EFI on Four Banger Flathead Ford

[NathanStewart]

Big injectors for that amount of power is right whew. Sounds like it idles ok. What kind of pulse width you running at idle? What kind of AFR's? Just wondering if you had trouble keeping it in check with those bigguns. Will you be able to hit your target HP boosted or will you need to add injectors to the setup? How was the fuel run? I didn't understand the two Reg's with one being dead headed, or are you running secondary injector set up with bigs and littles injectors?

Idles at about 1ms and 12-13:1 AFR.  It bounces because of the overlap.  The tune is more or less stupid rich (10's) but the engine sounds very happy plus it's making the power we wanted.  We've had lots of problems with heat issues and pre-ignition in the past and I'd rather run it on the rich and safe side versus trying to push it for only a few extra horsepower.  The injectors have been sized to provide enough fuel to make 300hp at ~60psi of pressure and 60% duty cycle with a BSFC of 1 (for E85).  No room for secondary injectors; they've got to be perfectly positioned to only supply fuel into their respective cylinders.  If I added a second set of injectors they'd be further up the runner which would only lead back to the original problem of one cylinder stealing fuel from the other.

The second regulator is being used as a dampener and so far it appears to work very well.  

Nathan, what fuel pressure are you running? You state that you are running two regulators with one to regulate fuel pressure and the other as a dampener. I assume that you are thinking that there are pressure ripples from the fuel pump (?)Regulators make pretty poor dampeners and they certainly cannot respond at the frequency of the fuel pump output. You would be better off to run a piece of rubber hose in place of the "dampener" regulator and plug the end the added capacitance will be enough to reduce the pump ripple to almost nothing. To check what the pump ripple is you will need a high response pressure transducer probably 0 to 250 psi and a scope or laptop with soft ware to be able to read it . All of the Bosch style fuel pumps are a type of vane or gear pump so pressure ripple it at the number of vanes or gear teeth and as the pressure goes up the ripple drops because the internal leakage goes up and acts as a dampener.

 

Rex, we're running 40 psi of pressure now.  As I mentioned above, the current setup is working very well to stabilize fuel pressure and Scott is correct; I'm trying to dampen out the pulses from the injectors opening and closing.  I have a sensor in the line that's being sampled by the ECU at 125hz so I'm getting lots of data and surprisingly enough it's very smooth.  Not bad for just an idea that we tried on a whim.  I only found one or two universal aftermarket fuel pressure dampeners and realized that it's nothing more than a diaphragm and spring which is exactly what's in a fuel pressure regulator and what do you know it works.

I have the option to reference the top side of the dampener diaphragm to manifold pressure but for now it's open to atmosphere.  I'll try both way once we put the turbo on and see which way works best.  I can also adjust the spring pre-load as well.

BTW it looks like we're moving on to the 5 main crank.  Not sure if it'll just be the 5 main crank in the 3 main block or if we'll do the full girdle too.

[Rex Schimmer]

Nathan,
You almost have to reference the control side of the pressure control valve to manifold pressure in a turbo set up or it will be almost impossible to get the correct tune. The injector is an orifice and the flow through an orifice is proportional to the square root of the pressure differential, so if your fuel pressure is at 40 psi and your manifold pressure goes to 15 psi then the differential pressure will be 25 psi and the fuel flow through the injector will be reduce by about 20% and you will find that aluminum form the top of the piston is a pretty poor fuel. You certainly could set your fuel curve to compensate for this but it would only be accurate at one differential pressure. On my little 2 liter Zetec engine in my modified I reference the control pressure to the intake manifold, it is normally aspirated, and it made a big difference in the mid range drive ability,something you probably not concerned with.

Another thought is running a smaller injector at a higher pressure (dieselgek please comment here as I am sure you have probable done this) which should give you better resolution on your tune up. If you ran at 60 psi you could then run an injector that would be 22% smaller and get the same flow. I am not sure what the maximum pressure that the Bosch style pump will run at but I have ran my Bosch pump at 75 psi before and did not have a problem.

Regarding your use of a second pressure regulator as a dampener, as you said the part that does the dampening is the diaphragm in the valve, using a piece of -6 hose with a plug in the end and tee ed into the very end of the fuel rail would do the exact same thing and be cheaper and probably do a better job. That is a trick from my old hydraulic engineering days,we used this as a fix for a control problem on a 5000 psi pump, worked every time.

Rex

[NathanStewart]

Rex, I'm fully aware of the need to reference the fuel pressure regulator to manifold pressure.  I think you misread my post; I have the option of referencing the dampener to manifold pressure if needed (now it's open to atmosphere).  The fuel pressure regulator has always been referenced to manifold pressure. 

This may be my first time (or thee first time for that matter) putting EFI on a siamesed intake port four banger flathead but this ain't my first rodeo. 

[McRat]

Just curious.  Why didn't you go direct injection?  It's been available at junkyards for 4-cyl turbos for a few years now.

[dieselgeek]

Just curious.  Why didn't you go direct injection?  It's been available at junkyards for 4-cyl turbos for a few years now.

DI requires a ridiculous amount of testing and development of chamber & piston design.   For basically no reward, you end up spending a million bucks...   there are a ton of other problems with it as well.  DI fuel injection systems, like your diesel, rely more on fuel pressure management than pulsewidth management for fuel quantity.  Developing that, and the electronics to control it, is prohibitive, especially when the reward is "better emissions during warmup" or similar OEM goals.

DI really isn't on the radar for hotrod gas engines any time soon, unless you're Katech or a Formula One team.

[NathanStewart]

Scott hit it on the head.  Entirely prohibitive for something of this level.

[dieselgeek]

Nate are you using an Infinity system on this engine?   or Series II or I?

[NathanStewart]

EMS-4 which is based on the Series 2 platform.  FWIW the Infinity is slated to do DI.  I might step up to the Infinity once we go boosted because of its additional capabilities over the existing platform but for now the EMS-4 works great.

[dieselgeek]

just making sure you don't get to use an Infinity too much before us lowlifes here in the midwest

can't wait to get my hands on one,

-Scott

[Rex Schimmer]

Nathan,
Really sounds like you have a handle on this thing, I don't know if you are the first guy to do the electronic injection on a two port head especially with your design to get all of the fuel into each cylinder specifically when the intake valve event is happening but in I know some 3 port GMC guys that are sure interested in what you are doing. Can't wait to  see what it does with the hair dryer on it.

Rex

[NathanStewart]

No ports in my head Rex.  It's a frathead, remember?   

There's a group in the UK that's been using their own custom EFI on 5 port (two intakes, 3 exhaust) Mini's and honestly they were the genesis behind this whole idea.  I've yet to come across another two port, four cylinder flathead with sequential EFI.  Not sayin, just sayin'. 

[dieselgeek]

No ports in my head Rex.  It's a frathead, remember?   

There's a group in the UK that's been using their own custom EFI on 5 port (two intakes, 3 exhaust) Mini's and honestly they were the genesis behind this whole idea.  I've yet to come across another two port, four cylinder flathead with sequential EFI.  Not sayin, just sayin'. 

Are those the guys using megasquirt/microsquirt?  Lots of guys using it in the UK on mini engines, must be them.   http://www.jbperf.com/sequential/index.html

[dieselgeek]

"There are 2 injection modes specifically designed for siamese-port engines such as the A-series engine of the classic Mini and the B-series engine of the MGB. Since these engines have 2 intake ports for a 4-cylinder engine with the cylinders paired having 180 and 540 crankshaft degrees between the firing events, there is a need to have injection timed in a very specific manner and two modes are provided to do semi-sequential injection which does not require a cam sensor and full sequential injection which requires a cam sensor. More information on the peculiarities of port injecting a siamese-port engine can be found here."

[4-barrel Mike]

Nathan:

Do you know what they're running on the Matrix Machine?  I was under the impression that it has efi.   

Mike

[NathanStewart]

Are those the guys using megasquirt/microsquirt?  Lots of guys using it in the UK on mini engines, must be them.   http://www.jbperf.com/sequential/index.html

Nah, these guys: http://www.canems.co.uk/siameseports.php

Mike, Joel's T has 4 intake ports.  Very trick motor.