FWD drivetrain loss

[ZX2 S/R Black]

Just wondering what it is for our car or for FWD cars in general...

If anyone knows what our STOCK ZX2 WHP is that would be cool... that or a STOCK S/R...

I know it's 130hp for a stock ZX2 and 143 for an S/R but that's at the crank... I want to know what it is at the wheels

Thanks

[TheGhostInTheMachine]

106-108whp in a regular zx2. 116-120whp in the s/r.

[zxtwou2]

i've heard to expect 17% power loss through the drivetrain...if that helps.

[krux]

17% for manual and around 20% for Automatic. Thats whats ive heard as general rule

[00EscortZx2]

Didn't the Cossie scort have like 360hp at the crank and only like 250 at the wheels? that was AWD tho

[TTFOWIA]

well from what I heard, on a zx2 it's 11% loss... I think I read that on the old site but Im not sure though...

[AZN_ZX2]

http://teamzx2.com/showthread.php?t=129

read the newbie thread!

[ZX2guy19]

It is 17% for a manual and 27% for an automatic.

[mechtech]

The percent is around 16 or so [MTX], but goes down as power of the engine increases.
The drivetrain load doesn't change much at all when engine power goes up.

[ZX2 S/R Black]

With built internals it would be less then 17% right? cause pretty much all the forged stuff seems to be lighter like the connecting rods....

[mechtech]

Built in internals have nothing to do with drivetrain loss.
Nothing at all.

[ZX2 S/R Black]

Well, doesn't it though... because drivetrain loss is cause by basically loss of power through rotating parts right? so if you lighten up the rotating parts then it should not lose as much power due to it being easier to rotate right?

Here is a second question... if you were to delete the PS and AC... it would no longer have to use energy to turn those pullies so that would also reduce drive train loss right?

Same thing with using a fidanza flywheel over stock... it's 10 lbs lighter... so its that much easier to rotate... do you see what I am saying?

Or am I wrong? if so, please explain why.

[JonsZX2SR]

Closer to 14-16% for a MTX and 17-22% for an ATX. With the ATX the torque converter contributes an extra 4-6% when unlocked and a residual 1.5-3% when locked (due to parasitic drag on the fluid.)

Stock MTX is typically 102-109 WHP depending on the weather and S/R is 116-121 WHP. Normal variations in the intake cam timing alone can account for a difference in +/-3 WHP. Apparently the cam timing at the factory was less than optimal. (The VCT position sensor and control makes static timing of the exhaust cam less critical...)

[Beodude123]

Built in internals have nothing to do with drivetrain loss.
Nothing at all.


Uh... Usually I agree with you, since you definitely know your stuff, but theoretically, if you have lighter internal components, wouldn't it decrease rotational loss? I know it probably wouldn't amount to much, but every bit helps. It would be no different than having a lighter wheel.

[ZX2 S/R Black]

Okay, learned a few things... So in theory it does help to have the lighter internal components... but this is where it might get tricky to understand

When calculating the loss you take whatever you are putting out at the wheels and then divide it by what is put out at the crank... so the thing is, even though the internal built parts may be lighter, that only helps with the acceleration. Once the parts are rotating I guess I hear that it makes no difference really... and when you are calculating loss, you do it on a dyno when the parts are all already moving... so I might be able to understand why they may not have a big difference, I still would think they make a small one though... Mech if you could chime in an explain yourself that would be great...

Thanks

[Beodude123]

You are kind of wrong about the internals part.. They are constantly spinning, so a reduction in weight would always help, not just during acceleration.

[zxtwou2]

^i thought that was backward...lighter internals are good for acceleration...but without as much momentum, it idles worse...like the car has to make a bit of power to keep it going.

[Beodude123]

It would be like having a lighter flywheel I guess...

[yellow2000S/R]

Engine internals isnt driveterrain as far as I'm concerned... It's everything like the flywheel, clutch, all the gears in the trans, axles/shafts, and hubs. Light internals have nothing to do with how the car idles.

Some forged pistons make noise at 1st while they are cold but as the temps go up as it heats, it gets quiter. You need to get your crank counter-weightes machined down some so they are the correct weight to counterbalance the rod/piston combo. If you have an idle issue, its most likely the tuning or has something to do with the spark / fuel partially or fully failing.

[zxtwou2]

^but when you talk about drivetrain loss...the crank and everything attatched to it is connected to the drivetrain, and therefore has a direct relation on the drain or gain.

[Beodude123]

But when engine horsepower is calculated, they connect the flywheel of the engine to a brake (hence the brake hp number that is used). So when calculating the loss of a drivetrain, internals are not included.

[zxtwou2]

^ah, touche....but how could you claim a certain loss if you've messed with the amount of effective brake horsepower? you'd need to do a BHP dyno, then a wheel dyno to measure the difference....once you mess with the BHP, you have no idea what your drivetrain loss is going to be IMO. it might show less loss because you will be making more at the crank than you'd account for.

[yellow2000S/R]

^but when you talk about drivetrain loss...the crank and everything attatched to it is connected to the drivetrain, and therefore has a direct relation on the drain or gain.

There is a differenc between the rotating mass of the engine internals and drivetrain loss (which is basically rotating mass gearset/diff/axle/hub (wheels/tire) components). Lower rotating mass of the engine = faster revving and in most cases, some more power. When it comes to drivetrain, there isnt much you can do besides lighter axles to make the setup have less loss. And then of course lighter wheels/tires.

Yea, I'm sure there are lighter internals for the trans like gearsets, but thats more than most of us can afford / are willing to put into an Escort.

[AZN_ZX2]

There is a differenc between the rotating mass of the engine internals and drivetrain loss (which is basically rotating mass gearset/diff/axle/hub (wheels/tire) components). Lower rotating mass of the engine = faster revving and in most cases, some more power. When it comes to drivetrain, there isnt much you can do besides lighter axles to make the setup have less loss. And then of course lighter wheels/tires.

Yea, I'm sure there are lighter internals for the trans like gearsets, but thats more than most of us can afford / are willing to put into an Escort.

Is there any axles that would make a significant difference and not require and modifications to fit?

[Beodude123]

Not really.... Since it's a rotational loss, you would have to make up a large amount of weight on the axles because they have a small radius. The farther out you put something from the center of rotation, the harder it is to spin.

[yellow2000S/R]

Not really.... Since it's a rotational loss, you would have to make up a large amount of weight on the axles because they have a small radius. The farther out you put something from the center of rotation, the harder it is to spin.

Yep.

[mechtech]

Drivetrain loss is the difference between the crank HP and the wheel HP.
If you do any engine mods to increase/decrease the crank HP, it does not affect the drivetrain .
Of course it can go up or down - and be a net gain or loss, but engine internals have nothing to do with drivetrain loss. That is determined by the friction in the tranny, axles, wheel bearings, brakes, and wheel/tires.

[JonsZX2SR]

Correct (as you usually are) most drivetrain losses occur during constant speed and therefore zero acceleration.

Losses include frictional losses from bearings and goear tooth faces, drag due to shearing of fluids such as lubricants, aerodynamic losses due to wind drag on clutches and wheels, viscoelastic losses from tire deformation, etc.

Other losses include bending and twisting of rigid flexible componenst, including driveshafts, CV joint (beyond what is expected from frictional losses) etc. One expects energy stored ina spring to be returned without loss, but relaxation (the source of hysteresis) results in energy being permanently lost.

These losses are turned into noise, vibration or heat.

Fluid pumping and drag losses, even when the torque converter is locked up, result in the ATX being 2-3% less efficient than a MTX.

On a 4WD vehicles, some tire scrub (front try to spin slightly faster by design under most conditions than the rear results in additional losses. this is done for stability.) An front/rear differential or torque converter can minimize this loss but also contributes losses in itself.

[ZX2 S/R Black]

Thanks for the comments guys... and to mech... i didn't think you were wrong, I just wanted to understand

I'm happy for the more knowledgeable stepping forward and helping me understand, this has become a very knowledge pacted thread thanks to you guys :)

[mechtech]

Jons - I kinda like that vibration and heat thing you mentioned.

[ChillinZX]

It's a 16.8% loss, final answer.