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Engine Specific Info and Questions => IDI Engine => Topic started by: RabbitJockey on July 26, 2009, 02:33:11 pm
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i'm getting my hybrid motor built, should i get my flywheel lightened? or does it make it run rougher
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also does anyone have an idea of how much it cost to have your bottom end balanced
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flywheel, do it.
balancing, do it yourself, its good practice. professionals will charge way way too much for the amount of work required.
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flywheel, do it.
Manual flywheel ?
balancing, do it yourself, its good practice. professionals will charge way way too much for the amount of work required.
Yeah, if you're talking about static balancing, get a "drug dealer's" scale and do it yourself. If you want a real balance, start with the static balance and pay a pro to do a dynamic balance. Then you'll have a smooth engine, but likely making your flywheel lighter will negate and smoothness you got from the dynamic balancing.
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are there any links to static balance how to's?? i'd love to have a crack!
Cheers
Ryan
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are there any links to static balance how to's?? i'd love to have a crack!
Cheers
Ryan
There have been a number of books written on "Blue printing your engine" - basically, you weigh the 4 pistons, and shave a bit off the skirts of the 3 heavier ones until they are within 0.1g (or how ever close you want to get) and same with each moving component (rods, caps, etc) Some guys even do the valve train, but I think that's a bit over the top.
You might find this on the net too.
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I think that the RPM's these run it's really not necessary and these things are gonna have some vibration no matter what, and balancing is not making one thing stronger which is what I would worry about if I was going to try to make a bunch of HP. I'd spend that money on something that would make a known difference like a Giles pump or something of that nature.
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balancing is supposed to be only 100-200 to have done. getting the crank balanced, then doing a static balance is all you need to do on a 4 cylinder since it's in line, but you need the little hangy thing to do the connecting rod, which i'm sure i could rig up... i dunno maybe i will do it. does a lightened fly wheel really make them rough? i was only thinking of going down to 8-9 pounds
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8 or 9 pounds is way light on a diesel. they usually use those on hot rod revver gas engines. isnt gonna have much torque with that flywheel.
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I agree with Libby.
After driving with both OE and lightened flywheels I don't feel there is an advantage to a lightened one at all.
As a matter a fact I think it hurts you off the line.
These little suckers just don't rev fast period and they aren't supposed to either.
Sure you may get a .010 faster time with a lightened flywheel but your going to loos your off the line from a stop sign torque.
Just my 2 cents.
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I'd rather have the smoothness of a heavy flywheel. I've heard nonsense like "a light flywheel won't maintain it's speed on a hill as good as a heavy one", but that's wrong, the engine is what's making the power. I guess a light one would help in like 1st and maybe 2nd gear since the rpms are changing fast but after that it's just along for the ride.
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I have a lightened flywheel and have no complaints. Revs are snappier but not neck snapping.
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It is Newton's first law at work...Man I can't believe I just used something I learned at school :D
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I agree with Libby.
After driving with both OE and lightened flywheels I don't feel there is an advantage to a lightened one at all.
As a matter a fact I think it hurts you off the line.
These little suckers just don't rev fast period and they aren't supposed to either.
Sure you may get a .010 faster time with a lightened flywheel but your going to loos your off the line from a stop sign torque.
Just my 2 cents.
And more than likely the .010 quicker is just due to the car being just a little lighter period.
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i get it, they just have more momentum. so it wont die off as much when leaving off the clutch
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I've got a 210mm lightened flywheel with a 200mm Bug solid disk. No issues with shifting or power loss. Also I can ease out the clutch at idle and will not stall out.
Yes it does rev faster and return to idle faster.
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Just did this about a month ago, car is a '92 four door Jetta with an AAZ. Cut the flywheel from about 14 pounds to about 10. Stopped there because of balance cuts that were in the outer ring, left them alone. Would I do it again? Yes, in a heartbeat. Pretty sure the car is more responsive, just feels like everything is a little looser, runs free compared to before. Torque and horsepower haven't changed, just momentum in the flywheel. Did stall it twice the first day I drove it , but it didn't take long getting used to the the change and haven't noticed it since. Next one I have apart will get cut farther!
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I've got a 210mm lightened flywheel with a 200mm Bug solid disk. No issues with shifting or power loss. Also I can ease out the clutch at idle and will not stall out.
Yes it does rev faster and return to idle faster.
You have a solid disc? I'm interested in running one but concerned on street use. You say the word i'll get one. Its my daily driver. Also you used a bug disc?
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My lightened 190mm flywheel, presure plate and disk weigh maybe 14 to 15 lbs total. Using a solid kennedy 4 puck disk. For street driving, I would not do the solid puck disk. I autocross this car. recipricating parts in engine are balanced within a couple grams. The motor quits pulling hard around 5700 RPM. Yes, Giles did my pump. It does rev VERY fast, but it is a complete package, not just the light flywheel.
For street I would lighten a 210 and use a regular spring center disk if I went with a lightened setup. The 4 puke solid can get anoying in stop-n-go rush hour traffic. I've been thinking of switching to my lightened 210/spring center disk to see if it will help on pro-solo drag race starts. The solid disk is not a problem with regular autocross since time doesn't start until several feet after you launch.
A good machine shop is worth their weight in gold. They have the tools and know how to do it right the first time. Just like Giles does with the pumps.
hope the info helps.
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I too daily drive my truck in stop and go trafic. Still with the setup I run, no slipage, no chattering, no stalling.
The complete engine and clutch, rotating assembly all balanced and lightened.
I guess I could of used the 190mm flywheel but I'm not planing to use it long in there, so I used it for now.
Yes a Sachs, Bug solid clutch disk with a 16v pressure plate.
Works great for me.
I running a 1.6 MF bottom end with the AAZ ported and polished head. Stock manifolds and down pipe.
I guess I've got some power to put to the clutch set for now 8).
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I too daily drive my truck in stop and go trafic. Still with the setup I run, no slipage, no chattering, no stalling.
The complete engine and clutch, rotating assembly all balanced and lightened.
I guess I could of used the 190mm flywheel but I'm not planing to use it long in there, so I used it for now.
Yes a Sachs, Bug solid clutch disk with a 16v pressure plate.
Works great for me.
I running a 1.6 MF bottom end with the AAZ ported and polished head. Stock manifolds and down pipe.
I guess I've got some power to put to the clutch set for now 8).
I've got about the same setup as your engine. If it doesn't chatter and isn't an on off switch. Is the bug disc a puck style? What material is it? I like a firm clutch engagement but it needs to be able to slip a little on take off.
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The Bug disk is an organic full surfaced dish with a solid hub.
It'll slip if ya let it, kinda hard to do, but I know it hold good though when I want it to.
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I'll get the PN and let you know.
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Got one from the local vw guy he does lots of sand rails and water cooled stuff too. Solid 200mm disc RUN IT! Thanks for the help. Don't know why i never thought to use one of them? It cost $34. EMPI brand says street and off road on the package. ha