Jaycar Boost and Fuel Control

[illusiVe]

make sure u put the jumpers on those pins.. *oops* (will try hooking up again shortly..)

[simboo]

It won't work you MUST have a vent, otherwise there is nowhere for the trapped boost (pressure) to escape.  So the wastegate stays open until the solenoid opens.

Put a vent in and try it.  Your problems should have dissappeared.

cheers

<{POST_SNAPBACK}>

Ahhh! I quickly read over the instructions and read about the vent and thought... bah what would I need that for! lol

I bought the 1/4 brass T-piece ages ago anyway, just never ended up making it into a vent. What size could you perhaps suggest to be drilled if I solder it up and re-drill? 2.0mm?

This makes sense now why I couldnt go over 8psi properly

I'll do it in the next few days and hopefully have good results...

thanks!

Simon

[ian]

Thanks 3intheback,

it's all swapped back & i only took it for a little run with the hoses swapped, so hopefully no damage. (crosses fingers) I have done the solenoid wiring mod & it works quite well.

Thanks again,

Jeff

<{POST_SNAPBACK}>

So is it all working ie installed - if so do you want to put up some pics etc? It would be good to see before I do my S2! (and what is the wiring mod?)

I also have an S2 and like you probably got confused with the description on hose routing in this thread as you wont find any hose with stripes of any colour on them.

...Don't do any  experimentation until you get a boost gauge. Run the gauge from the blanked off nipple towards the rear of the plenum.

<{POST_SNAPBACK}>

Don't all the S2's have a boost gauge as standard (mine does)?

Ian

[chrissso]

Don't all the S2's have a boost gauge as standard (mine does)?

Ian

<{POST_SNAPBACK}>

Mine has a boost guage. It only goes up to 7. Which is a problem if you want to hit 8,9,10,11,12,etc PSI.

[AlexCim]

You sure its 7PSI not the normal skyline "+7" which means 14.7psi... one bar?

[ian]

Mine has a boost guage.  It only goes up to 7.  Which is a problem if you want to hit 8,9,10,11,12,etc PSI. 

<{POST_SNAPBACK}>

Alex is correct - the gauge is in 100mmHg (millimeters of mercury) thus they go from -700 to +700mmHg.

Given -

One atmosphere is 760mmHg, or 101.325 kPa, or 14.7psi

Thus the gauge goes from -13.54psi to +13.54psi

[Sydneykid]

Ahhh! I quickly read over the instructions and read about the vent and thought... bah what would I need that for! lol 

I bought the 1/4 brass T-piece ages ago anyway, just never ended up making it into a vent.  What size could you perhaps suggest to be drilled if I solder it up and re-drill? 2.0mm?

This makes sense now why I couldnt go over 8psi properly

I'll do it in the next few days and hopefully have good results...

thanks!

Simon

<{POST_SNAPBACK}>

Hi Simon, 2 mm is usually a bit too big, around 1.25 mm to 1.5 mm seems the most common.

cheers

[simboo]

Hi guys,

I soldered up the piece this morning and put a 1.0mm hole in it for the vent. The controller works sweet as now!

at 40% solenoid duty I am getting about 9.5-10psi. I noticed a few times when I let the car rev up to 5,000rpm in 1st and 2nd gears, I got a bit of missfire (sounds like rev limiter type missfire). Could this be due to a short spike in the boost pressure that doesnt show up quick enough on the gauge?

I've basically started out with injector duty 1-18 the solenoid is fully closed, injector duty 19-50 the solenoid is 40%, injector duty 51-64 the solenoid is fully open.

I'm wondering if this is a boost/fuel cut because the airflow meter is maxing out @ its specific fuel cut level (4volts I think)

Would I be better to test out with keeping the solenoid at 40% in stead of closed from injector duties 1-18?

Simon

[chrissso]

Hi guys,

I soldered up the piece this morning and put a 1.0mm hole in it for the vent. The controller works sweet as now!

at 40% solenoid duty I am getting about 9.5-10psi. I noticed a few times when I let the car rev up to 5,000rpm in 1st and 2nd gears, I got a bit of missfire (sounds like rev limiter type missfire). Could this be due to a short spike in the boost pressure that doesnt show up quick enough on the gauge?

I've basically started out with injector duty 1-18 the solenoid is fully closed, injector duty 19-50 the solenoid is 40%, injector duty 51-64 the solenoid is fully open.

I'm wondering if this is a boost/fuel cut because the airflow meter is maxing out @ its specific fuel cut level (4volts I think)

Would I be better to test out with keeping the solenoid at 40% in stead of closed from injector duties 1-18?

Simon

<{POST_SNAPBACK}>

Ah.. There are so many problems tha cause this. Cracked coil packs - rich rich mixture, worn spark plug or incorect gap. I was getting them at high revs from a fuel pump that was on the way out and the ECU was was going rich and retard from to much knock on the sensor.. I guess it was just retard, as there wasn't enough fuel getting to the engine!! Check all of these starting from the easiest first I guess.

Thanks

[simboo]

Ah..  There are so many problems tha cause this. Cracked coil packs - rich rich mixture, worn spark plug or incorect gap.  I was getting them at high revs from a fuel pump that was on the way out and the ECU was was going rich and retard from to much knock on the sensor..  I guess it was just retard, as there wasn't enough fuel getting to the engine!!  Check all of these starting from the easiest first I guess.

Thanks

<{POST_SNAPBACK}>

Ahh this is a possibility.

I rebuilt the engine ground up and I ditched the coilpacks for Bosch external coils + leads. They are brand new coils that I installed with the rebuilt engine. The fuel pump is a brand new Bosch 910 (around 400hp or 130lt @ 5bar) though I am only using a small lift pump to my surge tank.

I guess that narrows down to the:

Leads? I am using only average 8mm leads.

Bosch super4 (or whatever) spark plugs rated for my engine.

Crappy lift pump

What I am thinking is that it might be blowout from incorrect gapping?

I gave the car a short run in the cooler weather this morning and on my LOW boost setting @ 9.5psi the car ran fine and didnt 'missfire' or whatever it is. As soon as I switched over to the HIGH boost setting which is about 11-12psi, the car would feel like it hit a soft rev limiter high up in the revs in 1st and 2nd (5,500rpm). Pulling from low revs (2000-4000) in 2nd the car wouldnt have a problem @ this PSI.

I'll look into the issue of spark blowout and gapping now that you've mentioned it, as well as the specs for a good lift pump and also what good ($100 -_- ) leads would improve.

Cheers,

Simon

[Sydneykid]

As soon as I switched over to the HIGH boost setting which is about 11-12psi, the car would feel like it hit a soft rev limiter high up in the revs in  1st and 2nd (5,500rpm). Pulling from low revs (2000-4000) in 2nd the car wouldnt have a problem @ this PSI.

Simon

<{POST_SNAPBACK}>

My guess is standard ECU rich and retard strategy. Grab a Consult reader (Group Buy has lots of alternatives) and have a look at what happens to the ignition timing around those loads.

cheers

[simboo]

My guess is standard ECU rich and retard strategy.  Grab a Consult reader (Group Buy has lots of alternatives) and have a look at what happens to the ignition timing around those loads.

cheers

<{POST_SNAPBACK}>

Hi SK,

Unfortunately the CA18DET does not have a consult port as far as I am aware, otherwise I would definately get a consult reader for it.

I did however seem to find my problem. I remember when I built the engine, I went to get a set of BCPR6ES-11 (though the manual says cat convertor models should use PFR6A-11) But I ended up using some FR7DCX or something.. which is slightly colder and uses a 1.1mm gap standard. I took all the plugs out today when I got home from work, pushed em down to 0.8mm. I noticed instantly after taking off the engine felt a bit smoother, and when I revved it out... I got nothing but roaring power

Looks like I'll be trying that high boost setting out again properly...

Cheers fellas.

Simon

[ellie]

Hi everyone!

I consulted a friend of mine that now works for a performance shop about the effectiveness in application of the dfa to my skyline(R32 with full custom exhaust. Othrwise dead stock). He straight up replied that air flow signal benders are a waste of time because a standard ECU will always be trying to return to its ideal base map of tune. which over time will nulify the voltage bender or won't maintain a good state of tune. Now i only plan to fit an enclosed cold air fed pod, intercooler and jay car boost controller in total. All i'd like to achieve is a little power with a decent afr through the rev range and some fuel economy to boot. So is my friend right or is he misguided? And do you think this would be a quality addition to my car for the mods i will have?

Any advice is appreciated (especially SK )

[NewKleer]

partially misguided. the ecu learns around the closed loop operation (ie, when the ecu is using the o2 sensor to get the AFR to 14.7:1 or whatever, while cruising). however most ECU's disregard the o2 sensor (and hence any adjustments) while in open loop, ie acceleration and so on, which is exactly where you want the adjustment.

[[SPESHAL]]

Anyone in Perth got one of these tuned?

I'm finding it hard to find anyone to do it. Speedworks wouldn't do it, mentioning something that because it doesn't have rpm related load points like the Apexi AFC its not effective.

[AlexCim]

Uhh, why should it be RPM dependent, you have different load ratings at at RPM's, therefore changing AF mixtures for a fixed RPM.

So, the fact that an injectors actually controls the fuel going into it, you would this it be a better indicator to tune off.

[Sydneykid]

Injector duration is a far better measure of load (and therefore boost generation) than RPM. Everybody knows that you get different boost in different gears at the same rpm because of the different load. Even up and down hills changes the boost rpm. So measuring load via injector duration is far more effective than rpm.

cheers

[[SPESHAL]]

So let me get this straight, the DFA uses injector duration (calculated via AFM voltage?) as tuning points?

[NewKleer]

injector is tuning points for boost controller - the DFA is tuned via AFM voltage (or moreso, 128 ranges of the AFM over the 0-5v range, or whatever)

[chrissso]

Alex is correct - the gauge is in 100mmHg (millimeters of mercury) thus they go from -700  to +700mmHg.

Given -

One atmosphere is 760mmHg, or 101.325 kPa, or 14.7psi

Thus the gauge goes from -13.54psi to +13.54psi

<{POST_SNAPBACK}>

Well there you go, I didn't know this!! I thought mine had shat it's self...

Am I right in saying that it's reponse is slow?

Chriso