Trying to find a performance (lightweight) flywheel. Ideas?
- Thread starter HarleyMick
- Start date
Because they'd be a waste of money and time for a Jeep with the old design OHV engines we have. Some 2.5 owners run extra-heavy flywheels to help reduce stalling but that's about it.
X2 to this. A lightweight flywheel on old tractor engine? Might as well add a throttle body spacer while you're in there
Seriously, you stand to gain nothing at all from a lightweight flywheel on a Jeep, and there's a reason you don't see them for Jeeps.
I see you're running a stroker, are you trying to get a faster rpm rise or something to do with acceleration? How many counterweights does your crank have, that would probably have a bigger influence than a flywheel. I don't know of any lightened flywheels for the "4.0" but typically gearing is where you will see the most benefit.
OP
My crank has holes instead of counterweights, but I get your point. I thought it might be slowing me down.
If anything you should be looking for a heavier one. A light flywheel will be more likely to stall out the engine on you. You want that inertia spinning when at lower (sub 3000) rpm. A lightened flywheel only benefits folks looking to get their rpms up faster and higher. Both things that a straight 6 are not designed to do.
Exactly.
On a high revving Honda S2000, you want a lighter flywheel so that you can reach the upper RPMs (where that engine makes power) much quicker. On a 4.0 where your power band is very narrow (and it doesn't rev very high), a lighter flywheel would be completely counter-intuitive. You'd actually end up ruining the way it drives.
OP
Thanks, guys! So the consensus is a 22 lb flywheel diminishes nothing up to 5,000 rpm regardless of the horsepower or torque. Guess I was getting greedy!
I actually picked up a heavier flywheel for mine. Haven't gotten around to installing it yet, though. I will install it in a future preemptive clutch replacement. I certainly wouldn't want a lighter flywheel.
https://www.quadratec.com/p/centerforce/high-inertia-flywheel-jeep-vehicles-40l-engine
https://www.quadratec.com/p/centerforce/high-inertia-flywheel-jeep-vehicles-40l-engine
OP
prevents stalling at low RPM's, which means that the engine can lug easier without dying.
I have the light crank and a flex plate on my stroker with a low stall converter, lugs pretty good for a 250ish hp engine. I built one of the first strokers about 12 years ago, not many around here had them back then. I have another crank in the garage for the LJ when the time comes for a rebuild.
OP
My Golen Engines 4.6 stroker tops out at 276 hp on the dyno from about 4,800 - 5,000 rpm and has a 4.88 ring and pinion with a 5 speed. Torque is 325 at around 3,800 and starts dropping off around 4,200 rpm. I'm not concerned about lugging around in first gear, but to stretch the power curve for acceleration. This is a show Jeep that is also fast. Wouldn't a heavier flywheel slow it down? If I go that route, where did you find a light flywheel?
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If you are using a Jeep as a Jeep you want a heavy flywheel. If you are using a Jeep as a Honda you want a lighter fluwheel.
Caution! These 4.0 engines don't like high rpms. They were not designed for it.
Have you ever seen those old photos of the giant steam tractors plowing up the virgin prairie pulling 20 or more plows at a time with a bunch of men on the plow platform constantly adjusting the plow bottoms? They made little horsepower. MASSIVE torque. They had flywheels weighing TONS. Literally. All that rotational inertia kept it moving in between the cylinder strokes. That's what a heavy flywheel does.
Ever watch those Formula 1 cars slot around a corner and go from 6000 rpm to 10000 in a split second? That is what a light flywheel does.
Obviously there are other major differences (like burning race gas versus coal) but that illustrates what difference in weight of the flywheel can achieve.
Hope this helps.
Caution! These 4.0 engines don't like high rpms. They were not designed for it.
Have you ever seen those old photos of the giant steam tractors plowing up the virgin prairie pulling 20 or more plows at a time with a bunch of men on the plow platform constantly adjusting the plow bottoms? They made little horsepower. MASSIVE torque. They had flywheels weighing TONS. Literally. All that rotational inertia kept it moving in between the cylinder strokes. That's what a heavy flywheel does.
Ever watch those Formula 1 cars slot around a corner and go from 6000 rpm to 10000 in a split second? That is what a light flywheel does.
Obviously there are other major differences (like burning race gas versus coal) but that illustrates what difference in weight of the flywheel can achieve.
Hope this helps.
OP
Thank you. As a show car that is also fast it is no longer being used as a Jeep, so to speak. Red line is 5,500 rpm and 5,000 is the optimal shift point in head to head competition. The entire engine has been blueprinted, balanced and is optimized for performance within inherent limitations. The frame, suspension and all underneath look new or freshly painted.
The interior is immaculate and it has a substantial Kicker sound system. With 4.88 gears the 5th gear overdrive puts 70 mph at 2700 rpm. It is totally stable and easy to drive at 90 mph with the sport tuned suspension. I'm not trying to make it a dragstrip vehicle but every show car should also have some go. It does. Golen gives it a 3 year unlimited mileage warranty with the rev limiter set at 5,500 rpm. When it's not going to a car show or cruising on a beautiful day it is in the garage under a car cover. In the 15 years I've owned it I have done my share of mudding and rock climbing but it's 21 years old and I'm 67.
Purpose has changed, but the next owner will be getting a 'new' 1999 Sahara with lots of power they can modify to suit their own purposes. I hope the purists on here understand I'm not ruining it, merely tweaking it to suit my current preferences. Back to the original question, does anyone know where I could find a light weight flywheel if I go that route?
One more important point. The factory setup had 225 lbs. of torque, it now has 325 with the 22 lb flywheel. (see above dyno results) Would a 15 lb flywheel really cost me that much pull?
The interior is immaculate and it has a substantial Kicker sound system. With 4.88 gears the 5th gear overdrive puts 70 mph at 2700 rpm. It is totally stable and easy to drive at 90 mph with the sport tuned suspension. I'm not trying to make it a dragstrip vehicle but every show car should also have some go. It does. Golen gives it a 3 year unlimited mileage warranty with the rev limiter set at 5,500 rpm. When it's not going to a car show or cruising on a beautiful day it is in the garage under a car cover. In the 15 years I've owned it I have done my share of mudding and rock climbing but it's 21 years old and I'm 67.
Purpose has changed, but the next owner will be getting a 'new' 1999 Sahara with lots of power they can modify to suit their own purposes. I hope the purists on here understand I'm not ruining it, merely tweaking it to suit my current preferences. Back to the original question, does anyone know where I could find a light weight flywheel if I go that route?
One more important point. The factory setup had 225 lbs. of torque, it now has 325 with the 22 lb flywheel. (see above dyno results) Would a 15 lb flywheel really cost me that much pull?
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