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WEASEL149 · Joined: 19 Aug 2005 Posts: 595 Location: UK, Sheffield

Go for thick-walled aluminium tubing, at least for the straight parts. This soaks even more of the intake heat up through thermal mass.
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1979 UK 932

Arvidw · Posted: Mon Mar 25, 2013 11:25 pm Post subject:

Thick walled pipes are not compatible with the beat roller the welder uses

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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

WEASEL149 · Joined: 19 Aug 2005 Posts: 595 Location: UK, Sheffield

Arvidw · Posted: Mon Apr 15, 2013 4:25 am Post subject:

Worked on the IC piping today:

The ductape is for holding together 3 70mm coupers as I still have to order 200mm couplers. I think that will give sufficient flexibility for the engine to move freely.

The recirculation valve will be placed here:

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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

Arvidw · Posted: Sat May 18, 2013 6:28 am Post subject:

Time for a small update: Some of the piping has been welded, some hasn't. I made some really nice flanges for the supercharger and recirculation valve but didn't take pictures.

The recirculation valve has been modified so now it is closed at 100kPa and is completely open at around 55kPa. It used to be the other way round but fortunately it is really easy to modify this valve (used to be a mitsubishi diesel vacuum operated throttle valve)

Furthermore I took some pictures of the characteristic of the valve, it is not too bad but I would like to see it opening with around 10kPa less vacuum. Maby I'll add a little helper spring. I'm really curious how well this is going to work, I haven't seen anybody running a massive 54mm bypass valve on a post-blower supercharger setup yet. Hopefully it will give very good drivability with very low parasitic losses

Next up, piping for the recirculation valve and the idle valve.
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

leadfoot · Posted: Wed May 22, 2013 6:16 pm Post subject:

remake the cam disc and use multiple holes at set degrees to get what you're after,
probably easier to modify the return spring pressure than add a helper spring though...
Stu
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Arvidw · Posted: Fri May 24, 2013 5:04 pm Post subject:

That is indeed a good idea

I'll have to make a new cam disk anyway as the current one is aluminium and can not be tag-welded to the butterflyvalve shaft.
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

leadfoot · Posted: Sun May 26, 2013 10:52 am Post subject:

you could always drill and tap the shaft and put a bolt on the end with a spring washer, then it could be changed.
stu
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Arvidw · Posted: Thu Jun 20, 2013 6:10 pm Post subject:

Still working on the IC install. I got fed up of not being able to TIG weld so I spend some cash on a nice german AC DC tig welder. This set me back a little because I'll have to lean to tig-weld before burning holes in all the pretty aluminium pipes

Yesterday I made some brackets and welded to the intercooler (or what you would call it, it looks like shit, still learning...) . It is now solid as a rock and I think even a deer will get through it in an accident.

I have however some conserns about the airflow. I had to space the radiator to make room for the intercooler. As a consequence the air is able to pass around the radiator because it does not seal to the body anymore: (old picture, the aluminium U-profile at the bottom of the IC is gone)

I thought of two solutions, however I'm not entirely sure which is best...

I'm leaning toward the second one with the shroud covering the entire IC. Anyone idea's or input which to choose? The gap between IC and Rad is now around 50mm.
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

Second one looks dumb to me...
IIRC the optimal distance from IC to radiator is ~25mm...
i would not use any shroud..actually i dont...and guess what..its just fine.
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Supercharger and EFI kits
https://www.the924.com

Arvidw · Posted: Mon Jun 24, 2013 7:02 am Post subject:

Thanks, thats very useful advice. You just saved me some time

Yesterday I tested the flowrate of my pump and it was a bit disappointing. It only managed 1480cc/min @ 6bar while my injectors run in total 1420cc/min @ 100% duty cycle. Something had to be wrong so I replaced the fuel filter. Did some measurements before and after: (I've set my base fuel pressure to 5bar to get more flow from the injectors. Under boost the fuel pressure increases to approximately 5.7-5.8bar so that's what the pump needs to run worst case)

With the new filter fuel flow increased 36% @ 6bar to 2020cc/min. It could have been higher if the pump actually received 12.6v. I only got 10v at the pump.

Futhermore I started tagging and welding the IC piping. As I only have 2 hours of TIG welding experience it's not that good looking. Futhermore the flanges warped and I spend 30min sanding them flat on a flat plate. Next time I'm going to bolt flanges down..

Mark up:

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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

what fuel filter are you using? i need a propper one.
i only found a shitty plastic one for sale and the guy at the parts shop told me i should not run it more than 3000 km

btw, i like your engine bay

_________________
Supercharger and EFI kits
https://www.the924.com

Arvidw · Posted: Mon Jun 24, 2013 11:26 pm Post subject:

Thanks

I just bought one of ebay, I believe it was this one:

http://www.ebay.co.uk/itm/Porsche-924-2-0-1984-UFI-Fuel-Filter-04-77-04-81-/270958799668?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3f16672b34
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

flosho · Posted: Wed Jun 26, 2013 6:46 am Post subject:

Is 5-6bar of pressure acceptable to run with standard (non 'direct injection') injectors?

I've always thought it was common to run around 3bar pressure?

1420cc is a ton of fuel for our cars, I think my injectors are around 500cc.

Just curious the details on the rest of your fuel system?
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[This Space For Rent]

Grenadiers · Posted: Wed Jun 26, 2013 7:09 am Post subject:

Jason, 500cc for all four injectors, or each one? I think his 1420cc for all four of them, 355cc each I reckon.
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke