Mods to reduce drivetrain power loss?
 

Been thinking about mods that could help reduce drivetrain power loss (I think stock is about ~15%?) for these cars...

1. Lightweight driveshaft (leaning toward CF to reduce rattling, ~9lbs lighter than stock)
2. Lightweight wheels/tires (TWS T66-F 17inch and Dunlop SportMaxx RT, should reduce about 9lbs per wheels compared to stock)
3. Possible lightweight pulley set (not sure how this will impact the car, but not planning on touching the flywheel which may make the car harder to drive in traffic)

Any other ideas? :iono:

Lose weight yourself, then gut out your car. Replace body parts with carbon fiber, lexan glass.

If your still worried about power loss, sell car get a motorcycle.

Convert to a transverse mounted I4 engine with transaxle gearbox for best reduction in drivetrain power loss...

:lol:


Flywheel is a great mod, I've yet to do it for the FR-S, but do plan on it...won't ruin daily driveability. Had an 8lb ACT Prolite in an Integra before and it was perfectly well mannered and daily driveable...even in stop and go traffic jams. Lot more getup and go in the first 2 gears....2nd gear was a blast!

Other than that the only other things possible for driveline loss reduction is the driveshafts, bearings, and fluids (engine oil, transmission, and differential)....

Mods to reduce drivetrain power loss?
 

Do 1 & 2. Light weight pulley don't do anything other then makes you feel good. 😁

Rear axle too. Any other stuff is super expensive.


Sent from my iPhone using Tapatalk

Well you did mention wanting to keep the car easier to drive in traffic so I assume you are looking to improve performance and not mess too much with its daily driver appeal ie NVH levels and ride?

I'd research some basic weight reduction ie removing the spare wheel or switching it to a space saver, if you have a full size wheel in the boot (like my BRZ does). I hear switching the battery out for a lighter one is a good move too.

Then look to the drive shaft, as you mentioned, but I was thinking of an aluminium one rather than CF. You mentioned they rattle? First I heard of this and CF ones are a good deal dearer and not much lighter.

I'm a big fan of upgrading the FD ratio. That speeds up each gear like a 4.556 makes each gear roughly 10~11% faster or so.

Then look to lighter wheels / tires and possibly coil overs with a bias towards better ride (more of an NVH impact).

None of the things you mentioned actually reduce the drivetrain losses. They only reduce drivetrain inertia. Which is good, you'll get a performance benefit from it. But to actually decrease drivetrain loss is much more difficult, and kind of tricky. You're looking for ways to decrease friction in the engine block between the rods, pistons, cylinder walls, transmission gears, rear end gears, etc. Aside from using different viscosity oils, you would have to be willing to rebuild the whole engine and drivetrain. Your drivetrain losses are pretty much set from the factory.

The FR-S will be a DD for me, I want to improve the performance of it with mostly bolt-on parts (at least for now) and don't want to mess with the drive-ability or NVH much.

I have been reading about after market driveshaft and looks like the aluminum one is a little lighter than the CF ones, but the CF ones are said to be better at absorbing rattling and vibration compared to aluminum, both should be considerably lighter (8-9lbs) compared to stock. I will keep the car NA so I think CF should be sufficient.

Already thought of wheels and wires, TWS T66-F wheels, 17x8, et42, weighs about 13.95lbs, and should clear BBK and discs up to 345mm. Will probably go with 225/45/17 Dunlop SportMaxx RT, which weighs about 3lbs less than stock Primacy HP.




I think drivetrain losses is not the accurate word here(I sucks at physics), what I meant was to reduce the drivetrain inertia and therefore improve the WHP and responsiveness because of less rotational mass....fail on my part :lol:



Thanks, I did some more reading about pulley and looks like they are a waste of money like you said, probably will cross those off my list now :D



I heard some light weight flywheel may mess with driveability, if you ever do it for your FR-S, I'd like to hear your experience :D


Working on losing weight myself now :bellyroll:

Lol my fatass needs to start working out

get motor mounts. less wheel spin and I swear i feel a little regained power shifting into 2 with wot

Just like TorqueMan777 mentioned, thread title is misleading, as most posts were more about reducing rotational and rotational unsprung weight. It will net better acceleration/braking, but none of that is related to drivetrain power losses, which is mostly made up from friction in engine parts/gearbox/diff/multiple bearings/rotational resistance of tires. Most of those with exception of maybe tires are not easily changeable (and stock oem primacy tires to begin with are eco low rolling resistance tires, so most probably tires with higher grip and wider thread width will add to those losses).

But regarding to reducing rotational & rotational unsprung weight most including you were writing of:
1) go for TWS T66-F 16" wheels for even more weight savings (imho there are lighter forged wheels then these in 17" size), don't go for too wide wheels and too wide tires.
2) add aftermarket BBK kit to save weight also on brakes
3) your mentioned CF driveshaft
4) lightweight crank pulley. Little to no gains from other small ones.

And few other generic weight reduction items:
1) aftermarket exhaust (gaining also extra power/torque alongside)
2) soundtube delete
3) reduced volume window washer liquid tank
4) lightweight battery
5) lighter suspension components
6) lighter body CF components like roof/doors/bonnet/side mirrors and so on ..

Rest of items to reducing weight depending on how far you are willing to go/how much comfort you are willing to give up:
0) generic choice of car at lower trim with unheated cloth seats/without fog lights/few other extras of higher trims
1) racing seats (maybe just one, with delete of passenger seat)
2) rear seats delete
3) AC delete
4) audio delete
5) sound proofing delete
6) interrior panels delete

As last batch is usually done for track-only cars, then there probably will be some weight added back by installing rollcage, possibly some aero elements (like wing, splitter, side skirts), brake ducts, oil (and maybe diff) rad addition, possibly wider tires then stock.

What are the lighter forged wheels that you mentioned? These were the lightest one I could find from a reputable brand that's known to be compatible with BRZ/FRS and BBK. 16s would be sweet but thought that may put a lot more limitation on the BBK setup that I could go with.

My dream set of wheels - BBS RF 17x7.5 +48

http://www.ft86club.com/forums/showthread.php?t=12621

http://www.tirerack.com/wheels/Wheel...+Black+Painted

$515 USD a wheel on tirerack - 14.3lbs (Forged)

You can fit the existing 215's on them and, once you use up their tread, go to 225. Both will comfortably fit on that rim and its design with thin spokes makes it look like an 18" without being one. Also reading through the thread you will see they clear Brembo's.

Thanks for the info, that's definitely a set of wheels that I would look into besides the T66-F. As for BBK I'd probably go with some Project Mu stuff instead of Brembo :D

Low-friction wheel bearing.

SKF is now OEM supplier for Mazda2 and Honda Civic with low friction wheel bearing, see:

http://www.bearing-news.com/the-new-...s-co2-savings/

I have not see any low-friction wheel bearing mod available specifically for FT86, but there are racing shops that offer to install low-friction ceramic balls to fit any OEM wheel bearing.

Light-weight lug nut. OEM lug nuts weigh about 60g each (if I remember correctly), a set of ultra-light lug nuts, at 25g each, will save about 175g (about 6 oz) of rotational and unsprung mass per wheel.

One last item: a friction modifier, eg CERATEC by Liqui Moly. I know, it sounds like snake oil. Anyway, it is cheap and should not do any damage. I actually tried it myself, and it seems to work. I did not take a pre- and post mod dyno comparison, but fuel consumption did improve (under similar driving condition), so I conclude this snake oil works (since there is no change in all other variables).

In principle, these (fairly inexpensive) items should help reduce power loss in the drivetrain.

WPC treatment of all the gears and rear diff good for 1-3% power increase from loss.
Additionally heat and friction wear items faster, break down gear lube ect.

Part of the plan for my build

FRSW12: > these TWS T66-F of 16" size - just 10.63lbs 4.82kg.
As for 17" ..
AG Forged SMK Monoblock AG3-SMK26 17x7.5 9.5lbs 4.3kg
Velox PG-Rev10 17x7 11.5lbs 5.2kg
Watanabe F8 Magnesium 17x7 11.5lbs 5.2kg
OZ Forgiata 17x7.5 13.2lbs 5.99kg
J's Racing PR 6 17x7.5 13.2lbs 5.99kg
Tom's Racing EP-02 +50 17x7 13.2lbs 5.99kg
RAC Monolites RS110 17x8 13.3lbs 6.03kg
Buddy Club P1 Racing QF 17x8 13.6lbs 6.17kg
> Volk TE37 SL - should be lighter then CE28N
Volk CE28N 17x7.5 13.8lbs 6.26kg or 12.32lbs 5.58kg?
Racing Hart CP-035R 17x8 13.6lbs 6.17kg
Toybox48 Hethel 17x8 13.7lbs 6.4kg
Tehnicraft T6 +43 17x8 13.8lbs 6.26kg
Velox PG-5S +42 17x7 13.8lbs? 6.26kg
TWS T66-F 17x8 13.93lbs 6.32kg
> Kosei K4R +50 Cast 17x7 14.0lbs 6.35kg
Motegi MR221 Traklite 1.0 Cast 17x7 14.0lbs 6.35kg
SSR Type-C +38 Cast 17x8 14.3lbs 6.49kg
Velox VX-6R +42 17x7 14.5lbs 6.58kg
Kosei K1 TS +50 Cast 17x7 14.6lbs 6.62kg
Enkei RPF1 +42 Cast 17x7 14.8lbs 6.71kg
.. most of forged lighter ones are discontinued. But at least Volk TE37 SL & CE28N you should still be able to buy. Or check from tirerack Kosei K4R. Yes, they are cast, but you can buy 3 sets of those Kosei-s for price of 1 forged set and they weight only very slightly (300gr) more then TWS T66F 17x8.

I just purchased an aluminum driveshaft, it's pretty fun.
Slight gear-y noise, kinda reminds me of a supercharger, but alot more quiet.
I can definitely feel the improved throttle response.
Carbon fiber one is 2x the price for 1 pound less. Dumbbb.

he's deleting a joint in the drive shaft; this is reducing a drivetrain loss..

The TWS 17x8 is the lightest 17x8 you can get. The CE28 is close, and the TE37 is much heavier.

nobody said flywheel?

Lose the entire stock drivetrain. Start over.

Wait, just kidding. The differential is fine. You can keep that.

Throw the rest out.

Essentially everytime you convert the mechanical energy from one system (i.e. the engine) to another (the input shaft on the transmission) you loose energy in the forms of heat, friction and other things. To reduce this or even change this, you would need to basically redesign the drive train.

Can feel better throttle response... even less weight is dumb?
Because of the price?
PS some short shifters do not clear the aluminum shaft because the diameter is larger than stock

It looks like the active ingredient is boron nitride, which I have heard of as a high temperature lubricant available as an aerosol spray like "Slide hi-temp 1800 Mold release" or "ZYP Boron Nitride Mold Release".

I stand corrected. I forgot the driveshaft is 2 piece.

CSG Mike: You are sure about TE37 SL being heavier then CE28?

Others are more expert then me, but my basic understanding is anything that moves before the tires is taking energy. Get that torque to the wheels!

So pistons, bearings, gears, clutches, flywheels, driveshafts, rear-ends, CV-joints, axles all require power to rotate. All drivetrain to chassis mounts also absorb energy and they require it to hold everything in place.

Reducing power loss through transfer = more power

Simple and cheapest solution is attack the chassis first. So in a perfect world (where NHV doesn't matter) you could make all flexible mounts as stiff as possible.

Solid motor mounts
Solid tranny mount
Single piece driveshaft
Solid rear-end bushings
Solid rear subframe bushings

This set-up it would probably rattle your teeth out but it would reduce a lot of power-transfer loss for the drivetrain.

Horsepower turns heads, torque wins races

I hate you. I now want those wheels and they cost $2k...I'm not buying, but maybe one day :drool:

I would reckon flywheel and wheels to be the biggest improvement that you can feel. Wheels spin slowly compared to the rest of the drivetrain but you have 4 of them and most of the mass is on the rim. 16" wheels bring it 1 inch closer to the center and make the wheel stronger, reducing the amount of metal needed. Flywheel has both large diameter and it spins way faster than the wheels.

Don't bother with bearings and gears, those cost way more money and time. If you want to repack the wheel bearing grease yourself go ahead but you won't feel the difference.

Its all a matter of perspective. For you its $515usd but for me its $712aud a wheel, then add shipping... arrrg.

Gorgeous wheels though. The more I stare at them the more I want them!

Failing that I'd have to go with RPF1's, but that seems like such and overplayed thing these days. Also not fan of the unfinished centre cap and design in general.

I think what he meant was it's not cost effective to spend 2x the price on the CF shaft to only save 1 additional lb of weight. For that extra price you could save considerably more in other locations. ie $500 just about nets you a flywheel and front bumper beam replacement @ 15.4lbs total savings, 10 of that rotating mass.

Personally I went with aluminum though as 2 separate carbon ones disintegrated on my Vette (and I don't drag race). The weak link is the epoxy that holds the carbon to the aluminum yoke. Over time and heat it breaks down and lets go then the yoke spins free in the carbon tube.

What I liked about the RPF1's (aside from the design) is that in 17x8 with a 245 Direzza Z2 Star Spec you're only adding 4oz per wheel. Yes it's rotating mass, but the grip you get in exchange makes the weight negligible at best.