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Porsche 924 supercharger
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morghen  



Joined: 21 Jan 2005
Posts: 7825
Location: Romania

PostPosted: Thu Dec 08, 2016 6:50 pm    Post subject: Reply with quote

chris79 wrote:
If I would like try with cis, supercharger must aspirate air from cis plate and push into intake manifold? And I have to reduce advance for avoid detonation ?
Then I think installation is simply, but I have to make oil into supercharger? And for limit air pressure without elettrics systems?


Yes, supercharger must aspirate air trough the CIS.
Yes, you have to dial a bit less advance to avoid detonation.
If you use the Toyota MR2 AW11 supercharger you don't have to plumb any oil lines as it has its own oil system integrated(quoting snakoil)
To limit air pressure mechanically you can use a larger pulley for the supercharger but I'm sure the supercharger has its integrated BOV that you can set to a fixed value quite easily.
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Raize  



Joined: 18 Sep 2013
Posts: 81
Location: UK

PostPosted: Fri Dec 09, 2016 6:21 am    Post subject: Reply with quote

Yay this thread again.

Maybe you can succeed in this project where I had to stop because of no money...

I believe the best option would be the Eaton M45 supercharger off a mercedes, like this one:
http://www.ebay.co.uk/itm/MERCEDES-BENZ-E200-W211-2004-1-8-KOMPRESSOR-RHD-SUPERCHARGER-A2710902080-/252385159602?hash=item3ac353e9b2:g:apkAAOSwBs1XMgdj

People use these M45 superchargers on MX-5s and claim up to 180-190rwhp or so, which is plenty for a 924 drivetrain.

You can see that it has an integral recirculating blowoff valve (actuated by that wire you can see in the pictures). You'd just need to hook that wire up to a pressure switch and that's a large part of the system taken care of.

Whether the whole assembly can fit down in the space where the aircon would normally be, I don't know, and it would be even more difficult on LHD cars I am sure.

The N/A CIS is not sufficient for any worthwhile power increase, you would need to look at either an EFI conversion or using a CIS fuel distributor from something with more power like a 924 turbo, or turbo volvo, and so on. I measured the injector flow on my 924 with the air plate moved to the end of its travel at 200cc/injector/minute, which is not enough for over 150hp or so.
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chris79  



Joined: 29 Jan 2014
Posts: 551
Location: milan

PostPosted: Fri Dec 09, 2016 8:24 am    Post subject: Reply with quote

Yes, I think use 931 cis , this project require no a lot of money, the only big cost is for supercharger, but it's possibile find one from destroyed car.
It may be I start soon this project.
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Porsche 924 2.0 na 125hp (1979) euro
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Alfa Romeo Spider "Duetto" 1.6 104hp (1986) euro
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chris79  



Joined: 29 Jan 2014
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PostPosted: Sat Dec 10, 2016 5:49 am    Post subject: Reply with quote

With standard 924 injectors is possibile that high pressure push them out of head?
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morghen  



Joined: 21 Jan 2005
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PostPosted: Sat Dec 10, 2016 6:20 am    Post subject: Reply with quote

do you plan to run high pressure?
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chris79  



Joined: 29 Jan 2014
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PostPosted: Sat Dec 10, 2016 6:29 am    Post subject: Reply with quote

I don't know for now how much pressure I can set, but sure is higher than aspirated air.
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Joined: 18 Sep 2013
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Location: UK

PostPosted: Sun Dec 11, 2016 3:27 am    Post subject: Reply with quote

The diameter of the injector seal is about 0.6 inches.
Therefore the area is 0.28 square inches.

F = P*A

So for each PSI of pressure, the injector will be pushed upwards by a force of 0.28 pounds.

If you can determine the minimum amount of force required to pull the injector from the head, then we can determine how much pressure can be applied before it will push the injector from the head (including a significant factor of safety, of course).

Might want to try it on a hot engine as well as a cold engine just in case it makes a big difference.



If it does turn out to be a problem, you could probably make some kind of plate that bolts down over the injectors to hold them in.
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chris79  



Joined: 29 Jan 2014
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PostPosted: Sun Dec 11, 2016 6:39 am    Post subject: Reply with quote

But if I use 931 cis, how I have to set control and system pressure, considering supercharger installation?
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Alfa Romeo Spider "Duetto" 1.6 104hp (1986) euro
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Joined: 18 Sep 2013
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PostPosted: Sun Dec 11, 2016 11:03 pm    Post subject: Reply with quote

The 931 CIS should work reasonably well without any changes to system or control pressure assuming you use a 931 WUR. The 931 WUR provided boost enrichment, unlike the N/A 924 WUR which is just a cold-start aid.
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chris79  



Joined: 29 Jan 2014
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PostPosted: Sun Dec 11, 2016 11:13 pm    Post subject: Reply with quote

I see and tested that on 924 wur it's possibile to change initial pressure and then final pressure moving position of metal inside, beating with hammer on this red point:

https://www.google.it/search?q=wur+924&client=ms-android-wiko&prmd=imsvn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiI3rPAjuzQAhWMWxQKHVyJDBIQ_AUIBygB&biw=360&bih=511#imgrc=pC0NyzxI_DBonM%3A
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Alfa Romeo Spider "Duetto" 1.6 104hp (1986) euro
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chris79  



Joined: 29 Jan 2014
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PostPosted: Mon Dec 12, 2016 5:55 am    Post subject: Reply with quote

But Mercedes e200 compressor is not too large to place instead of air conditioned in 924 engine?
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Alfa Romeo Spider "Duetto" 1.6 104hp (1986) euro
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Joined: 18 Sep 2013
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PostPosted: Tue Dec 13, 2016 11:18 pm    Post subject: Reply with quote

I don't know if it will fit or not and I'm not about to drop 100 on one just to find out.
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chris79  



Joined: 29 Jan 2014
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PostPosted: Fri Dec 23, 2016 9:26 am    Post subject: Reply with quote

I can buy eaton SLK compressor for 100 euro, I think have small size, It can go well for this project?
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Alfa Romeo Spider "Duetto" 1.6 104hp (1986) euro
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Joined: 18 Sep 2013
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PostPosted: Mon Jan 02, 2017 8:47 am    Post subject: Reply with quote

The MX-5 guys use the same Eaton M45 compressor to get up to 190 rwhp.
Google "MX5 M45 supercharger" for some info.

The only real difference for the Mercedes SLK version is the housing.

I have ABSOLUTELY NO IDEA if it will fit.
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nickthompson  



Joined: 26 Mar 2013
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PostPosted: Mon Jan 02, 2017 1:53 pm    Post subject: Reply with quote

People on this board have run the M45 successfully on their cars. You'd have to do some digging to find the post though.
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