Silvia Club of NSW :: View topic - SilviaNSW Dyno Night

Seeing as this is the dyno thread i have a few questions.

1. Whats kw @ the flywheel? Why is this higher then say kw @ the wheels.
2.Whats kw @ the wheel?
3. How is this all measured?

Was watching the drag racing on SBS and some guy had 1000hp at the flywheel i think...

tehyoungone wrote:

1. Lookup what a flywheel is. Usually, when you see a factory-rated power figure e.g. "The new Aurion with 200kw of power!!!", that figure is derived from the crankshaft or flywheel.

2. kW @ the wheels is a power measurement of the cars output literally from the wheels spinning rolling thingies on a dynamometer or 'dyno'. kW at the wheels is always lower than the factory rated power figures because on average cars lose 30% of their power from the engine through the drivetrain.

For example, a stock S15 has 147kW at the flywheel from factory. On the dyno, it will pull between 108-110kW.

The new Aurion with 200kw of power

i want a silvia wrote:

The new Aurion with 200kw of power

200 Killer Wasps!

For example, a stock S15 has 147kW at the flywheel from factory. On the dyno, it will pull between 108-110kW.

i want a silvia wrote:

For example, a stock S15 has 147kW at the flywheel from factory. On the dyno, it will pull between 108-110kW.

how accurate is that? my stock s14a pulled 128.8 at the wheels at unigroup.

It's a fair bet that he'd be referring to the significant amount of head work zac had to have done to make the engine breath enough for a 300+ figure.

I've seen curves similar to zacs on rb20's with big turbos and a lot of head work. Bottom end response suffers as well as the initial bit of midrange, but once the thing gets where it needs to be power just goes vertical and you end up with a fairly high stable peak (within 30-40rwkw) power over a good 3-4k rpm so you have silly good average power in the 4-8k range. The setup is basically optimised for flow and power, not bottom end torque.

182go is banging on about his felt more responsive, i don't doubt it as he had the stock ports, cams and valves so improved gas velocity and better torque in the lower end of the rev range. He would have hit the same wall zac did a year or so ago when the engine wouldn't make more than 260-270rwkw.

Author:	funsiz [ Sat Apr 19, 2008 7:38 pm ]
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when the new motor goes in ill have to bring my copen to the next dyno night

Author:	badhairdave [ Sat Apr 19, 2008 7:58 pm ]
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as long as it isn't a CA you'll be welcome

Author:	tehyoungone [ Sun Apr 20, 2008 3:24 pm ]
Post subject:
Seeing as this is the dyno thread i have a few questions. 1. Whats kw @ the flywheel? Why is this higher then say kw @ the wheels. 2.Whats kw @ the wheel? 3. How is this all measured? Was watching the drag racing on SBS and some guy had 1000hp at the flywheel i think...

Author:	i want a silvia [ Sun Apr 20, 2008 3:47 pm ]
Post subject:
tehyoungone wrote: Seeing as this is the dyno thread i have a few questions. 1. Whats kw @ the flywheel? Why is this higher then say kw @ the wheels. 2.Whats kw @ the wheel? 3. How is this all measured? Was watching the drag racing on SBS and some guy had 1000hp at the flywheel i think... 1. Lookup what a flywheel is. Usually, when you see a factory-rated power figure e.g. "The new Aurion with 200kw of power!!!", that figure is derived from the crankshaft or flywheel. 2. kW @ the wheels is a power measurement of the cars output literally from the wheels spinning rolling thingies on a dynamometer or 'dyno'. kW at the wheels is always lower than the factory rated power figures because on average cars lose 30% of their power from the engine through the drivetrain. For example, a stock S15 has 147kW at the flywheel from factory. On the dyno, it will pull between 108-110kW.

Author:	tehyoungone [ Sun Apr 20, 2008 7:32 pm ]
Post subject:
i want a silvia wrote: tehyoungone wrote: Seeing as this is the dyno thread i have a few questions. 1. Whats kw @ the flywheel? Why is this higher then say kw @ the wheels. 2.Whats kw @ the wheel? 3. How is this all measured? Was watching the drag racing on SBS and some guy had 1000hp at the flywheel i think... 1. Lookup what a flywheel is. Usually, when you see a factory-rated power figure e.g. "The new Aurion with 200kw of power!!!", that figure is derived from the crankshaft or flywheel. 2. kW @ the wheels is a power measurement of the cars output literally from the wheels spinning rolling thingies on a dynamometer or 'dyno'. kW at the wheels is always lower than the factory rated power figures because on average cars lose 30% of their power from the engine through the drivetrain. For example, a stock S15 has 147kW at the flywheel from factory. On the dyno, it will pull between 108-110kW. Ah it all makes sense now. Thanks.

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SilviaNSW Dyno Night - Sat 12th April 2008 https://forum.silviansw.com/viewtopic.php?f=7&t=29694	Page 34 of 35

Author:	SamBo [ Mon Apr 21, 2008 11:46 am ]
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i want a silvia wrote: The new Aurion with 200kw of power 200 Killer Wasps!

Author:	i want a silvia [ Mon Apr 21, 2008 11:57 am ]
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SamBo wrote: i want a silvia wrote: The new Aurion with 200kw of power 200 Killer Wasps! I was waiting for someone to say that

Author:	radism [ Mon Apr 21, 2008 12:01 pm ]
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i want a silvia wrote: For example, a stock S15 has 147kW at the flywheel from factory. On the dyno, it will pull between 108-110kW. how accurate is that? my stock s14a pulled 128.8 at the wheels at unigroup.

Author:	mokompri [ Mon Apr 21, 2008 12:06 pm ]
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radism wrote: i want a silvia wrote: For example, a stock S15 has 147kW at the flywheel from factory. On the dyno, it will pull between 108-110kW. how accurate is that? my stock s14a pulled 128.8 at the wheels at unigroup. 100% stock ? ive seen 2 or 3 and they were all 105-110

Author:	radism [ Mon Apr 21, 2008 12:28 pm ]
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guaranteed stock as a rock. only mod was a head unit... unless they wired that to the ecu and remapped it

Author:	mokompri [ Mon Apr 21, 2008 1:18 pm ]
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your figure gives a 13% drivetrain loss all up, which is pretty low maybe it was a happy dyno day

Author:	blu80 [ Mon Apr 21, 2008 5:49 pm ]
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30% power loss sounds much more realistic then 13%... indeed i think it was happy dyno day

Author:	182Go [ Mon Apr 21, 2008 7:44 pm ]
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badhairdave wrote: It's a fair bet that he'd be referring to the significant amount of head work zac had to have done to make the engine breath enough for a 300+ figure. I've seen curves similar to zacs on rb20's with big turbos and a lot of head work. Bottom end response suffers as well as the initial bit of midrange, but once the thing gets where it needs to be power just goes vertical and you end up with a fairly high stable peak (within 30-40rwkw) power over a good 3-4k rpm so you have silly good average power in the 4-8k range. The setup is basically optimised for flow and power, not bottom end torque. 182go is banging on about his felt more responsive, i don't doubt it as he had the stock ports, cams and valves so improved gas velocity and better torque in the lower end of the rev range. He would have hit the same wall zac did a year or so ago when the engine wouldn't make more than 260-270rwkw. You know I could have sworn that I had Tomei 270 / 12.5 intake and exhaust cams in there and I replaced the intake with a 260 / 12mm to try improve vacuum. I also thought that I had Tomei adjustable cam gears, Tomei springs and Tomei rocker stoppers in there. I also was under the impression that Sam at Westend Performance ported the head and I port matched the intake. Man do I feel like a dope for spending 5k and winding up with a stock head No the epiphany came when it was pointed out that I wasn’t comparing apples with apples. Chris asked if I was impressed, to which I answered something like not overly (very few things impress me ever). If something is going to impress me it has to leave an impression that blows my mind not just go well. For a bench mark I use a car I helped build the engine for, a 383 stroker that was running a tunnel ram style manifold, aftermarket ported alloy heads, massive solid cam, huge compression and running AV Gas. It ran a 10.02 on it’s first pass down the quarter and used to lift the passenger side front wheel about 10 inches off the ground on take off. When he stepped on it I could not literally pull myself out of the seat to grab the dash, using that as a bench mark most things come up short of what I would call impressive. But as Yarvus pointed out that car was running a 4500 rpm stally so the revs flashed to those revs before attempting to move the car. If you launched Zac’s car at those same revs when it was on full boost it would feel damn impressive too. When I thought about it he was right you have to compare the exact same situation to get a fair and accurate comparison.

Author:	badhairdave [ Mon Apr 21, 2008 8:02 pm ]
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i'd forgotten about your head work, apologies if i have offered some offense

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Author:	fergo308 [ Mon Apr 21, 2008 8:02 pm ]
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that's part of what the discussion was about. not comparing apples with apples. and in defending your blase attitude in regard to Zac's car,you say that because a 383 stroker with lots of other work that had easily double the torque and triple the capacity was more impressive to drive than a worked 2l turbo car,you seriously feel that that is a fair yardstick to compare them by? that's not apples and apples,that's a grape versus a watermelon. if all that impresses you is 6L + capacity V8's,maybe you should stick to those. Justin...