Fuel Injector Booster aka Frequency Valve

[BoxsterGT]

Since the Andial 930 CIS Fuel Booster (shown on the Rt) is now over $600 and by this time may even be NLA, I was asked if I could build a substitute using a standard Bosch Fuel Injector.

Here is what I am working on presently....



It is a housing to retain this standard Bosch Fuel Injector along with Injector End caps that are sealed by the injector O-Ring and allow Fuel Hose to tie in to the standard fuel system.

This will provide additional fuel when under Boost or heavy load/acceleration. Of course hoses/lines will be made up to match whatever system this will tie in with.

I welcome comments as we proceed with this project.

Len.Cummings at verizon.net

[Reanimotion]

Pretty cool Len
add a pressure sensor to the banjo fitting on the inlet side and you have a basic eWUR with feedback

feel free to crosspost into the FrankenCIS thread if you like

[reclino]

A couple of questions.
How large does the fuel injector need to be to flow enough fuel in this application.
I thought I remembered there were some problems with "common" fuel injectors operating at CIS pressure?

[BoxsterGT]

Perhaps someone can add their expertise to this thread. I do not know myself.

Higher fuel pressures means more fuel delivery, so a smaller injector could be used I expect. The Bosch style injector offers lots of choices.

This housing assy brings an option for more fuel when needed.

The electronic control is what makes the mixture correct.

Len

[Reanimotion]

Bosch specs for the original frequency valve 0 280 150 300
242cc @ 4.7 bar (supposedly 190-200 @ 3 bar)
the Andial injector was around 50% larger flow from memory

Injector type is going to be the main issue with CIS pressures
Control pressure on CIS is around 70 psi and can be upwards of 90 psi on the 930 Turbo setups
the chosen injector needs to be strong enough to open at full control pressure
Design also comes into play, Pintle vs Disc, the pintle style is generally able to operate at higher pressures.

[flightlead404]

Originally Posted by Reanimotion

Bosch specs for the original frequency valve 0 280 150 300
242cc @ 4.7 bar (supposedly 190-200 @ 3 bar)
the Andial injector was around 50% larger flow from memory

Injector type is going to be the main issue with CIS pressures
Control pressure on CIS is around 70 psi and can be upwards of 90 psi on the 930 Turbo setups
the chosen injector needs to be strong enough to open at full control pressure
Design also comes into play, Pintle vs Disc, the pintle style is generally able to operate at higher pressures.

365 kPa or 3.65 bar or 53 psi is the spec for warm control pressure on the '86 US 930.

From what I can glean typical EFI fuel pressures are in the 40-80 range, so 53 is more or less in the lower end of that range.

[GJF]

Just run a additional injector controller and add what ever injector you want.........

[Alan L]

Can someone explain how this worked? A 7th injector? Down the throat like the CSV?
Mounted where?
operated by what system?
Thanks
Alan

[GJF]

CIS has a limit as to how much fuel it can supply the engine. So.. Andial added a fuel injector but connected it to the factory harness to give the engine more fuel.
Now jump outside the Porsche world, HKS and several other companies make up a device for cars already equipped with EFI or carburetor, to control a added additional injector (AIC). These devices have the ability to be set to turn on by set parameters to deliver specific amounts of fuel at a given time to supply the correct enrichment that the factory fuel system is capable of providing. It was developed when factory EFI systems couldn’t be tuned easily like today. Back then you had custom e prom chips that could be swapped to enhance performance. The AIC was a way to really crank up boost safely without going to a standalone EFI system. In the Porsche world Andial, Miller/Woods did the same thing before everyone else, only they did their enrichment devices using mostly factory parts. In the aftermarket world a lot of companies built their own variations based off what the Porsche tuners did but using parts outside all marquess. Back to the AIC, you would simply weld in a bung in the charge line right before the throttle body. Select a given injector based off the engines needed enrichment requirements, and plumb it for fuel. The AIC typically can be controlled by boost so a MAP sensor will be needed as a trigger. Connect the controller to the injector and triggering sensors, set the parameters as to when it needs to turn on and off. Adding more fuel when it is wanted. A simple way to enrich without converting to EFI.

[gsxrken]

Thanks for the tech, G. I’ve heard of the ANDIAL enrichment but not how they worked. I can’t imagine the normally air-only pancake manifold would deliver a very uniform amount of atomized fuel to each cylinder, but it was undoubtedly better than nothing for the guys in the 1980s. That and the Dial-a-Death knob. Old School.

Originally Posted by GJF

CIS has a limit as to how much fuel it can supply the engine. So.. Andial added a fuel injector but connected it to the factory harness to give the engine more fuel.
Now jump outside the Porsche world, HKS and several other companies make up a device for cars already equipped with EFI or carburetor, to control a added additional injector (AIC). These devices have the ability to be set to turn on by set parameters to deliver specific amounts of fuel at a given time to supply the correct enrichment that the factory fuel system is capable of providing. It was developed when factory EFI systems couldn’t be tuned easily like today. Back then you had custom e prom chips that could be swapped to enhance performance. The AIC was a way to really crank up boost safely without going to a standalone EFI system. In the Porsche world Andial, Miller/Woods did the same thing before everyone else, only they did their enrichment devices using mostly factory parts. In the aftermarket world a lot of companies built their own variations based off what the Porsche tuners did but using parts outside all marquess. Back to the AIC, you would simply weld in a bung in the charge line right before the throttle body. Select a given injector based off the engines needed enrichment requirements, and plumb it for fuel. The AIC typically can be controlled by boost so a MAP sensor will be needed as a trigger. Connect the controller to the injector and triggering sensors, set the parameters as to when it needs to turn on and off. Adding more fuel when it is wanted. A simple way to enrich without converting to EFI.

[Alan L]

OK - thanks. I am interested - because I am on the ragged edge for getting enough fuel. I have kindly been sent a pic of the Andial setup. It seems to me in the WUR line - not feeding fuel direct to the engine. Runs off the return line from the FD - that is low pressure.
So was the Andial just dropping the WUR pressure? In which case you are still limited by the FD capacity ie not supplying fuel beyond the FD
Thanks
Alan

[reclino]

I picked up one of these last year and looked inside briefly. Simple driver circuit that was triggered by a Hobbs pressure switch. It had a 3 position? switch for varying level of fuel boost. The circuit is pretty simple, driven by a 555 timer.




David
Performance EngiNerding

[GJF]

https://twistedtuning.com/products/aic2-v-additional-injector-controller-voltage-mode-aic2-v66hi-for-inline-6-engines

[flightlead404]

Originally Posted by reclino

I picked up one of these last year and looked inside briefly. Simple driver circuit that was triggered by a Hobbs pressure switch. It had a 3 position? switch for varying level of fuel boost. The circuit is pretty simple, driven by a 555 timer.




David
Performance EngiNerding

Dirt simple. And if it works, why complicate.

the next step up would be something controlled by an ardiumo/atmel or a picaxe, which would allow more finess rather than simply on/off or a step function.

After that, FrankenCIS, then full eFI.

[Alan L]

I'm still not clear how the Andial thing worked? Was it simply bleeding WUR pressure of to return via injector loop? Just lowering WUR pressure in a controllable (to a point) manner?
In which case it is still not delivering more fuel than the maxed out FD.
Alan

[TurboKraft]

The ANDIAL FEC (Fuel Enrichment Controller) was *not* a conventional AIC (Additional Injector Controller) in that the fuel injector was not positioned in the intercooler outlet pipe and spraying fuel into the intake manifold like the tiny cold start valve does.

Instead, it was manipulating pressure in the Fuel Distributor. When activated, it was akin to to running the car in cold start mode. Activation was from a Hobbs switch, and it had a 5-position switch (off plus 4 levels).

If ultimately could not overcome the flow limit of the FD.

[Alan L]

Thanks Chris. So if I am already running at a maxed out FD the Andial system won't supply any more fuel. In a sense it is doing in a more controllable manner , the same as increasing the boost dump. You get a to a point tho , in terms of dropping the WUR pressure, when it makes no difference.
Regards
Alan

[RarlyL8]

It's basically doing the same thing as your adjustable WUR. The boost control pressure is set remotely/electronically instead of mechanically. Your system should not be maxed out, that is puzzling. Do you have a way to measure the amount of fuel that returns to the tank when the injectors are full open?

[TurboKraft]

Originally Posted by Alan L

Thanks Chris. So if I am already running at a maxed out FD the Andial system won't supply any more fuel. In a sense it is doing in a more controllable manner , the same as increasing the boost dump. You get a to a point tho , in terms of dropping the WUR pressure, when it makes no difference.
Regards
Alan

Exactly, that's our experience, too. At some point you can't flow any more fuel, dropping the control pressure more makes no difference, and pushing down on the AFM CO adjusting screw while on the dyno makes no difference either. You're done.
Remaining options are
(a) modifying the FD for more flow -- good luck
(b) piggyback injectors like the AIC setup described above -- and hope that the manifold's airflow distributes the fuel evenly...
(c) go with electronic injection

[Alan L]

Thanks Chris - that is what I figured. I would go for option b if I do anything - more do-able than most others, in spite of manifold limitations. More fuel has to be better than leaning out all 6. My regs mean I have to stay with CIS.
Brian - I haven't measured return flow - but I can calculate it - because I know my total flow (1700cc/30 sec) and I have measured my injector flow at WOT (1050cc/30 sec). So I am returning about 650cc/30 sec - on two 044 pumps. So I have some spare fuel - just a matter of getting it in there. And it doesn't look like the Andial thing will fix that .
Regards
Alan