Jump to content
SAU Community

Recommended Posts

It's not the same as lightening the flywheel.  The flywheel gives the engine end of the drive train additional momentum, which assists with maintaining revs (helps you to not stall) when you let the clutch out.  This improves driveability.  There are some other benefits during gear changes. 

A lighter driveshaft (or lighter wheels) will not have this effect on driveablility, as they are on the other side of the clutch.  There is no downside - beside the cost.  :rolleyes:

I don't understand your logic. The tailshaft is a rotating piece of the drivetrain, exactly like the flywheel.

I'd argue that there is a lot more bang for buck in things with large diameter because inertia does after all have a r^2 component.

I'd pick flywheel lightening to be biggest bang for buck for reasons of weight, angular velocity range and diameter.

The rest would be hard to separate. Wheels get the vote for weight and diameter but you want the weight removed from the extremities, which may be difficult to achieve.

Tailshaft is relatively skinny so i'd think it's bang for buck is pretty low.

  • Replies 119
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

the down side of a lightened flywheel is that engine revs will drop quicker when gear changing, because there is less energy to keep the momentum going

what hes saying is that the tailshaft is disconnected from the engine when the clutch is in on gear change, so you dont get this affect

the car itself may lose momentum quicker(although would probably be marginal), but the engine revs wouldnt be affected

the down side of a lightened flywheel is that engine revs will drop quicker when gear changing, because there is less energy to keep the momentum going

what hes saying is that the tailshaft is disconnected from the engine when the clutch is in on gear change, so you dont get this affect

Right on.

I agree that the flywheel will offer greater performance benefit from an inertia perspective (hence, I have one in my track car). However, you do pay for it with driveability. The driveshaft offers less bang for buck, but if I had an infinite supply of loot, I'd buy one. :)

Another benefit to a lighter flywheel is that it spins faster than the driveshaft in the gears lower than 4th. As such, it needs to accelerate faster and therefore offers further potential gains from lightening. The driveshaft spins faster than the wheels, but with 4 wheels there is a greater opportunity for weight saving.

Edited by clayoth

As you can see, they aren't actually made by Trust: http://www.trust-power.com/14import/carboneshaft.html

There was one for sale on Yahoo JP a few weeks ago (brand new I think). Unfortunately it was for an R34 (IIRC), otherwise I would have been sorely tempted.

im not a big fan of nismo i havent had the best of advice from them

Ummmmm.. are you talking about www.nismo.com.au, or Nissan Motorsport (aka. Nismo)? BIG difference.

only reason the GTR ones are $4000 is because it has GTR written on it

you know what i mean

all i want is a place that sells these shafts not snide remarks leave that for the SDU forum

I'd say it would the carbon fiber that costs the money, not those three letters.

vivid racing might be able to help. $US + Shipping, though.

face it. this is an expensive way to go faster. why not just get a shorter diff?

eh - and the snide comments are free.

why not get it directly from

http://www.acpt.com/

I think it will only cost around $AUD1500

may be someone should organise a group buy for these badboy. There are also some safety benefit with cf driveshaft. However I've never heard of gtr driveshaft breakage.

the down side of a lightened flywheel is that engine revs will drop quicker when gear changing, because there is less energy to keep the momentum going

what hes saying is that the tailshaft is disconnected from the engine when the clutch is in on gear change, so you dont get this affect

the car itself may lose momentum quicker(although would probably be marginal), but the engine revs wouldnt be affected

Engine revs change during gearchanges anyway tho, so I still can't see the downside of having a lightened flywheel.

If you are going to use this argument then you would also have to say that weight savings anywhere on the drivetrain side (or anywhere else in the car) will have a negative effect during gear changes. ie car will slow down more quickly.

Edited by browny

iwells i was talking about www.nismo.com.au

ebola thoes three letters cost in this case $3500 more for a simlar product

thanks for your help guys i will have to inquire the places in the above mentioned and see what happens if you have any other sites let me know

I see there are a few people commenting who actually don't have any experience with either a lightweight flywheel or tail shaft.

Neither the lightweight flywheel nor the tail shaft cause drivabillity issues.

Thats from experience.

Keep thinking about it. and then ask someone who builds race cars.

I have just got info back from Jame Martin the product manager at ACPT.

They have off the shelf designs for R33, R33 & R34 GTR tail shafts. The price including shipping to Australia is $2,160 Aussie dollars for just one, I am sure we can get it a tad cheaper again if we group buy.

This makes it half the price of the jap units and more than attractive enough as a modification when you consider that there aren't too many mods for $2k that are as good as the accelleration you are going to pick up from one of these bad boys.

I shouldn't go on but the mines R34 is equiped with carbon tail shaft and it is quite a big reason behind the 'response' of the car.

Here is one test of a rotational mass reduction on a V8 setup, the big thing to note is the massive reduction in time taken to achieve both maximum horsepower and torque once weight is taken out, that boys is accelleration increases. Note this is taken in 4th gear under load.

http://www.vetteweb.com/tech/0407vet_flywheel/

Group buy anyone ? :P

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • So, that is it! It is a pretty expensive process with the ATF costing 50-100 per 5 litres, and a mechanic will probably charge plenty because they don't want to do it. Still, considering how dirty my fluid was at 120,000klm I think it would be worth doing more like every 80,000 to keep the trans happy, they are very expensive to replace. The job is not that hard if you have the specialist tools so you can save a bit of money and do it yourself!
    • OK, onto filling. So I don't really have any pics, but will describe the process as best I can. The USDM workshop manual also covers it from TM-285 onwards. First, make sure the drain plug (17mm) is snug. Not too tight yet because it is coming off again. Note it does have a copper washer that you could replace or anneal (heat up with a blow torch) to seal nicely. Remove the fill plug, which has an inhex (I think it was 6mm but didn't check). Then, screw in the fill fitting, making sure it has a suitable o-ring (mine came without but I think it is meant to be supplied). It is important that you only screw it in hand tight. I didn't get a good pic of it, but the fill plug leads to a tube about 70mm long inside the transmission. This sets the factory level for fluid in the trans (above the join line for the pan!) and will take about 3l to fill. You then need to connect your fluid pump to the fitting via a hose, and pump in whatever amount of fluid you removed (maybe 3 litres, in my case 7 litres). If you put in more than 3l, it will spill out when you remove the fitting, so do quickly and with a drain pan underneath. Once you have pumped in the required amount of clean ATF, you start the engine and run it for 3 minutes to let the fluid circulate. Don't run it longer and if possible check the fluid temp is under 40oC (Ecutek shows Auto Trans Fluid temp now, or you could use an infrared temp gun on the bottom of the pan). The manual stresses the bit about fluid temperature because it expands when hot an might result in an underfil. So from here, the factory manual says to do the "spill and fill" again, and I did. That is, put an oil pan under the drain plug and undo it with a 17mm spanner, then watch your expensive fluid fall back out again, you should get about 3 litres.  Then, put the drain plug back in, pump 3 litres back in through the fill plug with the fitting and pump, disconnect the fill fitting and replace the fill plug, start the car and run for another 3 minutes (making sure the temp is still under 40oC). The manual then asks for a 3rd "spill and fill" just like above. I also did that and so had put 13l in by now.  This time they want you to keep the engine running and run the transmission through R and D (I hope the wheels are still off the ground!) for a while, and allow the trans temp to get to 40oC, then engine off. Finally, back under the car and undo the fill plug to let the overfill drain out; it will stop running when fluid is at the top of the levelling tube. According to the factory, that is job done! Post that, I reconnected the fill fitting and pumped in an extra 0.5l. AMS says 1.5l overfill is safe, but I started with less to see how it goes, I will add another 1.0 litres later if I'm still not happy with the hot shifts.
    • OK, so regardless of whether you did Step 1 - Spill Step 2 - Trans pan removal Step 3 - TCM removal we are on to the clean and refill. First, have a good look at the oil pan. While you might see dirty oil and some carbony build up (I did), what you don't want to see is any metal particles on the magnets, or sparkles in the oil (thankfully not). Give it all a good clean, particularly the magnets, and put the new gasket on if you have one (or, just cross your fingers) Replacement of the Valve body (if you removed it) is the "reverse of assembly". Thread the electrical socket back up through the trans case, hold the valve body up and put in the bolts you removed, with the correct lengths in the correct locations Torque for the bolts in 8Nm only so I hope you have that torque wrench handy (it feels really loose). Plug the output speed sensor back in and clip the wiring into the 2 clips, replace the spring clip on the TCM socket and plug it back into the car loom. For the pan, the workshop manual states the following order: Again, the torque is 8Nm only.
    • One other thing to mention from my car before we reassemble and refill. Per that earlier diagram,   There should be 2x B length (40mm) and 6x C length (54mm). So I had incorrectly removed one extra bolt, which I assume was 40mm, but even so I have 4x B and 5x C.  Either, the factory made an assembly error (very unlikely), or someone had been in there before me. I vote for the latter because the TCM part number doesn't match my build date, I suspect the TCM was changed under warranty. This indeed led to much unbolting, rebolting, checking, measuring and swearing under the car.... In the end I left out 1x B bolt and put in a 54mm M6 bolt I already had to make sure it was all correct
    • A couple of notes about the TCM. Firstly, it is integrated into the valve body. If you need to replace the TCM for any reason you are following the procedure above The seppos say these fail all the time. I haven't seen or heard of one on here or locally, but that doesn't mean it can't happen. Finally, Ecutek are now offering tuning for the 7 speed TCM. It is basically like ECU tuning in that you have to buy a license for the computer, and then known parameters can be reset. This is all very new and at the moment they are focussing on more aggressive gear holding in sports or sports+ mode, 2 gear launches for drag racing etc. It doesn't seem to affect shift speed like you can on some transmissions. Importantly for me, by having controllable shift points you can now raise the shift point as well as the ECU rev limit, together allowing it to rev a little higher when that is useful. In manual mode, my car shifts up automatically regardless of what I do which is good (because I don't have to worry about it) but bad (because I can't choose to rev a little higher when convenient).  TCMs can only be tuned from late 2016 onwards, and mine is apparently not one of those although the car build date was August 2016 (presumably a batch of ADM cars were done together, so this will probably be the situation for most ADM cars). No idea about JDM cars, and I'm looking into importing a later model valve body I can swap in. This is the top of my TCM A couple of numbers but no part number. Amayama can't find my specific car but it does say the following for Asia-RHD (interestingly, all out of stock....): So it looks like programable TCM are probably post September 2018 for "Asia RHD". When I read my part number out from Ecutek it was 31705-75X6D which did not match Amayama for my build date (Aug-2016)
×
×
  • Create New...