924Board.org

[Eturbo924]

Hey I am sure this has come up before but has anyone run a 924S or 944 with out the ballance shafts hooked up?

Yeah yeah I know the 2.5L is all about the smoothness and this would kill that but it would also increase the Hp... if just slightly and reduce the complexity of the front end service if you could live with the harshness that would obviously be there.

Anyone?
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[Rasta Monsta]

Plenty of people have. . .by accident. I think I read in that Morgan book that 5-10 HP are lost by driving the shafts.

Awfully damn vibrate-y, though. Bet it would start spitting out fasteners.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Eturbo924]

Yeah it is some where around 10hp as I recall.

I am sure it would be rough going but I do not think it would shake itself apart.

Some one can correct me if I am wrong... you always do... but I think the race 924 turbo that used the 944 engine went without the ballance shafts for 24 hours under race conditions.

Or... at least I know I read of a 944 engine that raced with out the shafts doing their job... some where.

Just thinking... 10 more hp... less drag on the engine...meaning more mpg and less maint cost. Yes more vibration but I am used it it with the 2.0l... though I am sure it would be worse with a 2.5L flying around.
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1982 924
1992 968
2003 C4S
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[peterld]

Here in Oz there is a specific race series for 944s supported by a local Porsche wrecker(breaker/dismantler/junkyard) . Refer aPorschaPart.com.au for details. NONE of the cars run balance shafts and never have and reliability is great. Cheers Pete

[John Brown]

It's 3 to 4 hp. Minimal.

Without them the motor shakes itself to failure. Stuff you might want not to break; notably the oil pickup tube for starters. And on from there. The vibration simply causes bolts and other fasteners and brackets to fail.

So far as I know Porsche never removed the balance shaft belts from any motor they ran.

I see Pete and the guys in Oz have had success without. All I can say is in the northern hemisphere we see a definite correlation between no belts and metal fatigue failures. Maybe we run more hours on the motors. Or maybe it's the opposite rotation of the earth down there. Don't know.

I wouldn't even consider taking them off.
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John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

[Off Camber]

The vibration has been known to crack fuel rails and the oil pick up tube.
I have heard the race engines can run easier without the balance shaft because the vibration harmonics are in the 1,000 to 3,000 rpm range and race engines spend most of there life above that.
I have a 924s and due to a miss aligned balance belt I have gone through 4 fuel rails. the vibration was insane it actually sheared some bolts so I have just cut the belt for this race season. Engine is comming out over winter for a rebuild so I may put belt back on then.
you ca do it.
It does improve hp
but do it knowing that Porsche put it in for a reason and from what I have heard they are pretty smart.
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"Growing Old is Mandatory"
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[Rasta Monsta]

Well engineers figured out long ago that 2 liters was the practical max for 4 cylinders inline due to harmonic vibration. . .balance shafts were invented to get past this barrier.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Eturbo924]

Aha aha

Nice shakes itself to death. Ah well. Figures.

Yes yes I know Porsche might know a thing or two about engines... a bit more... just a bit... than I do

Thought it was an interesting question though! right... hu?
_________________
1982 924
1992 968
2003 C4S
Parts Parts Parts and More parts.
E-mail me for parts you need!
Drive Fast!