Lightened Flywheel

[Doug D.]

Has anybody here had any experience using a lightened flywheel to improve low-end throttle response?

It's my understanding that a stock flywheel for a 1600 cc engine weighs about 14.5 pounds. I'm told that by switching to a lighter flywheel, 10-12 lbs for instance, that there are significant gains to be had in throttle response and low-end performance. My question would be, how would the lighter flywheel affect torque?

Any takers?

 

[DeathBySnuSnu]

I run a light flywheel, but with a heavily modified engine. I have tall (3.44) ring and pinion and .82 fourth gear. Throttle is quick even touchy at times when you don't want it to be.
I don't think I would go very light on a stock type engine, but would on a stroker motor.

 

[Doug D.]

Good info, I appreciate it! What engine mods are you running?

 

[DeathBySnuSnu]

Aftermarket replacement case that is cut, clearanced and welded to make room for crankshaft.
82mm cb performance super race forged stroker crank.
H beam stock length rods.
Eagle 2246 cam.
31 mm big foot lifters.
Cima forged offset pin pistons and jugs 90.5 mm.
Mofoco 050 heads, cnc D ported, 42mm in, 37.5 out ss valves.
Port matched intakes.
44 idf weber clone carbs.
Bosch 009 distributor.
Alum pulley.
Chevy alternator.
Maxi pump 4 externally ported oil pump.
Empi oil cooler, full flow hooked directly to oil pump.
Original oil cooler ports on case hooked to spin on filter.
Chromoly push rods, head studs and case thread inserts.
Scat 1.25 ratio slipper foot rocker arms.
Lightest (can not remem the weight) steel flywheel I could get without going to alum.
Kennedy pressure plate and a plain disc.

Not a single part of the entire engine actually came from VW.

 

[slick rick]

:wave4::wave4:...Doug I think Rex is a VW guru or just an 'ol HOT RODDER ,either way he's really seems to be sharp on one ....::10: :10:

 

[DeathBySnuSnu]

NOT a guru. I only ever had or worked on 1 and that one is mine. But.... I have had it since I was 14. I am almost 52 now. I am and old hot rodder. I have had other hot rods over the years and have been into several different types of racing.<br />
<br />
Ok Doug think about it. Everything hot rod is a trade off. If you take weight from the flywheel then that will mean that you do not have that rotational energy stored up in that spinning mass. So when you let out on the clutch the rpm is going to drop much more quickly.

On a stock type engine it may be that the lack of the stored energy (what I think you are calling torque) will make it "boggy" while engaging the clutch.<br />
<br />
Now on the flip side of this is that once the clutch is fully engaged then the weight of the flywheel becomes a burden to acceleration. Now you have to put energy into the flywheel instead of the energy going into moving the vehicle.<br />
<br />
So a light flywheel does accelerate faster, but on a stock or nearly stock engine the "boggy" engagement time in street use may be too much of a price to pay.<br />
You might not be too negative of draw back if your vehicle is very light or if you like to rev it up high to take off anyway.<br />
<br />
Stroker motor make bunches more torque and have heavy cranks with all the internal balancing that goes with a high rpm motor. So the lack of flywheel weight is not as noticeable at take off.

 

[slick rick]

:gah::gah:...Would you go a little slower ,,,please .....LOL,, :I know if I have trouble there's a couple guys on here I'm going to for information.

 

[Doug D.]

Rex, that's an impressive set of specs for your motor! I imagine it came with a hefty price tag, too. I say that, as I'm planning a new build for the trike, but mine won't be quite as beefy as that. And your answer to my flywheel question clears up a lot of mystery as well. Seems that would be an unnecessary mod in my case, not giving much in gains. I can't thank you enough for the information!

Hey, Rick, how was the holiday?

 

[slick rick]

Doug rained every day except one :gah::gah: ,took the boat out one time but still good to spend a week in the lake shack . ThumbUp We usually go every other weekend and we ride every other weekend but with all the rain that schedule is all screwed up .Maybe it's about over sure hope so . :Shrug::Shrug:

 

[DeathBySnuSnu]

Doug
Whatcha buildin? C'mon spill it.

Slick
Sounds like me. The weather is only good when I have to work all weekend.

 

[slick rick]

Doug
Whatcha buildin? C'mon spill it.

Slick
Sounds like me. The weather is only good when I have to work all weekend.

:gah::gah:,,,Yep really sucks but looks like good weather for the next few days MAYBE .........ThumbUp

 

[vwmaniac]

I have installed a lightened flywheel on my trike, it is a single port vw motor and have noticed a little more power and no bogging at all, it want to scoot down the road a lot more now than before, I figure for the price of one, wasn't much more than a stock one and it has paid off so far,
So good luck with yours too.

Far as the rain, we have been getting our share of it here too, enough to pass around to you if you want some,... lolll

 

[Doug D.]

Doug rained every day except one :gah::gah: ,took the boat out one time but still good to spend a week in the lake shack . ThumbUp We usually go every other weekend and we ride every other weekend but with all the rain that schedule is all screwed up .Maybe it's about over sure hope so . :Shrug::Shrug:

Yeah, the rain has really screwed up my road time, too. I like to ride to work through the season because it saves me a bunch on gas, but the worst part is the off time riding. Seems it rains the hardest when I have a day off! Oh well, at least ya got away for a few days. What I wouldn't give for that right now...

 

[Doug D.]

Doug
Whatcha buildin? C'mon spill it.

It's still in the planning stages right now, but nothing as sporty as yours!

Just thinking about something in the 1700-1800 cc range, with a little more cam than I'm running now and some balanced innards. Strictly a cruiser with a little more balls on the interstate. Built for endurance, for sure, as I plan to travel long distances on a regular basis, time and dime not withstanding.

 

[Doug D.]

I have installed a lightened flywheel on my trike, it is a single port vw motor and have noticed a little more power and no bogging at all, it want to scoot down the road a lot more now than before, I figure for the price of one, wasn't much more than a stock one and it has paid off so far,
So good luck with yours too.

What weight flywheel did you use?

 

[vwmaniac]

Will check and get back to you.

 

[Mo Lee]

In the early 80s while stationed in Germany I was racing VWs on dirt track, a German find of mine turned my flywheel to just over half the original weight and the throttle response was very quick. Upon reassignment to the states I built a full bodied beetle using all my race parts plus a few more that would pull the front wheels off the ground (full bodied) on take off. The cam was extremly radical for the street and on numerous occasion I saw 8 grand on the tach. When you start building VW make sure you upgrade the flywheel to 8 dowel pins (ask me how I know) and make sure you have a good gauge o monitor engine temp.

 

[slick rick]

In the early 80s while stationed in Germany I was racing VWs on dirt track, a German find of mine turned my flywheel to just over half the original weight and the throttle response was very quick. Upon reassignment to the states I built a full bodied beetle using all my race parts plus a few more that would pull the front wheels off the ground (full bodied) on take off. The cam was extremly radical for the street and on numerous occasion I saw 8 grand on the tach. When you start building VW make sure you upgrade the flywheel to 8 dowel pins (ask me how I know) and make sure you have a good gauge o monitor engine temp.

ThumbUpThumbUp,,,,GOOD IMFO.......ThumbUpThumbUp

 

[DeathBySnuSnu]

Doug:
Here is some opinion....
An improved performance engine (not a hot rod grenade motor like mine) that is good and durable.
A new AS41 case. Minimize the amount of major internal machine work thus keeping the structural integrity of the case. This will limit you to a 76 mm stroke.
So I would go 76mm counterwieghted stroker crank.
Stock bore cyl piston.
It will take some internal clearancing but nothing major machine shop. Just hand grinding.
Make sure the case has thread inserts on the head studs.
It will take some careful jug shimming to get the deck hieght right.
A good general performance stock type duel port head.
Light wieght H beam rods.
Eagle makes some good cams. Pick something mild or even one of the milage grinds.
Make sure it is all balanced well after all the clearancing and test fitting.
Increase the oil capacity, add a sump pan if you have the ground clearance, or add an external oil cooler. A spin on oil filter is real good to have.
Get a good set of rocker arms. I dont like the very high ratio ones, I like the 1.25 or stock ratio. But a good set goes a long way toward keeping the valve lash set.
Go with a ligher flywheel (the heavier stroker crank will make up the wieght).

Now here is where things get tricky.
A very good set up is the 009 dizzy and duel kadron (or other solex clone) carbs.
It is tunable, but sometimes tricky to tune.
If you can gather up the technical know how I would go with a micro squirt ecm and build my own fuel injection and distro less ignition set up. Most likely a ford edis 4 wasted spark ignition. They are simpler to work with, all the coil drivers are in a single module and it only needs a single word input for spark advance and has a crank position output for the fuel injection. Then mostly chevy injectors and sensors. I like chrysler throttle bodies becaude the idle air controll valve is easier to program. Then write your own fuel and ignition map, make it run however you want, very tunable with just a lap top.
One day my trike will have a simular set up for fuel and ignition. It may be a bit more radical in size and scope (mostly because of multiple throttle bodies). But I am collecting the parts from ebay. For some reason I just have not been able to get my 009 distro advance curve to match what the engine needs in its current set up. Next time it comes apart it is going back together with bigger jugs and fuel injection, up from a 2110 to a 2276. Just what I need in a trike 48 inches wide and 66 inch wheel base...LOL
But it is a hot rod and only a toy. I dont go far with it, I never have the time.

 

[DeathBySnuSnu]

O... and get a set of 3.88 r&p for the transaxle.