Cosworth Supercharger Owners Thread

[weederr33]

Originally Posted by killboy

Note he said bhp, not whp. That would translate to about 320whp I figure.

I'd honestly guess that would translate more to 350whp than 320.

Originally Posted by ajc209

Personally I wouldn't mess with crank damping with an sc installed.

I dont think these cars loose 60hp in the drivetrain. Perhaps 40hp.

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Why wouldn't you want to mess with the crank pulley? I realize a lot of debate has been thrown out there about LW crank pullies vs harmonic dampening of the stock. However, increasing the ribbing of a stock pulley shouldn't have that much repercussions (if any).

[ajc209]

Originally Posted by weederr33

I'd honestly guess that would translate more to 350whp than 320.



Why wouldn't you want to mess with the crank pulley? I realize a lot of debate has been thrown out there about LW crank pullies vs harmonic dampening of the stock. However, increasing the ribbing of a stock pulley shouldn't have that much repercussions (if any).

I was referring to undamped lightweight pulleys.

Machining the stock pulley to have 8 ribs will retain the stock damping but anyway you'll have a new bottom end at that point so I have no idea what damping it would require.





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[weederr33]

Fair enough. I specialize in biomechanics, not engine mechanics, so I'll let Matt or someone better qualified to determine that. Either way, I have something to save for this year!

[ajc209]

Originally Posted by weederr33

Fair enough. I specialize in biomechanics, not engine mechanics, so I'll let Matt or someone better qualified to determine that. Either way, I have something to save for this year!

Exactly.

They have all the proper gear to test this stuff too.

I hope we'll see a validated stage 3 in the future.

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[weederr33]

Well I've gotta save some serious money then, because it's going to be pricey. But they have till December, so I'm good. haha

[ajc209]

I've just spend all my money on Ohlins, brakes, wheels and tyres....#skint

But who knows in a few years....

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[killboy]

Originally Posted by ajc209

I dont think these cars loose 60hp in the drivetrain. Perhaps 40hp.

Originally Posted by weederr33

I'd honestly guess that would translate more to 350whp than 320.

I respect your opinions fellas, but keep in mind parasitic drivetrain loss is calculated as a percentage, not an absolute value.

Our cars stock make 200bhp, which comes out to 160-170whp...a 30-40hp loss, which is in line with the 15% rule. Now we're doubling the horsepower so guess what, double the losses. My number was being optimistic.

[ajc209]

Stock cars make about 190hp....

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[killboy]

Originally Posted by ajc209

Stock cars make about 190hp....

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Are you referring to bhp or whp?

[ajc209]

Bhp. If you look at the published graph by cosworth its shows their base stock engine with ~190hp

I think Matt told me their two engines came out at ~185hp and ~193hp


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[killboy]

Originally Posted by ajc209

Bhp. If you look at the published graph by cosworth its shows their base stock engine with ~190hp

I think Matt told me their two engines came out at ~185hp and ~193hp

Gotcha, so revised to 20-30whp loss stock, (or 28.5hp @ 15%) and that puts us at about 57whp loss from 380bhp so 323whp. Was off by 3.

Whole point being I don't think it's anything you can't handle, weederr. Now make it happen already, I'm all set over here Cosworth!

[weederr33]

I'd hope they make the pulley's a cool color, too. That would be sweet. Like an anodized red or blue, or silver.

[Kodename47]

Originally Posted by killboy

Now we're doubling the horsepower so guess what, double the losses.

No, you don't. There will be an increase but the % increase will be a fraction of the total losses.

[ajc209]

Originally Posted by Kodename47

No, you don't. There will be an increase but the % increase will be a fraction of the total losses.

I used to think that but actually % loss is better approximation than a static loss.

Estimating drivetrain losses as a % is a basic principle, Helical gear, bearings, joints ect exibit a fairly linear increase in losses with power assuming there is no flex or movement that causes more friction. Doubling the power output can also change lubrication films, introduce strain and flex in places that didnt before.

There are built in losses that dont change with power such as pumping around oil, but its fairly insignifiant compared to the main losses in the drivetrain.