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Supercharging a 944 - Why so hard?

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Old 11-28-2017, 10:08 AM
  #76  
jderimig
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Originally Posted by Eric_Oz_S2
Eaton is not very thermally efficient (high temp), prone to heat soak and does not have a good top end. Ok for a street cruiser, bad for track use. Not really in keeping with the character of a Porsche in my view.
The Eaton is a tradeoff for sure. Typically the appeal of Eaton is the cheap (~$200) cost of admission. Perhaps its false economy.
Once you go to new centrifugals (not a lot of used centi's on ebay for sub $300) another whole world opens up. What about twin-screws? (Whipple).
Old 11-28-2017, 11:59 AM
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twinscrew (whipple, etc) are almost "best of both worlds" but still crazy expensive, on par with or greater than centrifugals.
Old 11-28-2017, 12:19 PM
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Seems very competitive with centrifugals. I have seen Whipple W100AX (97 ci/rev) discounted to ~$2100. Par with Rotrex, cheaper than ProCharger. Smaller than a M90 (maybe a little longer 14.6" with shortest stock snout) . Seems like the ideal unit for a 2.5L. What's the downside other than cost?
Old 11-28-2017, 01:31 PM
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nothing, but do you want to spend $2100 on a blower for a $2100 car?
Old 11-28-2017, 01:46 PM
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Originally Posted by V2Rocket
nothing, but do you want to spend $2100 on a blower for a $2100 car?
i bought My 951 for 14$
new engine And parts..15...
Old 11-28-2017, 01:53 PM
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Still cheaper than a s2 motor swap. Isn't it about where you end not where you start?

Again I want to avoid a value discussion or else we will get the inevitable "just buy a turbo or s2 or 968 or Volvo S60" post.
Old 11-28-2017, 03:16 PM
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Ok, with that in mind, no reason you couldn't/shouldn't use a twin-screw or centrifugal if that's what you want to use. They are definitely more efficient and probably easier to package.

For me, NFW I'm going to spend that $ on a single part, no matter how much I "want one"...I'll make do with something else at that point.
$2100 is almost as much as I paid for my 944 + Outback, combined...
Old 11-28-2017, 03:33 PM
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No, don't get me wrong I would rather get my M62 or M90 working first.

If I had the choice of turning a fun $2100 944 into a REALLY fun $2700 944, or tuning a $2100 fun 944 into a REALLY REALLY fun $4500 944, I would try the first one first....

I am guessing your VEMS wasn't exactly cheap compared to the cost of you car? That was a single part.

However if you have a really nice 944 sample I could see someone using the Whipple for other subtle NVH considerations. There are quieter and not everyone loves the roots blower whine.
Old 11-28-2017, 04:27 PM
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VEMS was $1200 or so I think, but I was able to sell my Rogue MAF+DME tuner setup to offset most of that so it was "OK" in my mind. Totally worth it.
..
Whipple being quiet...

Old 11-28-2017, 04:42 PM
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That video was using a KB, probably a large one. They are known for screaming.

I haven't heard one in person but the consensus on the various forums is that the Whipple is significantly quieter than the the KB which in turn is quieter than the Eatons. All other things being equal, RPM, i/rpm etc etc. Some complain about the Whipple as they miss the Eaton or KB scream. But what do I know without hearing one in person.
Old 11-28-2017, 06:38 PM
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Originally Posted by DarrenD

I used Rogue's NA tune and the tunibility was amazing. I ran a front mount IC.
So what caused the demise of your motor?
Old 11-28-2017, 06:44 PM
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Originally Posted by jderimig
So what caused the demise of your motor?
I had never checked the compression/health of my motor. It turns out somebody along the way had built my NA motor with very high compression and It also had a fair number of hard miles on it. I cracked the rings in 3 of the cylinders.

My brother has the setup now and has built a proper motor for it so it will live on.
Old 11-28-2017, 06:49 PM
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I spent 2400$ canadian for my entire setup(Not including the previously purchased NA-Tune). The SC was $100. I spent a few bucks on a rebuild kit. The piping and materials were a few hundred dollars. It wasn't cheap, but the performance was amazing. I had a well know local mechanic/racer drive it and he was amazed. Loved the power, as well as the throttle response. It idled perfectly, cruised nicely., and would light up the tires in first at will. It was the perfect mod for an NA car, IMHO, how they should have come from the factory. I don't like my current turbo car nearly as much and have contemplated twin-charging it.
Old 11-28-2017, 07:11 PM
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Originally Posted by DarrenD
I had never checked the compression/health of my motor. It turns out somebody along the way had built my NA motor with very high compression and It also had a fair number of hard miles on it. I cracked the rings in 3 of the cylinders.

My brother has the setup now and has built a proper motor for it so it will live on.
Darren, what compression ratio do you recommend for your level of boost?
Old 11-28-2017, 08:27 PM
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some motivation for this thread
https://grassrootsmotorsports.com/fo.../131357/page1/


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