Labold

I purposely bought a low mile '01 knowing I would mod it. Sounds like I've got alot of modding ahead of me to run with the ever mighty C6Z. It's kinda fun being the underdog

Higgs Boson

I did the same thing except now I wish I'd gotten a base model since everything that makes my car a Z06 is gone (except for the fixed roof)....

ZeeOSix

If it does, I don't think it is very much percentage wise. All the HP lost throughout the drive train is frictional loss. Friction creates heat, and the heat generated from the HP loss is directly proportional to the fictional losses. If a drive train had zero friction it would lose zero HP and it would not heat up at all, and you would get all the crank HP to the rear wheels ... wouldn't that be nice?

When the load on the drive train is less at low speeds and low throttle (ie, not much crank HP being made), then the absolute amount of lost HP and heat generated in the drive train is also much lower. I don't think the percentage lost in the drive train is much lower at low HP levels than at high levels ... maybe a percent or two IMO.

For example, if you could find some accurate dyno info on RWHP for a low powered, rear wheel drive, manual tranny car and compare the RWHP to the factory claimed FWHP you would see that the HP loss between the crank and wheels would be close to the same when compared to a car with 2+ times the crank HP while making the same RWHP to FWHP % loss calculation. A less extreme example is to just look at the RWHP vs the FWHP of a bone stock C5Z and a C6Z. They have 100 FWHP difference between them with basically the same drive train components (and therefore frictional losses). But the HP loss to the rear wheels is not numerically the same amount between them. The C6Z will lose about 15~20 more HP through the drive train at full HP output compared to the C5Z.

The frictional losses are primarily friction from all the moving parts in the drive train. Seals have a constant frictional drag force on them. The HP lose in frictional items like seals, parts running in gear lube, etc is linear and follows the relation of HP = FV. The faster they spin or move, the more HP is lost, linearly.

Gears and bearings experience increased frictional forces as the loads increase on them. The basic frictional equation is linear and related to the frictional equation F = uN. As the torque loads (and hence HP loads) increase, so does N and F. The term u is the friction coefficient which should stay relatively constant depending on the gear lube, etc in the system.

This is the factor that could contributes to the increased % loss at higher HP levels. This is because as the torque increases the frictional losses also increase, but when multipied by the velocity it now becomes a larger number than it would have been if the torque load was smaller.

So you really have two components. A totally linear one from things like seals and parts moving in fluids, and a slightly non-linear one that is dependant on the level of torque being transmitted through the mechanical system as describe above.

Exactly! Make sure the parking brake isn't dragging.

Bigstik

And if you ever go up against a driver name Ranger, just bend over and take it, and then have a nice day.

vrybad

[QUOTE=ZeeOSix;1566430623]
For example, if you could find some accurate dyno info on RWHP for a low powered, rear wheel drive, manual tranny car and compare the RWHP to the factory claimed FWHP you would see that the HP loss between the crank and wheels would be close to the same when compared to a car with 2+ times the crank HP while making the same RWHP to FWHP % loss calculation. A less extreme example is to just look at the RWHP vs the FWHP of a bone stock C5Z and a C6Z. They have 100 FWHP difference between them with basically the same drive train components (and therefore frictional losses). But the HP loss to the rear wheels is not numerically the same amount between them. The C6Z will lose about 15~20 more HP through the drive train at full HP output compared to the C5Z.[/QUOTE=ZeeOSix;1566430623]


See, that's where I've had questions in the past.

Based on MY research, the average C5 z06 dynos about 350rwhp.
The average C6 Z06 dynos about 450rwhp.

They both lose about 50hp(give or take) thru the drivetrain, if we can trust the factory fwhp specs.

I don't think there is enough evidence to suggest that the C6 z06 loses an additional 20hp at the wheels on a consistent basis, due to dyno variances for both the C5 zo6 and the C6 zo6.

We have all seen freaks that make more, and weaker examples that make less, but I'd say that averages are as I've stated above.

That's what led me to believe that loss was closer to a fixed amount in a given drivetrain(the C5 and C6 z06 drivetrains are very similar thru 4th gear)



[QUOTE=ZeeOSix;1566430623]
The frictional losses are primarily friction from all the moving parts in the drive train. Seals have a constant frictional drag force on them. The HP lose in frictional items like seals, parts running in gear lube, etc is linear and follows the relation of HP = FV. The faster they spin or move, the more HP is lost, linearly.

Gears and bearings experience increased frictional forces as the loads increase on them. The basic frictional equation is linear and related to the frictional equation F = uN. As the torque loads (and hence HP loads) increase, so does N and F. The term u is the friction coefficient which should stay relatively constant depending on the gear lube, etc in the system.

This is the factor that could contributes to the increased % loss at higher HP levels. This is because as the torque increases the frictional losses also increase, but when multipied by the velocity it now becomes a larger number than it would have been if the torque load was smaller.



So you really have two components. A totally linear one from things like seals and parts moving in fluids, and a slightly non-linear one that is dependant on the level of torque being transmitted through the mechanical system as describe above.
[/QUOTE=ZeeOSix;1566430623]


This I do understand,

BUT

That's where it gets muddy for me, not being an engineer by trade, and not being familiar with the math(I'm no dummy, just not schooled in that manner! )

I still find it hard to believe when using the percentage idea, that a car making 750rwhp loses 132hp (750/.85=882, 882-750=132)
and a car making 450rwhp loses 79hp (450/.85=529, 529-450=79)

That's an additional 53 hp lost thru a fixed drivetrain, just due to friction? (an additional 353fwhp(882-529=353), (353*.15)=53hp

Or are ALL fwhp increases subject to the 15% loss, even though there have been no changes to the drivetrain?

Maybe you're correct.
Maybe we can apply 15%(or thereabout) as a loss percentage to a given drivetrain.

I still have questions about this whole thing.
Maybe I do need to see some hard math on paper to help me understand.

zeevette

Perhaps you haven't raised the ire of the engineers to the proper level yet. They're educated, and arrogant in their knowledge. I've lived in the Hanford, WA. area for 30 years, and the ratio of engineers to human is unusually high locally. They're not much fun at parties. This attitude leads to a myopic view of most issues, where the numbers rule, and be damned with common sense. The kind of guy that'll hire a pump-jockey to install a catback.

Labold

Didn't know Ranger was into that kind of stuff

Bigstik

[QUOTE=vrybad;1566434698]

See, that's where I've had questions in the past.

Based on MY research, the average C5 z06 dynos about 350rwhp.
The average C6 Z06 dynos about 450rwhp.

They both lose about 50hp(give or take) thru the drivetrain, if we can trust the factory fwhp specs.

I don't think there is enough evidence to suggest that the C6 z06 loses an additional 20hp at the wheels on a consistent basis, due to dyno variances for both the C5 zo6 and the C6 zo6.

We have all seen freaks that make more, and weaker examples that make less, but I'd say that averages are as I've stated above.

That's what led me to believe that loss was closer to a fixed amount in a given drivetrain(the C5 and C6 z06 drivetrains are very similar thru 4th gear)




As far as the Dynos of C5 Z and C6 Z, from what I have read the C5 Z (02-04) will give in the area of 360 stock RWHP, and the C6 Z will give about 440. as to the accuracy in the dyno, i have no idea.


Not sure if this will help simplify anything but think of this, and yes i know this is not going to involve cars, but more to the point of more force (HP/TQ) = more drag (Friction). Say you are in a pool of water and you move your hand through the water slowly. It feels very easy to move, but as soon as you try to move your hand quickly there is a great deal of force acting against you. More force traslates to more friciton. Same for engines, the harder you try to move the parts and the faster you move them, the more by-products are generate (friction).

rbartick

Buy the C6Z.

vrybad

I definitely understand your point.
My question is relative to the measurement of that force.

On a dyno, it takes more force(tq) at any rpm to rotate that drum QUICKER over time, which results in a greater measurement on the dyno chart.

I'm just still not convinced, as in my example above, about two cars, one with 750rwhp and one with 450rwhp, that there would be an additional 53hp lost during that dyno pull.

Maybe that is correct.
It just seems to me alot of additional hp lost to friction alone.

That's why I stated that maybe ALL increases to fwhp are subject to the dynamic loss %, which strangely, seems to make sense to me.

bvillezo6

While the debate rages on youve succeeded in proving to everyone that youre a jacka$$

zeevette

Welcome to the club.

ZeeOSix

... I think he has engineering envy or something. zeevette -- don't feel bad and go on the attack mode just because you don't understand the physics involved. Not everyone can be smart in this subject matter.

zeevette

Nor can all people be smart in a wide range of subjects, not to say that you aren't...Perhaps I did over-generalize, and to other engineers, I apologize.

AU N EGL

Haven't had this much entertainment since I over head two guys at a bar talk about the new GT-R

If you have a question, go get your car dyno'd.

ZeeOSix

Who's claimed to be an engineer? Perhaps you are, and that's why you're apologizing.

ZeeOSix

Right here is disagreement on what an average bone stock C5Z and bone stock C6Z puts down for SAE RWHP. I’m sure if someone searches the forums you will find polls that will give a good idea on the avg numbers seen on the dynos. Maybe I’ll do some digging if I find some time.

But taking Bigstick’s data, you can see there is a 80 RWHP difference when the FWHP difference is 100 HP. That means 20 more HP was lost in the drive train on the more powerful C6Z.

C5Z -- 405 (.85) = 345
C6Z -- 505 (.85) = 430
The delta in RWHP using a straight 15% loss is 85, meaning 15 HP of the 100 extra FWHP was lost by the C6Z.

Sure there are differences in the cars and the dynos, but using a large sampling of dyno data and comparing against the 15% loss of the factory rated FWHP gives a pretty close correlation IMO.

tiger1

Why not just try to match the performance of the Z06 (I assume that's what "hang with" means), and forget about all these silly "RWHP" numbers that don't make a hill-of-beans difference. Ask any ricer-burner and he'll tell you his Camry has 317.39 RWHP (although it should be FWHP, hehehehe). Who cares. It's all either: 1) lies, or 2) BS. I agree with at least one other poster. There is no magic "flywheel times 0.85 fits all" solution. These horsepower numbers really do mean things. Every horsepower is 746 Watts. So a 2hp loss somewhere (assuming it's being lost to heat) is what a floor space heater consumes. Every Watt is the same as 3.4 BTU/hr, so a 1 horsepower loss is 2536 BTU/hr. Show me a guy with 100 horsepower drivetrain loss and I'll show you the same guy with boiling transmission fluid. Where else is it being lost in? Power is either being lost to heat or to work. Assuming that the loss isn't being consumed by work (compression of spring or gas) then it's lost as heat. Again, 100hp is a staggering amount of heat. This is why I reject all these goofy-@ss rules of thumb that again, serve only to make up one's avatar power numbers.

If you can accelerate to 60 in 3.5 seconds, you've accomplished your mission :

bvillezo6

I don't know for sure either, but you can disagree with some class and actually have a conversation about the different ideas surrounding the topic, i.e. vrybad. My .02 is that ive done enough math...i dont have an engineering degree nor am an engineer by trade...to know that physics equations dont lie...ever. that being said.....rage on!

Jim


PS...are you a raptor pilot?...usafa?

zeevette

There you go, spinning the data to try and prove your point.

How 'bout this.... The average C5Z puts down 350 RWHP
The average C6Z puts down 450 RWHP

I'm not a college graduate, but it looks like 100 RWHP difference, which coincidentally is the same as the rated difference. Say what you will, but there's enough possibility of error to prove both theories,(or "school of thought") which would in turn disprove both.