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> something other than...........
SLITS
post Jul 9 2009, 02:28 PM
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Ah fuck it .... I deleted my post too!
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RJMII
post Jul 9 2009, 02:38 PM
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QUOTE(karmanbuilt @ Jul 9 2009, 12:00 AM) *

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.............



(IMG:style_emoticons/default/welcome.png)

I noticed you have four posts going. (IMG:style_emoticons/default/smile.gif)

Were you able to find the answer to your question?
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ghuff
post Jul 9 2009, 02:45 PM
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This is certainly not what I expected down here.
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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?
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mike_the_man
post Jul 9 2009, 02:58 PM
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Wow, you really hate MFI! Did it kill your dog or something??? Why so much anger? Have a (IMG:style_emoticons/default/beer3.gif)

QUOTE(ghuff @ Jul 9 2009, 12:45 PM) *

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?
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zymurgist
post Jul 9 2009, 03:11 PM
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QUOTE(RJMII @ Jul 9 2009, 04:38 PM) *

QUOTE(karmanbuilt @ Jul 9 2009, 12:00 AM) *

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.............



(IMG:style_emoticons/default/welcome.png)

I noticed you have four posts going. (IMG:style_emoticons/default/smile.gif)

Were you able to find the answer to your question?



Indeed... (IMG:style_emoticons/default/welcome.png)
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turnaround89
post Jul 9 2009, 03:11 PM
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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.
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zymurgist
post Jul 9 2009, 03:14 PM
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I would gladly trade my left nut for this MFI beast.

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Derek Seymour
post Jul 9 2009, 03:45 PM
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porsche was pretty happy with MFI in the RSR (IMG:style_emoticons/default/confused24.gif)
(IMG:http://www.historika.com/images/parts/74_porsche_rsr_30_sl-06-rh_e01_edited56.jpg)
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jasons
post Jul 9 2009, 03:49 PM
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jhadler
post Jul 9 2009, 03:54 PM
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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
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zymurgist
post Jul 9 2009, 04:25 PM
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QUOTE(Derek Seymour @ Jul 9 2009, 05:45 PM) *

porsche was pretty happy with MFI in the RSR (IMG:style_emoticons/default/confused24.gif)
(IMG:http://www.historika.com/images/parts/74_porsche_rsr_30_sl-06-rh_e01_edited56.jpg)


(IMG:style_emoticons/default/wub.gif)

Mine's not nearly so pretty.

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Katmanken
post Jul 9 2009, 04:31 PM
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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.
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karmanbuilt
post Jul 9 2009, 05:02 PM
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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.
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jasons
post Jul 9 2009, 05:41 PM
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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.

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Rand
post Jul 9 2009, 05:46 PM
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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. (IMG:style_emoticons/default/biggrin.gif)

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Derek Seymour
post Jul 9 2009, 05:54 PM
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QUOTE(kwales @ Jul 9 2009, 03:31 PM) *

Mechanical fuel injection (MFI) can indeed be used with the 914-4 but will have to be a custom mod to the engine.


mmmmm... do you know of a system out there (oem on another make/model or aftermarket) that could be adapted?
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underthetire
post Jul 9 2009, 05:56 PM
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Don't get upset. This same thing happens when carbs Vs. fuel injection is asked. (IMG:style_emoticons/default/welcome.png)

AND I"M NOT STARTING/ASKING/OR OTHERWISE BEGINNING A THREAD ABOUT IT!
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jhadler
post Jul 9 2009, 06:47 PM
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QUOTE(Derek Seymour @ Jul 9 2009, 04:54 PM) *

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


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
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post Jul 9 2009, 07:13 PM
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QUOTE(zymurgist @ Jul 9 2009, 05:14 PM) *

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

(IMG:http://proteamcorvette.com/cars/photos/1021A.jpg)



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 (IMG:style_emoticons/default/welcome.png) 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.
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post Jul 9 2009, 07:38 PM
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I vote for Josh as our new United Nations representative.

rich
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