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found a leak in my cooler... guess thats why the boost was spiking so hard... fixed it up... the boost is still falling off a little bit in the top end but will do some finer tuning once i get the map sensor...

kenbam wrote:This is my trace after a 30 min logging run, mostly open motorway, trying to set up lean cruise. I use a techedge wb sensor.

When you use the data from the AFR 3D trace, do you put the table on "display type: current" or do you put it in "display type: average?"

I use "display type: average", if you use current, how do you know the cell value wasn't taken while the car was under deccel? Also wouldn't the data be more accurate if you averaged it out, instead of taking the "current"?

Or do you just do "current" and then a couple of full throttle runs and then stop logging?

You dont know if it is under deceleration. I've just added an action item to not record AFRs in this table under decelaration. That should allow averaging to work better

I use current most of the time (gets the last reported value) but averaging is good if holding around particular RPM to collect a reading

I was using "current" to make sure I was getting the most accurate data possible - and just disregareded the obvious dud measurements. Rather than have an average of good and bad values.

PL

Matt wrote:I've just added an action item to not record AFRs in this table under decelaration. That should allow averaging to work better

If only you knew how awesome you where...
I had written a python script to strip the csv of all "lines" which had TPS values < 4volts. I one day dreamed something similar would make it into the nistune software, but I never dreamed it would be so soon.
Can't wait for that feature to make it into a release.

I've just been out for an hour trying to get the stock solenoid to respond with adjustments to the High boost duty, Boost Loads scale and Boost RPM scale.

Can you (pete? ) clarify exactly what these 3 do, so I know I'm in the right area - I tried to make it easy for me to see changes by changing all the values in high boost duty to 128, what I would expect is a higher boost level in all areas - not what I found however.

I don't really know what the other two registers, load scale and rpm scale to in relation to the boost solenoid - and whether getting a higher level of boost requires removing the restrictors?

Any advice on this would be great!

Thanks

The load and RPM scales will be the same sort of deal as for fuel and IGN maps. I've not played with these yet - I did exactly the same as you did and I got the same result. Zip.

I'm gonna have to have another play with this on the bench - last time I messed with it I could see a definite change in the duty cycle of the signal going to the boost control solenoid. So I thought it'd be all sweet on the car. Somebody else mentioned that you need to change the jet sizes so that was gonna be my next move.

My mate with the S15 is a school teacher and school holidays have just started here so I'm expecting a call. He's fitted his 2871R and he's just been waiting until we're both free so he can drop around and we'll fit the 550's and Z32 AFM and tune to suit. He's keen to use the factory solenoid for boost control so I'll let you know how we go.

PL

Talking of jet sizes, I've just removed the brass restrictor in the hose from the solenoid to the T connector. I haven't touched anything else, and upon my journeying tomorrow I will report any effect it has.

The standard solenoid duty maps look like they are running at approximately 57% capactiy at their highest point (one cell only), so I would guess that given a good condition solenoid it will hold at least 15PSI, maybe 20 if lucky?

Any chance you can test the maximum capacity if you have a rig set up Pete?

I've modified the Boost /RPM scale to suit an 8k rev limit - what do you think? Does the TP load limit have any direct influence to this solenoid? Also, how is the first and second gear boost limit controlled?
Anyway...see attatched

Update -

without the brass restrictor in the pipe from the T peice to the solenoid, the boost comes in VERY early, which is lovely for torque, but spikes and soars way above 10PSI, in higher rev ranges almost 17PSI.

It is uncontrollable in this fashion, so I will replace the restrictor, and perhaps remove the other one in the other pipe coming from the T peice.

You may need to try using a needle valve in place of the jet(s) to give youself some adjustment. I've not played with that local S15 yet - just got back from MotoGP.

PL

OK. Finally got to do this local S15. I played around with the boost control maps and got it to respond on the bench. You have to use the latest address file (download latest ROM pack from NIStune site) - Matt must have updated the file at some stage and it now looks at different data for the boost control maps.

They look kinda weird - and all values across each row are the same. I'd post some shots but I can't here at work. The bottom line is that this effectively makes them 2D mas rather than 3D. Not to worry - you can still map boost to RPM.

The trick is that you need to change all the values in each row or it won't respond. I tried it on the car and it works. The car isn't fully tuned yet so we didn't crank much boost into it but we were certainly able to increase boost in the midrange to higher values than standard.

I'll report back once we do some serious boost increases. He wants to try running 18psi so it'll be interesting to see what we can get out of it. May need to adjust the jets sizes too.

PL

Guys guys!! (great excitement!)

I've just been doing some more testing with this S15 ECU.

Here's the go: I monitored the boost control solenoid and was able to adjust it from 0% duty to 100% duty. This means we have full control over boost on these things - (we may need to adjust the jet sizes to get exactly what we want in the real world).

Even better - "0" in the maps means 0% duty cycle (valve closed) and "100" in the maps means 100% duty cycle (valve fully open). The valve takes a finite time to react though (like injector latency) so the effective values are actually 10 (fully closed) to 90 (fully open).

So there you go. We have boost mapped to RPM on S14/S15 SR20DET.

Sweet!

Note : I had to adjust the values in the "Knock Boost Duty" maps for it to work. Further investigation shows that the main/knock boost control maps are backwards so jump into the address file and swap them around. Note to Matt: please fix this on next release of ROM pack.

HIGH_BOOST_DUTY = F100
REG_BOOST_DUTY = F000

Getting there now!

PL

PS: Chris - how's your S15 going? We've got the 2871 on there, Z32, 550's and we're ready to lean on it!

i would be more than keen to check out what you have been doing with this boost control...

As fort he car well the 550's were flow tested and checked... the z32 is collecting dust... but I have not got the money to go to a new turbo... so the question is do I put them on and just boost up the t28 ??? most people are telling me it is a waste of time... let me know your thoughts... I am running 15PSI and it goes well and the afrs were ok although I had to shift the load scales a little for the fuel as it was a little lean in the middle... I also turned off the o2 sensor in the transition to boost... then trimmed up the fuel... Yavuz is going to dyno it soon and tell me what he thinks...

Also I did upgrade the inlet with 3" all the way to the turbo... my own custom manifold...

As for your boost control with the stock system I have 2 things to report....

1. you will need a jet smaller than the one you have already in the boost signal line... ( i think there is also another one in the actuator line but could also be in the vac line I cant remember (white stripes)) They are different sizes as well the one in the boost line is the smaller of the two I think...

or use a simple bleed valve inline..

2. Alternatively you could use a better boost solenoid that is able to flow more air... but the less you bleed the quicker you'll boost...

All in all I ended up using a tie rod on my actuator... and a gated tee bleeding off such a small amount of air it isnt funny... result was boost coming on really early... I was quite suprised with the result... I have a map sensor on my system thats plugged into nistune with the afr gauge...

I will get you a log from it... Keep us up to date on your stuff it kind of was a no goer for me.

AFRs are at 11-12.0 Not much traction in 1st and second.... so I am thinking coil overs and wider tires first.... if the clutch holds up...

Heard about reversion problems with the z32... would like some pics of the install if possible, I will show you mine...

I would also recommend a 1 bar actuator... for that..

Hey Chris,

I think you're actually in quite a good place with your S15. Stock turbo + FMIC + zorst + 14 to 16psi is probably the best performance for the $$$ that you're likely to get. You should see around 180 - 190rwkw give-or-take with this setup. And you'll have great boost response.

Plus you don't need to upgrade injectors or clutch! AFM would be debatable. You'll probably get away with it but it'll be maxxed out.

The question is whether you need more power than that. The 2871 won't give you much more than the T28 up to 16psi. We usually see around 200rwkw on 16psi with the 2871's. But full boost will be about 500rpm later which makes a bigger difference than you might think.

If you want more than 16psi then there's no question - the 2871 is the go.

But then you need the bigger injectors, AFM and by the sounds of it a better clutch too.

Graeme has just replaced the flywheel and clutch on his S15 - he got a CroMo flywheel but stuck with full face organic driven plate with an upgraded pressure plate. $1000 worth of stuff!

I'll keep you posted on how the boost control works out.

PL

Update:

Did some more with the S15 boost control solenoid today. All good - we have total control. Mwuhahahaha!!

In its stock form the factory boost control solenoid will give you between 8psi (solenoid closed so boost level dictated by spring in wastegate actuator) and around 12psi.

With values of 0 to 10 in the boost maps the solenoid is closed. Values of 90 to 100 will see the solenoid completely open. Values in between will see the solenoid chattering away at various duty cycle values from 0 to 100%.

OK, so we wanted more than this, so we removed the jet in the hose between the tee and the solenoid. This allowed the solenoid to flow more air, giving higher boost. Boost is then limited by how much the solenoid can flow when fully open. This gave around 16psi with values of 100 in the maps. But we wanted more....

The next step was to decrease the size of the jet in the hose that runs from the inlet manifold (boost source) to the tee near the solenoid. The factory jet has a 1.6mm hole. This was decreased to 1.4mm. Max boost was now 20psi. That's more like it!

Values in the boost control maps were then decreased to around 80 - getting us back to between 14 and 16psi. Boost is now programmable between 8 and 20psi. This was all done on the road. Next step is to get it on the dyno for final tune. It'll certainly be nice to be able to adjust the boost level across the RPM band.

PL