The 18R-GTE reference manual ...

[jabbatron]

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[JustenGT8]

A bit of a topic revival on lightened flywheels. I found a good link that explains the clear benefits in laymans terms and also the full mathematical enchilada for those that like headaches

How a lightweight flywheel works

It doesn't mention the downsides so much, but seeing none of us with lightened flywheels have found any I guess that's not much of a surprise

[longboy]

A bit of a topic revival on lightened flywheels. I found a good link that explains the clear benefits in laymans terms and also the full mathematical enchilada for those that like headaches

How a lightweight flywheel works

It doesn't mention the downsides so much, but seeing none of us with lightened flywheels have found any I guess that's not much of a surprise

Did you find any changes in the torque characteristic going up hills or from takeoff?

sources:
gran turismo

[jabbatron]

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[JustenGT8]

Strange as this is the best bang for buck mod I have done on every manual car I have had...and the physics doesn't lie sounds like you just needed the right turbo..price was irrelevant.

I didn't notice any down side on take off or hills but cars have always had an abundance of torque/power and other aspects eg button clutch; were bigger issues. I am sure there were some losses in ramp down torque but overall the difference was very much positive.

With a cast iron truck flywheel, an upgrade is a no brainer for any RG

[o_man_ra23]

IAT should be as close to the throttle body as possible to give a good indication as to the air temperature going into the engine. If it is getting hot, you need to get the heat away from it, not it away from the heat as it is there to protect the engine.

[river]

Hi,

Horses for courses.

The stock fly wheel, though heavier than a lightened one, is fine for a daily drive. If I was using my car on the track or drags then a lightened fly wheel would be a no brainer.

My style of driving, where I'm a relatively slow and lazy gear changer, would not suit a light flywheel. Others like it and think it's great, as it suits their style of driving.

As I said, horses for courses.

seeyuzz
river

[o_man_ra23]

River, I agree with your sentiments regarding mass differences, and indeed in your case the mass of the stock flywheel better suits you. However I disagree with using a factory flywheel for any turbo application. As I have stated before, if you do go for a hard run (some young whipper snapper disses lawn bowls and you need to set them straight) and you over stress the flywheel with a bit of clutch slip and one of the many 30+ yr old stress fractures says goodbye, it is your legs in the firing line.

You can get heavy flywheels new, and would be a great safety investment without changing the tractor dynamics.

[river]

Hi,

Seriously dude, please show me the evidence that supports a turbo engine will shatter a stock flywheel.

Flywheels shatter through centrifugal force, and not due to the clutch pressure or dropping the clutch or a hard run. The faster the engine revs the more stress it places on the flywheel. So if you are building your engine to rev faster than it's stock limits then you are in dangerous territory regarding flywheel failure, if you keep the stock flywheel. If your engine, be it NA or turbo, runs at the usual rpm limits of the engine then the stock cast flywheel will be within operating tolerance and will be fine.

You will need a beefier clutch for a turbo to take the extra torque generated by the engine, but this has nothing to do with the flywheel.

The majority of street driven cars which have had a flywheel shatter is because they have lightened the stock flywheel. So, if you are dumb enough to machine out the stock cast flywheel to make it lighter, then you're taking a chance with losing a foot when the flywheel shatters. You should purchase a proper lightened flywheel rather than skinny-out the stock one.

seeyuzz
river

[Bananaman]

Interesting read. My flywheel is 12-13kg (!) - I had planned to change it when everything comes out for paint, but that link pretty well locks that decision in

[jabbatron]

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[JustenGT8]

River is on the money on both counts...but, he is the only person I know that has turbo'd a RG for non performance intent

And is more than a coupla hp....could easily be as much as 40 hp depending on how light you went from stock. My arse dyno is pretty good thanks but show me a track car, an OEM sports car, any serious build where a lightened flywheel hadn't been used? Must be a fad and those pesky calculations are wrong?

[jabbatron]

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[jabbatron]

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[river]

Hi,

River is ................ is the only person I know that has turbo'd a RG for non performance intent

Yeah, I admit to being a little different in that regard.

The engine is a beautiful motor, and very well built with custom turbo manifold. It's built to take 23pound boost, but I run a baby GT25R. She puts 170rwkw at 12-15lb boost, which, for a dinosaur 2litre with small turbo, is a pretty good figure. The whole system is set up to take larger turbo's, which can be bolted straight into place, and I'm running Sard 700cc injectors in the event I wish to upgrade the turbo. So, if I wanted to I could very easily and relatively cheaply get this engine spinning around 250rwkw or more.

However, I like it just how it is. It's fun, it's nimble, and reliable and suits me perfectly. I've never put my foot down and let it growl out to max rpm and through the gears to see just what she's capable of. One day, I may take her to the drags for shits and giggles just to see how it goes. In the meantime, I just cruise about, rarely on boost and am content that I have that power should I need it. Sort of like having a nuclear bomb... it's more about having the power as opposed to using it... if that makes sense.

Originally it was to be a quad ITB NA engine, but the cost was greater than the turbo set up and generated less power. Of course ITB can give me some lovely induction sounds, but I can get that from The88 with her NA 18R-G, so I opted for the turbo. Why? Why turbo an 18R-G for non performance reasons.... well, why the fuck not! And I did!

seeyuzz
river