Mexi-Beetle EFI injectors

[madoski]

Hi,
I'm getting ready to put a Mexican EFI onto an 1835 (1969 Ghia)....first experience with EFI and I just want to become familiar with its workings before I graduate to turbo-EFI. What I have is pretty much everything thrown into a box except for ECU, and injectors and rails. I'm not sure what works and what doesn't (I think I may need to buy a new intake air temp sensor), but I'm planning on buying a Megasquirt ECU (MS1 with 2.2 board...I hope I can use the Digifant harness with it) and I already have an EDIS crank trigger ignition to replace the distributor.

My question is, what injectors and rails can I use with this system? I don't know if something from a Golf or Jetta would be interchangeable or not. I'm sure I could get the MS to talk to them, but just not sure what would fit the injector ports, and what rails I need to hold them in. I see a lot of used injectors for sale online. I'll probably have more questions as I get further into this...but it's something I've wanted to do for years, and the time is right!

Edit #1...Was just reading the thread below mine and was reminded that I'm going to need an O2 sensor as well (wideband I guess).
My goal is not to make a ton of power with this engine, just get it running reliably and make at least as much power as it would with my Kadrons, and knowing my way around the system, how to troubleshoot, set up fuel/spark curves, what I need to do to get a clean installation on the next go-around, etc. I live at 4k feet altitude, and I'm hoping that the MS will tell my engine how to run up here, and then adjust on its own when I drive down to where I work.

[Piledriver]

Welcome to the STF!

Make sure that when you order your MS setup you have the bits to do dual MAP sensors.

(one is just for altitude compensation) or get one with a MAP-Daddy or such with it built in.
I'm not personally familiar with how the MAP-Daddy setup works, but I use the dual std sensors, haven't really had a use for it to date, but you will.

As to ignition, The most common setups will use a 36-1 wheel behind the crank pulley and a VR sensor, although there are other possibilities. I personally found the LS2 coil setup to be very easy and it reduced the noise issues to non-issues.

The Mexican manifolds take some oddball sized (physically) injectors, choice basically is to either find some or make adapters, the std injectors have relatively huge manifold ends, it has been suggested just to drill/tap the manifolds for an aluminum or brass pipe plug and modify the plug to be the injector seating surface.

Fuel rails will also be ~custom or Vanagon-ish (barb type w/hoses) depending on what injectors you use, you have to get the injector spacing and aim right, straight in may or may not be ideal--- the factory probably knew best there.

How you hold down the rails or injectors depends too much on what injectors you use to guess... It's really NOT that hard to make something that works properly if you have any fabrication skill/tools etc. (Making it look trick may require $ and or thought)

If you adapt to "standard" injectors, and make rails, you will have a wide range of injectors to choose from.. you need ~14-19 lb by the book, although you can probably go larger with modern injectors (EV6 or similar off motorcycles, mine work out to ~24ish lb, from a Yamaha R1-motored jet ski, my max duty cycle on an 1800 (sort of stockish T4) is ~30%, but it idles fine and gets ~30 MPG pushing a squareback. Plenty of headroom for the originally planned motor perhaps with some boost.
(I threw together a scrape the floor motor to "sacrifice" to learning to tune MS... tuned out it liked it)

[mcmscott]

A run a 1904 with mexican injection, ecm and all. You can use just about any Bosch type injector, you just have to use the mexican injector seals or simmular. They look like t-3 seals however are not. I use injectors from a 5 liter ford, non ho

[madoski]

Thanks, for the welcome...

Now I'm a bit confused, do I need to go the pipe plug route and fab some adaptors, or will anything from Bosch be close enough as long as I have the Mexibeetle seals? I'm going to ask a really stupid question....it seems like it would be logical for the injectors to screw in to the manifolds like spark plugs, but I gather that they don't. So why not? I assume that the rails clamp them in/onto the manifolds and have to provide enough clamping force to seat them into the manifolds. I don't have a lathe, drill press, etc, so I need to keep the fab work to a minimum....in fact, I'm pretty close to having to rely on a tree stump in the backyard for my workbench. I've worked in machine shops and have nothing against doing some fab work, just very limited on space and tools here. Whatever I do, I have to be pretty creative about it, or just go with bolt on.

....oh, and won't the ambient altitude (or density altitude) show up on whatever MAP I have in the MS unit? I'm not sure I understand why I need two....i.e. if it's hot and dry enough down in Bakersfield (about 100 ft above sea level) that what my engine sees looks like 3000 ft. on a cool day then I want the fuel and spark to look at what's getting pulled into the manifold and the result with the wideband adjust accordingly, am I missing something? I'm getting a used unit, so I'm kind of stuck with whatever's in it...just want something to cut my teeth on!

[madoski]

...so I was reading some MS forums, and convinced myself I need two MAPs for whatever reason (still don't quite understand, maybe something to do with telling the engine true elevation above sea level, still not sure why it should care..maybe something to do with resolution or range of the MAP sensors...), and then I came across this:

http://www.msextra.com/doc/ms1extra/MS_ ... tm#conbaro

...great, I may not have to solder after all, but it leads to the question, how can I set up my car to run "Alpha-n", and should I....what's the difference between it and "hybrid alpha-n"?


EDIT:
did some more digging and found this...http://www.msextra.com/doc/ms1extra/MS_ ... htm#alphan
...interesting, I'm going to have to read through this a few more times before it sinks in!

[Piledriver]

The short reason for the separate sensors:

Resets and continuous correction.

The std MS code takes a altitude reference sample at power on from the single MAP sensor.
This might cause some issues if the system gets a reset and decides to take a sample at 3000 RPM and 45 MAP.
The separate sensor is reset-proof-ing.

Also, if you fire up your car and then climb a few thousand feet, there will be no altitude correction updates until you park it and turn it off.
(The std altitude compensation only happens at turn on/reset... The separate sensor makes it continuous)

If you feel like using an AFM or Ford MAF sensor it works automagically, as those are both mass airflow measuring devices.
The second MAP sensor is cheap and the code is well proven. YMMV.

[vwgillybilly]

If you look at my thread below I've asked similar questions regarding the injectors & I'll share my findings with you. The site below & the guy who did the build were helpful.....

http://www.latebay.co.uk/index.asp?page ... bPages\EFI and Turbo\SubPages\Parts

There are several types of Bosch injector which fit, however you must use the Mexi seals, as the guy in the link above did. Obviously the closer you can size your injectors from the donor car the beter they will work. The guy in the thread above built a 1955 motor & used Saab 2.0 Turbo injectors.

I will be sticking with a 1600 for now so I plan to use something like these below.....

http://cgi.ebay.co.uk/ESCORT-FIESTA-RS- ... 2a1173d24f

They're from a 1600 Ford RS Turbo & probably allow a bit of scope for tuning.

Thank goodness for the Ford RS Turbos & Renault 5 Turbos as they're a great source of parts & ideas for DIY builders here in Europe!

Gill.

[Jadewombat]

I used Mexi-end castings on my bus T1 engine, I used an older set of Bosch injectors with my injection (not running MS currently) but I also had a set of VR6 injectors laying around and remember fitting them just for kicks and they seemed to work with the manifolds and fuel rails no problem.

[madoski]

(Injector sizing question is for the most part resolved, thanks very much everyone!)

Ok, so I guess what I was thinking would "do it all" was a MAF and not a MAP...starting to come clear now (thanks for the education!!!), pressure alone doesn't give the computer all it needs to determine what's going on with the engine (duh)! Simple fluid mechanics I suppose.

My question remains, can I run alpha-n mode and just use the TPS and RPM signals (along with target AF ratio) and leave the MAP sensor alone to make the constant barometric correction? It sounds like it could be simpler, but on the other hand, they're saying that it won't work with a turbo, which is what I want to do eventually...

[mach4]

You're asking a lot of the same questions I did as I embarked on my as yet unfinished Mexican FI - Megasquirt project. A lot of my ongoing research I cataloged online and which can be found at the research page. I've subsequently abandoned the VW throttle body component of the system in favor of an Escort one, but am using the rest of the Mexican intake system including the end castings, fuel rails, etc.

These are research notes, not necessarily solutions, so use accordingly.

[vwgillybilly]

That's quality mach4 and definitely a useful guide for people new to EFI like myself.

Thanks.