4age power loss through driveline?

[Maxwedge]

Does anyone know what power is lost through the driveline as a percentage? So if a smallport for example is putting 100 Kw through the flywheel, what would this equate to at the wheel once friction etc is calculated?

[sergei]

it is not a fixed percentage.
I would say aim for about 8-10% (10% is stretching), but when you increase power the loss does not increase proportionally.
The loss basically would stay pretty much same (in terms of power, not %), while you could produce 300hp.

It is very complicated subject, but if tuner says "this vehicle makes 500hp at the engine because the dyno reads 400hp" walk away from that tuner, he does not know what he is talking about.

[RedMist]

I'd say considerably less than that. Possibly 4%

Energy cant be destroyed only converted. So you are converting kenetic energy to sound and heat. I cant see a gearbox, UJ's (CV's) and a diff creating 10's of KW's of noise and heat.

[strx7]

the BEST way to think about it, is actually a reading discrepency, rather than a HP loss

[pc]

Does anyone know what power is lost through the driveline as a percentage? So if a smallport for example is putting 100 Kw through the flywheel, what would this equate to at the wheel once friction etc is calculated?

Completely irrelevant. If you want to know how much power a car is putting out, put it on the dyno.... then you can say on *insert dyno here* I get *insert power number here*
Dyno numbers are good for tuning, or good for bragging rights if all your mates go to the same dyno... but not much else.

I'm not aware of anyone putting their vehicle on a dyno then pulling the engine out and measuring the engine by itself on the same equipment.

[Akane]

While we're on the subject, you hear a lot of kiddies saying taking 15% drivetrain loss or some crap and boast their "flywheel figure"

Just think of it this way, say 200kw, losing 15% = 30kw? most of that energy would be converted to HEAT. 30kw of heat is like having a furnace cooking your gearbox and diff. Not going to happen.

I get 292hp at the wheels, I'd say my flywheel would be 310hp max.

Edit: oh, there's a very "famous" tuner in New Zealand, who a lot of people thinks is a very good tuner, but imo all the dynos that company produces are BS. Like making 252kw @ rear wheels with factory SR20DET injectors. :/ Just imo tho.

[method]

While we're on the subject, you hear a lot of kiddies saying taking 15% drivetrain loss or some crap and boast their "flywheel figure"

Just think of it this way, say 200kw, losing 15% = 30kw? most of that energy would be converted to HEAT. 30kw of heat is like having a furnace cooking your gearbox and diff. Not going to happen.

I get 292hp at the wheels, I'd say my flywheel would be 310hp max.

Edit: oh, there's a very "famous" tuner in New Zealand, who a lot of people thinks is a very good tuner, but imo all the dynos that company produces are BS. Like making 252kw @ rear wheels with factory SR20DET injectors. :/ Just imo tho.

Ive heard figures up to 30% for 4wd drivetrain loss.

Remember the engine is under full load, it pretty much is a furnace under full loan and you will have things glowing red and breaking in no time.

And i took my 1530kg car to this famous tuner, got 194kw at the wheels then managed to run a13.0 backed with a 13.06 at meremere which is pretty quick considering the weight and the amount of power it out out. On regular street tyres too.

[AE82 FXGT]

Sorry for my ignorance but can you name/give clue about this tuner?

[matt dunn]

Just think of it this way, say 200kw, losing 15% = 30kw? most of that energy would be converted to HEAT. 30kw of heat is like having a furnace cooking your gearbox and diff. Not going to happen.

Dunno about that, have you seen how hot gearboxes and diff's get in race cars? Remember they only drain that much under full load, which in a road car is only a small % of the time, but in a race car it all the time.

We logged diff temp's of close to 190deg in the focus before we fitted the cooler's,
and cant touch the gearbox in the DX after an 8 lap race without getting burnt. there is a LOT of heat in there.

[stalker]

Is there a way to work it out though??

Ie. I got my car dyno'd and was told I had 118kw! (woot) But then I looked and saw that the dyno sheet said that was at the flywheel...how did they get that if id was sitting on a hub dyno??? And how do I work out what the "at the wheels" figure would be??

[matt dunn]

Is there a way to work it out though??

Ie. I got my car dyno'd and was told I had 118kw! (woot) But then I looked and saw that the dyno sheet said that was at the flywheel...how did they get that if id was sitting on a hub dyno??? And how do I work out what the "at the wheels" figure would be??

No, and there is no way to work it out as far as I know,
and they probably guessed,
which is why dyno figures really mean bugger all,
unless everyone ran an the same dyno on the same day,
or you are comparing you previous reading to the next one on the same dyno.

[stalker]

No, Ive only ever had the one dyno done on the car.
Just seemd weird cause these guys build race cars all day long, and they know what they are talking about and everyone seems to rave about them.
I have no reason to question them...just wonderd how they got the flywheel figure when they dynod my car on the hubs lol

Maybe we should email/call the dyno makers themselves and ask how they work it out and how to convert it maybe???

[pc]

Just ask them to reprint the sheet with the actual power output on it... instead of 'converting' it.

[Akane]

I don't know about that guys, 30kw is enough to smelt the alloy on your gearbox casings.

I'll just stick to my guns for now.

[~SlideWays~]

While we're on the subject, you hear a lot of kiddies saying taking 15% drivetrain loss or some crap and boast their "flywheel figure"

Just think of it this way, say 200kw, losing 15% = 30kw? most of that energy would be converted to HEAT. 30kw of heat is like having a furnace cooking your gearbox and diff. Not going to happen.

I get 292hp at the wheels, I'd say my flywheel would be 310hp max.

Edit: oh, there's a very "famous" tuner in New Zealand, who a lot of people thinks is a very good tuner, but imo all the dynos that company produces are BS. Like making 252kw @ rear wheels with factory SR20DET injectors. :/ Just imo tho.

Ive heard figures up to 30% for 4wd drivetrain loss.

Remember the engine is under full load, it pretty much is a furnace under full loan and you will have things glowing red and breaking in no time.

And i took my 1530kg car to this famous tuner, got 194kw at the wheels then managed to run a13.0 backed with a 13.06 at meremere which is pretty quick considering the weight and the amount of power it out out. On regular street tyres too.

Man I though the evo4 was around 1300kg not 1530kg!!?