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Discussion Starter · #1 ·
Was doing some research and talking to some people.... anyways, can somone confirm if the flywheel from an 850R would be a direct replacement for the R? If so this should be a 10+ wheel hp gain.
 

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Re: flywheel 10whp gain (R_Rated)

irrespective of whether it fits, a reduction in rotational mass will not increase HP, it will only allow the HP to "build quicker" under certain dynamic conditions.......
 

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whatever you call it - lighter flywheels will make the car faster.<p>i used to have a miata...not the fastest car in the world. when i redid the clutch, i added a lightweight flywheel.... it made the car noticeably quicker....shifted quicker too.<p>less weight to rotate means it will pick up revs quicker and shift quicker. all good for us speed junkies.<p>Jim is right though - it technically will not make "more power".<p>if that could be fit to the car - it might be worth looking into. given how costly a clutch job is though, many of us will wait until the car needs a clutch.... i'm not that far away with 52k miles on the odo..
 

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Discussion Starter · #4 ·
on the dyno it will show an improvement of 10-12 whp... regardless of what "realy" happens the car will make more power. <p>FYI, Spec is having a sale on the stage III+
 

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Re: (23109VC)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>23109VC</b> »</i></TD></TR><TR><TD CLASS="quote">given how costly a clutch job is though, many of us will wait until the car needs a clutch.... i'm not that far away with 52k miles on the odo..</TD></TR></TABLE><p>If you're not abusing the clutch it should last much longer, Volvo clutches are pretty durable. I have 82500 miles on my T5 manual and still on original clutch! <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0">
 

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Re: (R_Rated)

An underdrive pulley would do that for sure, but a lighter pulley, maybe 2-3 hp on a dyno, which would be within the margin of measurement error.
 

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Re: (R_Rated)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>R_Rated</b> »</i></TD></TR><TR><TD CLASS="quote">on the dyno it will show an improvement of 10-12 whp... regardless of what "realy" happens the car will make more power...</TD></TR></TABLE><p>Not more total power. More acceleration, which is what the dyno measures. The power the engine makes has to accelerate the engine itself (including flywheel), drivetrain, wheels(much discussed before), tires, and dyno mass. Reduce any of these masses and the same power gives more acceleration.<p>Same power developed by the engine (exclusive of flywheel), but MORE of it gets to the road during acceleration. This is the "dynamic" condition Jim Lill referred to.<p>Once everything is up to speed, steady-state horsepower is the same. But who cares? It's those little bursts of acceleration you feel and interpret as a more powerful engine.<p> <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/embeer.gif" BORDER="0">
 

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Re: (ljjones)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>ljjones</b> »</i></TD></TR><TR><TD CLASS="quote">Same power developed by the engine (exclusive of flywheel), but MORE of it gets to the road during acceleration. This is the "dynamic" condition Jim Lill referred to.</TD></TR></TABLE><p>In other words, the load on the engine is reduced.
 

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Re: (R Salesman)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>R Salesman</b> »</i></TD></TR><TR><TD CLASS="quote">In other words, the load on the engine is reduced.</TD></TR></TABLE><p>Only the "dynamic" load.<br>And dynamic load is all most low cost dynos have nowadays. So of course the lighter flywheel shows up as increased power. <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0"> <br>
 

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Re: (R Salesman)

Lighter wheels would make a bigger difference.<p>Tom.
 

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Re: (tmtalpey)

doesn't all this mean no actual change at all in engine horse power,<br>but some increase in wheel horse power due to more efficient drivetrain ?<p>
 

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Re: (Serdar-S60T5)

Yep. But I'd disagree with the word "efficient". I'd go no further than "lighter", i.e. lower rotating mass. There is no energy loss here.<p>Tom.
 

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Re: (tmtalpey)

This is all about inertia... you can easily get knee deep in physics but a quick read here is worthwhile....<p><A HREF="http://en.wikipedia.org/wiki/Moment_of_inertia" TARGET="_blank">http://en.wikipedia.org/wiki/Moment_of_inertia</A><p>Changing rotational inertia has the same effect as changing the mass. So we all know that a lighter car (same HP) will accelerate quicker. Likewise, one with less rotational interia, as gained by having less rotating mass, will accelerate faster, again with no extra HP. Any dyno which uses acceleration to determine WTQ and thus WHP, will give you +HP but the real steady-state HP remains unchanged. Your top speed is a function HP versus losses. Changes in mass do not effect top speed (except for added tire and related frictional losses).<p>
 

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Re: flywheel 10whp gain (JimLill)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>JimLill</b> »</i></TD></TR><TR><TD CLASS="quote">irrespective of whether it fits, a reduction in rotational mass will not increase HP, it will only allow the HP to "build quicker" under certain dynamic conditions.......</TD></TR></TABLE><p>This raises an interesting question for me. And, since this is your field, I completely defer to you.<p>While watching an episode of Sports Car Revolution on the Speed Channel (last year), they were working on an Audi A4 with APR, I remember them saying something about slightly heavier rims actually decreasing hp to the wheels. ("Huh?") But, since the nominal decrease in hp would be offset by gains in performance, the loss made sense. Now, my recollection might be a bit clouded since the episode aired last season - but I remember thinking about the discussion and wondering if they explained something poorly or if I misunderstood it. Either way, it didn't make sense to me. Any idea what they might have been talking about?<p>-Eric
 

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Discussion Starter · #16 ·
Wether is frees more HP or makes more HP... regardless, the car is faster and and the dyno will show more HP. Anyway you look at it the car will be more powerful.
 

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Re: flywheel 10whp gain (R_Rated)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>R_Rated</b> »</i></TD></TR><TR><TD CLASS="quote">Was doing some research and talking to some people.... anyways, can somone confirm if the flywheel from an 850R would be a direct replacement for the R? If so this should be a 10+ wheel hp gain.</TD></TR></TABLE><p>Which flywheel? Single mass or dual mass? They're completely different and one sucks and the other doesnt. Got a pic of a flywheel from a p2 R?
 

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Re: (R_Rated)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>R_Rated</b> »</i></TD></TR><TR><TD CLASS="quote">Wether is frees more HP or makes more HP... regardless, the car is faster and and the dyno will show more HP. Anyway you look at it the car will be more powerful.</TD></TR></TABLE><br>not really.
 

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Re: (R_Rated)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>R_Rated</b> »</i></TD></TR><TR><TD CLASS="quote">Anyway you look at it the car will be more powerful.</TD></TR></TABLE><p>Yep, the car as a dynamic <i>system</i> will be more powerful, the engine by itself, will remain the same.<p>
 

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Discussion Starter · #20 ·
Re: (R_Rated)

<IMG SRC="http://www.thisboardrocks.com/forum/images/smilies/dead-horse-fast2.gif" BORDER="0">
 
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