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twincharger project
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Tue Mar 13, 2012 9:52 pm    Post subject: twincharger project Reply with quote

about halfway through the twincharger project now,
reworking the alt relocation bracket, the first one I had cut wasn't working quite right, converting to 4pk along with the water pump pulley
sc manifolds need to be finished and there's another front mount intercooler going in, so lots of piping to configue too and some reworking of the rad mount
sc's being controlled off the coil via a frequency switch.
Stu





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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Fri Mar 30, 2012 10:17 pm    Post subject: Reply with quote

Completed the primary intercooler installation, measurements for the core are 550x180x65mm endtanks push the width out to 700mm
had to redo the radiator support bracket , changing the angle of the cross braces,
also modified the tow point support, as it had to be mostly cut out and required the extra bracing




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Joes924Racer  



Joined: 03 Nov 2002
Posts: 11964
Location: Oregon, Denver Colorado native!

PostPosted: Sat Mar 31, 2012 1:28 am    Post subject: Reply with quote

Awesome man that looks sweet .. its big.
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morghen  



Joined: 21 Jan 2005
Posts: 8166
Location: Romania

PostPosted: Sat Mar 31, 2012 6:11 am    Post subject: Reply with quote

looks great ! keep us posted with the progress
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WEASEL149  



Joined: 19 Aug 2005
Posts: 595
Location: UK, Sheffield

PostPosted: Tue Apr 03, 2012 7:32 am    Post subject: Reply with quote

Excellent work Stu. Looking forward to more updates
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Harm  



Joined: 02 Apr 2009
Posts: 1351
Location: Holland

PostPosted: Wed Apr 04, 2012 1:59 am    Post subject: Re: twincharger project Reply with quote

leadfoot wrote:

You wanna make sure you don't get stranded…
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Wed Apr 04, 2012 6:35 pm    Post subject: Reply with quote

Theres another one one the back too I did once have to push my car out of an undercover carpark, that wasn't fun... Stupid n/a alternator placement...
Found a good supplier of stainless tubing today, should be able to work on my manifolds and piping over the easter break
@RC
Hows the lathe work goin mate ???
Cheers Stu
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Tue May 01, 2012 7:03 pm    Post subject: Reply with quote

Some details for the build,

EJ20 pulley - 4PK drive inside , 5PK outside
stock pulley has a notch for keyway, this was bored out to 30mm to fit over the crank centre bolt
the front face of the pulley had a small step and this was levelled
inside ID of the pulley bored out to accomodate the bolt pattern of the 924 along with the locating bushing, although after adding the shim this was not necessary on the pulley, bolts required are round head with the recessed allen fitting
5mm shim required for clearance to oil relief valve, at a later date I swap this for a toothed cog crank sensor




A big shoutout to RC for making me water pump and alternator pulleys out of aluminum, these are both 4pk drive
The WP pulley (125mm) was negative offset hence the flat face, this actually weighs identically to the stock steel unit and doesn't use the 4mm shim



The Alt pulley (80mm) is recessed at the back 1mm to allow flush fitting to the vent housing, this will also serve as a backing and add some reinforcement to the pulley and belt edge. There were some clearance issues with the manifold so the pulley had been design to sit as far back as possible allowing the alt to sit as far forward. The suds on the B and 30 connections still needed to be cut down.
The stock mount is used albeit with a few modifications to the bracket, new bolt hole tapped and also the support bracket was cut and offset welded 10mm for belt clearance

I've also finished the intercooler piping, SC manifolds and SC mounts so will put some pics up soon... also finished a new crossover coolant pipe but am waiting for a solenoid to arrive so I can weld the mounts onto this as well.
Stu


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morghen  



Joined: 21 Jan 2005
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Location: Romania

PostPosted: Wed May 02, 2012 4:40 am    Post subject: Reply with quote

great progress !
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Sun May 06, 2012 8:27 pm    Post subject: Reply with quote

Some pics of the coolant crossover pipe,
25mm stainless pippe from front to back attaching to the larger coolant flange connection,
the small connection off the coolant flange goes to the solenoid hose input, this is a stainless unit with viton seals and a rebuildable unit. The operating temp range is 130C and have a 0 - 115 psi range, meaning it requires no preesure assistance to open the valve. It does however weigh a bit more than your stock plastic valve.
The valve comes with 1/2" connections so I used brass adaptors 3/8" on the input and 5/8" on the output to go to the firewall heater connection, the return is then plumbed to the brass adaptor just after the right angle bend.








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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Mon May 07, 2012 9:45 pm    Post subject: Reply with quote

Wow, that coolant pipe is a slick bit of engineering!!!
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88 924S SE | 82 931 Holbert | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition
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morghen  



Joined: 21 Jan 2005
Posts: 8166
Location: Romania

PostPosted: Mon May 07, 2012 10:15 pm    Post subject: Reply with quote

ideola wrote:
Wow, that coolant pipe is a slick bit of engineering!!!


+1

i'm going to copy that design..but keep the old valve
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simsport  



Joined: 06 Nov 2002
Posts: 573
Location: UK Warrington

PostPosted: Tue May 08, 2012 7:43 am    Post subject: Control Reply with quote

Hi, project is looking good. The big issue for me was how you might control the transition from blower to turbo?

Have you got a drawn plan for the installalation? I looked at one system used on a ford that ran a 'K' valve which redirected the air from the filter and throttle at set rpm and also bypassed the turbo until the ideal boost/flow was achieved after which it cycled the supercharger in a closed loop.

Very interested to understand how you aim to manage this, sorry if you have written about it already!

Cheers
Simon
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Cédric  



Joined: 27 Aug 2004
Posts: 1975
Location: Sweden

PostPosted: Tue May 08, 2012 3:27 pm    Post subject: Reply with quote

Like a vw twincharger?

Or a different setup?
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leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Tue May 08, 2012 8:35 pm    Post subject: Reply with quote

compound setup / multiplying pressure ratios, no bypass valve planned at this stage so far as switch over system..., just heat management via two intercoolers,
sc will be controlled off a rpm based trigger, the trigger point and hysterisis of the circuit can be set independently, i.e, trigger on and active bandwidth can be set, e.g on at 1100 rpm , low rpm off 3500 rpm ( for switch over circuit) or a high rpm off 7500 rpm (above rev limit) as I plan to run constant on.
below is a link to probably one of the easiest articles to explain twincharging...
http://www.articlesbase.com/automotive-articles/twincharging-concept-and-example-application-986630.html
Stu

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