Source for frequency valve?
 

Now that Andial no longer sell their fueller kit (they told me last year they'd sold out of the original production run of fittings and declined to have anymore made), what's the best/cheapest source of a frequency valve suitable for modifying the control pressure via a Greddy or Split Second (or EMS etc. etc.) injector controller?

Is the Lambda valve from a US SC or late 930 suitable? Seems like this would probably bolt on with the minimum of fuss/fitings, but does anyone know if it'll flow enough fuel/drop enough pressure at a sensible duty cycle to be useful?

Thanks.

Ping for Thierry?

At least on lambda port it flows enough for some control. Dunno about the flow using wur control line.

:)

Hello !

Actually the frequency valve itself ( Bosch) is very easy to find. The problem is to find all rest of the plumbing . (banjo etc )

Personnally, I was a lazy boy and I bought an andial kit ( in order to save my time and sourcing) . Thus , I used this "assembly" frequency valve of this kit. ( The original andial controller is still somewhere on my shelves ).:)




Playing with "lower chamber" pressure versus playing with controle pressure doesn't provide exactly the same results.

Deacrease lower chambers pressure allows more fuel ( due to the differential pressure) . So you get more fuel at low and middle RPM but the metering plate keep the same position. This method doesn't allow to get the max of fuel @ high RPM. Attention, this method is somewhere quite sensitive to adjust.

Lowering controle pressure allow the metering plate to move a bit larger. So the metering pin move a little bit more . Thus it allows more fuel ............ but it also decrease the airflow restriction !!! ;)

Did your test show no more fuel on higher rpms when using the lower chamber control?

I had to use that one as my car came with a lambda fuel head but without the lambda valve so now with the controller I have managed to get more fuel up top. Did you only try your andial valve or did you try the lambda valve too? I bet the lambda valve flows less so it's easier to MAP on the lower chamber line.

Hello :)

Actually, on my C2T, I made a simple test. At wot, the stock lambda frequency valve is triggered at fixed duty cycle ( 50%). With a simple switch, it is possible to change this duty cycle to fixed 75% . So I made a complete pull from 2000 to 6000 with the lambda freq valve triggered at constant 75% duty cycle . Then I compared AFR curve , with constant standard 50% and with constant upgraded 75% duty cycle .

With 75% I 've got a ton of fuel in mid RPM ( AFR drop arround 9.3 near 3000 rpm) and the car almost stall.:eek: Then , step by step the AFR went up and above 4800 RPM the AFR curve was the same . There was no difference between the two different duty cycle triggering from arround 4800 to red line.... no additionnal fuel. As I could not get more fuel on top end and as the mid was very sensitive with little duty cycle variation, I didn't go in this direction to tune my CIS. ( In addition I wanted to keep the lambda function on my car :))

As you suggest, maybe the flow rate of the stock freq valve versus andial freq valve is different! Maybe the andial freq valve can allow a bit more tuning at high RPM. (In such case, the mid would be worst to adjust ) . Of course, this is also a a good possiblity to tune the fueling ! ( with interesting reactivity if correctly managed) . Just one point, for airflow purpose, I do prefer to reduce the CP and to allow the metering plate to have a little higher excursion. ;)

The plate can stall though. IIRC you had a failing fuel pump so was your 75% test with the new pump or the bad pump?

Not failed pump exactly .... actually 1 missing fuse !:eek:

At that time I made the test after I put a new fuse . So both pumps were in function and I've got suitable fueling under 0.9 bar of boost pressure. At that time I also verified the fuel pumps flow according the factory procedure and it was correct . ( from my memory , a bit more than 1.5 l )

Something, in the mean time I made the 75% test , I also made the CP lowering test . ( I made both separate test and both together test). I didn't get any extra fuel on top RPM with the 75% test but with CP lowering , I've got about 0.5 drop on AFR at high RPM. ;)

Ok. So it seems that lowering the lower chamber pressure is only good in my case where I had a lambda fuel head without lambda valve. I got my lean high rpm issue solved when I installed a new lambda valve (thanks for the valve lowfat) with the AIC on the lower chamber port.

Sorry but I am not sure to get your exact meaning ...:confused:

Do you mean that you 've got your issue solved by swapping from a stock frequency valve to andial frequency valve ( in both case driven by AIC ) ? Finally which model of freq valve do you use ?

To be honnest with you I tested the difference between the constant stock 50% duty cycle and constant 75% duty cycle only ! But I never tested with 0% duty cycle. I do believe this could lean a little at high RPM.

Anyway, your way to proceed is very interesting and you solved your fueling problem ! Great ! :)

As to the AIC mapping, did you meet some difficulties to map it ? What is your opinion ?

Thanks Thierry!

Yes, my laziness is what is prompting trying to use a Lambda valve, rather than sourcing something and cobbling up hoses and fittings.

My fuel head is RoW with no Lambda port in the lower chamber, so my plan was to operate on the control pressure circuit anyway - good to know that actually offers the maximum extra fuel @ high RPM, because over 5,000 RPM is the only place I need more fuel :)

There are alot of other cars like BMW 320i, 323i, Audi's, Saab's, Volkwagons, Mercedes, and some others that had lambda CIS on them too. Even the 512BBi Ferrari...

Gives you more places to look and the more common cars with CIS are or were in common salvage yards and the you pull it yards have low prices on stuff like that.

Fuel that goes to the control pressure chamber above the control plunger and the fuel going to the lower differential pressure chambers both go through small orifices first to restrict the flow so it can be varied by returning some of it to the tank.
It's not alot of fuel flow but it's being used for hydraulic pressure instead of being injected into the motor.

I had no valves first and then I installed a lmbda valve with the AIC to control the lower chamber pressure. I had no real problems to dial the MAP for more fuel. I need to still dial the spool cells for some more fuel as it gets initially pretty lean on low rpm WOT.

Hello Spuggy :)

Freq valve + AIC will help you to decrease AFR about 0.5 at high RPM ( can be less, can be more, depending your usual setup and RPM measurement). After install, if you still need more additionnal fuel, you will have to upgrade your fuel pump. ;)

By the way, with stock or mild cam ( like SC) and under 1 bar of boost pressure it is not so necessary to drop AFR below 12.5 above 5200 RPM. ( Assuming the injectors are in good conditions and matched!) Actually, the additionnal fuel increase the EGT, increase engine temp ....

Fittings for the freq valve:
If these are so hard to get, we can make some injector holders in billet aluminum IF there is enough interest -- 20-30 pieces. Then you could use any standard length Bosch-style injector (you pick the flow, quality, price point). Fittings would probably be -4AN, though can make to accept metric threads like an M10x1.0mm or M12x1.5mm hollow bolt.

It 's a good idea Chris !!!:) :)

If the offer is still on the table I am also interested. I am going to use the AIC for feq valve control and boost control as someone here is doing (can't remember who, maybe it is Thierry himself) when I order the AIC, what impedance should I be looking for and is absolute pressure the way to go?.

Hi EMON

My AIC is the SPLIT SECOND model AIC1-019 (with internal clock oscillator). There is internal absolute pressure sensor (from 0.7 to 30.7 PSI). There is 2 high impedance output (with individual mapping ).

You can contact SPLIT SECOND for more information about it.

:)

Great info, I already ordered an injector holder, this way I will be able to change injectors should I have duty cycle capacity problems. So now I need a Hi Z 30lbs injector and a Hi Z boost solenoid and the fittings.

One more question Thierry, you are such a great source of information. I saw that you tapped into the WUR, but that same hose connects to the back of the fuel distributor, there should make no difference if I tap into the back rather than on top of the WUR should it?

The reason I am considering this is that it may be easier to find the extended banjo bolt and fitting to tap into the back rather than the modded bolt that connectors from the top which I presume you got from the Andial kit.

thanks again..