BCS testing data
Nov 2, 2008, 05:44 PM
#19
The BCS testing thread
I finally got around to setting up all the equipment needed to do some realistic measurements of how well a BCS can relieve boost pressure at the WGA. The test setup is as follows:
- Air pressure source set to 28 psi.
- Water hammer arrestor used to simulate a WGA
- 30 psi pressure gauge in-line with the simulated WGA
- Tubing, fittings, etc.
- 14.0 V system voltage
- Variable resistor that can be set to anything from 1 to 10 ohms
- BCS wired in series with the resistor.
- 20 Hz square wave signal generator with adjustable duty from 20% to 80%.
I finally got around to setting up all the equipment needed to do some realistic measurements of how well a BCS can relieve boost pressure at the WGA. The test setup is as follows:
- Air pressure source set to 28 psi.
- Water hammer arrestor used to simulate a WGA
- 30 psi pressure gauge in-line with the simulated WGA
- Tubing, fittings, etc.
- 14.0 V system voltage
- Variable resistor that can be set to anything from 1 to 10 ohms
- BCS wired in series with the resistor.
- 20 Hz square wave signal generator with adjustable duty from 20% to 80%.
I know that typically mechanical response greatly out weighs electrical response in most systems, but I'm just wondering if the signal generator you used can produce significantly higher instantaneous current then what the stock ECU driver can do?
Nov 2, 2008, 05:56 PM
#20
Would the driver in the ECU change the response characteristics of the BCS system?
I know that typically mechanical response greatly out weighs electrical response in most systems, but I'm just wondering if the signal generator you used can produce significantly higher instantaneous current then what the stock ECU driver can do?
I know that typically mechanical response greatly out weighs electrical response in most systems, but I'm just wondering if the signal generator you used can produce significantly higher instantaneous current then what the stock ECU driver can do?
Nov 2, 2008, 06:21 PM
#22
Ill be sending you a Ingersoll rand one probably sometime in the next week or so. Kinda hard to justify to my wife that i am sending out something that cost outta pocket with a newborn lol. Gotta go into my G14 classified expenses hahhaa, but you can keep the GM one i sent you and you can also keep the ingersoll rand when you get it.
Nov 3, 2008, 11:56 AM
#24
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ok, got it (again). :-) I need to spend some time looking at the subroutine to drive it in.
I'm sure that the BCS driver hardware in the ECU is just an SSR controlled by the processor. An SSR will give a nice square wave by virtue of its design. I used the signal generator to control an SSR, so I'm sure the wave I used is essentially exactly the same as the wave produced by the ECU. What would vary on the car though would be the driving voltage. Its going to be the battery voltage. I used 14 V because that's where the voltage on my car sits. If the voltage goes a bit lower, the latency might increase slightly, but not by much, probably by less than 1/2 of a millisecond.
I'm sure that the BCS driver hardware in the ECU is just an SSR controlled by the processor. An SSR will give a nice square wave by virtue of its design. I used the signal generator to control an SSR, so I'm sure the wave I used is essentially exactly the same as the wave produced by the ECU. What would vary on the car though would be the driving voltage. Its going to be the battery voltage. I used 14 V because that's where the voltage on my car sits. If the voltage goes a bit lower, the latency might increase slightly, but not by much, probably by less than 1/2 of a millisecond.
My calcs gives 60ms
Nov 3, 2008, 04:42 PM
#25
Both the GM and the Prodrive have a resistance of about 24 ohms. The stock BCS has a specified resistance range of 29 - 36 ohms. Should be safe to use a 5 ohm resistor, and a 5 ohm resistor gives 95% of the performance of a 1 ohm resistor. No resistor is probably ok too because the circuit current is still very low with no resistor. And razorlab says he's got a few customers that have been running the GM with no resistor for over a year.
Thats what I am using in my GM 3 Port Setup. I used three 1/2 Watt 15 Ohms resistor in parallel to produce an Req of 5 Ohms and 1.5 Watts in power. That gives the 29 Ohms min as per Service Manual and provides a lower voltage drop and therefore faster response for the solenoid activation. A 5 Ohms produces 11.1 Volts and 10 Ohms produces 9.5 Volts at the soleloid coil based on a battery Voltage of 13.5 Volts. Power rating of a single 1/2 Watt 10 Ohms resistor is 312.5% and three 1/2 Watt 15 Ohms in parallel is 72%. Both assuming 100% DC which is not the case for the GM 3 Port.
One watt 10 Ohms resistor are not common unless you use a Ceramic resistor which is huge. Still using a 1 Watt 10 Ohms produces a rating of 156%. Thats the reason I decided to go with the 3 in parallel setup. Maybe I am paranoid but I just wanted to be on the safe side.
Using the GM 3 Port without any Resisitor could pottentially overdrive the ECU driver output for the boost solenoid. But since you are not always on boost and not at 100% WGDC while boosting it is not easy to burn the Solenoid output on the ECU. And as you said there is people running without any series resistor for soemtime now. For me 5 Ohms is a good tradeoff.
Last edited by racer135; Nov 3, 2008 at 04:54 PM.
Nov 3, 2008, 05:04 PM
#26
Most people I know run 100%wgdc in the lower rpm range to improve spool up so during the majority of cruising conditions there is full current going through that circuit.
Running 2 10 ohm/1 watt resistors in parallel to form a 5 ohm/2 watt resistor from Radioshack HERE would be the best solution. There would only be roughly 0.6 watts passed thru each 10 ohm resistor.
Running 2 10 ohm/1 watt resistors in parallel to form a 5 ohm/2 watt resistor from Radioshack HERE would be the best solution. There would only be roughly 0.6 watts passed thru each 10 ohm resistor.
Last edited by Jack_of_Trades; Nov 4, 2008 at 11:32 AM.
Nov 3, 2008, 05:50 PM
#27
On my car cruising is not 100% WGDC. It only goes to what the table says when I step on it. I believe some 03 and 04 ROM IDs are at 100% while cruising but mine is not. Mine (96420008) behaves like the 05 in that respect.
I do not like to use 100% up too high because I once overboosted while driving at 5th gear at I believe about 20 or 30 mph. If you do a 3rd or 4th gear pull you will not overboost because there is not enought time on that RPM range but could if you go too high on the RPMs for the 100% DC while trying to accelerate in 5th gear.
Those two 10 ohms are a good choice. I guess they were not in stock when I went to my local RS.
I do not like to use 100% up too high because I once overboosted while driving at 5th gear at I believe about 20 or 30 mph. If you do a 3rd or 4th gear pull you will not overboost because there is not enought time on that RPM range but could if you go too high on the RPMs for the 100% DC while trying to accelerate in 5th gear.
Those two 10 ohms are a good choice. I guess they were not in stock when I went to my local RS.
Last edited by racer135; Nov 3, 2008 at 05:59 PM.
Nov 3, 2008, 06:28 PM
#28
The lowest rpm value I have in my base WGDC table is 3000rpm and I have it set to 100%. Any rpm below 3000 rpm seems to use what is in the lowest RPM value on the table (MrFred can correct me if I'm wrong). My WGDC tapers down quickly after 3000rpm until peak boost.
Do drive in 5th gear at 20-30mph often?lol I would think the error correction would have MORE time to control the overboost condition in a long gear rathe rthan in a shorter gear?
Do drive in 5th gear at 20-30mph often?lol I would think the error correction would have MORE time to control the overboost condition in a long gear rathe rthan in a shorter gear?
Nov 3, 2008, 11:15 PM
#30
The lowest rpm value I have in my base WGDC table is 3000rpm and I have it set to 100%. Any rpm below 3000 rpm seems to use what is in the lowest RPM value on the table (MrFred can correct me if I'm wrong). My WGDC tapers down quickly after 3000rpm until peak boost.
Do drive in 5th gear at 20-30mph often?lol I would think the error correction would have MORE time to control the overboost condition in a long gear rathe rthan in a shorter gear?
Do drive in 5th gear at 20-30mph often?lol I would think the error correction would have MORE time to control the overboost condition in a long gear rathe rthan in a shorter gear?
the 05-06 are 0% WGDC until the load is reached in that "Min Load for Boost Control" table.