Jump to content

Underdrive balancer and pulleys?


ken666

Recommended Posts

  • Donating Members
  • Member For: 5y 2m 27d

Hey guys,

Got a quick question about underdriven balancer and pulleys on Barra turbo motors...

Do they make any worthy gains/difference when fitted?

Would prefer dyno comparison numbers if anyone has some.

I know that they be beneficial on a N/A motor that is tuned within an inch (mm for the new age guys!) of the setups limits, but I keep thinking that on a boosted engine that it could actually be more of a disadvantage by reducing the cooling systems low RPM flow... especially when tuned to boost levels 21psi and higher?

Has anyone here experimented with big boost, hot days and underdriven setups?

Cheers Ken 

Link to comment
Share on other sites

  • Donating Members
  • Member For: 5y 2m 27d

Cheers mate didn't think so, I am just about to buy a new one to suit the higher RPM range (7500+!!) of my engine I'm in the process of putting together and thought I'd check if there was anything I didn't miss while analysing  the options available.

I thought the money would be better spent on a higher quality unit instead.

Ken

Link to comment
Share on other sites

  • Donating Members
  • Member For: 5y 10m 19d

I have an under drive pully on my na+turbo 400whp sh*tbox ute, mainly used for drift.

I have not encountered any cooling related issues with the under-drive, car still has stock rad and a 82deg thermostat & functions perfectly fine with the varied rev range of drifting.

I convinced myself it would be better for the higher rpm operation of the car, but honestly it was a waste of money.

 

Na maybe you will get the claimed hp gains, but you wont notice jack on the turbo models.

Link to comment
Share on other sites

  • Dropping a turd
  • Gold Donating Members
  • Member For: 16y 5m 1d
  • Gender: Male
  • Location: Perth

If you are adding a forged balancer may as well add underdrive. I have cracked 2 balancers above 6000rpm 

Edited by arronm
Link to comment
Share on other sites

  • Member
  • Member For: 12y 1m 19d
  • Gender: Male

When I spoke to brad @ atomic about this very question, he didn't recommend it for the barras as they're very long stroke makes them quite bad for vibrations and harmonics. He recommended sticking with a standard balancer to keep the mass greater on the front of the crank. That and a heavy flywheel he said are a must.

IMO I tend to agree and unless your Dion from Dynamite, turning engines to 10k rpm, the benefits are not worth the trade off...

Link to comment
Share on other sites

  • Member
  • Member For: 12y 1m 19d
  • Gender: Male

Yeah agreed, but unless it's a complete race engine then how much time is the engine really spending up there. Not much id say.

I reckon dampening the harmonics and not pounding the bearings and rotating assembly are more important than AC and an alternator

Link to comment
Share on other sites

  • 4 weeks later...
  • Donating Members
  • Member For: 5y 2m 27d
On 05/08/2019 at 8:58 PM, demon1300 said:

When I spoke to brad @ atomic about this very question, he didn't recommend it for the barras as they're very long stroke makes them quite bad for vibrations and harmonics. He recommended sticking with a standard balancer to keep the mass greater on the front of the crank. That and a heavy flywheel he said are a must.

IMO I tend to agree and unless your Dion from Dynamite, turning engines to 10k rpm, the benefits are not worth the trade off...

And you will find that most engines turning at those RPM (the ones that last) are destroked from anywhere between 3.2-3.9L, and that changes the whole rotating/reciprocating  configuration requirements.

My engine has been balanced to very high standards, and while the assembly was being done I had an extra balancer and flywheel done as spares (just in case one fails)

It would be a waste of good money and so much time put into getting the balance to such high standard, if and when I need to swap one out. 

Link to comment
Share on other sites

  • Donating Members
  • Member For: 5y 2m 27d
On 05/08/2019 at 9:31 PM, HI PSI said:

Alternators and air con compressors don't  like 7500 rpm. Hence why I  instslled an under drive balancer. 

I can't say that I have ever experienced one fail due to higher RPM.

If they are in good condition, and/or rebuilt to spec with quality bearings etc.

I used to rev a cleveland to 8500+rpm on a regular basis, and that was in an XE falcon.

Which didn't even run a serpentine belt, it was modded to run twin V belts though as it spat belts frequently when single! 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
  • Create New...
'