HotGemini.com - Holden Gemini heaven
Home What's New About Help Contact




Gains from machining flywheel

 
Post new topic   Reply to topic    hotgemini.com Forum Index -> General Gemini Chat
View previous topic :: View next topic  
Author Message
Benjamin
backyard mechanic


Joined: 05 Oct 2001
Posts: 525

PostPosted: Thu Apr 17, 2003 12:27 pm    Post subject: Gains from machining flywheel Reply with quote

I am having my G200 rebuilt at the moment and we are planning on machining some weight from the flywheel. Anyone done this? What can I expect to gain from doing this?

From what I have heard, she will idle rough as guts and be a little harder to drive smooth, but I don't care as long as she goes like the proverbial off a shanghai.

Engine spec:
G200 - 88mm bore with dished pistons
32/36 Weber
Slightly ported inlet manifold
Hella shaven TX head
Reground cam (as far as she will go)
Genie extractors
Electronic ignition
High-volume oil pump

All this in about two weeks I will be on the road.
Cheers
Back to top
View user's profile Send private message Send e-mail
Frederick Stienheld
petrol head


Joined: 05 Sep 2002
Posts: 2719

PostPosted: Thu Apr 17, 2003 1:10 pm    Post subject: Re: Gains from machining flywheel Reply with quote

Why do you plan to do it if you don't know what it will do? Basically your engine will rev up a bit quicker and in theory you will lose a bit of torque going up hills etc. but I doub't you'd notice the torque factor
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Benjamin
backyard mechanic


Joined: 05 Oct 2001
Posts: 525

PostPosted: Thu Apr 17, 2003 1:29 pm    Post subject: Re: Gains from machining flywheel Reply with quote

That's why I am asking... derr! A couple of friends had suggested the mod. I was more curious as to what to expect from a Gemini, maybe even a rough estimate of power increase or otherwise.

The reduction in torque would make sense, but seeing as it is a G200 I can't imagine it being as weak as a G161.
Back to top
View user's profile Send private message Send e-mail
Reddez
tinkerer


Joined: 29 Oct 2002
Posts: 353

PostPosted: Thu Apr 17, 2003 3:00 pm    Post subject: Re: Gains from machining flywheel Reply with quote

Easier revving up basically because you have less weight to have to overcome, but less torque because of the same factor. There is a fine line with this too, too much and your flywheel can shatter, particualrly if you have a high performance clutch, however if done right you may gain a little bit of top end power, what are you using the car for??? I'd keep the torque, more usable than top end power.
Back to top
View user's profile Send private message Send e-mail
Benjamin
backyard mechanic


Joined: 05 Oct 2001
Posts: 525

PostPosted: Thu Apr 17, 2003 3:53 pm    Post subject: Re: Gains from machining flywheel Reply with quote

Mainly street, however I will be putting the car through club racing later this year. After driving a G200 which didn't want to rev, I would like mine to just have that little extra zing.

I have been driving a G161 for many years and so I am used to not having mountains of torque, or molehills of torque for that matter.

Driveability is not an issue.
Back to top
View user's profile Send private message Send e-mail
Frederick Stienheld
petrol head


Joined: 05 Sep 2002
Posts: 2719

PostPosted: Thu Apr 17, 2003 7:29 pm    Post subject: Re: Gains from machining flywheel Reply with quote

Wank factor is an issue here, he wants to be able to say he has a lightened flywheel Razz
Back to top
View user's profile Send private message Send e-mail Visit poster's website
tx1975
tinkerer


Joined: 21 May 2002
Posts: 321

PostPosted: Thu Apr 17, 2003 10:13 pm    Post subject: Re: Gains from machining flywheel Reply with quote

cast iron flywheels arent meant to be machined as will loose some strength, if u give it a hard time at club events and that u will prob crack it.
shattered flywheel=nasty :s
Back to top
View user's profile Send private message
Ben Wight
backyard mechanic


Joined: 04 Oct 2001
Posts: 946

PostPosted: Fri Apr 18, 2003 4:33 pm    Post subject: Re: Gains from machining flywheel Reply with quote

Hey Ben,

I noticed two things being the general concensus, that being the engine will rev quicker, but make less torque.

Well the first is right, the engine makes x amount of torque, and if the rotational mass is less, the engine will accelerate quicker.

The second isn't, the engine will still make x amount of torque, no matter how much rotaional mass there is.

Therefore, if you come to a hill, there will be less roational inertia to and the engine will decelerate more quickly that it would with a bigger flywheel, but on the upside, it will also accelerate more quickly when you put your foot down.

Ben Wight
Back to top
View user's profile Send private message Send e-mail Visit poster's website
GeminiCoupe
tinkerer


Joined: 10 Jan 2003
Posts: 172

PostPosted: Fri Apr 18, 2003 8:14 pm    Post subject: Re: Gains from machining flywheel Reply with quote

Because of the flywheel being lighter and rotating quicker/easier, this would mean with a worked engine you'd get on the cam quicker?
Back to top
View user's profile Send private message
Frederick Stienheld
petrol head


Joined: 05 Sep 2002
Posts: 2719

PostPosted: Sat Apr 19, 2003 12:18 pm    Post subject: Re: Gains from machining flywheel Reply with quote

yep
Back to top
View user's profile Send private message Send e-mail Visit poster's website
smee
rice boy


Joined: 07 Oct 2001
Posts: 26

PostPosted: Sun Apr 20, 2003 12:43 am    Post subject: Re: Gains from machining flywheel Reply with quote

Have a look in the workshop area under installing gearbox and clutch.
In there you will see a picture of the lightened clutch that was doing service in my rally car.
A huge amount of material was taken off the flywheel and a flex plate and drive gear from an auto gemini was attached to it. A shirt load of work went into this wheel and it made good gains. engine reved freely and quite high.
Back to top
View user's profile Send private message Visit poster's website
Ben Wight
backyard mechanic


Joined: 04 Oct 2001
Posts: 946

PostPosted: Mon Apr 21, 2003 1:03 am    Post subject: Re: Gains from machining flywheel Reply with quote

Yes the engine will rev quicker, so the power band of cam would arrive sooner, but also finish sooner! In short, you get more acceleration.
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    hotgemini.com Forum Index -> General Gemini Chat All times are GMT + 10 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group
© HotGemini.com 2000-2007 | Privacy Policy | Terms of Use | Site Map