Jaycar Boost and Fuel Control

[Sk0pe]

I am looking at different ways to integrate the high/low map switch into my driving style. One current option I am considering is a throttle position sensor (using Jaycar kit KC5377) with a 3 way override switch. It would work this way:

3 way switch position:

Down = Low map

Middle = Throttle position sensor auto-select

Up = High map.

I can then program the throttle position sensor to automatically switch between high and low map based on how far I put my foot down - plant it and it switches to high map, back off it switches to low map (only possible in an auto!!). The beauty of this is the switch-over point is completely customisable

Thoughts anyone?

[Sydneykid]

I am looking at different ways to integrate the high/low map switch into my driving style. One current option I am considering is a throttle position sensor (using Jaycar kit KC5377) with a 3 way override switch. It would work this way:

3 way switch position:

Down = Low map

Middle = Throttle position sensor auto-select

Up = High map.

I can then program the throttle position sensor to automatically switch between high and low map based on how far I put my foot down - plant it and it switches to high map, back off it switches to low map (only possible in an auto!!). The beauty of this is the switch-over point is completely customisable  

Thoughts anyone?

OK, I have a thought....why?

I have never used the low map on mine, even in the rain the high map is fine. Maybe with another 60 rwkw, it might be, but I am not even sure of that.

[Sk0pe]

Hmmm... fair question. My reasoning is that the low map, being lower boost, would be more fuel efficent. If this is a misconception, please dispel it.

[Sydneykid]

Hmmm... fair question. My reasoning is that the low map, being lower boost, would be more fuel efficent. If this is a misconception, please dispel it.

If your turbo is running at lower than its maximum efficiency on the "low boost map" and at its maximum efficiency on the "high boost map", then there are certainly arguments that say your are loosing economy. Obviously, if you drive around using zero boost, then "high" or "low" map makes no difference. At idle and cruise it the ECU is closed loop with a target A/F ratio, so "high" or "low" map would make no difference there either.

I reckon, tuning the A/F ratios (for open loop) will make more difference than "high" or "low" boost settings at the same speed. I would much rather have my turbo running at its maximum efficiency when I use the throttle, which is after all the most effective fuel economy device.

Interesting isn't it?

[Rskyline33]

i finally got my iebc working 2 day after 2 weeks finished building it, had a few dramas but got there.. my r33 was running stock boost so i did get a big kick out of it after installing it, couldn't stop driving it.. boost definately comes on faster and smoother. one thing though, i cannot get boost over 8psi, even on the high map, i set it to 100% output put it only goes up to 8psi, i got a big fmic so i want to run 11psi, is there anything else i need to do to get more boost

[fusi0n]

i finally got my iebc working 2 day after 2 weeks finished building it, had a few dramas but got there.. my r33 was running stock boost so i did get a big kick out of it after installing it, couldn't stop driving it.. boost definately comes on faster and smoother. one thing though, i cannot get boost over 8psi, even on the high map, i set it to 100% output put it only goes up to 8psi, i got a big fmic so i want to run 11psi, is there anything else i need to do to get more boost

you have to lower the output.. 100% output means the soleniod is completely open.. sending all the air to the wastegate actuator (opening it)..

lower all your 100% output pts to say 60% or 70%.. if boost doesn't rise.. lower it even more..

mine is set to around 28%.. which gives me 15psi.. but every car is different.. so just play around..

Suggestions follow;

1. Nope, not in my experience

2. Yep, that's what I would expect, the higher gear means more load on the engine and therefore more exhaust gas flow. Hence more boost.

3. Nope, input point 19 corresponds with a certain injector duration.

I know where you are going, but don't worry about it. Because you have the wastegate closed, you are getting more boost at the IEBC input point than you would have if you had limited the boost. So the injector duration is higher than it would be if you had limited the boost, because the airflow is higher.

It's a closed loop (well almost), start limiting the boost (by opening the wategate) and you won't have a problem, because the injector duration will change. This will mean a different input point on the IEBC, which you have set at a different wastegate opening. As I said, it's a circle, by not limiting the maximum boost you have broken the circle.

I have read that again and it makes sense to me, I hope it makes sense to you.

after playing around for about an hour I finally got a map which holds boost in every gear.. a nice 14.5-15psi in every gear..

the output duty range i'm using is quiet low (2%-28%).. according to the mag i should increase the vent size.. should this really matter tho? does it have any ill effects on the soleniod?

one thing i did notice is that altho boost seems to hold very well in every gear.. if I rev thru the gears very fast.. and change from 1st to 2nd to 3rd to 4th at close to red line.. i get a small spike from 2nd->3rd and 3rd to 4th..

1st.. 14.5psi all the way to red line..

2nd.. 14.5psi all the way to red line..

2nd->3rd.. 16psi.. and settles on 15psi to red line..

3rd->4th.. 16psi.. and settles on 15psi.. then i run out of road.. :headspin:

any theories on this? or does you car do this?

i will post up my map in a second..

[fusi0n]

See attachment..

[resonance]

I have been running the DFA in my 180 (SR20DET) for a few weeks now. I've recently put in a Greddy boost gauge; I hooked up between the plenum and fuel pressure regulator (I think thats what it was).

I just have a few questions.

Firstly, the only mods I have is a 'very breathable' exhaust and a (old dirty) K/N pod filter. The exhaust is breathable because it's a 3" CES dump/front pipe + high flow cat + N1-style 3" catback which has barely any bends in it at all. It's kinda loud at full throttle too but not as loud as some.

Anyway, with my boost gauge - because it's on the plenum side of the throttle, it shows about -500mm Hg vacuum on idle, and upon pushing the accelerator, goes down (up) to about atmospheric pressure (0 on the gauge), as you'd expect. Is where I connected it the best place? or is it better on the other side of the throttle? I'd guess not because then it'd read pressures seen by the BOV and would not be as useful.

I ask because, I have no boost mods and it's reading about 0.85 bar. This is stock (seems to spike to about 0.9 then settle at 0.8 or just a bee's dick over). That's about 12-13 psi. It doesn't feel really that powerful too, though I haven't had it dynoed or anything. Is this an inaccurate reading or has my exhaust really added 5 psi to my boost? I'm a bit saddened now because I don't want to increase the boost any more with the IEBC when I install it - I'll only just try to get more boost down low. So no more power until I one day get a FMIC

The other question I have is for those using the DFA.

Like I said, I've had it in for a while and I have currently no way of reading or knowing what the AFR is, so I'm doing it by feel.

I've pretty much set it to -7 for all points (starting at around 36 or 38, my car idles at about 40) until about 100 when I set it down on a slope to about -20 or so by load point 128 (at full boost it reaches about 123 or so). I had it at -6 for a while then changed it today to -7 and it has helped a few things - low end (off boost) response, the 'burbling' (backfiring) I get when slowing down completely off throttle at sub-2000rpm, and backfiring when changing gears up whilst at full throttle at high revs.

I still do get burbling though, but what I'm not sure about is how far to lean it generally. Is -10 a lot? or a little? Is -20 a better choice? I've been adjusting it by 1, I started at -3 then went to -4 and now I'm at -7. I know that at cruising and idling, the ECU uses the closed loop feedback from the oxygen sensor, so it would ignore my settings for this, but like I said, the adjustments to -7 I've made for load points ~38 - 100 have helped (though not the hugest).

Also, should I expect an improvement in power with the DFA? I haven't noticed any at all on full throttle to be honest. Just down low rpm its a tiny bit more grunty and less sloppy.

Thanks

[Sydneykid]

I have been running the DFA in my 180 (SR20DET) for a few weeks now. I've recently put in a Greddy boost gauge; I hooked up between the plenum and fuel pressure regulator (I think thats what it was).  

I just have a few questions.  

Firstly, the only mods I have is a 'very breathable' exhaust and a (old dirty) K/N pod filter. The exhaust is breathable because it's a 3" CES dump/front pipe + high flow cat + N1-style 3" catback which has barely any bends in it at all. It's kinda loud at full throttle too but not as loud as some.  

Anyway, with my boost gauge - because it's on the plenum side of the throttle, it shows about -500mm Hg vacuum on idle, and upon pushing the accelerator, goes down (up) to about atmospheric pressure (0 on the gauge), as you'd expect. Is where I connected it the best place? or is it better on the other side of the throttle? I'd guess not because then it'd read pressures seen by the BOV and would not be as useful.  

I ask because, I have no boost mods and it's reading about 0.85 bar. This is stock (seems to spike to about 0.9 then settle at 0.8 or just a bee's dick over). That's about 12-13 psi. It doesn't feel really that powerful too, though I haven't had it dynoed or anything. Is this an inaccurate reading or has my exhaust really added 5 psi to my boost? I'm a bit saddened now because I don't want to increase the boost any more with the IEBC when I install it - I'll only just try to get more boost down low. So no more power until I one day get a FMIC

The other question I have is for those using the DFA.  

Like I said, I've had it in for a while and I have currently no way of reading or knowing what the AFR is, so I'm doing it by feel.  

I've pretty much set it to -7 for all points (starting at around 36 or 38, my car idles at about 40) until about 100 when I set it down on a slope to about -20 or so by load point 128 (at full boost it reaches about 123 or so). I had it at -6 for a while then changed it today to -7 and it has helped a few things - low end (off boost) response, the 'burbling' (backfiring) I get when slowing down completely off throttle at sub-2000rpm, and backfiring when changing gears up whilst at full throttle at high revs.  

I still do get burbling though, but what I'm not sure about is how far to lean it generally. Is -10 a lot? or a little? Is -20 a better choice? I've been adjusting it by 1, I started at -3 then went to -4 and now I'm at -7. I know that at cruising and idling, the ECU uses the closed loop feedback from the oxygen sensor, so it would ignore my settings for this, but like I said, the adjustments to -7 I've made for load points ~38 - 100 have helped (though not the hugest).

Also, should I expect an improvement in power with the DFA? I haven't noticed any at all on full throttle to be honest. Just down low rpm its a tiny bit more grunty and less sloppy.

Thanks

First off, any questions about SR's should realy be directed to the Silvia forum, however I am willing and able to answer DFA questions.

Firstly I would NEVER EVER connect a boost gauge between the fuel pressure regulator and the plenum. If you get a small leak in the long vacuum hose to the gauge, it will lean off the engine as the fuel pressure will drop. I would always use a unique connection for a boost gauge, that way if it leaks you will get rich running.

My understanding is S13's run 10 psi standard, you should expect around 1 psi increase fro m the exhaust. Maybe your boost gauge is 1 psi out then. Check others people's experiences on the Silvia forums.

Secondly, what you are doing is very dangerous, leaning off an engine without any A/F ratio readings is asking for trouble. So be VERY careful, make adjustments slowly, listen for pinging and check the spark plug colour regularly.

My suggestion is to get along to your next local club dyno day and spend the $25 or so finding out where you are at with A/F ratios. At least you will know if you are heading in the right direction.

I tuned a full set of DFA maps in 20 minutes on the dyno, it's not a big cost. Especially compared to a new set of pistons, which is what you will need if you go too far.

You will find a big improvement in boost build with the IEBC. Take your time tuning the maps and you will be amazed at how fast you can have lots of boost.

[someonestolecc]

Hi guys, it is not impossible that is is a bad component, but (based on my experience) it is unlikely.  Burnt resistors are a sign of excessive load (going through them), so I would work my way through the circuit diagram and check the components on either side of the resistor.

Let's give it a go using the circuit diagram on page 141 of Performance Electronics for Cars;

It's a 10ohm resistor that sits between diode 2 and and zener diode 2 in the power supply circuit comtrolled by reg 1.  So I would be checking the polarity of D2, ZD2 and Reg 1 and the value of the 1000uf, 10uf and 1000nf capacitors.  I have marked them with red dots on the cicuit layout below (page 137 of Performance Electronics for Cars);.

I know someone has already suggested it, but the problem is in the power supply circuit, so the first thing I make ABSOLUTELY sure of is that the polarity of the power source is correct.   Test it at least 3 ways, such as wire colour, multimeter voltage in and multimeter voltage out.  The test voltages are shown on the circuit diagram above.

Hope that is of some help:cheers:

Ok I have tested my resistor for this, and all these components look fine, my hand controller was not plugged in, nor was my input/output.

It's strange that fusion would have the same resistor burn up and put it down to the h/c cable, yet mine isn't plugged in and this resistor burns.

Also it worked fine before, all I did was unplug it, mount it and plug it back in. The 12v is coming from my accessories as it was before (I'm actually scared to wire it up to the ECU power now incase it causes something bad to happen). I've double checked the polarity is correct.

I'm all out of ideas - my last hope as I see it is replace all the components S-Kid has outlined in red and try again.

Does anyone have any suggestions?

[Sydneykid]

Ok I have tested my resistor for this, and all these components look fine, my hand controller was not plugged in, nor was my input/output.

It's strange that fusion would have the same resistor burn up and put it down to the h/c cable, yet mine isn't plugged in and this resistor burns.

Also it worked fine before, all I did was unplug it, mount it and plug it back in. The 12v is coming from my accessories as it was before (I'm actually scared to wire it up to the ECU power now incase it causes something bad to happen). I've double checked the polarity is correct.

I'm all out of ideas - my last hope as I see it is replace all the components S-Kid has outlined in red and try again.

Does anyone have any suggestions?

The problem is in the power supply circuit, that usually means reversed polarity, voltage spike, poor earth or too much load. On the diagrams I posted it has the voltages (12v, 11.4v and 5v) at various points on the circuit. Check them once you have replaced the resistor. That will tell you which direction to head when looking for the real culprit. Make sure you know where the test points are and be ready with the multimeter, before you turn on the power. Check the voltages real fast, you won't have long to stuff around.

[xRHETTx]

I have been running the DFA in my 180 (SR20DET) for a few weeks now. I've recently put in a Greddy boost gauge; I hooked up between the plenum and fuel pressure regulator (I think thats what it was).  

I just have a few questions.  

Firstly, the only mods I have is a 'very breathable' exhaust and a (old dirty) K/N pod filter. The exhaust is breathable because it's a 3" CES dump/front pipe + high flow cat + N1-style 3" catback which has barely any bends in it at all. It's kinda loud at full throttle too but not as loud as some.  

Anyway, with my boost gauge - because it's on the plenum side of the throttle, it shows about -500mm Hg vacuum on idle, and upon pushing the accelerator, goes down (up) to about atmospheric pressure (0 on the gauge), as you'd expect. Is where I connected it the best place? or is it better on the other side of the throttle? I'd guess not because then it'd read pressures seen by the BOV and would not be as useful.  

I ask because, I have no boost mods and it's reading about 0.85 bar. This is stock (seems to spike to about 0.9 then settle at 0.8 or just a bee's dick over). That's about 12-13 psi. It doesn't feel really that powerful too, though I haven't had it dynoed or anything. Is this an inaccurate reading or has my exhaust really added 5 psi to my boost? I'm a bit saddened now because I don't want to increase the boost any more with the IEBC when I install it - I'll only just try to get more boost down low. So no more power until I one day get a FMIC

Thanks

Hey man,

Still havent put my IEBC in because i was waiting for my Pivot stepping motor boost gauge to arrive. Its here and in now, I connected the tubing using a tee piece from the existing stock boost gauge take off hose.

My gtst has a cat back exhaust and a pod filter, and without the IEBC in is running 0.75 to 0.78 bar boost, which is 10.8 to 11.3 PSI. So no boost increase for me either, i'll just have to try for quicker boost build-up. Im pretty sure i dont even have a aftermarket dump/front pipe (unless its the rusty thing thats under the heat shielding.)

I know they are different cars and engines but i dont think the gauges would be off. I know mine is brand new.

[Sydneykid]

My gtst has a cat back exhaust and a pod filter, and without the IEBC in is running 0.75 to 0.78 bar boost, which is 10.8 to 11.3 PSI.

Why? Surely a simple question, but maybe not. I have an R32GTST with a high flowed RB25DET turbo with a split dump, no cat and a 4" Apexi titanium exhaust and it runs 10 psi. It had 10 psi with the standard RB20DET turbo, standard dump, original 1990 cat, and a 3" no name exhaust. I did not get 0.1 psi increase in boost when I changed over.

The common link here is the standard R32 GTST wastegate actuator, it is 10psi. So I would expect nothing more (or nothing less) than 10psi.

My experience was the standard wastegate started opening at 5 psi, so you should find a big difference with the IEBC.

[someonestolecc]

The problem is in the power supply circuit, that usually means reversed polarity, voltage spike, poor earth or too much load.  On the diagrams I posted it has the voltages (12v, 11.4v and 5v) at various points on the circuit.  Check them once you have replaced the resistor.  That will tell you which direction to head when looking for the real culprit.  Make sure you know where the test points are and be ready with the multimeter, before you turn on the power. Check the voltages real fast, you won't have long to stuff around.

Thanks S-Kid that's exactly what I wanted to hear.

The reversed polarity thing is getting to me. I'm going to try to flip the polarity over from what I think is right just on the off chance the wiring got switched somewhere along the way... I don't see how it's possible but at this stage murphy's law should be eliminated.

I'll check the ground too.. I have 5 resistors left so when I exhaust those I'll head back to jaycar, buy another pack and a multimeter

Thanks S-Kid.

[benl1981]

About how long does it take to tune the boost controller while driving. Can you get it pretty well set up after about 30mins to 1hr of driving? Combined with the fuel adjuster could you eliminate the richened mixture and retard you get from increased airflow that people talk about when running higher boost i.e because you are trimming the AFM signal? I guess you may have to retard base timing 1-2 degrees in some cases if pinging is detected...

Some people say that once you hear it pinging it is too late. I think most turners use their ear along with knock sensors right? I have heard my car ping, and it has a knock sensor so it obviously didn't detect it (I didn't feel it retard timing). Since the R34 cooler went in I have not heard pinging..maybe it was more inlet temp related?

Thanks

[Oosh]

You can get a basic setup in it in no time at all. Start conservatively and wind it up bit by bit, then you can work on ironing out the "bumps" as you drive it around.

[Sydneykid]

About how long does it take to tune the boost controller while driving. Can you get it pretty well set up after about 30mins to 1hr of driving?  Combined with the fuel adjuster could you eliminate the richened mixture and retard you get from increased airflow that people talk about when running higher boost  i.e because you are trimming the AFM signal?  I guess you may have to retard base timing 1-2 degrees in some cases if pinging is detected...

Some people say that once you hear it pinging it is too late.  I think most turners use their ear along with knock sensors right?  I have heard my car ping, and it has a knock sensor so it obviously didn't detect it (I didn't feel it retard timing).    Since the R34 cooler went in I have not heard pinging..maybe it was more inlet  temp related?

Thanks

Couple of interesting questions there, let's start with pinging.

The standard ECU doesn't warn of knock until ~40. I have no idea what 40 means. Is it %, number of occurances in minute, a second, loudness, there is one microphone on some RB's and 2 on others, is 40 on one with 2 microphones twice as bad as 40 on one with one???? To me it doesn't matter, the fact is it is not ZERO, that means SOME knock is OK with Nissan. Keep in mind 40 is a lot of pinging at low to mid rpms, it comes up pretty fast at 7,500 rpm.

So I have heard plenty and seen no ECU response. After many years of tuning high performance engines, I can hear one ping and identify it. So I am not a subscriber to the line "that once you hear it pinging it is too late". I tune my own engines by advancing the ignition timing until it pings, then retard it a little. We have a pair of Snap On brand headphones/amp/mike in the dyno room which can hear even the lightest ping.

I spent a long time tuning my boost curve, maybe 3 hours all up, spread over a couple of weeks. It was really hard when I tried it on my own, watch boost gauge, Controller and the road, all at the same time while doing warp speed. You need to have high injectors loads to confirm the settings, particularly if you do what I did and try to hold the boost stable all the way to the rev limit. This requires carefull/progressive closing of the wastegate (reducing solenoid duty cycle).

It was much faster on the second car I did, because I had the owner driving it and I knew what to look for. Plus I found a nice long hill that gives enough load without doing warp speed. I had a really good boost curve and dynamite boost build in a bit under 10 minutes.

Best suggestion I can give is to have a good play with the Controller before you move and get someone else to drive or point a video camera at the boost gauge and the controller. That way you can plug in most of the load points by watching the video.

Hope that helps:cheers:

[benl1981]

Thanks for the responses. Sorry to side track the thread a bit. So the fact that I can hear slight pinging while driving and the ECU doent do anything means that is is below 40. Is this normal to hear some pinging and it still be below 40? Or should I be replacing the knock sensor?

Are you going to limit the turbo life much by eliminating wastegate creep and the boost drop off?

I don't really reach max boost (only get to about 4-5psi) in 1st gear when I get about 7-8psi in the other gears. This is an R33 manual with the solenoid earthed. Is this normal. WIll I get more boost in 1st with this setup?

[Sydneykid]

Thanks for the responses.  Sorry to side track the thread a bit.

1. So the fact that I can hear slight pinging while driving and the ECU doent do anything means that is is below 40. Is this normal to hear some pinging and it still be below 40? Or should I be replacing the knock sensor?  

2. Are you going to limit the turbo life much by eliminating wastegate creep and the boost drop off?  

3. I don't really reach max boost (only get to about 4-5psi) in 1st gear when I get about 7-8psi in the other gears.  This is an R33 manual with the solenoid earthed.   Is this normal.  WIll I get more boost in 1st with this setup?

Suggestions follow;

1. I think the real question here is why is it pinging? It is not good, so I would always fix it.

2. Nope

3. Ist gear, being a low ratio, doesn't develop a lot of load on the engine. Less load = lower exhaust volume and that = less turbo rpm and that = less boost. The IEBC will make sure the wastegate is absolutely closed, so it will develop the highest boost your engine and turbo will produce.

[benl1981]

The pinging has gone since I fitted the R34 intercooler but I will check my base timing.

I realise that with 1st gear there is not as much load on the engine - thought I could still reach max boost though. Maybe the boost controller may help develop a little more boost...

Thanks for thie info