This topic has probably been asked before, but.........can MFI mechanical fuel injection throttle bodies be setup on the 14, instead of running EFI?? Saw PMOs MFI for the 911, soooo.............

Why would you want to do that when it is worse than carbs and EFI? You get the worst of both worlds with MFI.

Buying velocity stacks and runners to stick CIS injectors in them is akin to turd polishing.



The only win with CIS is the fuel atomization, CIS injectors are *great* at that and that is about it.

MFI and CIS are two different things in Porscheworld, and it appears you know little about either. Well setup MFI has HP advantages over carbs, CIS, and EFI. Right off the bat, there's more HP, you can use seriously rowdy cams, and the throttle response can be phenomenal. CIS makes the car pull like a tractor from minimal RPM to redline, but requires a relatively mild cam. EFI is cleaner, but also requires a mild cam and loses HP and torque. Carbs are dirty, inefficient, and offer poor fuel economy. Good throttle response, but they require serious tinkering to get as right as they can get, which isn't very. The Cap'n

That is great, it appears you do not understand what EFI can do.

Just how different is MFI than CIS? Both mechanical fuel injection, both garbage.


If you think "rowdy cams" are a problem, then please do explain how K20 powered honda cars run cams that are so huge and locked into vtec all the time on what is essentially a stock ECU with a map sensor? These cars run enough cam to where if I posted a video of my friends running you would think it had a giant vacuum leak. He has no problems cruising around and daily driving this car.

Because in the real world, EFI is EFI. "Rowdy cams" cause the same odd pulses in a honda or vw motor that they do in a porsche motor.

Do you think a porsche motor with cams is super special because it makes little to no vacuum?

How are you losing hp and torque with EFI? How are you metering your air and changing it for MFI?

This efi makes less power talk might have been true in the 70's or 80s but this is 2009 and cars do not come with flapper airboxes or some cruddy d-jet map sensor.


Carbs take tinkering and you get more tunability than you would out of CIS.

https://www.youtube.com/watch?v=dHVCyj4GqPo



https://www.youtube.com/watch?v=1nidxuvNoqk




EFi

To answer the original question (sheesh!), yes, you can put MFI on a six motor in a 914. I've heard it is very difficult to adjust the MFI pump in the car due to access limitations around the fan housing in the 914, but if you drill a hole or two in the firewall it's probably doable. I've only seen one 914 with MFI before (Gwen's car).

I'm pretty sure John knows what EFI can do



That may make interesting discussion on a ricer board but most people here really don't care.

The Krusty one knows his stuff! And last time I checked, no one has a V-Tec in their engine bay around here.

To the original poster, I know next to nothing about MFI, other than it looks really cool. Are you talking about trying to put it on a 4, or installing a 6 with MFI? If you're thinking about doing it on a 4, it could make an interesting project, though not sure it would really be worth it in the long run.

Cheers,

Yeah I guess the type IV and porsche motors are very special and they adhere to entirely different principles of physics. They have no vtec so obviously they cant be compared in any way what so ever with a plebeian japanese engine!



I am going to go remove the 1000cc injectors from my daily driver, and run MFI so I can have 300whp out of a 1.8l and 28mpg with a factory idle. Let's get rid of that 5 wire wideband O2 sensor as well and the ECU that samples it regularly.


I guess you guys can not learn from the "ricers" who are lightyears ahead of you guys on the tuning curve.

Silly plebeians and their pathetic appliance race cars.

To the guys who are saying you can't run EFI with rowdy/wild cams - you are wrong. I've done it (and it was even on a 914) and drivability was excellent, except for a lumpy idle that did not sound unlike the Hondas in the video above.

There are only two advantages MFI has over EFI that I can see:

1. You can use very free flowing intake systems like ITBs without worrying about MAP or MAF sensors.

2. You have a 200psi high pressure side driving the fuel injectors, which theoretically results in better fuel atomization and some free HP.

Aside from that, MFI is a bitch to tune and a compromise on anything other than the exact engine it was designed for, so most likely you could get a better tune with EFI (and more HP) on any given non-stock engine combo.

Also, to the guys who are telling the Honda guy to shut up, it might pay to have a more open mind.

I'm making an assumption here, but I think the original poster and Krusty were both referring to the original stock Fuel Injection on a 914. If that's the case, then I'm pretty sure running crazy cams doesn't work. With a true modern EFI, it's a whole different ball game.

In any case, the point of this thread was to ask if it's possible to run MFI in a 914. Honda boy seems to have gotten things off topic here. Unfortunately, I know next to nothing about MFI, so I can't give a helpful answer.

Cheers,

Deleted, so as not to offend anyone.

I'll keep my opinions to myself.

Sorry, I thought that they both meant aftermarket EFI. If you're talking about D-jet, then yes, D-jet is very limited.

And regarding MFI, I answered the original posters question above. I drove a car with MFI for years and tinkered with it constantly (because it never ran right, it had a worn out injection pump and what was likely a non stock motor). I would say that I have an above average knowledge of the MFI system.

Mark, I don't like the attitude expressed in your post. I have a lot of respect for the Captain and would have much less respect if I was forbidden to disagree with him occasionally, whether I voice it here or not.

I also don't like the hostility I see here towards people whose automotive knowledge doesn't happen to be 100% 914-centric.

It makes over 300whp daily driven on a very conservative amount of boost. I have enough fuel injector to make 600 wheel horsepower to 700whp on 93 octane pump, about 500-550whp on E85 ethanol. I average 28mpg with my foot out of it putting around.









I don't know though, since this is a simple plebeian car such as a volkswagen or an audi, it can not simply even exist in the same dimension or be subject to the same laws of thermodynamics, physics and reality as a fine auto like a Porsche.


I also guess since I used a honda oem fuel injection component on the vehicle that it has been tainted by crappy rice, and that nullifies the fact that the car makes well over 300whp and 300ftlbs at the front wheels


I would love to see these results with MFI. Oh yeah this is all done on a stock ECU as well, stock ignition coils. Just different injectors and a honda part!

*Gasp*

Ghuff, calm down. Holy crap....

That's why I bought my 911. The PO did a stellar job of modding a 2.4 MFI unit (from a T), combined it with S cams and heads (IIRC), and it makes 190 horsepower and the 40-80 acceleration (seat of the pants feel) is phenomenal for a 40 year old car.

My favorite part about my MFI car was winding it up to redline and letting off the throttle. It would make this incredible intake howl all the way back down to idle, scaring any pedestrians or other drivers in the immediate vicinity... Great fun!

No worries. If we're talking about aftermarket EFI, then yes, it's awesome. Once I rebuild my 2.0L, I'm really hoping to get some sort of EFI on it. No more crappy MPS would be wonderful!

MFI looks equally or more complicated that good ol' D-Jet to me, but at least I understand D-Jet.



Nice Volkswagen, and impressive numbers! Now throw a D-Jet FI system on there and see how it does!

OK, lets just say each system has it's own place/pro/con etc, EFI, CIS, MFI.

BUT, if you want to know what MFI can do on boost:


FYI, I will be doing an EFI conversion on my old M110 Mercedes and future 914 motors...easiest way to have a more modern fuel delivery on an old car.

Also think we lost the whole idea of the original post, I think the poster has ITB and MFI mixed up.

Ah fuck it .... I deleted my post too!

I noticed you have four posts going.

Were you able to find the answer to your question?

I am not sure you can get less restrictive period than a map sensor and a wideband o2 sensor.

Can you? 3mm internal diameter map feed and the O2 in the exhaust stream.


Can you have anti-lag and launch control, aka stuttering your ignition or somehow building boost at launch to avoid turbo lag?

I have all of that on a stock ECU. When my TPS value > 85% and the clutch switch engages as the pedal moves my ignition cuts and raw fuel is dumped into my turbine housing igniting it between shifts and keeping boost built....

The value it cuts the ignition is selectable between 50ms-1000ms so a 90 year old could use it.


Off the line I have an adjustable window to stutter my ignition to the same effect so I can leave under boost....

Can MFI do all of that?

Wow, you really hate MFI! Did it kill your dog or something??? Why so much anger? Have a

Indeed...

what if he doesn't need mfi to do all of that? He never mentioned running a turbo, so building boost at the line is pointless, unless he has a turbo, which i don't think he has mentioned.

I would gladly trade my left nut for this MFI beast.

porsche was pretty happy with MFI in the RSR

ghuff...

Dude, chill. The question was asked about MFI...

What exactly do you think MFI is? MFI is a system that was used on late 60's and early 70's Porsche and BMW models, as well as others (I think there was an MFI Vette if I recall). It is Mechanical Fuel Injection. There is no MAP sensor, to MAF sensor or otherwise. It is a metered, mechanical fuel pump that is connected -directly- to the throttle. This means careful tuning needs to be done to an MFI car as there is nothing more than the state of the tune to meter the A/F ratio. I have driven some MFI cars, and the throttle response is unlike anything else I've ever driven (and I've driven quite a lot of different cars, both in stock trim, and race trim).

A very well tuned MFI system is a joy to drive. But they're hard to tune that well.

I'm sure someone has already said this, but CIS is -not- MFI. CIS uses an airflow metering plate that is connected to the fuel pump.

EFI is great, it can be tuned to compensate for a vast array of different configurations and conditions. It is inherently more flexible of a design than MFI, but is limited in the sense that it usually requires measurement of the air in the manifold, either by vacuum (MAP), or air flow (MAF). These sensors can sometimes be fooled by uneven pulses in the intake manifold due to large amounts of overlap in the cam(s). There are some simple EFI systems that are based solely on rpm and throttle position, but they lack the flexibility of the EFI, or the immediate throttle response of the MFI.

Ghuff, you seem to be tooting your horn pretty loud about turbo and vtec cars, cool. I like turbo cars, and I like EFI for turbo cars because it's flexible enough to allow for all sorts of reconfigurations and varying boost levels.

But this topic started asking about MFI, and MFI is a very particular and unique beast.

To the original poster - yes MFI could be done. On a four, I'd say a reconfiguration of the MFI off a BMW 2002 tii would be one way to do it. Custom throttles would be needed, probably modified aftermarket ITB's.

And by the way ghuff, this board is really here to talk about 40 year old sports cars that we enjoy. It's not everyone's favorite thing, but it's ours. If you think the Hondas and VW's are superior, you may be right. They certainly have 30 to 40 years more engineering behind them. But it doesn't change how we feel about our cars. Don't like 'em? That's okay, there are a lot of cars out there I don't like either. But here, we try to keep the focus on 914's and related cars...

-Josh2

Mine's not nearly so pretty.

Mechanical fuel injection (MFI) can indeed be used with the 914-4 but will have to be a custom mod to the engine. The MFi system can be found on some 911-6 engines.

The MFI systems do provide the advantages listed by the Krusty one, but the systems are $pendy and serviced by only a few.

MFI systems use a mechanical cam system that controls the amount of fuel squirted to each injector port. In essence, the electronic brain box is replaced by a mechanical pump and regulator system that controls the duration and amount of the fuel squirt to the injectors.

Here is a link to a site describing the fun to be had with a Bosch MFI system.
http://www.pelicanparts.com/techarticles/9...MFI.htm#Setting idle mixture & throttle body maintenance

The Krusty ones information is correct but some of the information given above is wrong. For example, there are no CIS injectors on a MFI system and somebody is confusing different systems. CIS stands for constant injection system and uses injectors designed to squirt constantly. MFI stands for MECHANICAL fuel injection and uses timed controlled squirts matched to engine requirements, not constant spraying. Alfa Romeo also used a similar MFI system called the Alfa Spica system on their 4 cylinder engines. My dad's 1967 Alfa Berlina had the Alfa Spica system.

WOW........didn't realize I would get sooo hammered on this threrad!! Guess I should have asked my FRIENDLY Porsche shop. It makes it a turn-off to ask uneducated questions to engineer grads......guess I'll just throw on carbs, and try to get this post removed.

I don't think you got hammered. And, you didn't do anything wrong. It was a reasonable question. The thread just got derailed. I think if you wade through the static, you can find some tidbits of good info. At least 2 people tried to answer your question.

Don't take it personal, and don't be afraid to ask anything around here. Questions are what make this place go around. It's a friendly place! The thread got a little wonky, but just consider it entertainment.

mmmmm... do you know of a system out there (oem on another make/model or aftermarket) that could be adapted?

Don't get upset. This same thing happens when carbs Vs. fuel injection is asked.

AND I"M NOT STARTING/ASKING/OR OTHERWISE BEGINNING A THREAD ABOUT IT!

Not sure I understand the question. But the BMW 2002 tii had MFI, and it was a 4-cyl motor. I think the right person with enough knowledge of the kugelfisher fuel pumps could retune it for the 2.0l Type IV...

-Josh2

I had one and my friend that died last fall had one that is in his garage. His widow is about to put it up for sale..

karmanbuilt It will get better from here.

My 69 911S with MFI was the fastest car I've ever driven and I've owned some Bad to the Bone cars. Surprisingly the MFI system in that S never gave me 1 second of problem. Heck my ex-wife used it as her daily driver - as I had my 57 Vette + 914-6 as toys and a 16V Scirocco as my DD

T.C.

I vote for Josh as our new United Nations representative.

rich

Damn! I was ready to get into a fist fight.

Wow... Thanks... Uh... waitaminute... should I be insulted???

Sorry, I'm already a federal employee. Thanks, but I'm good...

-Josh2

Not your fault at all. You asked a reasonable question in a respectful manner.

I get the feeling that I probably can't afford it, though. Not without liquidating what's left of my 401K, anyway.

One of my customers told me that his 914-4 race car used to have Kugelfisher MFI when he was in Germany.

You nailed it.. that's what I was looking for.



Cool... so it's been done! Noted for future plans

Here's your donor car!!!

http://cgi.ebay.com/ebaymotors/1979-BMW-32...p4506.m20.l1116

-Josh2

I can't imagine that a Kugelfischer system would work very well on a type-IV without a custom space cam. It would be interesting to see if it would even run - but how would you drive the injection pump? Is Kugelfischer cam driven like Bosch MFI?

Yes ...

Looks like this discussion has happened umm..... somehwere else

The Kugelfischer system:
http://www.thetiiregister.com/pump/pump_guide_v1.pdf

The Bosch version:
http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm

If I remember right the rochester FI corvette was rated at a lower hp number than the two four factory carbs. Maximum hp and torque can always be achieved with mechanical fi or carbs but the drivability will always be easier to achieve with efi in my shade tree opinion.