[Charles Geer]

I will be forwarding pictures of my new ($450.oo OUCH) 944 s2 Harmonic Balancer pulley. This part was deleted from the 968 and was replaced by a rather cheap looking pulley ($34.00).



The Harmonic Balancer (pictured to the left) weighs 4.5 pounds and has a thin layer of rubber embedded in the center of the pulley for absorbing damaging vibrations caused by big four cylinder engines.





The 968 pulley (pictured to the right) only weighs a half a pound and is partly responsible for the snappy resonsiveness of the 968 motor.



Racers using the heavier 944 S2 unit experience reduced breakages (oil pickup tube) and smoother running engine.



Thanks to GARY GRIGSBY for his work in discovering this much needed part for 968 clubracers.



I will keep the forum posted on the reliability of my recently purchased 54,000 mile engine with the modified oil pickup tube and the 944 S2 Harmonic balancer pulley.



IF PICTURES DO NOT SHOW I WILL HAVE A FORUM MEMBER RESEND.

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[Bart]

[quote name='Charles Geer' date='May 12 2006, 10:17 PM']

I will be forwarding pictures of my new ($450.oo OUCH) 944 s2 Harmonic Balancer pulley.



I think the one I picked up from NISMO for my 510 was in the $500-600 range, which is ridiculous. But you pay to play. We use for much the same reason it sounds like you are on the 968 except that it isn't for the big 4, its is a 1.6 liter 4, its for the added compression. At least that is what the crew chief said when he was prying the $$ from my hands. I was saying "how much for a freakin pulley? You have got to be crazy!!!"



Isn't racing fun!!!!!

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[Charles Geer]

[quote name='Bart' date='May 12 2006, 08:33 PM']

[quote name='Charles Geer' date='May 12 2006, 10:17 PM']

I will be forwarding pictures of my new ($450.oo OUCH) 944 s2 Harmonic Balancer pulley.



I think the one I picked up from NISMO for my 510 was in the $500-600 range, which is ridiculous. But you pay to play. We use for much the same reason it sounds like you are on the 968 except that it isn't for the big 4, its is a 1.6 liter 4, its for the added compression. At least that is what the crew chief said when he was prying the $$ from my hands. I was saying "how much for a freakin pulley? You have got to be crazy!!!"



Isn't racing fun!!!!!

[right][post="20936"]<{POST_SNAPBACK}>[/post][/right]

[/quote]



Find out his explanation on how this could possibly add compression. Maybe this story has a happy ending afterall. I was told that this heavier pulley will make you loose about 1 hp but the reliability more than makes up for it.

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[josephsc]

Interesting.... Is this related to why the 968 went to a Dual-Mass Flywheel? Less rotational mass overall? I always wondered how the S2 got away with lighter flywheel w/o getting the chatter....

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[flash]

yeah - not sure why they departed from the time tested harmonic balancer - every other car i've hever had has had one of those



hmm - having a thought - i wonder what this would do now that i have the aluminum flywheel - maybe it might dampen the noise a bit

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[mitch968]

I'm thinking the same thing, since I have the Fidanza too. If it would make a real improvement I'd probably do it.

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[Charles Geer]

[quote name='mitch968' date='May 13 2006, 11:23 AM']I'm thinking the same thing, since I have the Fidanza too.  If it would make a real improvement I'd probably do it.

[right][post="20957"]<{POST_SNAPBACK}>[/post][/right][/quote]





How do you guys like the Fidanza flywheel. Is it just at idle that you get the chatter...or is it constant?



Is the 944 s2 a single mass flywheel?



I think that this harmonic balancer can only improve smoothness. I will certainly post my results.

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[ds968]

and there's this :



LIGHTER MOVING PARTS, FOR ENHANCED

SMOOTHNESS

Reducing reciprocating component weights of an

engine will also contribute to smoothness.

Weisacch’s engineers have achieved further improvements

in the 968’s engine by reducing the

weight of the crankshaft, using forged connecting

rods, and forged light alloy pistons (Porsche pistons

are forged for strength and durability; they

now actually weigh less than the original 2.5 liter

944 pistons!) These reductions are significant

enough to allow elimination of the crankshaft’s vibration

damper (a component found on virtually

every other car on the road).

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[josephsc]

[quote name='Charles Geer' date='May 13 2006, 07:17 PM']How do you guys like the Fidanza flywheel. Is it just at idle that you get the chatter...or is it constant?[/quote] I currently don't have a running car with a lightened flywheel, but I used to get it right at 2300rpm -- and very noticeable when decelerating down to 2300rpm.

[quote name='Charles Geer' date='May 13 2006, 07:17 PM']Is the 944 s2 a single mass flywheel?[/quote]Yes. Also, one of my cars uses a 968motor (w/o a harmonic balancer) mated to a S2 flywheel and I get no chatter -- but then there's alot of unusual things with that car...

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[flash]

yeah- it's really not the motor that is the problem - it's the G44 - loose tolerances, which make it smooth shifting, also make it rattle

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[Bart]

[quote name='Charles Geer' date='May 12 2006, 10:43 PM']Find out his explanation on how this could possibly add compression. Maybe this story has a happy ending afterall. I was told that this heavier pulley will make you loose about 1 hp but the reliability more than makes up for it.

[right][post="20938"]<{POST_SNAPBACK}>[/post][/right][/quote]



No, sorry for the confusion. I wasn't trying to say that it added compression. It had something to do with the added compression and trying to help keep things from breaking. This is in a car that is allowed to run relatively unrestricted. Same displacement as stock, max choke size in the carbs (can't use fuel injection) and a couple of cylinder heads you can pick from. That's all I recall right now.

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[mitch968]

I really like the Fidanza, but it's just like Joe said....some nastiness right around 2300rpm on deceleration especially. On a track car, that's no big deal because you're not spending any real time down there. On my street car, it was a bit annoying at first, but I've just adjusted my driving style to avoid it. I push the clutch in a bit earlier when rolling to a stop. Overall, it really does add noticeable "zing" to the car.



Flash, I would think the harmonic balancer might help a bit even though the noise is ultimately back in the gearbox, because the vibes that are causing it are coming from the engine. If this balancer reduces those vibes, it should also reduce the gearbox noise.



I'd love to hear feedback from anyone trying this mod. Giving up a HP for some smoothness on a street car would be a no brainer.

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[flash]

yeah - it might - that was what i was wondering myself - easy enough to find out

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[TheMirror]

Not sure how much 'seat of the pants' smoothness you'd get on the street out of a harmonic balancer, especially on an engine optimized to run without one.



Racers may notice a little more smoothness due to the hardwired nature of racecar construction: solid motor mounts, hard/bearing suspension bushings, roll cages, etc.



On a street car though, probably unlikely to notice much of a change if at all.



Cheers,

-Mirror

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[flash]

no worries - it's very smooth - just looking to quiet the 2300rpm rattle

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[TheMirror]

I'm interested in that rattle, as I will have one at some point......Fidanza flywheel is on the long list.



Perhaps it can be put up as "character"? <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />



Cheers,



-Mirror



[quote name='flash' date='May 15 2006, 09:17 AM']no worries - it's very smooth - just looking to quiet the 2300rpm  rattle

[right][post="20999"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[Charles Geer]

Info for Broken Oil pickup tube

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