I have built my own 3" twin exit exhaust, with 4x strait through mufflers and a exhaust valve to keep the noise down.

I have a pneumatic boost controlled exhaust valve on 1 of my exit pipes, it is shut under vacuum which makes the exhaust extremely quiet, eliminates the low db drone at idle and cruise rpms.

I have a turbosmart manual boost controller to adjust the amount of boost before it opens.

It reaches full boost by about 3 rpm, which causes a loud drone when trying to cruise under load.

Then I thought, I want it control it, to only open at a certain rpm, say 4 rpm and upwards.

Then I thought, sweet I have a spare wastegate solenoid that is rpm based and not being used.

So I hooked it up so that it bleeds off pressure, just like the factory system.

But the issue is, the solenoid does'nt do exactly what im telling it to do in the ecu.

I set it at 100% and it is only using 60% at idle, then under load conditions it is all over the place erratically.

It is being influenced by some other input that it is trying to adhere to.

Is there a way of telling it to stop listening to that other crap, and simply do what I tell you?

I was thinking of changing the address to (none) and see what happens .. But I don't reeally want to brick the ecu, so I just hooked up the mbc for now while I do some research.

Any ideas?

 

Interesting project. I was thinking about a valve controlled exhaust but it all got too difficult as I'd have to have someone else build it. Keep us updated with progress.

You may want to contact a some of the tuners for advice on the control signals. There's a Australian tuner on the forums 'beeble', I'm sure he could help.

 

the passivewgdc solenoid isn't influenced by anything else, or shouldn't be.

im assuming your using the passive one and not the active one?

 

I am using the active plug for the 3 port bcs.

Im trying to use the stock passive wgs to run the exhaust valve.
Yeh I thought the same thing aswel Tephra, but evoscan shows eratic behaviour (it reads 125% down to zero and everywhere in between) and also the exhaust is extremely loud, which backs up the conclusion that the solenoid is not doing what I am telling it to do, and openening prematurely.

Unless my evoscan lookup address is wrong?

Im thinking of using another 3 port bcs to control the exhaust properly, as in, shut all pressure from reaching the valve.

But there isnt much point if the ecu wont use what im telling it too..

Can someone test this for me please?
Set your passive wgdc to 100% throughout, and have a quick look with evoscan at what it is actually reading, try a quick pull down the road to see whether load has an influence on it?
Aslong as you are using a 3 port bcs ofcourse.

This would be very much appreciated!

 

What romid and memory variable are u using to log the passive wgdc? I'll confirm its right.

Now, you will need to make sure the valve is doing the right thing for the exhaust.. Boost is different from vacuum and you may/not need to bleed to atmo as well...

 

Rom Id 54560003 2009 JDM GSR
Evoscan is looking at 2380A52F

The Valve is boost operated, meaning, in its natural relaxed state, it is held shut with a 14psi spring, it then opens when pressure overcomes the spring.

There are 4 scenarios I could use

#1 Run the boost line off the top IC pipe directly to the valve, which will then open at 14psi + and shut again when the bpv releases pressure.
#2 Run the boost line off the top IC pipe directly to the valve, then T off to the stock passive wgs, to bleed back to the intake, (I have tried this manually in the workshop with the car set to 100%dc and a air compressor set to 20psi, and it did not relieve enough pressure to keep the valve shut, after which I found by datalogging the passive wgdc was set to 60%, so it might work if it opened to 100%)
#3 Run the boost line off the top IC pipe, directly through the stock passive wgs, then strait to the valve, I don't like this option, because it could potentially shut before releasing pressure back to the IC pipe, causing the valve to hold open.
#4 Run the boost line off the top IC pipe into the 3port wgs, back to the valve, relieving pressure to the intake with the third port, when shut again.

I like option #2 because it self bleeds and is cheap, but if it cannot bleed enough pressure to keep the valve shut, then it is useless.

Ideally I would use a 3 port, but if I cant control the input, what is the point? it will just do whatever it wants haha.

So now I need some help finding out how to control the passive wgdc, as when I logged it, it was allll ovvver the show ...

 

try logging 0x80a55f, thats the correct value to log (prepend it with 23 for Evoscan)...

 

Can you post some pics of the exhaust pls.

 

Thanks for the help Tephra!
Evoscan was logging the wrong address before.
Now it makes perfect sense.
I have used option #3 to block all boost from reaching the exhaust valve, with the stock passive ws, works a treat!
Have set values 0% upto 3500 then 100% at 4000+.
So it starts to open at 3500, just past the drone stage.
Sounds like vtec kicking in, only more monstrous.

Only thing on my mind is, I have T'd off the vacuum/boost line feeding the bpv .. Can anyone see any issues with this?
Delayed bpv response time?

The exhaust valve seems to be closing well within the time that the rpm drops, which then shuts the pws, holding what ever remaining vacuum/boost in the line going to the ev.
I would rather have a little vacuum in line to hold the ev shut while under full exhaust flow, as the ev opens just by blowing into the valve by mouth (which is very little pressure)
Is vacuum on a internal wastegate actuator super bad?
Premature diaphram failure?

Otherwise I will put a 3 port wgcs in place, to vent any remaining pressure/vacuum back to the intake to protect the ev. Fingers crossed the exhaust flow doesn't try force it open ..

 

in theory - you could even change the axis on that table to something else.. not just RPM... ie you could set it to vaccum/boost for instance... which might make things interesting...

 

Yes you could, absolutely,
People could chose between boost/load, rpm or even tps operated.
We must remember that this setup is electronic over pneumatic, so even thou the electronic valve says 'open' it still requires boost to actuate the exhaust valve.
So it's a bit of fun.

Went for a drive to my home through some winding country roads tonight, sounds soo nice, very comfortable cruising (barely hear the exhaust) gradually getting louder and angrier the higher you rev, not a hint of drone.
Foot flat at 3xxx and you get a back full of seat and a happy mrs listening to Money for nothing and your chicks for free ..

I will post some pics in a few weeks once I fix a couple issues.
Also a quick diagram as to hooking up the exhaust valve etc.
I built the exhaust a year ago, and have been keeping an eye on it, seems that, as it heats up and grows in length, the mounts I put on the rear mufflers are too strong and wont allow enough elongation movement, resulting in the bullet style resonator infront of the rear axle to mushroom up about 12mm worth (1/2" inch) which has pushed the tips out of square.
I have ordered a Jetex compensator to go in just behind the axle, just like the factory exhaust, to allow any twisting movement to grow and shrink comfortably, also I am going to take out the resonator and put in a strait pipe, if it makes any difference to the noise level, or creates a terrible note I will put a new one back in.
I highly recomend this setup for those who enjoy a nice comfortable journey, then a roar at wot!

 

I did a bunch of research to find out why exhausts get a drone, it's to do with exhaust pulse frequencies, to cancel out the low drone frequency, you need a physical wall to rebound the pulse back up a section of pipe of a minimum length, which makes it perfect by having a twin exit, I tried a simple strait through muffler on 1 side that flowed in a S shape, but it didn't work, as the pulse still exited the exhaust tip rather than going back up the pipe as it chooses the easiest exit first.
By using the valve right before the tip, with a muffler just in front of it, the pulse gets canceled out by the next pulse coming down the pipe and dispersed into the muffler.