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Insane
Joined: 20 Jun 2009
Posts: 65
Location: Kyiv
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 Posted: Thu May 27, 2010 8:16 pm Post subject: Is anyone running 300Hp on 924? How much boost do you have? |
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I have calculated aprox boost figures using formulas suggested TurboByGarrett and boost required for 300Hp @ 6500 rpm is ~20psi which seems to be too high.
How much boost & power do you have?
The only one turbo I've found which will allow 33 lb/min with 2.7 Pressure ratio was Garrett GT2871. At all other maps the point was too close to surge.
Download calc .xlsx
And if somebody needs:
Maximum Boost - Corky Bell.pdf
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Do you know where can I download Dynomation software? |
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ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
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Insane
Joined: 20 Jun 2009
Posts: 65
Location: Kyiv
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| Posted: Thu May 27, 2010 9:58 pm Post subject: |
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Thanks, really similar figures!
By the way, NA has 0.07 bhp/cid and I guess it should be equal for turbo application. |
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morghen
Joined: 21 Jan 2005
Posts: 9095
Location: Romania
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| Posted: Thu May 27, 2010 10:18 pm Post subject: |
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6500RPM sounds a bit too much...the 924 turbo engine makes max power ar 5800.
1.4bar(20psi) looks like quite alot for only 300hp.
an evo7 2L at 1.5bar makes 500+HP
but boost is not everything 
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Insane
Joined: 20 Jun 2009
Posts: 65
Location: Kyiv
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| Posted: Thu May 27, 2010 10:52 pm Post subject: |
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| morghen wrote: | 6500RPM sounds a bit too much...the 924 turbo engine makes max power ar 5800.
1.4bar(20psi) looks like quite alot for only 300hp.
an evo7 2L at 1.5bar makes 500+HP
but boost is not everything |
not sure about 500+,
see http://www.tdp.ie/?cat=
they are doing 408HP@6815 rpm.
they have AFR=11, 1.28 bar (1.51 max).
calc shows 1.3 bar with this settings considering BSFC = .5 and VE=97% and 110F* intake manifold air temp.
with the same parameters we get 300Hp@6000rpm with 0.92 bar of boost. Which is false for 924 Porsche.
I think there was a figure of .8 bar and 210 Hp?
That's why I'm looking for real test results to finetune the calc. |
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Scorpio
Joined: 05 Jul 2007
Posts: 1957
Location: Brisbane, Australia
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| Posted: Thu May 27, 2010 11:47 pm Post subject: |
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Ill tell you in two months time...garret T25 starting at 7 psi then inching my way to 12 
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1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT
Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!! |
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morghen
Joined: 21 Jan 2005
Posts: 9095
Location: Romania
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| Posted: Fri May 28, 2010 12:24 am Post subject: |
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the 924 turbo engine should make 210 BHP at 0.8 bar with CGT or similar advance curves and a propper intercooler...and around 240BHP with 1bar and a good intercooler.
with 1.1 bar, propper advance curves a good intercooler + a tuned intake&exhaust + a fresh valve seat job you should see ~270.
i'm actually quoting from the CGT series.
CGT 210 HP 0.8bar poor intercooler
CGT-S 245 HP 1 bar good intercooler
CGT-S-CS 275-285 HP 1.1 bar good intercooler, tuned intake and exhaust
PS: 20PSI = 1.38bar..thats 1.4
At 1.4 bar...with propper timing and fueling, intake and exhaust sorted out + some head work one should see ~350BHP
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simsport
Joined: 06 Nov 2002
Posts: 573
Location: UK Warrington
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| Posted: Fri May 28, 2010 4:53 am Post subject: Boost |
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I know its not a turbo but...........with the supercharger at 11/12 psi I get 246bhp and 245lbft torque.
Cheers
Simon
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morghen
Joined: 21 Jan 2005
Posts: 9095
Location: Romania
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| Posted: Fri May 28, 2010 5:31 am Post subject: Re: Boost |
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| simsport wrote: | I know its not a turbo but...........with the supercharger at 11/12 psi I get 246bhp and 245lbft torque.
Cheers
Simon |
Hi Simon, good to know you're still around.
thats quite alot of power at only 0.8bar
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ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
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| Posted: Fri May 28, 2010 6:52 am Post subject: |
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Note that my spreadsheet shows the potential HP of 296 at 17psi with the most optimistic bhp/cid rating of .077...
...not surprising it would be similar to the other calculator as I used Corky Bell's formulas as well. Also note that the intent of my spreadsheet was to help determine adequate compressor sizing based on flow requirements to achieve a targeted BHP, so not exactly setup the same way as the other calculator and admittedly probably a bit more rudimentary. Obviously, there are a ton of variables that would impact the target BHP, such as RPM and the VE of the head, which I don't think anybody truly has numbers on.
As for the CGT comparison, you have to remember, that car did NOT have the same turbine or compressor set up as the stock 931, so Morghen, without addressing the turbo, your figures are probably on the optimistic side.
Also, it's worth reminding everyone that just cranking up the boost is not necessarily going to be the best approach to increasing power. You could leave boost alone, and concentrate on reducing IAT by 50-80° and see a significant increase in power. There are a number of ways IAT could be reduced, including properly sized compressor that won't contribute as much heat due to higher compression; larger intercooler; improved intercooler efficiency; water/meth injection; and on and on.
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morghen
Joined: 21 Jan 2005
Posts: 9095
Location: Romania
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| Posted: Fri May 28, 2010 7:22 am Post subject: |
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yea i missed the compressor size thing...those figures that i've put on are on the optimistic side indeed.
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macBdog
Joined: 16 Aug 2004
Posts: 1111
Location: Brisbane, Australia
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| Posted: Fri May 28, 2010 2:14 pm Post subject: |
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I run 300hp in a 924. NA.
HARDY HAR HAR. Sorry I had to do it.
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| p-talk wrote: | | I'm still convinced the word 'Porsche' makes people crazy in all kinds of ways |
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Insane
Joined: 20 Jun 2009
Posts: 65
Location: Kyiv
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| Posted: Fri May 28, 2010 3:53 pm Post subject: |
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| macBdog wrote: | I run 300hp in a 924. NA.
HARDY HAR HAR. Sorry I had to do it. |
Than I wonder how much boost do you have and what modifications are done to the engine? |
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!tom
Joined: 28 Aug 2006
Posts: 1941
Location: Victoria, BC Canada
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| Posted: Fri May 28, 2010 3:56 pm Post subject: |
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Slightly modified engine, in that it's got 8 cylinders.
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78 924 NA
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Insane
Joined: 20 Jun 2009
Posts: 65
Location: Kyiv
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| Posted: Fri May 28, 2010 4:05 pm Post subject: |
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| !tom wrote: | | Slightly modified engine, in that it's got 8 cylinders. |
The best tuning is a SWAP! (c) Japanese car tuners |
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