Jaycar Boost and Fuel Control

[Sydneykid]

Thanks for the explanation.  

How much does it affect timing if for example you alter the AFM signal enough to go from 10:1 AFR to say 12:1 between 3000-5000rpm.  Would the timing be changed by more than 3 degrees?  I know the computer alters the timing a lot compared to the base 15deg BTDC...

Jut trying to get a rough idea on the effect of the dfa.

thanks

Sorry Ben, I have no practical experience, the only way to get that would be to drive around with someone strapped under the bonnet with a timing light. I can guess by looking at the Power FC ignition maps from the R34GTT, they are here somewhere in the Datalogit maps.......................

OK, in a few spots in the mid range 4 load points is +5 degrees ignition timing, and 6% less fuel, say an AFR change from 11.3 to 12 to 1.

So if it started to ping (because of the 5 degrees advanced igntion timing) you would have to back off the A/F ratio correction by say 0.2. That means you would end up at 11.8 to 1 instead of 12 to 1 but with only 3 degrees of ignition advance. Maybe that's enough to stop the pinging.

A few load points away it is only 3 degrees and 2.5% injector change for 4 load points.

Hence the problem, it's a big circular compromise.

[benl1981]

What Sk wrote...

"As well as making more power, I also leaned out the AFR's to a more fuel economy friendly 14.5 to 1 at the lower rpms (off boost). The standard AFR's were 12 to 1 off boost and went as high as 9 to 1 on boost, not good for power or fuel economy. I would have liked to go a little leaner than 11 to 1, but the ignition timing was getting a bit advanced as I pulled more fuel out of it with the DFA lowering the AFM voltage. It was the usual piggy back compromise, no doubt exacerbated by the standard exhaust, compliance cat and standard intercooler. I could trick the standard ECU just so much, then it would pull ignition timing and dump a whack of fuel in.

My biggest single observation with the Jaycar DFA was how easy it was to get rid of the usual RB25DET power dip around 4,250 rpm. With 100 settings at 128 load points I could fine tune it so easily. There is simply NO DIP, and anyone who has tuned an RB25DET will tell you that is hard to achieve with piggy back controllers."

My question is I'm under the impression that whenever you cruise or accelerate softly it is in closed loop (using o2 sensor reading to try and get back to stoic) ..so how do you know whether you are tuning a closed loop load or not?

You say you had as high as 9:1 on boost. Pulling that back to mid 11s to 12 was that a problem with timing??

You talk about rich and retard happening at fairly low boost levels...but is this the savage cut? What I have experienced is almost what feels like a fuel cut at around 10psi but is there a chance I am gietting it a bit before this where the power is dipping due to retarding of the timing but once enough air sensed will do the rich and retard worse..?

Thanks

[Sydneykid]

My question is I'm under the impression that whenever you cruise or accelerate softly it is in closed loop (using o2 sensor reading to try and get back to stoic) ..so how do you know whether you are tuning a closed loop load or not?

Idle and constant throttle cruise for closed loop. On the dyno it's easy to pick, you change the DFA settings and the A/F ratio readings don't change. Ooops must be in closed loop, toooooo simple.

You say you had as high as 9:1 on boost.  Pulling that back to mid 11s to 12 was that a problem with timing??

Yes, I wanted 12 but could only get to 11.

You talk about rich and retard happening at fairly low boost levels...but is this the savage cut?  

On the 4wd dyno it is like riding a bucking bronco, it sure as hell feels savage.

What I have experienced is almost what feels like a fuel cut at around 10psi but is there a chance I am gietting it a bit before this where the power is dipping due to retarding of the timing but once enough air sensed will do the rich and retard worse..?

I have NEVER EVER seen fuel cut on a Skyline, it would run lean and punch holes in pistons, Nissan aren't that stupid. They just richen it up and retard the timing, that drops the rpm, road speed and hence the load and so the turbo drops boost. There is less airflow, so no more need for R&R. The ECI reverts back to the normal maps and the power climbs again, then there is too much airflow and awaaaaaaaay we go again. You see it on so many R25DET dyn graphs, its either a drop or hold in power for a few hundred rpm, then increasing. Or it's a series of swoops in the power output.

Hope that clarifies:cheers:

[benl1981]

Hey Gary. Thanks a lot...

"You see it on so many R25DET dyn graphs, its either a drop or hold in power for a few hundred rpm, then increasing"

So this means that R&R can take the form of a not so severe encounter..

When I get what feels like the cut should I keep my foot down and see if the poer comes back...I'm not sure if is coil related or R&R...?

[Sydneykid]

Hey Gary.  Thanks a lot...

"You see it on so many R25DET dyn graphs, its either a drop or hold in power for a few hundred rpm, then increasing"

So this means that R&R can take the form of a not so severe encounter..

When I get what feels like the cut should I keep my foot down and see if the poer comes back...I'm not sure if is coil related or R&R...?

Yep, test it out. Every car is different, some feel like they are going to curl up and die, others just pause for breath.

Coils, coils, coils, I am sick and tired of hearing about coils. I have NEVER EVER had a problem with an RB coil. Copper spark plugs and the right gap will be fine, as long as the tuning is suitable. If it's too rich causing the missfire, then fix the problem (richness) don't stick a bandaid on it (bigger coils).

[benl1981]

Hmm. I read somewhere that you think the ECU goes into severe retard if it sees that te mixture is very rich...so is there a few different ways that you can get what appears to be the cut...i.e.

1. from airflow being too high;

and the other

2. from the ECU somehow detecting that the mixture is very rich then retarding the timing...

not sure what sensor would let it know this though.

My coils do have burn marks on the side but no visible cracks and no arcing can be seen.

I have new copper plugs gapped at 0.6mm BKR6E (I think they were). So you think the coils aren't to blame.

[Sydneykid]

Hmm.  I read somewhere that you think the ECU goes into severe retard if it sees that te mixture is very rich...so is there a few different ways that you can get what appears to be the cut...i.e.  

1. from airflow being too high;  

and the other  

2. from the ECU somehow detecting that the mixture is very rich then retarding the timing...

not sure what sensor would let it know this though.

My coils do have burn marks on the side but no visible cracks and no arcing can be seen.  

I have new copper plugs gapped at 0.6mm  BKR6E (I think they were).  So you think the coils aren't to blame.

The ECU KNOWS the A/F ratios are rich because it made them rich. The ECU knows that the injector openning should be 40% at 4,000 rpm with a throttle opening of 85%. But the AFM voltage is at 5 volts, so it goes for 70% injector opening when 55% would have been enough. Hence it KNOWS the A/F ratios are too rich.

Why do the coils have burn marks? Been washing the engine down and driving it without drying out the spark plug wells? That's the most common cause, puddles of water and electricity don't go very well together.

I use BCPR6ES-8 NGK copper spark plugs.

[CEF11E]

If i was to disconnect the o2 sensor while tuning the DFA would i get a better result because the system would not be able to run in closed loop?

Will this have any adverse effects?

Was in nessacery to calibrate the DFA as per the jaycar instructions using the 10k trimpot if you are using it to read 0 to 5v from the AFM?

I have heard sevral opinions on this depending on what your application is. One of the jaycar staff said its not needed if you are only using 0 - 5 volts (afm).

I have read this thread from the first post and have not found either of these questions come up before. so any help would be greatly appreciated.

Last Question!!! Where should i take my car to get dyno'd in sydney?

Thanks !!!

[benl1981]

Right. So the Rich and retard really happens at the same time?

[Sydneykid]

Right.  So the Rich and retard really happens at the same time?

Yes and no, as the airflow increases due to mods it moves the standard ECU to other points on the fuel maps. Nissan strategy has always been to provide rich (safe) running. So you most definitely can get rich running (down as low as 9's)without the ignition timing being retarded, other than it would normally be retarded for that extra airflow anyway. Conversely I have never seen retard without rich, unles the fuel pump or injectors have issues at that flow rate.

[Sydneykid]

If i was to disconnect the o2 sensor while tuning the DFA would i get a better result because the system would not be able to run in closed loop?

Nope, as soon as you plug the lambda sensor back in it will go closed loop (as normal) and that will overide what you have programmed.

Will this have any adverse effects?

Other than wasting your time, no.

Was in nessacery to calibrate the DFA as per the jaycar instructions using the 10k trimpot if you are using it to read 0 to 5v from the AFM?

I checked the calibration and it didn't need adjusting. I would still check yours, there are always minor variations in components.

Last Question!!! Where should i take my car to get dyno'd in sydney?

Any dyno shop should be able to do it, there is nothing unusual or tricky about how the DFA functions. It has more load points than an SAFC, other than that the functionality is the same. PM me if you want a personal recommendation.

[t34r]

I installed the iebc into my r32 yesterday, but it only seems to send a maximum voltage of 0.15 volts to the solenoid. It's getting 12V from the ecu, and when i tap the throttle i can see the load points change in view mode.

Before i installed it, I tested the unit by connecting a 12volt battery to it and I could see the voltage to the solenoid change from 0v to 12v.

I'll take a look at it today, but I was wondering if anyone has had a similar problem or perhaps has an idea of what i should be looking for.

Thanks.

[ian]

It would be interesting to see what values people are using - why don't a few post them so we can see? :-)

I bought the kit today, so I'll be trying it soon as well...

Ian

[Frink]

G'day all!

i recently purchased the boost controller and hand controller which everyone here is raving about. after reading all that has been writen (almost!), im glad i did buy it. however, all that everyine has writen here means very little to me as i am not very mechanically minded (thankgod im not installing it!!!). is it hard to tune and do you need to have it on a dyno while your doing it or can you have a passenger do it while driving?

[someonestolecc]

Ian - people have, scroll back through the thread.

Frink - You can do it on the road or the dyno. The road should be sufficient apart from legal and practical considerations. Whatever you tune it to for peace of mind it would be recommended to get it on the dyno anyway. And no, it's not hard to tune.

Good luck

[ian]

Ian - people have, scroll back through the thread.

Good luck

At 17 pages long, things are getting a bit hard to find in this thread :-), no wonder I missed them...

[Sydneykid]

I installed the iebc into my r32 yesterday, but it only seems to send a maximum voltage of 0.15 volts to the solenoid. It's getting 12V from the ecu, and when i tap the throttle i can see the load points change in view mode.

Before i installed it, I tested the unit by connecting a 12volt battery to it and I could see the voltage to the solenoid change from 0v to 12v.

I'll take a look at it today, but I was wondering if anyone has had a similar problem or perhaps has an idea of what i should be looking for.

Thanks.

The ECU switches earth not active, I suspect you are measuring an earth to earth voltage (0.15 volts). Try measuring the solenoid supply to active and you will find it OK.

[Maxboost]

great stuff guys!!!!

how much amps could the iebc handle?

isnt it the perfect nitrous controller?

greetings from germany

Heiko

[tikki169]

You get a nitrous kit from them aswell. TaDaaaaa they have everything.

PS nice looking punto.

[midnight]

a question about the boost controller, I dont know if its been answered yet and I dont feel like reading 17 pages at 1am so...

as the boost controller runs off duty cycle, when the ecu detects knock and jacks up the fuel, the boost controller will perform incorrectly due to the higher duty cycle right? what effect would this have and is there a way to counter this?