Dus10

I like the fact of being able to use ECUFlash as the Boost Controller so that if it detects any bad mojo it can detune the motor. Given the fact that the stock Boost Solenoid has a dump restriction which physically limits the amount it can dump I'm just curious if the stock Boost Control Solenoid is all that great. Would it be worth it to get the Perrin EBCS for $69? Does it control the wastegate any better? I know that some people remove the restrictor pill from the BCS to get it to dump more pressure off and then they restrict the pressure from the Turbo manifold hose to in affect lower the pressure acting on the wastegate actuator to get more boost, but can't a good Boost Control solenoid fix that problem?

Can a Boost Control solenoid finely adjust the amount the wastegate opens or closes? Or is it all the way open or all the way closed? Or is that a physical function of the vacuumn hose / restrictor size?

Evidently the stock vacuumn line is physically too small to allow the pressure to vent off enough to close off entirely the wastegate at high rpms. Hence why Work's say that you can remove the hose entirely from the BCS which allows it to vent at a 100% but the boost will still taper off in the higher rpm range, cause the hose is physically too small to vent off all of the pressure and there is enough pressure bypassing it and making its way to the wastegate actuator.

mrfred

iTrader: (50)

Besides removing the restrictor pill, a bleeder can be added before the BCS. This will lower the baseline pressure in the wastegate hoses, and then the stock BCS can be used to provide higher boost with a slightly flatter boost curve by changing the duty cycle tables.

jcsbanks

An alternative solenoid with 3 ports can help control because it can switch the actuator from the compressor outlet at 0% duty to atmosphere or the inlet tract at 100% duty, and all this without restrictors.

However, what causes taper is the exhaust manifold pressure opening the wastegate. This still happens even if you vent the actuator to atmosphere where it will see no boost. (NB doing this in the midrange would obviously result in a large overboost that your octane and mapping may not support LOL).

Stronger actuators to overcome this are also not always a help because they increase MAP at the expense of a larger increase in EMAP. VE can be thought of as MAP/EMAP. It is obviously flow we need rather than pressure.

MalibuJack

iTrader: (5)

I've actually quite a bit of experimenting with the GM solenoid, it ended up working out really well with the UTEC, but it eventually burned out.. the Perrin probably would work better, but you have to make sure you don't burn out the BCS driver on the ECU so if you do experiment with other BCS solenoids, don't forget to put a resistor inline to cut down the current (both to keep from burning out the solenoid, and drawing too much current through the driver itself and burning it out)

The funny part is I know next to nothing about using ECUFlash to adjust/tune the boost, I ended up using an Apexi AVC-R because of the type of testing I'm doing among other features it offers.. Honestly though, the built-in boost control, when its configured correctly, does offer similar features such as gear based boost control and other protections.

increasing the signal to the actuator will overcome the wastegate blowing open causing taper, adjusting the preload on the actuator arm will also help, but it increases spiking.

Using a 3 port GM or Perrin solenoid lets you use an unrestricted signal, and you can use it as a restrictor system in-line from the boost source to the actuator.. Or even as a bleed system (similar to stock, and more commonly used on External Wastegate setups) without the need for any restrictors.. However you need to readjust all the settings and work your way up since you want to be sure you don't get more boost than you need inadvertantly.

I left my stock solenoid intact since I eventually want to experiment with it as a bleed system with my Tial wastegate.. But not until I have the car safely tuned..

Evo_Jay

iTrader: (17)

Im am working on comlete boost control using the stock boost solenoid & ECUFlash. So far, Its working pretty good and and I seem to have complete control. I still need to do some more things like.....

1)I need to get some race gas and test out boost levels above stock (24+psi). It looks like its gonna work fine, but I still have to test it.

2)I kinda want to get the boost error correction to work. Right now I have pretty stable boost curves with the boost error correction turned off, but it would be very cool if I could get the error correction to work and have tabletop flat boost curves.

3)I need to take some more logs and get the whole idea of the control.

example, I would like to be able to tell people that if they mod the lines like I did and run WG @ 45-55 and have the correction table set up like so, it will result in a perfect 21 taper to 18, etc.

Also, after I get everything figured out, I have to write a good how-to. Hopefully I'll have everything done with in the next week or so.

jcsbanks

I would say that the boost error correction table - if you are changing it at all - should initially be scaled to smaller correction values on the right hand side of the table if you are running smaller duty cycles. Since it is set around 100% max duty cycle, you could use half the values in it to reduce oscillations if you actually only need 50% max duty cycle. This will keep the proportional and integral gains (the system is a combination of the two) closer matched to what is required. Bigger turbos will probably need smaller correction values again as the response time to duty adjustments is slower because of the heavier rotating mass, so the turbo changes speed slower when the wastegate is moved.

Evo_Jay

iTrader: (17)

^ that is exactly how I thought it would work. My new WG duty is around 40-60% and since its half of what it used to be (100%), all the correction number should be adjust accordingly (divide by 2).

I would liketo try & figure out what the different WG tables (#1,2,3) are for. FIrst I was gonna adjust on table real low, then drive around and see when the car boost real low. Repeat and try to figure it out. I pretty sure that each WG table i.e. #1, correclates to each "boost desired engine load" table i.e. #1. If this is so, you could maybe work out gear based boost control. I believe each gear goes to a different load (1st has the least load, 5th/6th the most), the you could use each table to see up boost for different loads (read-gears).

Anyways, if you know anything about how the WG tables correlate to the desired load table, that info would be greatly appircated.

jcsbanks

I didn't decipher it because on my JDM/UK IX I have two solenoids with 7 wastegate tables and 4 desired engine loads. I'll see what I can tell from an Evo VIII ROM - since I have RAM locations for speed, RPM, coolant, I might find routines that help it to decide. Everything that I can explain reasonably well or partly I will post up as usual.

jcsbanks

IF RAM location FFFF8890 bit 5 is
set use wastegate and boost map 1
clear use wastegate and boost map 3

IF RAM location FFFF8A2C<decimal 255
use wastegate and boost map 4

#2 maps don't appear to be referenced directly, although there could be an indirect method of access. This ECU's code is compiled and not nice to follow.

I've labelled the maps in the order they appear in the ROM, ECUflash seems to do the same so they should match.

Evo_Jay

iTrader: (17)

^ Is this for the VIII or IX??
Also, when you say 'set use" and "clear use", what do you mean??

Also, I already changed my boost correction accordingly, so I'll be testing that out tomorrow.

jcsbanks

If bit 5 is set or clear, then use one of the maps. Bit 5 is a flag. FFFF8890 seems to be one of many status variables the ECU uses. FFFF8A2C does appear to do something with vehicle speed, but I can't tell what.

This is for the VIII, but the IX will undoubtedly be the same with different locations.

Spooldyou

iTrader: (52)

that would be really Sick if you could use it for higher boost levels. 25+ That would cure that problem that i have of spinning all the way through first.

chrisw

iTrader: (2)

are you sure it's vehicle speed? I have been playing around with the stock BCS too and I have noticed that the selected boost and wastegate tables seem to be more driven by TPS more than anything else.

I think that makes sense, since opening or closing the throttle is directly proportional to the amount of boost you are going to run.

jcsbanks

The Evo IX US models appear to use boost 1 and wastegate 1 as a pairing. Boost 2 and wastegate 2 do not appear to be referenced directly from anywhere. Boost 3 and wastegate 3 do not appear to be used in the standard setup as they reference data values that effectively disable them. It is these #3 that seem to link to speed/gearing, but the code is convoluted.

The code also references another pair of boost and wastegate maps, but they are just headers, and oddly on the Evo IX US seem to run into the header and part of boost 3 and wastegate 3 which makes little sense either.

So I would suggest modifying boost 1 and wastegate 1 to start with.

There is logic that looks at octane value, coolant temperature and RPM as well as other stuff in there. But I can't link the variables between the routines.

My JDM/UK IX seems to use boost 1 with wastegate 1 and 2 (2 solenoids), or boost 3 with wastegate 4 and 5, or boost 4 with wastegate 6 and 7 (this last one seems to be equivalent to boost 3 and wastegate 3 on the US IX). Boost 2 and wastegate 3 are not referenced directly.

On the US VIII, boost 1 and wastegate 1, or boost 3 and wastegate 3 are used, with boost 4 and wastegate 4 being again the equivalent to boost 3 and wastegate 3 on the US IX. Wastegate 2 and boost 2 appear unused.

Mivecless

Ack, get an aftermarket EBC and call it a day.