Early car EFI conversion sources?

[lateapex911]

Ok, I'm really getting ready to take the plunge, as I haven't driven my 911 in weeks due to Webers disintegrating before my eyes.

So, i know there are sources and kits for converting to EFI. Motomotions sells a megasquirt version. Any links to threads covering this would be great. I've come up with some, but I imagine there's more.

Here's the short story:

73 E, but the engine is a non stock 2.7 built by Rick Deman of Deman Motorsports in NY. It's 9.5/1 with SSIs, Solex Cams, and a stock ignition (with a Crane optical conversion and MSD)

Currently it has the standard Weber setup, so keeping the linkage might be wise.

I know these things run into some serious change, but I'd like to keep it under 5K. I'm a decent wrench (built and maintain my ITA SCCA Mazda racecar, have built 911 engines as well,) and semi computer literate. (I prefer not to muck around with code and registry, but I'm not AOL simple either).

So, any advice, or links would be much appreciated.

(And yes, I dream about going MFI, but the costs, and the time, is daunting. I'd need heads and cams...acck)

[jpnovak]

Here's mine.

EFI Kicks A$$ - the ST goes electric

There is much information on EFI in the archives.

[Jeff Alton]

Mine is on the engine rebuild form.

Cheers

[sjf911]

You'll need a high pressure fuel system with a fuel tank return for the fuel pressure regulator which means a complete overhaul of your existing fuel delivery system. Next, you need to decide on a common plenum versus ITB's. I would think, coming from carbs with the Solex cams that ITB's would be the way to go. Next, you need to determine if your heads need modification to allow for the fuel injectors in the ITB's or appropriate spacers (do you have CIS heads?).
ITB'w will require a vacuum plenum arrangement for dampening the MAP (manifold absolute pressure) fluctuations.
A wide band O2 sensor/controller is extremely helpful for tuning (really should be mandatory) and running dual sensors is even better if your ECU will support dual tables.
ECU choices are many. I have MS-II and really like it but there are more sophisticated units (at much greater cost) that allow you to run goodies such as sequential.
You probably will want to upgrade to a crank angle sensor (toothed wheel on the crank pulley, necessary for electronic ignition) which will require at least a partial engine drop, although, the fuel plumbing will be easier with the engine and tranny out.
Then you have to decide on placement and type of the IAT (intake air temperature) sensor, "coolant" temp sensor (CHT), and idle control (IAC).
Cam angle sensor is required for sequential injection. Knock sensors can also be added.
Finally, plan on spending a lot of time tuning (probably as many hours or more than the mechanical project). I highly recommend using a local chassis dyno service. You will also need a laptop computer for self tuning.
In the end, it is really well worth the effort. It is, however, a labor of love.

[gsmith660]

http://www.bitzracing.com/

[Scott R]

Since you say it's a 2.7 I would second the Bitz kit. You really only need to source some CIS intake runners and part of an airbox, an AAR and a CIS or equivalent fuel pump. So say a used CIS setup, $200 + $1600 for the kit, and figure $150 for a pump, and you're most of the way home. Of course you need to address the fuel return line if you don't have one, like one of the other posters mentioned.

[gsmith660]

I also have an airbox and intake runners

[Halm]

Since you have Webers, why not go for PMO's? There is a lot less work with that change.

When I changed my 2.7 from Weber's to PMO's the difference was was night and day. Dyno power jumped almost 30 ponies.

[EarlyPorsche]

I owned a Porsche with PMO's and I currently have one with webers. Its a night and day difference. Webers were probably very nice in their day but unless you have them fully rebuilt and rebushed and redone completely you have almost nothing on your hands. I hate to stray off topic but I say stick with carburetors but just make them good ones. That would be either PMO's or fully redone webers built to your engines specifications. I personally think that a set of PMO's are the best option. Of course if you do go efi there is something in there to go bad on a back road, not the case with PMO's.

[sjf911]

I think the Solex cams will make a common plenum EFI conversion difficult due to the long overlap and reversion issue. You would probably need to regrind to an SC, 964 profile, or equivalent. That said, the tbitz kit is probably the easiest and least expensive option for CIS cars available. The question is, is it worth retrofitting your car to make that an option. From a cost, time, and aggravation standpoint, I think the PMO's are probably the best compromise unless you want an adventure.

[alphie]

I agree with Steve.

I had the bitz kit for a short time (on my '79). I upgraded my engine to 3.2 with DC20 cams. I got *really* tired of tuning with a laptop. Trying to get idle correct, trying to get hot start to work, trying to get high load-> low load/rpm flooding to stop.

I eventually sold the entire kit with CIS parts and bought PMOs (and upgraded the cams to DC40).

-Rob

[Scott R]

I don't know how to compare cams, however I'm running a 964 grind from Camgrinder, and high compression, my EFI is tuned perfectly for it. I have a dead steady idle, plenty of power where I need it, and good millage.

[alphie]

I agree, there are lots of success stories with the kit. But if you are having problems, they can be tough to solve. I've seen a bunch of people with those problems and struggling to get them fixed. And its not like you can bring it to the local shop for help. That was another decision in my selling the kit, lack of professional support.

[mb911]

Originally Posted by jpnovak

Here's mine.

EFI Kicks A$$ - the ST goes electric

There is much information on EFI in the archives.

this thread is by far the best and informative.. I would try that first..

[lateapex911]

Wow, thanks for the replies. Great info, and good opinions.

PMOs are probably a good consideration. I hate dicking around with jets and such, but, I imagine they'd be up and running pretty quickly after some initial tuning, and fine tuning could be done as time permits. And they look gteat. I'll admit that that's actually a concern. This car originally had MFI, and other than the big goofy air cleaner, it's a good looking set up. I'd like to keep the vintage-ish appearance of multiple stacks.

EFi has the potential of all around great performance, and looks cool to boot, and thats a good combination. PMOs are, from what I understand, nearly 3K all up. I should research that number more, but thats some serious coin for carbs, and I imagine that, when all is said and done, I'll still have cold drivability issues with them. For that money, it's tempting to look at ITBs and Megasquirt, plus, theres the spark option there as well.

Thanks for the links, very informative, I'll dig deep into them tonight!

[EarlyPorsche]

When you order the PMO's they will jet them as close as is necessary. What many people dont realize is that little jetting changes are important but not necessary at all times. The carburetor has various adjustments that will easily produce a combination that will also work. I say get the PMO's and just tell them about your engine (cams/intake/exhaust/ignition/timing) and they should be able to get you close. Then do as I did, install an O2 sensor bung into your exhaust and fine tune from there. You will get EFI tuning with none of the poor reliability they have. Only complaint I have heard of PMO's is that someone I met said they had a set that fuel just rushed out of the casting. Apparently they had some seriously rough casting that leaked. Mine were not like that and infact were very nice.

[rfuerst911sc]

I'll post another opinion on EFI. Aprox. 2 years ago I purchased a complete EFI system from Motomotions. This included TWM throttle bodies, Megasquirt ECU,all wiring harnesses,injectors,air cleaners,sensors etc. I did get it installed and running but it never ran right there was always a issue. While Mike and Souk at Motomotions were helpful in trying to troubleshoot in the end I ripped it all out and went PMO's. As a DIYer I rarely get in over my head but on this project I screwed around for a full year trying to get it to run consistantly and couldn't. I was a regular member on the Megasquirt forum and tried every trick in the book. The reason I am posting is as a DIYer if you do get in over your head local support for these systems is nada, at least that's what I found. I'll take my high tech old school PMO's anyday

[lateapex911]

Wow...just read Jamies awesome thread. First, THANKYOU, Jamie, for such a complete look into the world of EFI.

I think that going EFI is certainly an option, but....if there's one thing I know about myself, it's that my eyes and desires outstrip my time resources 10 to 1. I swim in charity events, race my car, and am adding a third floor to the house my girlfriend and I share. And she has an odd appreciation for a bedroom that remains mostly dry during a rainstorm.

PMOs are begining to look attractive. Where are they sourced from?

[alphie]

Steve Weiner of Rennsport Systems is a great source for PMO's, he comes highly recommended from the guys on this board.