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Discussion Starter · #1 ·
A few years ago, one of the 4wd mags had a "Low Buck Build-ups" section. One of the "build-ups" was to install a heavier flywheel as it would give the engine more momentum and more torque. For example, it would keep the vehicle rolling more steadily at idle than a vehicle with a lighter flywheel (which makes sense). But I want to know if it would do the same for freeway speeds. In the winter time where I live, the winds blow so hard that it slows my Jeep down a LOT on the freeway even though it has a v8 engine. I don't want to do a gear swap because I hate doing them so I just want to know if this low buck build-up would alleviate some of my freeway driving trouble. And if so, how hard is it to install one?

-Dorian
http://88 YJ w/ multi-speed wipers
 

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I researched this when I bought a Sami, and from what Ive heard and read, it makes the most difference on under powered ( SMALL ENGINE) vehicles..
IM pretty sure a V8 YJ doesnt fall into this catagory!

Honestly on a V8, I think youll only notice it revs a little slower..



ozarkjeep
1977 CJ5 looking for a Hard top near NW Arkansas!
 

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Heavy flywheels equal more torque. V6 Jeep in the sixties used a flywheel that was extremely heavy I believe close to sixy-seventy pounds. The torque on these engines was 235ft/lbs at 3500.

 

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/wwwthreads_images/icons/smile.gif Actually guys, the heavy flywheel doesn't add torque. The heavy flywheel only helps the engine to SUSTAIN torque...or RPM....or idle...WHATEVER it is at the time. The flywheel is a momentum increaser, and helps the engine stay doing what it is doing at the time. So....if you are at low RPM and your front axle comes up against a berm, the momentum of the flywheel helps carry the Jeep over it. The downside of this is the extra weight on the crank. Model A Fords had such a heavy flywheel (they were literally like a tractor) that it wore the main bearing in the rear out just from the weight. The Model A guys slap the wheel in a lathe and turn SIXTY POUNDS off it to help prevent excessive wear./wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 
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Discussion Starter · #5 ·
...and that's what my idea was: to use it to sustain RPMs while driving on the freeway.

You see, with 3.73 gears, 33" tires, and .78 overdrive my RPMs are about 2100 @ 70mph. Put that on a vehicle with the aerodynamics of a parachute and it doesn't take much to slow it down so what can I do to maintain speed? I live (more or less in the mountains) about 30 miles out of town so it's not as if this idea is just a solution to something temporary like occasional long freeway drives. And I hate to use 4th gear to keep up with traffic going up the pass because it wastes gas, puts more wear on the engine, etc.

-Dorian
88 YJ w/ multi-speed wipers
 

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its possible itll work that way Miller Time, I dont know for sure
but its generally used to stabilize the torque at startup ( when letting off the clutch)so its easier to GET rolling, npot sustain a certain speed



OzarkJeep
NW Arkansas
 

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/wwwthreads_images/icons/smile.gif Sudden gusts of wind would not slow you down as easily, but sustained wind would eventually slow you down because only HP can save you in a sustained pull./wwwthreads_images/icons/wink.gif Remember, the flywheel can add no HP, only momentum and inertia./wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 

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and Id loike to ad, Mr presidential candidta CJDAVE

I dont hink it can ad those things ( inetia, momentum)

only increase the load required to overcome the inertia mommentum it already HAS right?



OzarkJeep
NW Arkansas
 

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/wwwthreads_images/icons/tongue.gif The engine overcomes the inertia that the flywheel adds to the idling engine, and that "investment" of power is converted to momentum. Since the rotating mass is increased by the weight of the heavier flywheel, the crank-flywheel assembly has more overall inertia and resistance to changes in speed, either up or down. Wood chippers use this principle. They would have to have a tremendous engine to chip wood like they do, but they use a HUGE flywheel and a dinky engine instead. The heavy flywheel helps to resist the drop in RPM when the worker tosses a five-inch branch in there(or his buddy if the guy makes him angry). The load on the wood chipper is brief, and the flywheel helps the engine handle it. Once the wood is chipped, the engine goes to work "investing" more HP in bringing the flywheel back up to speed again and ready for the next branch. Simple, no? Am I elected?/wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 

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yeah thats pretty much what i said..

as long as that DINKY engine can stay ahead it isnt a problem...

back to the point,

Millertime, put a 87 LB billet steel flywheel in there

and tell us what happens... ( I have my theories!)

CJdave,

elected? hardly, you havent even Campaigned in Arkansas yet! haha

OzarkJeep
NW Arkansas
 

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/wwwthreads_images/icons/tongue.gif Headlines in the Arkansas Gazette: "Miller Jeep Sets New Record For Slow Acceleration" "Miller Jeep Jerks County Courthouse Off Foundation" "Miller Jeep Hailed As Breakthrough In Heavy-But-Brief Tractor Pulling" "Miller Jeep Disabled Due To Broken Crank Flange...Owner Sad" "Miller Jeep Climbs Straight Up Rock Wall For Thirty Seconds" "Miller Jeep Engine Spins For Record Thirty Hours After Ignition Shutoff" Well....you get the idea./wwwthreads_images/icons/laugh.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 
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