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Discussion Starter #1
Just something I was thinking about, but wouldn't a lighter flyweight, instead of just helping acceleration by allowing the engine to rev quicker, give you some more whp. The way I look at it is if there isn't as much weight that the engine must spin, you'll free up some hp taken away by the heavier flyweight. Anyone have thoughts on this?
 

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Discussion Starter #3
Well no I'm not right about thinking that way, but typically people don't say they've increased their hp by lightening their fly wheel and I was wondering if that was because it doesn't increase the hp anything worth mentioning or if it actually doesn't increase the hp at all.
 

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Their is no increase in horse power. Instead it alows the horse power you do have to be put to better use. For example for every pound off the crankshaft is about the equialent of 2.5 HP/lb, this can be a considerable amount considering that as much as 5 lbs can be lost off crankshaft wieght.
 

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Discussion Starter #5
Alright, so your car won't dyno and show more hp, but it will feel like there is more? Am I correct in saying that?
 

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Discussion Starter #7
Ok, that makes more sense. I know that the engine wouldn't be putting out more hp, but more would be transfered to the wheels.
 

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Garage Sultan
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Its not a bad mod to do, however if your thinking of it remember this:

The flywheel provides rotational mass to keep the engine going between gear shifts, it also provides the car with momentum.

If you had no (or one thats too light) flywheel the car would have a hell of a time matching revs on shifts and your ride would be rough as well as damaging.
The biggest thing you'll notice with with a lightened flywheel is that the car will accelerate quicker. Youll also probably notice that going up hills becomes more difficult (ie. getting a run at a big hill is useless), its more of the engine doing work than rotational momentum that already exists.

Oh since you have an automatic transmission, youll notice that your braking will improve a bit since the car has less momentum to cancel out.

If your gonna do the mod just remeber to pick a flywheel weight that matches your driving style and needs.

-Nick
 

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Discussion Starter #10
Actually I have a standard....how heavy is the stock flywheel and how much lighter can you go to still have a good streetable car?
 

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in^3,N20,RPM,PSI
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Not answering your question but if you make your flywheel lighter issues such as rough idling sometimes come up. But a few pounds ppl have done for a long time now. Better to find someone that makes the lightened flywheel for your car tho. The last thing you want is a idiot in a garage throwing your flywheel a busted up lathe randomly cutting away metal...
 

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Less Rotational Mass

I've been thinking about the lower rotational mass path to better acceleration. I don't have any intention of lightening my flywheel at this point but since there aren't a lot of mods available for the E16i, I have considered lightening the cast iron crank pulley, or borrowing a buddy's lathe and attempting an aluminum pulley. Does the ratio mentioned by 00sentra apply to the crank pulley? Namely, 1 lb less rotational mass = 2.5 hp? Also, UDPs are available for lots of other cars and they don't seem to have any concerns about a rough idle. Apparently there aren't any concerns about balancing the crank pulley.
 

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Yes, it most certainly does. The Nissan Motorsports pulley I put on my E16S made a huge difference. For $23, I put one on my Pulsar as well.
 

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I have the Nissan Motorsports book... can't believe I missed the pulley you're talking about. Do you know what page it's on or what is the part #?
 

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Remember that the Nismo pulley only has a single groove. You will not be able to have power steering or A/C.
 

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And it is designed for the B11/N12 E16 motor. It uses a V-belt as opposed to a serpentine belt. You have to find a pulley for your alternator and find a V-belt water pump pulley.
 

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Correct. I did find the aforementioned pulley in my Nissan Motorsports book and it was in the B11/N12 section. I'm trying to think of a very large favor I could do for a machinist friend so he would make an aluminum UDP out of a hunk of bar stock.
 

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I have that pulley on my old e15t motor. It actually came stock on one of the early e-series motors. Back in '95 nissan motorsports used to carry a "slim pulley set" made from billet aluminum. It was to be used in conjunction with a race header that wrapped around the side of the engine instead of below it. Unfortunately, both products have been long sold out.
 
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