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EFI Bolt On Kit
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Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2742
Location: Sydney, Australia

PostPosted: Sat Sep 17, 2005 11:02 pm    Post subject: Reply with quote

Here's an example kit from Blitz Racing using the MegaSquirt ECU http://www.bitzracing.com/products/Complete_kit/index.html

It's for the 911 but it will give an idea of what's needed.

This kit is fuel only, not fuel + ignition but then I suppose most people would be happy to just replace the CIS.
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1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

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Paul  



Joined: 02 Nov 2002
Posts: 9451
Location: Southeast Wisconsin

PostPosted: Mon Sep 19, 2005 12:25 am    Post subject: Reply with quote

That's exactly the type of kit we need for a 931! Since we need only 4 injectors, I wonder if the price would be cheaper than $1599?
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Mon Sep 19, 2005 3:30 pm    Post subject: Reply with quote

Update on the TPS throttle body, I have a measurement from the centre of the lower mounting bolt hole of the throttle body to the bottom of the TPS of 80mm/3.164". As it is, there is no way that will clear my S1 931 manifold, but it is really close on the '77 manifold that I have.

I'm going to play around with the linkage a bit and see if I can get to be a little shorter. If that fails, I'm thinking of building a simple 1/1 ratio linkage that could actuate it remotely. I'll update as I make progress...

If someone wants to measure the spacing for the 931 S2 throttle body spacing, I'll see if I can find another VAG throttle body with a TPS which will fit that. The MK3/MK4 2.0 8v throttle body looks to be about the same size with similar spaced bolts, but I need the dimension to be sure.
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'81 931 in various states of assembly
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Wed Sep 21, 2005 4:53 am    Post subject: Reply with quote

Looking at other Porsche throttle bodies, the 951 uses a square flange throttle body, and it has a throttle position sensor as well. It's quite likely that Porsche would base the 944 throttle body off the 931 series 2 body, and save the time and money of building a new one from the ground up.

Food for thought.

http://www.cannell.co.uk/images/Cannell_web/944T%2033%202.jpg

http://www.cannell.co.uk/images/Cannell_web/944T%2036%203.jpg

http://www.cannell.co.uk/images/Cannell_web/944T%2033%201.jpg

TPS is not on the manifold on these pictures, but they were the best ones that I could find...

Assuming that the casting is the same or at least that the 944 housing is based on S2 housing, an O ring in the groove around the body should be enough to seal it to the original intake pipe.
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flosho  



Joined: 01 Jul 2004
Posts: 3153
Location: Eau Claire, Wisconsin

PostPosted: Wed Sep 21, 2005 5:59 am    Post subject: Reply with quote

Paul wrote:
That's exactly the type of kit we need for a 931! Since we need only 4 injectors, I wonder if the price would be cheaper than $1599?


Thats exactly what I was thinking.. That a kit like that would probably be 2-300 dollars cheaper for our cars...
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Wed Sep 21, 2005 8:50 am    Post subject: Reply with quote

Hey Flosho, you've got an S2... ^_^

Wanna measure that throttle body? I'd almost willing to bet money that a 944 t/b will bolt up.
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-nick  



Joined: 16 Nov 2002
Posts: 2699
Location: Cambridge, MA

PostPosted: Wed Sep 21, 2005 10:01 am    Post subject: Reply with quote

I checked into using a 944 throttle body, unless the s2 931 intake manifold is very different than the s1, it isn't even close to fitting.

I can take any measurements you need, it's sitting out in the basement.

nick
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MikeDanger  



Joined: 21 Nov 2002
Posts: 495
Location: Denver

PostPosted: Fri Sep 23, 2005 6:29 am    Post subject: Reply with quote

i havent read all the replies, but ill chime in here. Im attempting to make the EFI system from a Turbo eclipse work on my 931.
the eclipse have a ton of parts and support available, Most of the parts are very cheap off ebay, ecu:$100, sensors between $10-$60, 60mm TB with all sensors i got for $30.

I i have the 450cc injectors from it (blue top), which are supposed to be good for upwards of 350hp. but i dont think they will work as this style doesnt have the o-ring seal at the bottom.
What is the formula to convert injector CC-lbs/hr??

I figure from one 2L-4cyl turbo motor to another.
it even has individual coils and wasted spark, and they even have a Conversion kit to use a GM hi flow, hotwire MAF, also it uses a Knock sensor, and a Cam angle sensor.

once i get this on figured out, ill be doing it to myother 931 and i might make a how-to on it and make some parts, like the TB adapter and the CAM sensor adapter available.
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Fri Sep 23, 2005 3:44 pm    Post subject: Reply with quote

Conversion formula is 10.5cc/min = 1lb/hr. 36lb/hr = 378cc/min, if my math is right. Then again, it has been a long day.

The S1 931 manifold uses the same throttle body as the 924 NA, which is the same housing as the MK1 Rabbit/Jetta, althouhg linkage is different. The S2 931 uses a large single blade throttle body, with a square flange. That's why I wonder if the 944 casting would fit, Porsche is known for making certain parts common among their models to save costs, the 931 wastegate being common with the 930 is an example.

If you have a 944 body that you can measure, that would be awesome!
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Sat Oct 08, 2005 9:56 am    Post subject: Reply with quote

I went to the scrap yard today, got myself the 65mm(I believe) throttle body, fuel rail complete with reg, and 6 injectors from a 90's EFI chevy 60 degree V6. I think it's a 4.3... Cost was $10. Yes, $10 canadian and it's all intact, I got the TPS, ECT and the AIT sensor as well, all the hard parts you need to convert to Megasquirt, or VEMS, or a TEC2 etc. It has a MAF attached to it, but that's most likely junk...
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Sat Oct 08, 2005 2:02 pm    Post subject: Reply with quote

Upon checking my injectors, looks like it was a Buick V6, a 3800 Series 2 that I pulled it from, injectors are rated for 18.5lb/190ccm@43psi. While they would be sized just right for a stock 924, they're not going to be up to the job for my modified 11:1 engine.

However, upon closer inspection, the throttle position sensor fits on an keyed shaft identical to the VW/Audi/924, so I'm confident I can fit the TPS directly onto the bottom of my 52mm throttle body and use it with my 931 manifold. Very cool, I'll try to post pics as I make progress.

Other interesting thing, I was only interested in the throttle body for the sensors, but there is an adaptor plate between the manifold and the throttle body, and the manifold itself is oval. I might go back and score the adaptor plate as well, and see if there is a way to easily modify the adaptor for a 924, and simply use the 65mm t/b.
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'81 931 in various states of assembly
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Sun Oct 09, 2005 11:31 am    Post subject: Reply with quote

After a little tinkering and playing around with parts, I've discovered that a you can pop a larger o-ring over the shaft of the EFI injector where the 14mm ring is supposed to sit, and it will seal perfectly against the inside groove of the injector holder. This leaves the injector's tip sitting FLUSH with the end of the holder and is completely airtight. Plug and play, boys.

The o-ring that I used were the ones that came off of the injectors in my parts car, I have no idea whether they are actually original or not. They sealed in a ring in the holder about 7mm from the very top of the holder.
The size of the o-ring is 11mm OD and 6mm ID.

Of course, this does leave the injector shrouded partially, but not all that badly. The higher the pressure you run, the better this will work.

IMO, if you're going to use EFI injectors, the best way to do it is going to be by welding bungs into the intake manifold and injecting there. This is far from bolt on though, as it requires removing the intake manifold and everything attached to it, drilling, machining, welding, etc.
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Mon Oct 10, 2005 3:31 am    Post subject: Reply with quote

Sitting pretty in it's new shoes




You can see the big groove at the top that the o-ring pops into.

http://i17.photobucket.com/albums/b96/sbcspeed/EFI/Hpim0412.jpg

http://i17.photobucket.com/albums/b96/sbcspeed/EFI/Hpim0413.jpg

This is the CIS 11mm o-ring and the EFI 10mm o-ring side by side.

http://i17.photobucket.com/albums/b96/sbcspeed/EFI/Hpim0414.jpg

http://i17.photobucket.com/albums/b96/sbcspeed/EFI/Hpim0421.jpg

http://i17.photobucket.com/albums/b96/sbcspeed/EFI/Hpim0423.jpg


Shot of the donor rail, with FPR removed.

http://i17.photobucket.com/albums/b96/sbcspeed/EFI/Hpim0428.jpg
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'81 931 in various states of assembly


Last edited by CBass on Sat Nov 26, 2005 9:43 am; edited 1 time in total
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ideola  



Joined: 01 Oct 2004
Posts: 15506
Location: Woodstock IL

PostPosted: Sat Nov 26, 2005 9:06 am    Post subject: Reply with quote

CBass, what happened to the pix???
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CBass  



Joined: 03 Nov 2002
Posts: 2807
Location: Vancouver, Canada

PostPosted: Sat Nov 26, 2005 9:38 am    Post subject: Reply with quote

I moved them to a different album, I'll edit the links so they show up again.
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