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Balance shafts

Posted: Tue May 27, 2008 11:16 am
by 4gpwr
I know that starion engs are old now and most people would remove balance shafts in rebuilds for reliablety i just want to share other peoples opions do you think they would make more or less torque or more horse pwr with or without balance shafts and has any one tried to prove thier results.

Posted: Tue May 27, 2008 11:19 am
by JD_Stazza_Brendan
Figures were thrown around on here or the Sigma-galant site that ~10hp at flywheel can be gained. Less rotating mass to spin.

balance shafts

Posted: Tue May 27, 2008 11:22 am
by 4gpwr
I dont want to offend But a 10 hp gain is forum bullshit

Posted: Tue May 27, 2008 11:24 am
by JD_Stazza_Brendan
Do you have the proof then?

balance shafts

Posted: Tue May 27, 2008 11:38 am
by 4gpwr
I dont know the results for a na motor but for my starion the engine was faster to accerate there was no meresable gain on the dyno but the amount of torque lost accually made the car feel slower on the street it did not pull as hard the only reason to remove balace shafts is to make it more reliabe for big rev motors i also have spun balance shaft bearings do you know why balance shafts are there in the first place i will get off my high horse now

Posted: Tue May 27, 2008 11:55 am
by JD_Stazza_Brendan
I know the biggest differences is rate of acceleration and the added reliability. Having a look on some sites they seem to say around 10hp but no proof of it.

they were put in to make the motors smoother. I remember seeing a magazine article/advert on the sigma that had a glass of water placed on the motor to show how smooth it ran.

Posted: Tue May 27, 2008 12:01 pm
by Lunacy
Its simple physics really the less rotating mass the engine has to move, the more power it will free up. Whether its 2hp or 10hp who knows.
The balance shafts can cause alot of frothing of the oil which isnt good, and the bearings are just another thing that can go wrong.
Im taking mine out as im not worried about a little extra vibration and like i said its less to go wrong with the engine.

balance shafts

Posted: Tue May 27, 2008 12:03 pm
by 4gpwr
Last couple of evo engines i have built we have just ground the balance shafts down in front wheel drive cars it makes it alot nicer to drive than with out balanceshafts in a north south eng i would not care but in my thing i wish i had left them there but it was very hard to find a block

Posted: Tue May 27, 2008 12:08 pm
by WidebodyWoody
If you saw no noticable difference in removing the balance shafts I would say you didn't do it right. The engines would become a bit rougher for starters. And yes, you WILL get a gain regardless. Same as removing Aircon. Whether or not its a big gain is up to debate

balance shafts

Posted: Tue May 27, 2008 12:14 pm
by 4gpwr
Give me an example how to do it right

Posted: Tue May 27, 2008 12:15 pm
by JD_Stazza_Brendan
Fully balancing the motor as well would be the perfect way.

Mate did just the BS removal on his scorpion and it was as smooth it was with them.

balance shafts

Posted: Tue May 27, 2008 1:03 pm
by 4gpwr
balancing a eng is a part of a rebuild

Re: balance shafts

Posted: Tue May 27, 2008 1:33 pm
by cheaterparts
4gpwr wrote:I dont know the results for a na motor but for my starion the engine was faster to accerate there was no meresable gain on the dyno but the amount of torque lost
so your engine driving more weigh makes more torque - interesting
or have you some way to get petrol to the balance shafts to drive the extra torque
balance shafts do not make torque

anything that the engine dose not drive frees up hp/torque
remove the alt or power steer pump and the engine still makes the same power/torque but uses less so will show more power on a dyno
as the engine uses power to drive these things

same goes fore the balance shafts ( which do not balance the engine )
but by removing them will free up some power
how much - dont know

the same goes for ligher flywheels - crankshafts - con rods
the only time you may do better with heavier bits and that may include the balance shafts is from standing when some torque is stored by these heavy items
and that means the balance shafts would need to be spinning fast enough for there weight to be driving though the tooth belt to help speed up the crank as soon as the crank is driving the shafts you are losing power

Posted: Tue May 27, 2008 1:39 pm
by www.18u
balancing a eng is a part of a rebuild
This is correct and you will also have to supply the clutch flywheel and balancer to be balanced correctly. If you were to remove the shafts out of 2 different stock engines they will be different to each other as it depends how well they were balanced up from the factory. You could have one with no vibration and one with heaps.

I think i should also point out that ralliart make shaft eliminators and mitsubishi also stock the block off cap for the timing cover.

balance shafts

Posted: Tue May 27, 2008 2:05 pm
by 4gpwr
Hey Mr cheaterparts i am not question your abailty I am the bloke who bought the ja starion shell that you were going to race but you could not get enough weight out of i have seen how much pwr your sigma makes and your in house macheing on your cranks flywheels ect but you have seen my eng you have heard it .My motor is built to spin that big turbo up and to take a big ping i need to put the motor under load to make boost if i put a lighter fly wheel lwr diff gears ect it makes my motor more slow to build boost I will stand by saying that the more load the faster the boost by the way i still got that shell and i have dummied a 3000gt eng in it i will bring some beer next time i come past