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Balance and weght mods- worth it? Bang:buck? What order? #2439932
01/24/18 11:20 AM
01/24/18 11:20 AM
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Connecticut, USA
MRGTX Offline OP
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Everybody knows that less mass and better balance means a more capable (and usually more fun) car.

Going from a stock car, which weight reduction mods would you start with? Which ones would you not bother with?

How far would you be willing to go with a street driven car?
What are your plans?

Lighter wheels?
Fiberglass hood?
Fiberglass front bumper?
Fiberglass rear bumper?
Aluminum bumper brackets?
Battery relocation?
Other fiberglass body part?
Lexan(?)windows?




Last edited by MRGTX; 01/24/18 11:21 AM.
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2439947
01/24/18 12:04 PM
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Bob J Offline
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I was thinking of moving the battery but you have the added weight of the cable. With modern light weight batteries is it worth it over the weight of the cable? On the rear fiberglass bumper my thought is after driving a 911 I don't want that large weight of bumper and brackets that far back. The large weight behind the wheels will move you around, granted it's less than in a 911 but it's way back there.


07 Porsche C2 997.1 6spd DD and SCCA Solo II SS
68 Plymouth GTX Convert. 493cu Hotkiss Wilwood Classic air, Building for Solo II Cam
65 Chrysler 300 Convert. project
57 Desoto 2dr. Firesweep 392 Hemi,Wilwood Project with son
2003 Dodge Dakota R/T "DEAD"
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2439975
01/24/18 01:04 PM
01/24/18 01:04 PM
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moparx  Online Content
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check out the "real world weight loss" thread in the race section. absolute TONS of ideas ! every little bit counts ! member FMJ is over the top when it comes to weight reduction. he makes jenny craig look like a 10,000lb. hippo ! biggrin
beer

Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2439985
01/24/18 01:21 PM
01/24/18 01:21 PM
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Another consideration and Bob touched on it, weight location.

There are certain things you cannot do without, even getting a lightweight battery, you still need a battery and it can be located in a more advantageous location. Putting the battery and the end of the vehicle is a bad choice. You want the weight of the vehicle centered and down low.

If you are going to relocate things, or can relocate them give thought to putting it and low down as you can and as close tot eh center as you can.

https://en.wikipedia.org/wiki/Moment_of_inertia


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They say there is always the exception that proves the rule.
Don't be the exception.
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440136
01/24/18 05:26 PM
01/24/18 05:26 PM
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RylisPro Offline
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Aluminum block would be my most difficult but most effective weight reduction mod. It took off around 80 lbs from the front end. Here is my car's weight on autoxcuda's scale last year at Big Willow.

If you do the math it ends as a 55%/45% front/rear split.

This was with 295's still so my car will be a little heavier this year with 315's. Fiberglass bumpers, hood, trunk lower valance, steel bumpers brackets, gutted interior with no wiper motor. Lighter wheels are a toss up as you really want stiffer and wider wheels as possible. Wider tires also weigh more as well. I'm going to work on gutted doors as I have a mild steel cage


73 `Cuda
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Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: Bob J] #2440235
01/24/18 09:22 PM
01/24/18 09:22 PM
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myduster360 Offline
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Originally Posted By Bob J
I was thinking of moving the battery but you have the added weight of the cable. With modern light weight batteries is it worth it over the weight of the cable? On the rear fiberglass bumper my thought is after driving a 911 I don't want that large weight of bumper and brackets that far back. The large weight behind the wheels will move you around, granted it's less than in a 911 but it's way back there.


Apples and Oranges,,A 911 is in the 40/60 range for weight distribution(for very good reasons) but most mopars are nearly the opposite,,they nearly have 60% of their weight on the front axle
Any Mopar has a LONG road just to get anywhere close to 50/50.

Any weight you can get off the FRONT end will not only improve handling but also braking. So YES get the battery in the trunk. Front Bumper & Brackets, hood

I'm going so far as to swap in a 300hp Pentastar V6 into my 72 Swinger. It's not only 200lb lighter but 10" shorter than an iron small block. So its light weight is also centered further to the rear.

www.forabodiesonly.com/mopar/attachments/upload_2017-12-23_19-5-46-png.1715123788


www.forabodiesonly.com/mopar/attachments/upload_2017-11-25_19-28-43-png.1715114595

Last edited by myduster360; 01/24/18 09:31 PM.

1972 Swinger 3.6L Pentastar
Diablo CMR tuner
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440258
01/24/18 10:18 PM
01/24/18 10:18 PM
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Colorado
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Bob J Offline
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I know that a 911 is a different animal but that bumper out back on a GTX is way out there. Drag racers also put the battery way out back for weight transfer. That and a steel bumper and brackets will only help getting the pendulum effect going. Moving the battery over the rear axle might be worth the added weight of the cable as it gets the weight of the nose. Or go with a battery that weighs 2 or 3 lbs but not cheap. Run 1 Hi Low horn not 2 as it's out front and cheap to do.

I'm trying to get my GTX under 3400 and most of the weight is from the nose of the car. You can also do some drilling. It's a power window assy. that I took a pound out of ans 1.5 lbs out of the backs.

IMG_1600 (1).JPG
Last edited by Bob J; 01/24/18 10:20 PM.

07 Porsche C2 997.1 6spd DD and SCCA Solo II SS
68 Plymouth GTX Convert. 493cu Hotkiss Wilwood Classic air, Building for Solo II Cam
65 Chrysler 300 Convert. project
57 Desoto 2dr. Firesweep 392 Hemi,Wilwood Project with son
2003 Dodge Dakota R/T "DEAD"
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440271
01/24/18 10:40 PM
01/24/18 10:40 PM
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Connecticut, USA
MRGTX Offline OP
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Awesome stuff, guys!
I’ve been sold on the concept of a battery relocation job for a while...I’m thinking that mounting it right behind the rear passenger seat would be optimal for handling. Has anyone done that?
Did you make your own kit or did you buy one? Most tracks (drag, road, Autox) require a metal box, correct?

While the Pentastar swap is an insanely cool project, some of us are V8 loyalists. smile too bad the Modern Hemi engines still run iron blocks! Aluminum heads seem like a golden opportunity at least...how much weight to be shaved there on a small block?

Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440293
01/24/18 11:27 PM
01/24/18 11:27 PM
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RylisPro Offline
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Moving the battery behind the passenger seat is not a bad idea. You would lose pounds of cable doing so. The battery box can be plastic but the battery itself has to be bolted down with metal to the body. I have also used a Deka 16 lightweight AGM battery on my old 340 before and it started up fine but had issues on hot days.

Aluminum blocks are available for the Gen 3 Hemi but it is another $4 grand extra


73 `Cuda
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Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440300
01/24/18 11:43 PM
01/24/18 11:43 PM
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myduster360 Offline
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You'll gain even more from relocating the battery if its as far back as you can get. So not the high up near the rear seat back but even further back by the bumper. If a 20lb battery is placed say 2ft behind the rear axle, it will create a moment about the axle and is like removing an additional 5lb right off the Front axle of a 3600lb B-body.


Removing rear weight hurts weight distribution but can still have its benefits. Hyperco rear fiberglass Leafs will shave a good 70lbs of static weight off the car but most of it is UnSprung weight, which is a great thing for a portly live axle.

Last edited by myduster360; 01/25/18 01:08 PM.

1972 Swinger 3.6L Pentastar
Diablo CMR tuner
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440312
01/25/18 12:09 AM
01/25/18 12:09 AM
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Next battery I buy will go under the passenger seat. Small gel cel like an Odyssey or something

My steering box is worn I'm thinking of a borgenson.

Going to upgrade front brakes with aluminum calipers, hubs, adapter

Going to install aluminum power steering pump with remote resivior.

Want to remove heater and heater box.


I currently have: one plastic horn, aluminum: heads, radiator, water pump, master clylinder,

My 68 Barracuda coupe:

Last edited by autoxcuda; 01/25/18 12:39 AM.
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: myduster360] #2440328
01/25/18 12:26 AM
01/25/18 12:26 AM
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Originally Posted By myduster360
You'll gain even more from relocating the battery if its as far back as you can get. So not the high up near the rear seat back but even further back by the bumper. If a 20lb battery is placed say 2ft behind the rear axle, it will create a moment about the axle and is like removing an additional 5lb right off the Front axle of a 3600lb B-body.




That thinking is adequate for straight line racing. Putting the battery far back is not ideal in racing involving turns. The farther you have a weight from the center the more it wants to resist turning. That is why a mid engined car out handles a rear engined one, all else being equal. Under the rear seat pass side for the battery, ala VW Bug, is ideal, but likely no room.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: autoxcuda] #2440480
01/25/18 11:57 AM
01/25/18 11:57 AM
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Connecticut, USA
MRGTX Offline OP
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Originally Posted By autoxcuda
Next battery I buy will go under the passenger seat. Small gel cel like an Odyssey or something

My steering box is worn I'm thinking of a borgenson.

Going to upgrade front brakes with aluminum calipers, hubs, adapter

Going to install aluminum power steering pump with remote resivior.

Want to remove heater and heater box.


I currently have: one plastic horn, aluminum: heads, radiator, water pump, master clylinder,

...


Awesome...I've come to realize that you have blazed a lot of trails with your Barracuda so I'm always interested in your findings, your advice and your plans!

Which brakes are you looking at? How much weight will those save over stock style disk brake calipers?

Plastic horn? This never occurred to me. Which one did you go with?

The aluminum steering pump sounds like a good opportunity to save a few lbs off of the nose but did you ever consider just going to a manual box?





Last edited by MRGTX; 01/25/18 11:58 AM.
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: Supercuda] #2440506
01/25/18 01:02 PM
01/25/18 01:02 PM
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myduster360 Offline
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Originally Posted By Θάνατος
Originally Posted By myduster360
You'll gain even more from relocating the battery if its as far back as you can get. So not the high up near the rear seat back but even further back by the bumper. If a 20lb battery is placed say 2ft behind the rear axle, it will create a moment about the axle and is like removing an additional 5lb right off the Front axle of a 3600lb B-body.




That thinking is adequate for straight line racing. Putting the battery far back is not ideal in racing involving turns. The farther you have a weight from the center the more it wants to resist turning. That is why a mid engines car out handles a rear engine one, all else being equal. Under the rear seat pass side for the battery, ala VW Bug, is ideal, but likely no room.


No, in fact its pointedly true for any car trying to turn.

The OP B-body has nearly 60% of its weight on the front wheels. That's a huge amount of weight. Same with autoxcuda's A-body. So the Center of Gravity of those vehicles is quite forward the car's geometric center. Its about the CG is where the vehicle will turn.

Its a fact that cars with a REAR weight bias both handle and brake better compared to a cars with a FRONT weight bias(All mopars).

Its also a fact that moving the heavy weight of the Battery furthest to the Rear of the car will contribute the MOST to moving the CG rearward. But move the same Battery half as far and that contribution will be diminished accordingly. Given the fuss of moving a battery, why bother moving it half way?

Seems the Spare Tire well of an A-body(like all LX cars) would be a great place for a battery. But using a set of scales to pick the perfect spot would be ideal.

Last edited by myduster360; 01/25/18 01:04 PM.

1972 Swinger 3.6L Pentastar
Diablo CMR tuner
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440632
01/25/18 05:04 PM
01/25/18 05:04 PM
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Originally Posted By MRGTX
Originally Posted By autoxcuda
Next battery I buy will go under the passenger seat. Small gel cel like an Odyssey or something

My steering box is worn I'm thinking of a borgenson.

Going to upgrade front brakes with aluminum calipers, hubs, adapter

Going to install aluminum power steering pump with remote resivior.

Want to remove heater and heater box.


I currently have: one plastic horn, aluminum: heads, radiator, water pump, master clylinder,

...


Awesome...I've come to realize that you have blazed a lot of trails with your Barracuda so I'm always interested in your findings, your advice and your plans!

Which brakes are you looking at? How much weight will those save over stock style disk brake calipers?

Plastic horn? This never occurred to me. Which one did you go with?

The aluminum steering pump sounds like a good opportunity to save a few lbs off of the nose but did you ever consider just going to a manual box?



Looking at Willwood or Dr Diff 13".

Universal JC Whitney/Summit type horn. Newer little cars have real small plastic horns.

I drive it a lot on the street and go down to more urban So Cal areas. Even on a road course I for a heavy street car I like it. I don't autocross it anymore, but I would not want it for that.

Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440635
01/25/18 05:11 PM
01/25/18 05:11 PM
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Mopar Mitch Offline
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Weight reduction is one the most important factors, along with balancing... side-to-side (l-r) for each half (f/r).... with the driver and as you plan to drive/race it the majority of time.

Front seats can drop weight 20-30-40 pounds.

Master brake cylinder.. go with aluminum. and consider keeping or removing the power booster.

Radio stereo? eliminating all can reduce about 20-30-40-50 punds, pending what you have.

Do you need the passenger door mirror?
Do you need a front and/or rear spoiler?
Carpeting and insulation?

The list from everyone can be further expanded.

But, are you considering running in any sanctioned organized club events that have RULES/restrictions per your chosen class? consider your choices. IF you're an outlaw... running without RULES for mods of your car, then there's no limits, but, if you choose to run competitively in a sanctioned club event with RULES/restrictions, then decide ahead and make your mods very selectively. In other words, you don't want to over-or-under-mod your car then find yourself not competitive... and not happy having the fun you're hoping for.

With my own Challenger T/A (cloned long time ago, back in the 70's.. 80's), I followed the SCCA E/Street Prepared Solo II class rules for any mods done to the car... was ultimately able to get the weight of the car down, legally, to ~3150 (1/8-1/4 tank gas) w/o driver, with ~52f/48r% balance, and also had the side-to-sides equaled nearly same to each other... with driver as raced. Its also street/hwy driven.. raced seriously and highly competitively at AX/HSAX/HPDE events.

My battery (lt-wt Optima) is located far r/r of the trunk...as that's where the scales showed it to be best located. I tried it centered above the differential... scales showed it better far r/r. Overall, car handles great!

Last edited by Mopar Mitch; 01/25/18 05:15 PM.

Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: Mopar Mitch] #2440684
01/25/18 06:57 PM
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Originally Posted By Mopar Mitch
My battery (lt-wt Optima) is located far r/r of the trunk...as that's where the scales showed it to be best located. I tried it centered above the differential... scales showed it better far r/r. Overall, car handles great!


Thats right where i'm figuring it should be, especially with the weight of the driver included.

52f/48r% is pretty decent.

Last edited by myduster360; 01/25/18 06:59 PM.

1972 Swinger 3.6L Pentastar
Diablo CMR tuner
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: MRGTX] #2440883
01/26/18 05:44 AM
01/26/18 05:44 AM
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Here's a great reference for weight reduction in A-bodies for common parts, no mention of F/R distribution change but it's pretty easy to get an idea which parts go on the front or back of the car...

A-body Mopar Weight Reduction

I haven't done much to reduce weight on my '70 Duster aside from an aluminum intake and gutting the factory A/C system from under the hood but I do plan to relocate the battery to the trunk; thinking of going with stock or slightly larger battery to maximize the offset effect. I also plan to replace the steel 15" Rallye wheels with something aluminum, probably no bigger than 17" for weight reasons (am I thinking right here? lol... tires will be 26" tall in front, 27" in back). I'm also thinking of ditching the factory power steering system and going with a manual box and electric P/S system out of a newer car; I've heard it's pretty straightforward and very cheap. I'll need the space anyway when I do my Gen 3 Hemi swap.


Khalid
1970 Plymouth Duster, 1993 Jeep Cherokee 4x4
Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: EagleDuster] #2440887
01/26/18 06:25 AM
01/26/18 06:25 AM
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Lighter wheels are a toss up. 17 inch wheels have a limited amount of Extreme Performance Summer sizes unless your are happy with 255/40-17's. 18 inch wheels will have a much wider range of performance tire sizes. That in turn will make the tire heavier. You really want wider and stiffer wheels because it will transfer more hp/tq to the road. This should translate to faster track times.



73 `Cuda
Instagram: @rylispro
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Re: Balance and weght mods- worth it? Bang:buck? What order? [Re: RylisPro] #2441261
01/26/18 11:34 PM
01/26/18 11:34 PM
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ahy Offline
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A couple of easy and relatively low cost items would be AL manifold and water pump. Add aluminum heads and radiator. These help both overall weight and F/R balance.

I do believe rear battery is a good idea for balance.

Aluminum block would be really nice but spendy.

Lighter body panels (fenders, hood) would really help but expensive and may look funny.

On wheels, high end forged AL wheels in size of your choice can lighten things up but spendy.

Personally, I would not lighten up bumpers or brackets or door beams w/o cage for safety.

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