbs of thick wires, battery box, Cut-off switch, brackets, and bolts. Combined that weight with the average battery, and you've got a 65.lb battery combo. (15+lbs heavier than a crapy stock Batt)
    **Spending $100 to relocate a battery; adding 20-25.lbs of extra hardware... Dosent seem worth it when you can spend $100 and buy a light 15.lb battery, and loose 35lbs.

    Is there anything I'm missing?..............
    ..................................WHAT DO YOU GUYS THINK?..................................

    Personally. For my style of driving; I'm starting to think that relocating the Battery to the rear of a DSM's is a waist of time, and money. The Drawbacks seem to out weigh the benefits .....BUT I'D LIKE TO HEAR WHAT OTHER's HAVE TO SAY ABOUT IT.....
    What other benefits, or drawbacks can You think of that are associated with relocating the battery to the rear of our DSM's??

    Thanks:thumb:
    ~SB
     

    855  6

    1991 Mitsubishi Eclipse GSX
    automatic · 2G DSM
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  2. staticbrainwash

    staticbrainwash Awaiting Email Verification

    1,622
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    Joined Oct 10, 2004
    Midland, Michigan
    The weight difference you talk about with AWD isn't accurate.

    Think about the weight difference already present with the motor being in the front of the car. Simply removing the batter will; yes, help with balance of the car, BUT, not significantly to the point where it would make the front lift.

    I mean hell, a battery only weighs around 30-50lbs.
     

    429  0

    1992 Eagle Talon TSi AWD
    automatic · 1G DSM
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  3. robs90tsi

    robs90tsi Proven Member

    536
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    Joined Jan 26, 2006
    grayslake, Illinois
    also, is that much weight really that important?? I mean come on, when did we turn into honda tuners?? Sorry, but thats just the way i feel, are cars are heavy, a battery wont make much difference really, besides the battery in the trunk cleans up the engine bay and frees up space for lets say, a magnus intake manifold??
     
  4. staticbrainwash

    staticbrainwash Awaiting Email Verification

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    Midland, Michigan

    429  0

    1992 Eagle Talon TSi AWD
    automatic · 1G DSM
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  5. MrBoxx

    MrBoxx Moderator

    2,842
    107
    Joined Aug 19, 2005
    Midland, Michigan
    I'll be doing a battery relocation on my car either this winter or this spring, depending on how long my current battery lasts and when I get all the parts together. I'll most likely do a good write-up on it, since good write-ups on good battery relocations in a 2g are hard to find. I'll also weigh all the parts for good measure.

    I recall hearing people say that relocating the battery over the rear differential improves handling feel. Also, I've heard it said, but don't quote me on it, that the rear passenger corner of the car is the lightest, due to the weight of the driver in the front driver's corner. Relocating the battery opposite that may offset the weight difference. RRE's Corner Weights Page seems to vary whether it's the driver's or passenger's side rear that weighs more, but it doesn't say whether those weights include the driver or not.
     
  6. Eclipsethis90

    Eclipsethis90 Proven Member

    119
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    Joined Jul 16, 2003
    Eastern, North Carolina
    Playing off of what the two previous posts have stated I can only see one more factor to address. Now this is not for the drag racer, but more for the corner carver type. Our engine and driver is in the front left of the vehicle, and as we all know the front left dives more in hard cornering because of that extra weight. By placing the battery in the rear right of the vehicle you would HELP compensate for the heavy left front. I emphasize help because the T/E/L is just naturally heavier on the left side and relocation would only begin to assist in leveling out the cars balance. If i do recall this process is called corner weighing. Weighing the vehicle at all wheels , driver included, and moving objects or ballast around to achieve an even balance of weight across the four tires. Thus giving the vehicle in question a balanced feel while cornering under high speed.
     

    221  0

    1990 Eagle Talon TSi AWD
    manual · 1G DSM
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  7. NewTurboTuner

    NewTurboTuner Proven Member

    385
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    Joined Jul 21, 2006
    Rslv, Arkansas
    I think you might have miss read me or I miss communicated.

    I think you've got me wrong. I meant lift... not as in popping full on wheelies. I meant it in the sense that it would lift(remove weight, and lighten) the front tires, so that they will be less effective with traction.

    I know a car weighs more up front, but when a car accelerates.... that front weight gets transferred to the rear of a car no matter if its RWD, FWD, or AWD. Its OK for a RWD car to transfer its weight to the rear wheel (cause the rear wheels are the driving tires). But with a FWD car you want as much weight forward as possible, and with a AWD car you want to keep the car weight as flat and even as possible, so that all of the tires get good traction.
     

    855  6

    1991 Mitsubishi Eclipse GSX
    automatic · 2G DSM
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  8. MrBoxx

    MrBoxx Moderator

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    Joined Aug 19, 2005
    Midland, Michigan
    With that said, the front corners of a 2g DSM are over 200lbs heavier than the rear corners, with the driver's side 30lbs heavier than the passenger side and 230lbs heavier than the rear pass. side. So going by your statement, moving the battery to the rear would be a step in the right direction.
     
  9. staticbrainwash

    staticbrainwash Awaiting Email Verification

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    Joined Oct 10, 2004
    Midland, Michigan
    Which is what i was trying to say.

    The battery isn't enough weight difference to pop the front. Usually, AWD owners will try to remove as much from the engine bay as possible to even the weight.

    IE, relocate the battery, remove AC/PS, emissions, CF hoods. . . Ect. . .

    I plan to relocate as soon as it gets nice again (or i get the money, whichever is first). Not for weight so much, but just for an easier/cleaner engine bay.
     

    429  0

    1992 Eagle Talon TSi AWD
    automatic · 1G DSM
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  10. project_tsi

    project_tsi DSM Wiseman

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    Eau Claire, Michigan

    687  0

    1993 Mitsubishi Eclipse GSX
    11.342 @ 128.880 · 1G DSM
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  11. BrokenTsi

    BrokenTsi Proven Member

    1,597
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    Joined May 3, 2003
    Rome, New York
    This is how I did mine. I purchased this battery on ebay. I made myself a bracket for about 5 bucks to hold the battery in place, and I used a universal tie down from autozone for $3. I didn't have to modify ANY of the stock battery cables. Oh yeah, I got a ground cable from autozone for $5 bucks. This battery has never given me any problems, its never gone dead, it always starts, and has given me NO problems whatsoever. The battery is extremely light. Now I have all sorts of room for intercooler piping and accessing whatever in that area of the engine compartment.

    *dont laugh at the 14b, I was just breakin in my engine before I put my other setup on. :cool: :thumb:

    itsdoneson011.jpg
     

    1K  0

    1990 Eagle Talon TSi AWD
    9.693 @ 150.800 · 1G DSM
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  12. BrokenTsi

    BrokenTsi Proven Member

    1,597
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    Joined May 3, 2003
    Rome, New York
    I like to save weight and make things look simple and clean. And I didn't have to buy an expensive "bling" battery hold down kit. It does the job and impresses the ladies.

    I was thinking of relocating the battery to the rear. But its SO expensive and to do this, I would HAVE to have a cut off switch to race at the track. PITA if you ask me.
     

    1K  0

    1990 Eagle Talon TSi AWD
    9.693 @ 150.800 · 1G DSM
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  13. xveganxcowboyx

    xveganxcowboyx Proven Member

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    Joined May 15, 2005
    St. Paul, Minnesota
    The thing to remember when comparing a lightened battery in the front to a relocation to the rear is the weight shift.

    If you assume a car weighs 3,200lbs and has a weight ratio of 60/40 front to rear that puts 1,920lbs in the front and 1,280lbs in the rear.

    If you get a lighter battery (assume you save 25lbs) you end up with 1,895 in the front and 1,280 in the rear. This means a weight split of 59.3/40.7%

    If you relocate a stock battery (assume it weighs 40 lbs) you end up with 1,880lbs in the front and 1,320lbs in the rear. This means a weight split of 58.75/41.25%. This is nearly twice the gain towards an ideal 50/50 split.


    And if you're dragging I say drop as much weight as possible and stiffen up the rear. Who cares about weight distribution.
     
  14. FullthrottleGST

    FullthrottleGST Proven Member

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    Joined Sep 21, 2004
    Bay Area, California
    werd
     
  15. awdtalontsi1992

    awdtalontsi1992 Proven Member

    287
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    Joined Feb 14, 2006
    Annville, Pennsylvania
    The reason I personally relocated the battery on my 1G awd was to gain some room in the engine compartment. I wasn't concerned about the weight or weight distribution. There are definate pros and cons to doing this. Here were some that factored in my decision.

    PRO

    "Better weight distribution" - you can take this for what it's worth from the previous posts. i'm not going to beat a dead horse and exsplain my views on this as it has been done adequately already.

    Free up some much needed space in the engine compartment

    Extremely easy fuel pump rewire straight from the battery.

    Good time to upgrade to a nice battery.

    CON

    Pain in the butt to get everything including big wire run and put in place

    Extra taxing on charging system to send current over longer distance.

    Cost - A sealed battery box is required since the passanger compartment and battery now share the same space. Both NHRA and IHRA don't mess around about battery boxes and their specs.

    Cutoff Switch - NHRA and IHRA require that relocated batteries have an cutoff switch for emergencies......NOTE: This can also be a handy tool since you don't need to remove a cable to power down the car.
     

    384  0

    1992 Eagle Talon TSi AWD
    manual · 1G DSM
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  16. echostats

    echostats Proven Member

    146
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    Joined Dec 7, 2004
    Massillon, Ohio
    I plan to move my battery to the back this winter but it is certainly NOT for performance reasons. I do not think there is really anyway you will gain much performance from transfer that kind of wait. Yes, there will be some difference, but nothing your average street racer would notice.

    I will be moving my battery simply to clean up the engine bay. It's just one less thing in the way and taking up room.
     

    268  0

    1998 Mitsubishi Eclipse GSX
    manual · 2G DSM
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  17. Syndicate13

    Syndicate13 Proven Member

    1,248
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    Joined Jan 5, 2003
    Ft. Myers, Florida
    I relocated mine because I needed that space for my alky tank. My battery now resides where the SMIC used to be.
     
  18. MILITISINVICTUS

    MILITISINVICTUS Proven Member

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    Joined Oct 17, 2005
    Beer, Maryland
    It's misleading to measure a change like this only on its individual merit. Upgrading your car an incremental process. If you make a bunch of little improvements, they'll add up. So if your goal is an optimally-performing car, every bit contributes to the total package. Consider someone stripping a car to shave weight, any particular cosmetic piece doesn't weigh much, but remove them all and you're getting somewhere..

    If you feel like making an improvement, can afford it, and can do it properly, I say go for it. That's what draws us to dsmtuners in the first place, isn't it?
     
  19. RotaryAE86

    RotaryAE86 Proven Member

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    Joined Feb 14, 2006
    West Palm Beach, Florida
    my .02
    weight distribution, itll help a little bit considering the engine and tranny are sitting over the front wheels. but all in all its a little step in a long process to have a better performing car
     
  20. redeclipse7782

    redeclipse7782 Proven Member

    453
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    Joined Oct 20, 2004
    Worcester, Massachusetts
    Since Optima batteries are already sealed, do you still need a battery box if you have an Optima?
     
  21. WatchItExplode

    WatchItExplode Proven Member

    287
    9
    Joined Jan 4, 2005
    Mesa, Arizona
    yes. The purpose of a battery box is to keep the battery from exploding and/or containing the explosion in the event of a fire.
     

    402  0

    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  22. Defiant

    Defiant DSM Wiseman

    25,196
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    Joined Jan 13, 2003
    glorious Galt, California
    Just be sure to use copper spray on your battery.
     

    3K  0

    1995 Eagle Talon TSi AWD
    manual · 2G DSM
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  23. 1FAST2G

    1FAST2G Proven Member

    124
    0
    Joined Sep 19, 2002
    La Puente, California
    I relocated my battery to my subframe. I use to have a pc680 lightwieght battery, but it didn't last to long (about a year). That thing was $115 shipped. I made my hold down out of a stripe of 2" wide aluminum from home deopt. I just used one of the old bolt holes that the stock battery tray used to bolt to and bolted the bracket I made there. Then I just drilled a small hole in my subframe and used a J hook for the other side. After my pc680 battery died I decided to try a different battery. I got a lawn and tractor battery from sears. It is the same size as the pc680. It is only like 1.5 to 2 inches thicker. You need to get the gold model though it has the most power, the regular model has less CCA. The gold model is only $5 more. This battery only cost me $40 and has more power than my pc680. I have not had any problems starting my car.
     

    517  0

    1995 Mitsubishi Eclipse GSX
    12.196 @ 139.030 · 2G DSM
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  24. scottsee

    scottsee Proven Member

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    Joined Mar 25, 2004
    casa grande, Arizona
    I did it because I wanted to be one of the cool kids...
     

    520  0

    1996 Mitsubishi Eclipse GSX
    12.422 @ 111.130 · 2G DSM
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  25. wret

    wret Proven Member

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    62
    Joined Jul 3, 2003
    Bel Air, Maryland
    Anyone ever look into using multiple, smaller batteries? It seems like it would be easier to maintain a lower center of gravity.
     

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