924Board.org

[Bockscar]

Hello folks,

I've officially embarked on the long trecherous journey of turning my 931 CIS dinosaur into a Megasquirt EFI tiger. I've already got my hands on a fuel rail, MS1 ECU, and MS Stimulator. I am currently trolling around looking for places to buy the rest of my parts.. Which lead me to my questions..

1. Injectors! I know there have been many, many topics regarding injectors and I've spent the past hour reading about them. I've decided to buy new injectors because I don't want to muck around with cleaning and testing them. However, the one last question that I have that I don't feel confident about is, do I need the fat and short injector style or the long and skinny injector style? For example I'm looking at this set here: http://www.034motorsport.com/fuel-injection-solutions-fuel-injectors-415-cc-genesis-fuel-injector-high-impedance-p-17563.html which is very cost effective, but the injectors don't look like the EV1 Green Tops that many folks talk about (The green tops I've seen are short and skinny.) I'm also looking at these injectors which look more like what people are talking about: http://www.diyautotune.com/catalog/delphi-42-lbhr-ev1-style-fuel-injector-hiz-p-274.html

2. Sensors: Since I will be needing both a CLT and IAT sensor, I was going to buy two of these: http://www.diyautotune.com/catalog/gm-open-element-iat-sensor-with-pigtail-p-62.html . However, don't our cars come with sensors we can repurpose? I swear I remember a sensor that looks a lot like this one mounted in my intake manifold..

3. Fuel Pump: This isn't normally even addressed in most EFI conversions but I figured I'd ask because my in-tank fuel pump is currently out of commission. Does the 2nd fuel pump (the one that is directly outside the fuel tank) generate enough pressure for the EFI system? I've asked this question before and the answer was yes but a friend of mine who will be working on the project with me expressed doubts so I'd like to be reassured.

That's pretty much where I am right now. I'll be putting together the MS stuff this weekend and next weekend hopefully be putting together stuff on the car. I have a Youtube channel where I'm keeping a Vlog of everything happening but I'll also post pictures here on this thread.
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Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped

[Raceboy]

You need normal height (65 mm between O-rings) injectors and later (pencil-style) are far better in atomization etc than old type ones. Here's Bosch 415 cc ones that are cheaper than you are planning to buy: http://shop.vems.hu/catalog/bosch-injector-410cc4bar-p-125.html

You need both CLT and IAT sensors. You can find bolt-on NTC CLT sensor in your local auto parts store for around 10$ that bolts right into coolant flange in the head (back side, right next to firewall) and NTC IAT thermistor with 2kOhm nominal costs around 1 $. Though 931 has a bung in the intake piping IIRC and you could find a suitable bolt-on part there.

You don't need to to anything with your fuel pump as both of these are more than enough (stock pump in good condition is good for at least 400-450 hp. CIS uses 2-3 times higher fuel pressure than EFI, just for reference (5-6 bar vs 2-3 bar)
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[Bockscar]

[Raceboy]

Yes, but in that case I would remove the intank pump, take off the pump itself (as it's a restrictor to the fuel flow) and put the intank pump housing back.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[Bockscar]

[Euro924S2]

Hi Bockscar. +1 to all the info you've been given above. I'm running 250bhp with over spec'd 565cc injectors from a 2010 WRX imprezza with a Ford fuel rail. I'm running a constant pressure of 3 bar and i've had no trouble with inadequate fuel delivery. As for the injectors, mine are quite short nosed so I milled the injector ports in the head to drop them lower into the air stream.

Finally, are you running batch injection, or full sequential? I'm running fully sequential using a crank and cam sensor. Also, whilst you'r at it, are you binning the Dizzy and going with electronic ignotion - your already half way there once the sensors are installed... Just something to think about!!

Best of luck, John.
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UK spec '83 N/A with 931 motor with Eaton MP62 'charger @ 15psi. EFI - 565cc inj. Standalone Adaptronic ECU. 951 FMIC. Ally rad. Twin throttle. Recirc valve. Custom manifolds and CAI. 232bhp

[WEASEL149]

Hi Bockscar, which fuel rail are you using?
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1979 UK 932

[Bockscar]

[Bockscar]

Alright folks, here's a little eye candy for ya

Before:

After:

Turns out my pricey little fuel injectors fit perfectly! My Youtube channel where I will be documenting most of the journey is here - http://www.youtube.com/user/BriansProjects#p/c/38BCFECEEDEC9C43

Also, I'm a little perplexed about how the fuel lines will connect to the fuel rail. I've read that the stock fuel lines need to be disconnected from the section next to the break booster (right where the fuel filter connects). However, after the stock 'hard' lines are disconnected there, what connects them to the fuel rail, and from the FPR? Standard braided fuel line from the auto parts store? Here is the area which I am referring to:

Tomorrow, I plan on fixing the throttle body, replacing the intake manifold, and finishing placing the fuel injectors. Stay tuned!
_________________
Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped

[Rasta Monsta]

Jumping in with both feet, eh? Good for you!

Looking forward to more updates.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Scorpio]

I'm at the same stage in terms of fuel lines to efi system.. You can use an an fitting that joins straight to the hard line ( or you can use a flare or double flare tool with AN fitting) then to an AN style fuel filter or you can add an AN 6 connector to the outlet of the 924 fuel pump( with from memory M 12 or M 14 x 1.5) end... Then AN 6 fuel line to fuel rail to adjustable fuel pressure regulator to AN 4 or 6 return line, which is slightly smaller then main line... Well that how I'm doing it
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

[flosho]

There is a 5/16" feed line and a 1/4" return line.

Originally when I went EFI. I left the fuel lines alone all the way to the left side of the engine bay where they turned to rubber. If you remove the old rubber lines, there are already properly sized barbed fittings. (Keep in mind you then have high pressure fuel line going across the hottest part of the engine bay which is just above where the turbo manifold is) From there you would just need to plumb standard FUEL INJECTION HOSE. *Note: It is important to get FUEL INJECTION hose and not just rubber hose. This stuff should be about $5/foot.

The plumbing goes:

5/16" feed line to front side of fuel rail >> Then from the back side of the rail you'll need 1/4" return line to the inlet on the FPR >> From there you then plumb 1/4" fuel line to the hard return line on the car.

Depending on how you end up doing it will dictate exactly what you need.

The reason I originally left the hard lines in is because 1) The stock fuel filter could be left in place 2) Convenience.

If you want, what you should do is actually disconnect the hard lines from where they actually enter the engine bay. They can be found just to the left and below the brake booster. Remove the hard lines from there and you can then use a universal EFI fuel filter and run the lines to/from there. This is the ideal solution in my opinion. You can use whatever filter you want (and a much smaller one) as well as shorten the fuel lines considerably and keep them away from the hot parts of the engine bay.
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[This Space For Rent]

[Bockscar]

[!tom]

If your throttle body has a TPS, then it's not stock, as these cars never came with a TPS (Throttle Position Sensor).

You're likely mistaking some switches that indicate if the throttle is at idle, at WOT, or in between as a TPS.

This is quite different.
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78 924 NA
5-lug

[Bockscar]