quick spool / boost-by-gear

[jbaker]

2003 S2000
Inline Pro 3mm head gasket
GM Boost Solenoid
Log manifold
KManager 3.2.2.0

Attached are 2 datalogs and the current calibration.

I am trying to figure out the duty cycle so I can boost-by-gear. My understanding is that the GM boost solenoid is normally open so I input a fixed duty cycle of 20%. I enabled quick spool with the desired boost settings I want and from my understanding, once the target boost is reached the boost solenoid will default back to the duty cycle.

Can someone look at these datalogs and give me a sanity check? The boost is going over the desired amount and I'm not sure why. I was rowing through the lower gears on the street. The boost in 1-2 gears feels sluggish. I'm trying to figure out where to go from here...

I want 8, 8, 15, 15, 18, 18 psi boost (for the associated gear 1, 2...n)

Thanks!

[Hondata]

Are you sure you have the solenoid connected to the right wastegate port? I would also disable the quick spool until everything else is working.

You can change the GM solenoid to normally closed by switching the port with foam vent with the port under it (not very pretty, but it does work). That way you can test off the wastegate spring and add boost with increased duty cycle slowly.

The other thing we've found is that 20 lbs would be about the limit of the GM solenoid. If you're getting close to the limit then the boost will change a lot for a small duty cycle change, so it is too soon to tell if that is part of the problem.

[jbaker]

Are you sure you have the solenoid connected to the right wastegate port?

Below is a pic of the setup. Port 1 (only port on that side) is connected to a "T" which goes to the turbo and bottom of the Tial Wastegate. The foam port is not connected to anything - atmosphere. The remaining port is connected to the top of the Tial Wastegate.

You can change the GM solenoid to normally closed by switching the port with foam vent with the port under it (not very pretty, but it does work). That way you can test off the wastegate spring and add boost with increased duty cycle slowly.

Could you explain this a little better? Are you saying to connect the foam vent port to the top of the Wastegate? And what do you mean by not very pretty? As in performance response and drivability or aesthetics?

The other thing we've found is that 20 lbs would be about the limit of the GM solenoid. If you're getting close to the limit then the boost will change a lot for a small duty cycle change, so it is too soon to tell if that is part of the problem.

Ah, so what this tells me is that my spring is greater than 20 lbs? So I should replace the spring if I want to be under 20 lbs correct? I have another datalog that showed almost 30 psi boost for a second when I had the duty cycle set to 40% - i got out of it real fast. Also, another note is that the boost doesn't last long at all, release the gas pedal and all boost is lost - normal? I would think it should hold longer than a second, I have to build it back up all over again.

***Edit*** I tore apart my WG and there is a 1.875" blue spring, so from the Tial website that is roughly 7-8 psi spring or 0.5 bar. I'll bypass the solenoid and verify to be sure.

[Hondata]

You can switch the second port and vent by pulling off the metal clamp around the foam. This will turn it into a normally closed solenoid, which makes it easier to test.

I would then run it off the wastegate spring and add duty incrementally.

[jbaker]

If I swap out ports like you suggested, would I also have to change the settings in KManager?

***Edit***Quick spool disabled. At 15% duty, I make 22 psi. I have a blue Tial 7 lb spring. I took data at 25 and 45% which showed boost drastically going upwards - I got out of it fast enough though.

So when I make pressure vs duty table...I start out with 15% duty and 20 psi boost? Or should I do redo the table and scale from 1-15% duty cycle?

[Hondata]

Going from 7 to 20 lbs at only 15% is not normal at all. Check the diaphragm for tears and leaks.

What boost did it make at 0% duty? ie off the waste gate

[jbaker]

When I did not have the BC enabled in KManager (the check box), it made about 7.4 psi - spring pressure. Then I ran it with 0% duty cycle (w/ BC enabled) and I made 20 psi. Just a reminder, at 25% and 45% it made much higher boost.
***Edit*** I selected the minimum duty cycle 15% and max 85%. I did not think to change it if I had 0% duty cycle.

I disassembled the Tial WG and gave it a good visual on the diaphragm - no tears or cracks. Do you suspect bad wiring of the GM BCS?

[Hondata]

Did you switch the setting from normally open to normally closed? If that was correct, then the next step would be to check the BC valve for flow.

[Spunkster]

Try resetting your quick spool settings back to default. (select them all, right click, reset to default)

[jbaker]

Did you switch the setting from normally open to normally closed? If that was correct, then the next step would be to check the BC valve for flow.

Yes. Changing the plumbing as you suggested along with changing the setting in KManager to normally closed. In both cases (15% duty) it gives roughly the same manifold pressure - 20-25 psi

Here is the plumbing re-routed for NORMALLY CLOSED:


I tested the GM BCS by flowing air into each port - energized and de-energized:

Try resetting your quick spool settings back to default. (select them all, right click, reset to default)

In both test cases at 15% duty cycle I had the quick spool settings at default - all 1.0 psi

Here is the result:


As you can see TPS indicates WOT - I floored it. I don't feel comfortable taking it in the upper RPMs until my boost levels get resolved. I'm using a log manifold (makes boost sick fast from my understanding). I have to keep my eyes on the road but when I glanced for split seconds...I didn't see anything above 11.2 psi on the PLX DM-6 gauge for boost/vac but then again that is why I datalog.

[Hondata]

I can't see anything wrong with the setup. At this point I'd have to say that something with your setup (size of wastegate, back pressure, flow through control valve) is giving a non-proportional response to the solenoid duty. It does seem there is a slight difference between 15% and 25%. There's probably two more things to try before switching valves. 1. If you added a diode in the ECU output to the solenoid, remove it. 2. Add a flow restriction to the pressure line between the 'T' and solenoid to reduce the pressure going to the top of the wastegate.

[jbaker]

I can't see anything wrong with the setup. At this point I'd have to say that something with your setup (size of wastegate, back pressure, flow through control valve) is giving a non-proportional response to the solenoid duty. It does seem there is a slight difference between 15% and 25%. There's probably two more things to try before switching valves. 1. If you added a diode in the ECU output to the solenoid, remove it. 2. Add a flow restriction to the pressure line between the 'T' and solenoid to reduce the pressure going to the top of the wastegate.

1. I'll inspect the wiring again...I have it spliced to the A6 pin. I'll upload pics for a sanity check.
2. I understand what you are saying by restricting flow. Leads me to believe something is wrong with the pulse rate of the solenoid if that is the case.

I have one wire connected to switched 12V and the other to pin A6. The connection to the A6 pin is spliced. To be clear, I did not remove the factory pin in the A6 location. Instead, I spliced one end of the GM BCS into the A6 wire. I did not cut the A6 wire. So that gives two wires going into pin A6...one being the GM BCS and other the factory wire.

[Hondata]

If you spliced into A6 then the boost output is connected to both the purge control valve and the boost control solenoid. Unplug the purge valve and see if that helps.

[jbaker]

If you spliced into A6 then the boost output is connected to both the purge control valve and the boost control solenoid. Unplug the purge valve and see if that helps.

I verified continuity with the purge control valve and the GM BCS - it's connected. I also verified 12v switched to the GM BCS and while I was at it, I verified 12v switched with the purge control valve. I also inspected the entire wire and found no diodes - the 12v test pretty much confirmed that but I inspected anyways. The wiring is good!

I disconnected the purge control valve and did a run WOT - there is no change. This time I watched the boost on the PLX DM-6 while I datalogged - 11.2 psi and not a penny more!

I have to ask a fundamental question here guys...MAP = manifold ABSOLUTE pressure. So if the same car but was naturally aspirated was to do a WOT...the MAP would see roughly 14 psi which would be atmospheric pressure. If you account for pressure drops in the lines that would be roughly 13.0 psi. My understanding of BOOST is that it uses gauge pressure which does not account for atmospheric pressure. So if I see a BOOST of 11.2 psi, that is 11.2 psi above atmospheric pressure (gauge pressure). Add the 2 together and you get 11.2+13 = 24.2 psi.

15% duty cycle (plumbed normally closed):
MAP is showing roughly 24.2 psi
BOOST is showing 11.2 psi

So help me out here...if I want 18 psi of BOOST, does that = 31 psi MAP? (18+13)

[Spunkster]

A naturally aspirated engine will never make any amount of boost. I you are seeing 14psi without a turbo then you have your units set up incorrectly. Change your pressure unit base unter the units tab of settings.