has anyone done an CF drive shaft or aluminum on isx50
10-11-10, 06:48 PM
#1
Lead Lap
Thread Starter
has anyone done an CF drive shaft or aluminum on isx50
was just curious...havent seen any one say they use them...I kno that the is350 is kinda limited as far as perfomance parts...they will free up some rwhp, maybe 5-7 rwhp..
10-11-10, 07:29 PM
#2
Im interested.. just sent an email to these guys, dunno if theyre any good though: http://www.pstds.com/index.htm
does anyone know which company is the best at this?
does anyone know which company is the best at this?
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10-13-10, 12:07 AM
#8
Lexus Test Driver
I had a MMC driveshaft made for a car from http://www.dennysdriveshaft.com/
If balanced, you should have zero vibration with most any driveshaft.
If balanced, you should have zero vibration with most any driveshaft.
10-13-10, 06:22 AM
#9
I had a MMC driveshaft made for a car from http://www.dennysdriveshaft.com/
If balanced, you should have zero vibration with most any driveshaft.
If balanced, you should have zero vibration with most any driveshaft.
That's pretty much what'll come down to... a properly balanced aftermarket shaft should work fine, but if it's 'worth' the cost will depend on the weight savings...
10-13-10, 10:31 AM
#10
Lexus Test Driver
from what I can gather on the interwebs, it looks like most STEEL drive shafts weigh 20-25 lbs.
This carbon fiber drive shaft would weigh in at 11.5 lbs. So we have a potential for 14.5 lbs in reduction.
Now, depending on what ratio you like to use for rotational vs static weight, we could see up to 145 lbs "reduction" in the weight of the car. This will probably shave .1 - .2 seconds off your 1/4 times.
Apparently aluminum and carbon fiber weigh similarly, the benefit with aluminum is that it has an 8-15% rotational twist allowance before it snaps and it resets each time.
A steel drive shaft may have a 5% allowance but if you twist it 3% in one acceleration you only have 2% left before it fails next time. Although I dont think this will be a problem with the relatively low hp the IS line puts down.
I dont know the twist allowance of carbon fiber but i bet its pretty stiff and it surely wont return to its original state like aluminum.
Is it worth it? Could be....I know it would be awesome to say you're rockin a carbon fiber drive shaft though as a pure crowd pleaser!
This carbon fiber drive shaft would weigh in at 11.5 lbs. So we have a potential for 14.5 lbs in reduction.
Now, depending on what ratio you like to use for rotational vs static weight, we could see up to 145 lbs "reduction" in the weight of the car. This will probably shave .1 - .2 seconds off your 1/4 times.
Apparently aluminum and carbon fiber weigh similarly, the benefit with aluminum is that it has an 8-15% rotational twist allowance before it snaps and it resets each time.
A steel drive shaft may have a 5% allowance but if you twist it 3% in one acceleration you only have 2% left before it fails next time. Although I dont think this will be a problem with the relatively low hp the IS line puts down.
I dont know the twist allowance of carbon fiber but i bet its pretty stiff and it surely wont return to its original state like aluminum.
Is it worth it? Could be....I know it would be awesome to say you're rockin a carbon fiber drive shaft though as a pure crowd pleaser!
Last edited by 06isDriver; 10-13-10 at 10:36 AM.
10-13-10, 10:39 AM
#11
Lexus Test Driver
CORRECTION: carbon fiber drive shafts have no rotational torsion. This is apparently their benefit over aluminum, allowing for instant and more efficient transfer of energy.
10-13-10, 02:10 PM
#12
Lead Lap
Thread Starter
on my other car ( camaro SS)I had a steel driveshaft(21 lbs) swaped to an aluminum and got less vibration..and could feel a differnce in accelration...could tell I had a few more rwhp..the aluminum was like 10 lbs lighter than my steel ds...a CF would be weigh even less and u would get a few more rwhp than the aluminum ds..but they were kinda costly!
10-13-10, 04:56 PM
#13
Tech Info Resource
iTrader: (2)
All well and good, but you'll see a lot more benefit from light wheels because the diameter of the wheel impacts rotational inertia (the thing you're improving with the lightweight driveshaft) far more than any driveshaft could.
If you already bought a set of 17 lb wheels and want more, then the driveshaft may be worthwhile.
Then you need to replace the torque converter with a titanium unit, lighten the crank by 15% or so and install oil scrapers,...there's a lot you can spend money to remedy excess weight from the factory's implementation.
If you already bought a set of 17 lb wheels and want more, then the driveshaft may be worthwhile.
Then you need to replace the torque converter with a titanium unit, lighten the crank by 15% or so and install oil scrapers,...there's a lot you can spend money to remedy excess weight from the factory's implementation.
10-13-10, 07:31 PM
#14
Lobux is right. Moment of Inertia is more dependent upon radius of the mass being rotated. Assuming that the shaft is solid, uniform density and radius throughout:
I = (mr^2)/2
~3-3.5in diameter shaft is much smaller than 18in diameter wheels, so the impact therefore from the shaft will be smaller than lighter wheels of the same or less diameter. There will be an improvement from the shaft but it won't be as significant, like sway bars vs chassis brace.
OT:
Then again for wheels, the moment of inertia can be broken roughly into two parts, one of a thin cylindrical shell and one of a solid disk:
I = mr^2 + (mr^2)/2
I'd be down to get lightweight CF driveshafts for ***** and giggles though, although the improvement in acceleration may be barely noticeable on street driving. A lightTrack and strip would be where the improvement will be felt mostly.
I = (mr^2)/2
~3-3.5in diameter shaft is much smaller than 18in diameter wheels, so the impact therefore from the shaft will be smaller than lighter wheels of the same or less diameter. There will be an improvement from the shaft but it won't be as significant, like sway bars vs chassis brace.
OT:
Then again for wheels, the moment of inertia can be broken roughly into two parts, one of a thin cylindrical shell and one of a solid disk:
I = mr^2 + (mr^2)/2
I'd be down to get lightweight CF driveshafts for ***** and giggles though, although the improvement in acceleration may be barely noticeable on street driving. A lightTrack and strip would be where the improvement will be felt mostly.