MFI for a Type 4, Any interst? Options

[Dr Evil]

I have been brain storming again and think that I may have found a feasable MFI pump for our beloved TIV 4cyl.

Any interest?

[Mueller]

would it happen to be made by MSD???

Brand new MFI assembly...slick (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

(IMG:http://www.msdignition.com/2005/images/Mech-Fuel-A.jpg)


(IMG:http://www.msdignition.com/2005/images/MFI-Pump.jpg)

[ClayPerrine]

That would be somewhat simple. Get one from a BMW 2002 Tii. They were MFI on a 4 cylinder, and the space cam should come close to what is needed for the type IV.

Mount it where the AC compressor is mounted. Install a cogged gear behind the fan.

Run the throttle cable to the pump and links from there to the butterflys.


I looked into this years ago, before I decided on a /6.


Finding the MFI pump is the problem. The BMW guys don't like to part with them.

[Dave_Darling]

Ron Mistak in Sandy Eggo has MFI on his four-cylinder race car (#22). Or had, several years back. It was pretty neat--I think it may have had slide valve throttles; the MFI "injectors" were right at the top of the velocity stacks--no filters. Looked trick as hell, but didn't run very well during the time I saw it. Had some "traditional" 914 problems (vacuum leaks, throttle linkage issues) so it wasn't running full-song.

--DD

[redshift]

Clay, you remind me of someone...

[lapuwali]

And they cost something like $1500-2000 to rebuild, and if the space cam isn't right NO ONE can help you fabricate a new one.

The pumps from '69 to '79 US Alfa Romeos would be cheaper and more plentiful, and there are versions with space cam suited to 1.8 and 2.0 engines. The main problem here is they have a huge port on the back that's meant to be open to the oil system on the block, which would require fabricating a plate with an oil feed and a return. Again, no help if there's any issues with tuning the space cam.

I like MFI a lot, but it does have some serious shortcomings (like they're all just alpha-N systems, with no load sensing). Now, marrying an MFI pump with full electronic control I'd find VERY interesting. Super high pressure injection for excellent vaporization with no problems handling full sequential injection under all loads. All you need to find is a fast actuator that can position itself to, oh, about 0.005", and can sweep through maybe 0.050" in under 1ms (rough guesses). The rest is easy.

[ArtechnikA]

QUOTE (lapuwali @ Jun 22 2005, 08:58 PM)

...marrying an MFI pump with full electronic control I'd find VERY interesting. Super high pressure injection for excellent vaporization with no problems handling full sequential injection under all loads.

sounds like VW TDI 'pumpe-deuse' system.

3000 Bar, computer controlled...

Formula Atlantic and SuperVee ran MFI.

the problem with crankshaft drive is that the pump is timed to the cam, so you'd need a crank drive cog with half the circumferance of the pump drive gear - putting the big gear on the pump could make it interesting to package.

[lapuwali]

QUOTE (ArtechnikA @ Jun 22 2005, 05:38 PM)

QUOTE (lapuwali @ Jun 22 2005, 08:58 PM) ...marrying an MFI pump with full electronic control I'd find VERY interesting.  Super high pressure injection for excellent vaporization with no problems handling full sequential injection under all loads. sounds like VW TDI 'pumpe-deuse' system. 3000 Bar, computer controlled... Formula Atlantic and SuperVee ran MFI. the problem with crankshaft drive is that the pump is timed to the cam, so you'd need a crank drive cog with half the circumferance of the pump drive gear - putting the big gear on the pump could make it interesting to package.

Crank drive is exactly what Alfa did with their pumps. They operate at "only" 1000psi. 3000 Bar sounds very high. That's 43,500psi, which is getting up into the tensile strength of some common materials (over that of aluminum). Sure you didn't mean 300 bar, or 3000psi? Common-rail diesel systems (aka EFI for diesel) are running about 20,000psi, which is still pretty damned high.

[ArtechnikA]

QUOTE (lapuwali @ Jun 22 2005, 10:35 PM)

3000 Bar sounds very high. That's 43,500psi, which is getting up into the tensile strength of some common materials (over that of aluminum). Sure you didn't mean 300 bar, or 3000psi? Common-rail diesel systems (aka EFI for diesel) are running about 20,000psi, which is still pretty damned high.

the first search i did mentioned "2000-3000 Bar" but

This Article quotes "only" 2050 Bar. i think the tuners are pushing that up a bit...

Pumpe Düse is the step beyond common-rail...

[Thorshammer]

The pumps are Kugelfisher and they aren't that hard to find. I did do one of these about 20 years ago, but it was on a type 1. The cams weren't really that difficult, and at that time were several (probably all dead now) people that could do them. One of the best projects I ever did, was converting a TII pump for use on my 13B rotary MG Midget. Now that was fun. Did not start for shit, but once it was warm, it hauled ass. Then there was the tapered roller bearings for the eccentric shaft Blah , blah, blah.... As for Mechanical injection, I bet after you bought a mech pump, and spent the time to get it right, you would spend more than a basic electronic system.

Erik M

[ClayPerrine]

QUOTE (redshift @ Jun 22 2005, 06:53 PM)

Clay, you remind me of someone...

Naaaa....

No mullett. And I don't carry a Swiss Army Knife.

[avendlerdp]

THe Alfa pump would be the low buck way to go due it's availability. There where only small changes in the space cam over the years with the '74 2.0 one being the best for Alfa performance. The oiling thing is easy to solve too. Just make a cover for the port in the side and fill the pump with oil. The oil barely circulates with the rest of the engine in the stock set up so I bet if you just changed it when you changes the engine oil there would never be an issue. It you wanted you could just have a high pressure line with a very small restrictor go the the pump and a drainback line. The pumps are very adjustable if you know how. There is a company called Wes Ingrham Inc. that rebuilds the pumps and can make custom cams etc.

I have a V8 though so don't ask me. (IMG:http://www.914world.com/bbs2/html/emoticons/aktion035.gif)

[lapuwali]

QUOTE (avendlerdp @ Jun 22 2005, 08:52 PM)

THe Alfa pump would be the low buck way to go due it's availability. There where only small changes in the space cam over the years with the '74 2.0 one being the best for Alfa performance. The oiling thing is easy to solve too. Just make a cover for the port in the side and fill the pump with oil. The oil barely circulates with the rest of the engine in the stock set up so I bet if you just changed it when you changes the engine oil there would never be an issue. It you wanted you could just have a high pressure line with a very small restrictor go the the pump and a drainback line. The pumps are very adjustable if you know how. There is a company called Wes Ingrham Inc. that rebuilds the pumps and can make custom cams etc. I have a V8 though so don't ask me. (IMG:http://www.914world.com/bbs2/html/emoticons/aktion035.gif)

I didn't know Wes could make new cams...Hmm.

No reason you couldn't do MFI with a V8. Alfa did with the Montreal. Two 4-cylinder pumps end to end, with only one logic section.

MFI, electronic or no, would be more expensive than an EFI system (and you don't really have to rebuild anything regularly on the EFI), but it has a number of inherent advantages. EFI has a really hard time doing sequential at anything over a 40% load or thereabouts, unless you use multiple injectors per cylinder and stage them. Vaporization is better with MFI just from the higher pressures involved. Since all gas MFI systems have just been modified diesel systems, and diesel is nearly always direct injection into the cylinder, you can make MFI into gasoline direct injection relatively easily. This brings a number of advantages in operating at the edges of the envelope, and can bring big gains in emissions while retaining wild valve timing.

[Dr Evil]

Ha! I knew that I would get the brains smoking on that one. i currently own a 4 cyl Diesel MFI Mercedes 240D. It has a 4cyl pump and they are stupid easy to find in the junk yards. My favoite shop here in SD (Mototrworks) redoes them for less than probably anyone. You can get gears made if you want. THe resources are out there. It was just a flickering thought that I had.

[ClayPerrine]

The problem with using a diesel pump is that a diesel engine will run with a wider variation in mixture. A diesel doesn't need the thermostat or altitude compensator that is on the gasoline version of the pump. The whole concept behind a diesel is that it injects the absolute leanest mixture possible to keep running. That's why most diesels dont' have a butterfly in the intake runners. Just limit the fuel, and it won't accellerate. With a gasoline motor, you have to stay real close to stociometric to get the engine to run without either burning the motor up due to a too lean condition or flooding the motor and washing the oil out with a too rich condition. Even with the Bosch MFI on the 911, the oil change interval has to be very low due to the oil getting contaminated with gasoline.

My thought is to keep the actual injection portion of the pump, but make an electronic control unit to do all the warmup, altitude compensation, and add an O2 sensor to allow it more accurate mixture control. I was thinking a megasquirt modified to run a servo that moves the control rack on the MFI pump.


Thoughts still wandering around my brain, but no forward progress. Maybe after I get my 914 on the road.

[ArtechnikA]

QUOTE (ClayPerrine @ Jun 23 2005, 08:54 AM)

My thought is to keep the actual injection portion of the pump, but make an electronic control unit to do all the warmup, altitude compensation, and add an O2 sensor to allow it more accurate mixture control.

have a look at how the TDI works.

very sophisticated electronic control, excellent efficiency, good emissions.
(boost control built in...)

the guys at TDIClub are really up on this stuff.

chances are what you need adready exists.

[rick 918-S]

What about a CIS instead off a Jetta or Golf?

4 cylinders appoximately 1.7 to 2.0, tons of them made and laying in Pick and Pulls all over the country. Volvo's too. I have a High Pressure electric fuel pump and accumulator off a Volvo running my 928 motor. Could this be an option?

[nein14]

Bosch CIS MFI for 78' thru 84' VW GTI's is a proven inexpensive system . It is extremely relable and parts are plentyful.
That's what is on my 914 Turbo GT. (IMG:http://www.914world.com/bbs2/html/emoticons/aktion035.gif)

[ClayPerrine]

QUOTE (rick 918-S @ Jun 23 2005, 07:08 AM)

What about a CIS instead off a Jetta or Golf? 4 cylinders appoximately 1.7 to 2.0, tons of them made and laying in Pick and Pulls all over the country. Volvo's too. I have a High Pressure electric fuel pump and accumulator off a Volvo running my 928 motor. Could this be an option?

CIS is not the same thing as MFI. CIS is a continuous spray of fuel into the intake runners even when the valves are closed. If you want to see what I am talking about, take one injector out of your car, turn the fuel pump on and lift the airflow flap. You will see that injector (and the other 7 that you can't see) spraying fuel like a fire hose.

MFI is different. It uses a camshaft like an engine cam to spray a high pressure stream of fuel into the cylinder when the valve is open. It is a true sequential injection. It will make more power than a CIS engine, and it doesn't have the drawbacks of the air flow meter flap in the air stream. A CIS engine cannot use and engine camshaft with a radical profile. The flap will ossilate (SP) at low RPMs and cause the mixture control to freak out. MFI doesn't have an air flow measurement, so it doesn't care if the cam has a lot of overlap.

[ClayPerrine]

QUOTE (ArtechnikA @ Jun 23 2005, 07:00 AM)

QUOTE (ClayPerrine @ Jun 23 2005, 08:54 AM) My thought is to keep the actual injection portion of the pump, but make an electronic control unit to do all the warmup, altitude compensation, and add an O2 sensor to allow it more accurate mixture control. have a look at how the TDI works. very sophisticated electronic control, excellent efficiency, good emissions. (boost control built in...) the guys at TDIClub are really up on this stuff. chances are what you need adready exists.

The VW TDI is a great design. But I don't think adapting a Diesel injection is the right thing. The TDI uses a small shot of fuel to set off the fuel burn in the cylinder before it injects the main charge of fuel. Plus, it's direct injection. I don't think that would work too well on an air cooled engine. We just can't control the engine temp well enough.


My thought was to retain the factory 911 pump, and make it Look like it's completely stock. I just want to improve the efficency of the MFI system. Reomve all the mechanical controls in the front of the pump, install a crank angle sensor, a tps, a servo to drive the control rack, and any other sensors necessary for the proper operation of the injection. Then run a discrete wire harness out of the pump to a programmable ECU. The advantage is that you retain the MFI's high pressure injection, and the apperance of the factory MFI system. But you get the advantages of the programmable computer controlling it.

This would allow the owner to hook up a laptop, and adjust the virtual space cam on the pump. Adding the O2 sensor also allows the ECU to adjust the mixture for more effeciency on the fly. It's still an Alpha-N system and not a speed density or afm system, so it will never be as effecient as a true EFI system. But a true EFI system will not match the MFI for pure power output. And a EFI system running through one throttle body will never Sound like the 6 MFI stacks when the engine is at full song!


BTW.. CIS is Great for Turbo motors. A turbo motor does not need, and cannot use the cam overlap that a high strung normally aspirated motor thrives on. They are different engineering approaches, and each works great for what it's designed for.

I am not trying to reinvent the wheel. I am just trying to make it better.