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Esprit Aviation · Joined: 06 Dec 2011 Posts: 7 Location: Upstate NY

EFI conversion finished on derelict 931 that was missing nearly the entire CIS system.

Has approx. 20 hours total runtime. mostly static; and 3-5 miles of driving with no anomalies noted. Going on road soon for everyday driving.

Addition of digital wideband AFR meter will be done ASAP for feedback to those who will no doubt believe that the engine will explode, disintigrate or otherwise suffer an extraordinary death with a more modern 2.0 turbo EFI system.

Taking orders now. HaHa!!

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

Sounds cool.

I think most people on here acknowledge the benefits of EFI.
The wiring puts a lot of people off, and I think a lot of people would like to do it but find it a little daunting.

I used to love my father's old 80's Saab 900 Turbo; great car. Seems logical that most of it would graft onto a 931.

Any details/photos or a complete write-up of the conversion would be very welcome I'm sure.

I hope it goes well for you when you get it on the road in everyday driving.
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1979 UK 932

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Esprit Aviation · Joined: 06 Dec 2011 Posts: 7 Location: Upstate NY

The wiring can be rather daunting. For those out there who have no interest in the wiring aspect, once the system is proven, I may undertake such wiring modifications on as part of my business. From 'Ala carte' harness mods, to providing entire plug and play systems, one-offs, etc.

The most important aspect would be using my 931 to test each and every 'Ala carte' component or entire system before it goes out the door; providing peace of mind for both parties involved.

After completing a 1993 Toyota MR-2 N/A to turbo (stock 5SFE to JDM 3rd Gen spec 3SGTE) I have realized the value in the marketplace for someone willing to plug in and test components and modified systems regardless of the type of vehicle or desired conversion.

As time permits I will add some details and pics.

Thank you for the comments!

flosho · Posted: Sat Jan 21, 2012 12:57 pm Post subject:

Interesting to see how well it does with some street abuse. Fwiw, my car idled and ran great for 2 months.... On 2 cylinders. Never would've been able to tell.

Any 924 n/a or turbo that I everown will be converted to efi.
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[This Space For Rent]

Esprit Aviation · Joined: 06 Dec 2011 Posts: 7 Location: Upstate NY

Looking forward to driving it. Bad time of year though. My old '77 N/A that ksis now owns had the head gasket leaking between 2&3 and it ran pretty well despite the lack of power.

BTW: I have 2) blank aluminum fuel rails which will work on the 931 if the injectors are positioned low enough (as they should be). I can also obtain a price quote for machining the injector holes etc. I may put them in the classifieds soon.

flosho · Posted: Sun Jan 22, 2012 1:16 am Post subject:

Any pictures of the saab efi stuff? Pictures are required for any efi conversion on this forum

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[This Space For Rent]

leadfoot · Posted: Sun Jan 22, 2012 10:22 am Post subject:

seeing as you went to alot of trouble to get this system integrated it would be nice if you could get it dynoed to the tune, it's going to give you a far more acurate mix reading and knock sensing,
I would also have a rising rate FPR on the system to tweak it out a little...
Stu
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Esprit Aviation · Joined: 06 Dec 2011 Posts: 7 Location: Upstate NY

As soon as I can scrape the snow off and bring it inside.

The following is a short 'How to' describing the most important aspects of the conversion.

My goal:

1) Save a gutted out 931 from being crushed with an inexpensive EFI solution (plus I already had a 1992 Saab turbo parts car). The engine has approx 155 psi on all cylinders.

2) Obtain stock HP and driveability.

3) NOT spend a lifetime tuning standalone for next to no additional power.
FWIW: Saab Turbo ECUs can be chipped.

Hardware:

1) 1989-1993 Saab 900 2.0 Turbo fuel injection system. This will include the APC unit and knock sensor. For simplicity and test purposes I have set them aside for later if higher boost levels are required. Some Saabs may have a crank position sensor in lieu of a distributor to provide timing signal to ECU. These should be avoided for ease of install. The 931 uses a crank sensor; however there is no way to adjust timing even if it would provide a proper signal.

2) Cold start valve block-off plate from Saab throttle body, use it to easily delete cold start valve.

3) Porsche 944 N/A or 924s throttle position sensor. Remove stock 931 throttle body to install simply because the saab unit rotates in the opposite direction; the harness connector will plug in w/ no mods.

4) Distributor from 1988-1993 VW cab, cor, fox, golf, jetta 1.8l
bosch # 0 986 237 638 or stamped # 037 905 205K. Remove drive gear from stock 931 dist and install on vw dist.

5) Fuel rail from Dodge Neon. This is a great place to start. There are many variants with same perfect injector spacing. Pics will illustrate the chrome type I used on mine; however the rail is rather small in diameter and is a non-return type; the Saab pressure regulator can be plumbed anywhere in the pressure line; you do not need to modify the 'valve stem' end of the rail for a return line. For those of you who have to have the fancy stuff, I have two really nice aluminum extruded blanks available that will fit with proper machining and injector depth in head.

Labor:

Disclaimer: Prototyping the harness mods was very difficult. It's never been done so there are no books or reference whatsoever. Unless you really understand which wires to cut and which to keep you may be better off retaining the CIS, especially if it is operational. I may provide a service to modify and test supplied Saab harnesses if there is enough interest.

I didn't plan on doing a write-up on the forum, so I have no schematic. Once a harness is obtained, remove all covering to become familiar w/ the wires and locations. As time permits, I will Identify all wires in my system and their purpose.

More info will be forthcoming. I will be happy to start fielding questions immediately.

Cheers!

Esprit Aviation · Joined: 06 Dec 2011 Posts: 7 Location: Upstate NY

Stu,

Sorry I just missed your reply. Thanks for the suggestions. I would love to tune on a dyno, but around here they are very scarce and time is pricey.

I plan on using my wideband o2 digital AFR meter to verify mixture especially @ WOT. If I should desire an increase in power, I may adapt the Saab APC system incorporating a knock sensor. The RRFPR may be very instrumental in raising power out; however, I am also experimenting with various types of fuel injectors to achieve more efficient results, possibly negating the use of an RRFPR.

Thanks!

pierce1216 · Joined: 24 Jul 2013 Posts: 5 Location: Upstate NY

Is there any updates on this car? I'm curious about trying this conversion
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81' 924 turbo

Esprit Aviation · Joined: 06 Dec 2011 Posts: 7 Location: Upstate NY

The car was never put on the road officially but I did drive it about 30 miles and it ran perfectly. I just started it after sitting for a year and there were no issues.

I have someone interested in buying the car, but it may not happen. I would be willing to sell the entire 'turn-key' injection / ignition system.

My plan was to market these systems.

Let me know if you have any other questions or are interested in the system. Where are you located in Upstate NY? My shop, Esprit Motorsports is in Horseheads.

Lee

pierce1216 · Joined: 24 Jul 2013 Posts: 5 Location: Upstate NY

im in corning, could i stop by and check it out sometime?
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81' 924 turbo

Esprit Aviation · Joined: 06 Dec 2011 Posts: 7 Location: Upstate NY

Today is rather busy, Probably sometime next week you could stop by & hear it run.

Anyone know why the Posted times are all screwed up?