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Benjamin backyard mechanic
Joined: 05 Oct 2001 Posts: 525
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Posted: Thu Apr 17, 2003 12:27 pm Post subject: Gains from machining flywheel |
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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 |
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Frederick Stienheld petrol head
Joined: 05 Sep 2002 Posts: 2719
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Posted: Thu Apr 17, 2003 1:10 pm Post subject: Re: Gains from machining flywheel |
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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 |
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Benjamin backyard mechanic
Joined: 05 Oct 2001 Posts: 525
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Posted: Thu Apr 17, 2003 1:29 pm Post subject: Re: Gains from machining flywheel |
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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. |
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Reddez tinkerer
Joined: 29 Oct 2002 Posts: 353
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Posted: Thu Apr 17, 2003 3:00 pm Post subject: Re: Gains from machining flywheel |
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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. |
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Benjamin backyard mechanic
Joined: 05 Oct 2001 Posts: 525
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Posted: Thu Apr 17, 2003 3:53 pm Post subject: Re: Gains from machining flywheel |
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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. |
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Frederick Stienheld petrol head
Joined: 05 Sep 2002 Posts: 2719
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Posted: Thu Apr 17, 2003 7:29 pm Post subject: Re: Gains from machining flywheel |
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Wank factor is an issue here, he wants to be able to say he has a lightened flywheel |
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tx1975 tinkerer
Joined: 21 May 2002 Posts: 321
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Posted: Thu Apr 17, 2003 10:13 pm Post subject: Re: Gains from machining flywheel |
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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 |
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Ben Wight backyard mechanic
Joined: 04 Oct 2001 Posts: 946
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Posted: Fri Apr 18, 2003 4:33 pm Post subject: Re: Gains from machining flywheel |
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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 |
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GeminiCoupe tinkerer
Joined: 10 Jan 2003 Posts: 172
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Posted: Fri Apr 18, 2003 8:14 pm Post subject: Re: Gains from machining flywheel |
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Because of the flywheel being lighter and rotating quicker/easier, this would mean with a worked engine you'd get on the cam quicker? |
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Frederick Stienheld petrol head
Joined: 05 Sep 2002 Posts: 2719
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Posted: Sat Apr 19, 2003 12:18 pm Post subject: Re: Gains from machining flywheel |
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yep |
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smee rice boy
Joined: 07 Oct 2001 Posts: 26
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Posted: Sun Apr 20, 2003 12:43 am Post subject: Re: Gains from machining flywheel |
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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. |
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Ben Wight backyard mechanic
Joined: 04 Oct 2001 Posts: 946
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Posted: Mon Apr 21, 2003 1:03 am Post subject: Re: Gains from machining flywheel |
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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. |
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