CIS to EFI for the 930

[tbitz]

There has been lot's of discusion in the CIS to EFI kit thread about making a conversion kit for the 930. I would like to keep that thread for the CIS to EFI for the NA 911 only, so I've started this thread for people to post their ideas and thoughts for a 930 conversion.

I will be looking at this myself, but am fairly busy with other projects at the moment.

I believe the simplest way is to machine the existing injector blocks to fit an EFI injector. The rails also need to be different from the NA kit as the fuel injectors don't sit at 90 degrees with the fuel rail. This means the pockets on the fuel rails need to be machined at an angle.

[89turbocabmike]

Originally posted by magic930
The other problem for the 930 is that the injectors are at a slight angle somewhere between 4-5 degrees, it is nearly impossible to measure this angle exactly and is part of the reason that the Pat Williams setup is expensive. My first idea is to use the "MSD 90degree Top Fuel Mounts". These would be attached to the bottom of the fuel rail allowing you to tilt them slightly to match any injector angle. The "U shape" rail would then sit sideways to point the adapters downwards
I have also invesitigated having some aluminum blocks made to replace the plastic. I have modeled the injector block in 3D with the bung built in to the design and with a known injector angle so the rail could be drilled accurately. However, these will be expensive to make unless made in large quantities... any interest?

Magic, I'd be interested in a set of the blocks. I'm planning on slowly collecting parts for the swap and these are a key peice to the puzzle. I'd agree with you that the stock ones are not worth playing with and this seems supported by the fact that no one I've seen uses them, of course most just go with the 3.2 intake!

[cowtown]

The thing that turns me off about the Carrera intake is the need for porting, and that's another engine teardown.

I can't provide the test blocks, but I'd be happy to give any measurements/data/photos/etc. for a 77 engine that anyone needs to help with developing them.

[RarlyL8]

I am interested in this - but only if you keep it simple and cheap.
Use stock parts only, such as modifying the existing injector blocks, and leave the engine as unmolested and simple as possible.

Blocks to experiment on should be easy to find. They all crack with age. Maybe a couple Pelicanhead P-mechanics could donate a set of cracked prototype fodder. It would be nearly manditory to have new blocks modified once the prototypes are perfected.

You can use the stock dizzy leaving fuel management as a stand alone. I can't imagine this would be too terribly expensive if the goal is simply improved driveability, fuel mileage, and a controlled correct air/fuel ratio throughout the RPM range.

[89turbocabmike]

RarlyL8, Magic addressed this on Tony's EFI thread so you may have missed it. I'm trying to keep with Tony's wish of keeping the NA and Turbo threads separate. Here's a recap on Magics findings:

Originally posted by magic930
I am working on the 930 injector block problem. I bored one out last weekend to 13.5mm. The brass unfortunately is not thick enough and is stepped to hold it in the plastic. You end up with stripes of brass and stripes of plastic when looking in the bored out hole. This will not be a safe way to make a seal on the injector. It will probably require a thin walled aluminum bung to work, I think standard bungs are 3/4 wide OD and there is not enough material left to bore to that diameter safely. Injector clearance may also be a problem. The maximum width of the injector body would not be able to exceed 24mm, other wise it will foul with the top edge of the injector block and bottom edge of the intake... this can be solved by using the newer Bosch type III injectors.

[tbitz]

Originally posted by RarlyL8
..... Maybe a couple Pelicanhead P-mechanics could donate a set of cracked prototype fodder. It would be nearly manditory to have new blocks modified once the prototypes are perfected.....

if anyone has a set (or just a couple) they wish to donate to the effort please send me an email.

I know MAGIC930 said he couldn't modify the existing blocks, but I've read about people doing it. I'll have to search and find out where I saw this.

[tbitz]

Here is the injector block we are talking about. I have a picture, but don't actually have one to play with.

[dean]

Originally posted by cowtown
The thing that turns me off about the Carrera intake is the need for porting, and that's another engine teardown.

I am in the process of doing an EFI conversion. I am going to use the Carrera manifold. I am not going to port the heads this year. So I will see how the huge step in the port works. I can't afford to do the porting this year. Plus it will be interesting to see what just the EFI does for my hp

[magic930]

Starting a new thread for the 930 is a great idea! Didn't mean to tread on the Megasquirt conversion process!

Here is a pic of a drilled out block, showing the strips of brass left in the plastic after boring it out to ~13.5mm (17/32). This might accept a standard Bosch injector but the seal would be questionable and a fire hazard.

[cowtown]

Can you bore it another mm then sleeve it?

[magic930]

That is the plan. I am shopping for injectors before I make any more cuts.

[beepbeep]

Hello!

EFI conversion for 930 w/o swapping out OEM intake manifold is like putting 19-inch tires on car with drum brakes.

OEM intake sucks, Period. It's squashed, flows unevenly to cylinders etc.

I suggest everyone that is converting to go for Carrera intake route. It has already injector holes and rails. Porting issue can be solved by dropping in tapered rings that make smooth transition from 38mm or whatever it is to 32mm that 930 intake uses. You could also put a rag into intake and port lightly w/o dissasembling the engine.

Unfortunately, changing to Carrera intake will involve new intercooler and/or cutting the intake so throttle points upwards.

There is no free lunch with those cars.

Other way, you could make billet aluminium injector blocks. If someone has a drawing, I can ask Mattias to look into it and start producing them.

Cheers!

[cowtown]

Beep, in theory I agree with you about the better flows, etc of the Carrera intake. But for those of us who aren't building a monster car and still want EFI, I think this would be a great compromise setup.

There are a couple guys on C2turbo.com who have gotten 350-400hp using EFI with the stock manifolds. I think the patwilliams site also has a couple dyno sheets. Flow tends to even out when it's being forced through rather than pulled through, right?

Another question for Beep: Going back to what you said about the Carrera intake with tapered rings: do you have pictures or sources of these adapters? Is this something that needs to be fabricated?

On port sizes, this is from "George Pilat" on C2Turbo. I need to dig out my Anderson Book and read up:

1978 to 1989 had the following specifications:

Intake valve 49 mm
Exhaust valve 41.5 mm

Intake port 32 mm
Exhaust port 34 mm

The 1976-77 3.0 liter 930 cars have the same size valves and intake port. The exhaust port is 36 mm, however, which is the difference.

The 1991-92 3.3 Turbo has the same size valves and intake port size. The exhaust port on these engines is 36 mm, the same as the 3.0 liter cars.

The 1994 3.6 Turbo made other changes.

Intake valve 49 mm
Exhaust valve 42.5 mm

Intake port 38 mm
Exhaust port 32 mm

[beepbeep]

Originally posted by cowtown

Another question for Beep: Going back to what you said about the Carrera intake with tapered rings: do you have pictures or sources of these adapters? Is this something that needs to be fabricated?

It needs to be fabricated but it shouldn't be too hard. Jocke has a pair of 930 heads and intake that I can check out and make drawings of.

I could manufacture a batch if there are enough byers.

[cowtown]

Dean, will you have to remove any material at all from your heads to get the 3.2 manifold on there?

Do the EFI injectors fit well in the CIS injector pockets in the heads?

[Amac]

I had a setup like your talking about, sold
it to a forum member last year.
It was a carrera intake turned 180, two stage
(12) injectors, four fuel rails, Andial intercooler,
intake to heads spacers.
The intercooler was in stock location and all
the plumbing was stock.
Replaced CIS with haltech, dyno'ed at 624hp.
This was a hot setup for a stock engin.

[RickM]

Could a modified Carrera intake be replicated by casting?

If cost was very reasonable is this a consideration?

[dean]

Originally posted by cowtown
Dean, will you have to remove any material at all from your heads to get the 3.2 manifold on there?

Do the EFI injectors fit well in the CIS injector pockets in the heads?

No I will not remove any material from the head. I was going to taper the head myself but was told that if I make the flow uneven then that will put different strain on the rods. So I will leave the porting to a pro.

The injectors fit. I don't know if it is well or not. I am sure it is not ideal but it will have to wait. I have a dog to put through collage

Dean

[cowtown]

Thanks for the info Dean. Can't wait to see how it works out.

[David]

Does anyone have dyno numbers with the only difference being the Carrera intake? With the 40mm Carrera intake, I'm concerned with bottom end power.

I'm in the planning stage of my EFI conversion. My three big decisions (in order of importance for me) are:

1) What system to use? I'm considering Motec, Autronics, and Electromotive. I'm considering Electromotive since the ignition is part of the package, but it seems like every so called expert I talk to recommends spending the money on Motec.

2) What intake manifold to use? Stock, Carrera, or custom? Stock would be cheapest, easiest and possibly best low end power, Carrera would be most expensive and best top end power, and custom would be most time consuming for me to fabricate but might offer best compromise of bottom and top end power.

3) To twin plug or not? I'm getting conflicting opinions on whether twin plugging really does much for a flat pistoned engine. I can see it on a high compression engine where the piston is splitting the combustion area in half but what is the advantage if there's an open combustion area?

A side question for item 3, what year did Porsche start twin plugging turbos, if ever, and does RUF twin plug?