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EFI Fuel Rails for late 931

 
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Bockscar  



Joined: 16 Nov 2010
Posts: 392
Location: Sandy, Oregon

PostPosted: Sat Aug 20, 2011 1:15 am    Post subject: EFI Fuel Rails for late 931 Reply with quote

After a long discussion with my cousin about EFI conversions (he has done many to old VW's), he has convinced me to convert the silly CIS injection system to mega squirt EFI. The first problem on the horizon is procuring a fuel rail.

I've seen talk on the forums about folks fabricating their own and selling them, but these discussions are very old and I'm not sure people do that anymore. I'd be surprised if there wasn't a fuel rail/system from a BMW or VW/Audi that doesn't fit. Can anyone provide any insight?
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fiat22turbo  



Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR

PostPosted: Sat Aug 20, 2011 1:28 am    Post subject: Reply with quote

Fuel rail from a Chrysler or Ford 4-cylinder has the correct port spacing. Lots of aftermarket options available for those as well.

Chrysler turbo cars have large enough injectors out of the box, so that's my preference, just stay away from OEM Neon parts as they don't have a return line on the rail.

Some just buy the blank fuel rail stock and machine it for their needs.

Some rails have regulators built-in. Make sure they are boost/vacuum referenced.

Threaded inserts need to be machine to hold the injectors.

A mounting solution is needed for the rail.

Biggest trick is getting the rail and injectors to fit under the intake tube/throttle body.

Tuning a non-turbo is not small feat. Tuning a turbo car requires a lot more caution. I would highly recommend adding a knock sensor and an intercooler to gain a little wiggle room in your tuning.

Seemed like you were so close to having it running, adding MegaSquirt will probably set you back more than a few months. Then there is the tuning.
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1979 924 Carrera GTS (clone-ish)
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Bockscar  



Joined: 16 Nov 2010
Posts: 392
Location: Sandy, Oregon

PostPosted: Sat Aug 20, 2011 1:44 am    Post subject: Reply with quote

fiat22turbo wrote:
Fuel rail from a Chrysler or Ford 4-cylinder has the correct port spacing. Lots of aftermarket options available for those as well.


Odd. I would have figured at least a VW or Audi would have something that may work considering the head is sourced from VW. I guess I could pilfer tons of fuel rails from my local pick and pull and see which ones work

fiat22turbo wrote:
Seemed like you were so close to having it running, adding MegaSquirt will probably set you back more than a few months. Then there is the tuning.


I was/am very close, but a bunch of crap suddenly happened. The fuel pump checked out while we were testing it, the holes where the AAV mounts to the intake manifold busted out while I was tightening it down, and I realized that I only put on 1 crush wash for each fuel line connectors. Given these nuances, I still have no guarantee that the stock CIS fuel system is even reliable enough to work. We just decided to tear out the outdated system and put EFI in.
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flosho  



Joined: 01 Jul 2004
Posts: 3160
Location: Eau Claire, Wisconsin

PostPosted: Sat Aug 20, 2011 2:43 am    Post subject: Reply with quote

I have an "endwrench" style one that I can sell you for relatively cheapt that I KNOW works because I've used it for 2 years.

You can also get in on the potential group buy for Ideola's aluminum version.

There is a Group Buy thread in the General forum.
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fiat22turbo  



Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR

PostPosted: Sat Aug 20, 2011 3:29 am    Post subject: Reply with quote

Bockscar wrote:
fiat22turbo wrote:
Fuel rail from a Chrysler or Ford 4-cylinder has the correct port spacing. Lots of aftermarket options available for those as well.


Odd. I would have figured at least a VW or Audi would have something that may work considering the head is sourced from VW. I guess I could pilfer tons of fuel rails from my local pick and pull and see which ones work

fiat22turbo wrote:
Seemed like you were so close to having it running, adding MegaSquirt will probably set you back more than a few months. Then there is the tuning.


I was/am very close, but a bunch of crap suddenly happened. The fuel pump checked out while we were testing it, the holes where the AAV mounts to the intake manifold busted out while I was tightening it down, and I realized that I only put on 1 crush wash for each fuel line connectors. Given these nuances, I still have no guarantee that the stock CIS fuel system is even reliable enough to work. We just decided to tear out the outdated system and put EFI in.


Engine is actually based on a Mercedes design and is closer to Audi than VW. Bore spacing doesn't match anything from VW. Chrysler (who cribbed the design of their 2.2/2.5 and subsequent 2.0/2.4L motors from VW) has a bore spacing very close to the EA831 (924 2.0L) Ford also uses a similar bore spacing.

Crush washers are cheap, pick some up and replace them. Don't sweat it.

I'm sure someone has a spare intake. I think the N/A and S1 intakes are the same? Not sure. I'm trying to remember if the AAV needs to be mounted to the intake or if it can be mounted elsewhere. If I were stuck, I would probably use JB Weld or Alumaweld rod to put the pieces together, followed by drill/tap for new threads. An afternoon's work and it would be solved.

Fuel pump is a pain, but I would check the wiring on the pump and the relay just to be sure. Or even pull the pump, clean out the inlet and bench test it. Even if it is bad, a new pump isn't the end of the world (you'd need one anyway)
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1979 924 Carrera GTS (clone-ish)
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Bockscar  



Joined: 16 Nov 2010
Posts: 392
Location: Sandy, Oregon

PostPosted: Sat Aug 20, 2011 3:47 am    Post subject: Reply with quote

fiat22turbo wrote:
Crush washers are cheap, pick some up and replace them. Don't sweat it.

I'm sure someone has a spare intake. I think the N/A and S1 intakes are the same? Not sure. I'm trying to remember if the AAV needs to be mounted to the intake or if it can be mounted elsewhere. If I were stuck, I would probably use JB Weld or Alumaweld rod to put the pieces together, followed by drill/tap for new threads. An afternoon's work and it would be solved.

Fuel pump is a pain, but I would check the wiring on the pump and the relay just to be sure. Or even pull the pump, clean out the inlet and bench test it. Even if it is bad, a new pump isn't the end of the world (you'd need one anyway)


The fuel lines are inflexible and a nightmare to work with. Drop a crush washer? Good luck getting it back. Not to mention the fuel lines look like they've seen better days. I'm not sure if I trust them.

We actually did JB Weld it but it broke again. On a 931, the AAV is located on the far end of the intake manifold, pressed right up against the firewall, damn near impossible to work with.

The rubber hose on the fuel pump was decayed and we replaced it, not a big deal at all. The unit still works, I just need to put it back in the fuel tank.

The CIS fuel system is simply a nightmare to work with. Not only is everything super cramped and tight in the engine bay, the fuel lines look like they are about to breath their last breath, I question the reliability of the fuel distro, and I still don't know the condition of the fuel injectors. It just seems like the right time to do the conversion.
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fiat22turbo  



Joined: 18 Jan 2006
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Location: Portland, OR

PostPosted: Sat Aug 20, 2011 8:11 am    Post subject: Reply with quote

Just an FYI:

The covering on the lines is just to protect the actual lines from the elements. Just because they might look ugly on the outside, doesn't mean the lines themselves are bad (thought I understand your concern, Rasta had his made from real braided hose by Oil Filter Service).

When I pulled the CIS from my car, I pulled the intake with the AAV attached and then broke the lines free. Much easier than bending over the car and destroying my back.

I had thought about putting the CIS back on until I broke a couple of CIS fittings off working on the injectors. That set my mind towards MegaSquirt. 6 years later, I've rebuilt the entire damned car and 6 months of that time has been spent getting MegaSquirt tuned well enough to have something I might consider a "car" Granted I made a metric ton worth of changes to the engine so there was a hellatious learning curve for me to tackle.

Either way, you'll be in for some work. I don't much like CIS either, but MS isn't exactly bolt-in
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Bockscar  



Joined: 16 Nov 2010
Posts: 392
Location: Sandy, Oregon

PostPosted: Sat Aug 20, 2011 8:18 am    Post subject: Reply with quote

fiat22turbo wrote:

The covering on the lines is just to protect the actual lines from the elements.


Coverings? Mine are just metal lines that are white and blotchy because of oxidation.

fiat22turbo wrote:

Either way, you'll be in for some work. I don't much like CIS either, but MS isn't exactly bolt-in


Meh, that's the fun, right? I'm a software dude so the idea of tuning the MS doesn't really bother me. It's a project car; it's suppose to be fun. CIS makes me want to kill myself. And I don't even have it running yet!
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fiat22turbo  



Joined: 18 Jan 2006
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Location: Portland, OR

PostPosted: Sat Aug 20, 2011 9:31 am    Post subject: Reply with quote

Bockscar wrote:
fiat22turbo wrote:

The covering on the lines is just to protect the actual lines from the elements.


Coverings? Mine are just metal lines that are white and blotchy because of oxidation.

fiat22turbo wrote:

Either way, you'll be in for some work. I don't much like CIS either, but MS isn't exactly bolt-in


Meh, that's the fun, right? I'm a software dude so the idea of tuning the MS doesn't really bother me. It's a project car; it's suppose to be fun. CIS makes me want to kill myself. And I don't even have it running yet!


Yeah, many of the cars came with a braided covering over the lines.

I'm a software guy as well and MS has caused its share of headaches for me so far (not too mention the muffler I blew up, among other things)

If you go that route, get TunerStudio and once you get it idling, enjoy the autotune feature of the software (provided you have realistic AFR and timing settings)
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Bockscar  



Joined: 16 Nov 2010
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Location: Sandy, Oregon

PostPosted: Fri Aug 26, 2011 12:30 pm    Post subject: Reply with quote

Hey Fiat, what do you think of this fuel rail? - http://www.cprracing.com/srt-4_neon.htm

It's for the Dodge Neon SRT 4. If it works, it likely won't have a return fuel line, but I can remedy that by simply drilling a hole for one.

Also, Flosho, I'll buy that fuel rail from you if you still have it for sale!
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flosho  



Joined: 01 Jul 2004
Posts: 3160
Location: Eau Claire, Wisconsin

PostPosted: Sat Aug 27, 2011 12:08 am    Post subject: Reply with quote

Bockscar wrote:
Hey Fiat, what do you think of this fuel rail? - http://www.cprracing.com/srt-4_neon.htm

It's for the Dodge Neon SRT 4. If it works, it likely won't have a return fuel line, but I can remedy that by simply drilling a hole for one.

Also, Flosho, I'll buy that fuel rail from you if you still have it for sale!


Sorry, been busy, will look into that this weekend. I know I have it, I want to make sure the spare one is saleable.
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Bockscar  



Joined: 16 Nov 2010
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Location: Sandy, Oregon

PostPosted: Sat Aug 27, 2011 12:11 am    Post subject: Reply with quote

flosho wrote:
Sorry, been busy, will look into that this weekend. I know I have it, I want to make sure the spare one is saleable.


Ok great! I'd rather buy from a forum member than an aftermarket parts retailer. Just send me a PM when you know!
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