JOMZSHAKES

iTrader: (1)

Im pulling my engine here within two weeks for my headers/cats install and im also adding 4.083 gears,
with the gears being different will my car be balanced better with a lighter flywheel or are the gears more dependent on the low end torque of a heavier flywheel??

running vq35de non revup with bolt ons and tune, expecting 260-270hp

Z1 Performance

iTrader: (564)

The lighter flywheel will promote faster engine response as well as quicker engine braking at the expense of some driveability when engaging first gear from a dead stop. There is also a noise byproduct that comes with removing the factory dual mass unit. The heavier, stock flywheel will be easier to engage 1st gear from a dead stop, but will not feel nearly as responsive as the lighter weight units

Chris@FsP

iTrader: (4)

Why are you pulling the engine?

JOMZSHAKES

iTrader: (1)

Okay, sounds good.
im ready for the chattering and the more difficult launches

should i get one thats steel or aluminum?

Why im i the only person that thinks the jwt flywheel seems bad?

or is there clutch flywheel combo what im looking for?

Z1 Performance

iTrader: (564)

idk why you think it seems 'bad'

both steel and aluminum have plusses and minusses....I prefer the solid nature and ability to resurface that steel affords you.

there are lots of clutch/flywheel combos - depends on your useage and budget

Steve-O Z33

iTrader: (10)

If you mean that the JWT is too heavy, Tilton makes one that is 9 lbs. iirc. I've seen videos and it revved crazy fast. That is more of a track flywheel but I'm sure people use it.

And as Z1 Performance said, why would you pull the engine for headers/cats/4.083 ring and pinion?

Headers can be installed without removing the engine in most cases. Cats are within reach under the car. And the 4.083 gears are in the rear diff. (Which I'm sure you already know)

Zazz93

iTrader: (2)

Take it from a guy who had to put thread inserts into a aluminum fly, look closely at the all steel units.

doshoru

iTrader: (3)

I don't know what you mean by "balanced", but both are going to make the car rev faster and feel more responsive.

Here is an EXCELLENT synopsis of how a lightweight flywheel works: http://www.uucmotorwerks.com/flywhee...heel_works.htm

Inertia is the key word when talking about rotating mass, such as the flywheel/clutch. Simply put, Inertia = resistance to change. Rotating mass acts like a buffer -- it is stored energy. When you hit the gas, the engine transmits power to the rotating mass. It takes X amount of power to get the rotating mass moving, after which acceleration can commence. When you let off of the gas, a "heavier" rotating mass will want to continue moving. On the flip side, if you have less rotating mass (e.g. a lightweight fly/clutch combo), you have less mass to get moving when you hit the gas, but when you let off of the gas....you'll start to decelerate more quickly as well.

Less rotating mass means the car will both accelerate and decelerate more quickly, while more rotating mass will resist acceleration/deceleration.

Most people forget the latter part of the above when evaluating a lightweight flywheel -- you undoubtedly gain acceleration, but "driveability" certainly becomes a concern, at least in daily driving. Not only is it more difficult to "coast", the car feels more "twitchy", as your throttle input buffer has been drastically reduced. It will arguably be more difficult to launch, as well -- if you bog a car, a heavier flywheel will want to continue spinning, granting you time before you stall to react....a lighter flywheel can come to a stop almost instantly if you bog, as there is little stored energy to combat traction.

Now, all of those effects matter most in 1st gear, a large amount in 2nd, marginally in 3rd...and everything after that is probably a wash. This is because you see the largest "changes" in momentum in the first few gears. Once you get to 5th/6th gear, you're really not accelerating that quickly at all. Think about it -- if you're at 150+ mph, it can take seconds to gain even 2mph -- even if you have a 15% advantage in inertia vs your opponent, you're going to be pulling at what.....0.3mph quicker? Big deal, right?

So a lightweight fly is a tradeoff -- great acceleration benefit in 1st, measureable in 2nd, questionable in 3rd and beyond vs the tradeoff in driveability (personal preference). I've seen a few hardcore n/a guys here go lightweight and then back to stock b/c of the driveability aspect.

Now gearing...you somewhat accomplish the same goal as a lightweight flywheel -- you'll be going through the revs more quickly, but with a slight twist. Gears are a "static" change in every gear from the standpoint that you will have essentially 14-15% more effective torque in each gear. The tradeoff is that there will be points where a stock geared car will be applying more effective torque than the geared car. Example -- The geared Z (HR in this example) will have to be in 3rd gear at 60mph, whereas the stock-geared Z can still be in 2nd gear -- advantage stock geared Z...The question becomes, do I gain more time from the gears than I lose? I'm sure Onagao will chime in here and say that gears only matter if you start in 1st...but I'm not so sure...

There's one video that shows two Z's, one with gears, and one without, starting at different speeds, and they are virtually neck-and-neck. I don't like to draw a conclusion on a single example, but my opinion (in theory-space, here) is that the geared Z is quicker. There will be scenarios, regardless of the gearing you choose, where it won't be optimal vs another car. That said, I believe shorter gearing to be better overall for a street car, where MPG is not a concern. I feel it gives you more options in gear selection, vs the stock-geared Z that is at illegal speeds less than halfway through 3rd!

edit: My guess is that you're going to have traction issues in 1st, depending on how much grip you have!

JOMZSHAKES

iTrader: (1)

heres why im pulling the engine

i need to pull off my radiator support to realign my front end,I did a cheap rebuild after front end accident years ago "headlight mount is out of place"

take off my plenum to paint it and add my 5/16th spacer

drain coolant because its narly from mixing to types

drain brake fluid to put in dot 4

drain clutch fluid to add ss line and dot 4

install headers and cats and front tanabe under brace

swapping out my stillen ground wire kit because my engine heat turned them all brown



If i do the headers alone with out pulling the engine it will take 6-8 hours and i wont be able to torque the bolts down correctly cause its a pain in the ***

Every thing i listed there is necessary when pulling the engine so i might as well do it all at once to save time and make things less knuckle busting

also considering taking advantage of engine being pulled by swapping to stiff motor mounts and flipping clucth/flywheel while im at it

All my parts are in my room waiting to be installed except for clutch flywheel, motors mounts and ground wire kit

JOMZSHAKES

iTrader: (1)

heres my original post on if i should pull my engine

https://my350z.com/forum/engine-and-...my-engine.html

Z1 Performance

iTrader: (564)

tilton does not make a flywheel...they make a clutch/flywheel assembly (cannot be used separately), and if it's still made, was insanely grabby and not weighted for a street car (it revs really fast but it's nearly undriveable for day to day use IMHO)