Camshaft capers

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Camshaft capers

Postby oldspa » Sun Jul 03, 2016 7:55 am

Whilst my 998 was out for gearbox work we decided to go from an R23 to a GE3. Newman Cams have just started doing these. Fitted it and took it to the rolling road. Way down on power, what would normally be 75+ bhp at the wheels was now barely 63. Seems their first batch is out of tolerance and they are working to sort it wondering if anyone else had a similar issue with these :?:
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Re: Camshaft capers

Postby benwick3 » Sun Jul 03, 2016 11:42 am

Been using GE3 cams in my racing Clans for several years now. I believe one was from Newman and I've not noticed any discernible difference in performance.

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Re: Camshaft capers

Postby SimonBenoy » Sun Jul 03, 2016 9:05 pm

Also had good experience of GE3 cam, more tractable than an R23 and better lap times.
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Re: Camshaft capers

Postby greenbeast » Sun Jul 03, 2016 9:18 pm

According to Lotus-e-Clan's famous table (see viewtopic.php?f=6&t=30417) your dynamic CR just went from 7.45 down to 7.15 with that cam, and valve overlap, change.

I'm guessing that would do it. Or undo it. :)
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Re: Camshaft capers

Postby Lotus-e-Clan » Mon Jul 04, 2016 6:11 am

camSCRdata.png
camSCRdata.png (18.2 KiB) Viewed 1223 times


What GreenBeast suggests may account for SOME of the loss at least ..

ie GE3 might benefit from a SCR increase - especially if your SCR was on/below the lower margin for the R23 in the first place- ie well below 12:1. BTW. the right hand column indicates the SCR for each cam to restore the 9.08:1 dynamic CR of the std cammed engine.

Perhaps play with cam timing to find an undocumented sweet spot - the dodgy Newman tolerances might yield something different?
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Re: Camshaft capers

Postby oldspa » Wed Aug 03, 2016 7:08 pm

compared the Newman cam with a kosher ge3, totally different, the real one is a flatter profile across the top, completely different to the naked eye, more than a few thou here and there. Newman have now supplied another so we'll see what happens on the rolling road Imp003
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