A few questions -
Are the runs you recorded at wide open throttle, or at partial throttle?

By "Boost", I'm assuming you mean intake manifold pressure, right? Is that the number you're getting from the KLR? Something looks wrong - the number doesn't indicate vacuum in the intake manifold, but the dash gauge (I assume that's also being driven from the KLR...) does indicate vacuum.

Is the sensor that you have on the compressor outlet psig or psia? Are you sure that the sensor is defined correctly in your logging/graphing software?

Looking at the top graph in post 101, something doesn't make sense to me - at the starting point, the measurement box says that the compressor outlet is under slight vacuum, but the "Boost" is at zero. If the compressor outlet is in vacuum, I would expect the manifold pressure to also be in vacuum. At the second measurement box, the compressor outlet is reading 2.43 psi, but the "Boost" reading is still zero.

Same thing for the top graph in post 102 - it looks like you're in deceleration, with an afr of 22, rpms were dropping, throttle must be closed. I would expect to see a lot of vacuum in the intake manifold, and close to atmospheric pressure in the compressor outlet. Instead, both numbers are only .5 psi apart. Seems a little strange...

If you could post a graph with the measurement box showing values at idle, it may help clear things up.

One last thought - has anyone measured the pressure in the line that goes from the CV to the wastegate? Might be able to see if it's back pressure blowing open the wastegate, or the CV or KLR actually opening the wastegate.

A few questions -
Are the runs you recorded at wide open throttle, or at partial throttle?

Sox: At wide open…paddle to the metal.

By "Boost", I'm assuming you mean intake manifold pressure, right? Is that the number you're getting from the KLR? Something looks wrong - the number doesn't indicate vacuum in the intake manifold, but the dash gauge (I assume that's also being driven from the KLR...) does indicate vacuum.

Sox: It is from the manifold, the measuring system is set up to only report values above 14.7 psi so it ignores the vacuum.

Is the sensor that you have on the compressor outlet psig or psia? Are you sure that the sensor is defined correctly in your logging/graphing software?

Sox: It is gauge, and I have calibrated it with known pressure source while actually monitoring its output on a dvm and the logging software simultaneously. Both reported the same thing.
Transfer function used

Output (V) = {[0.8 x Vsupply/(Pmax-Pmin)]x (Pressureapplied – Pmin.) }+ (0.10 x Vsupply ) (ABP series sensor)


Looking at the top graph in post 101, something doesn't make sense to me - at the starting point, the measurement box says that the compressor outlet is under slight vacuum, but the "Boost" is at zero. If the compressor outlet is in vacuum, I would expect the manifold pressure to also be in vacuum. At the second measurement box, the compressor outlet is reading 2.43 psi, but the "Boost" reading is still zero.

Sox: Not sure I follow “post 101”
Boost will never show below 0 for my setup as explained above.
The compressor does lead occasionally I believe due to the delay in the pressure build up through the inter-cooler.

Same thing for the top graph in post 102 - it looks like you're in deceleration, with an afr of 22, rpms were dropping, throttle must be closed. I would expect to see a lot of vacuum in the intake manifold, and close to atmospheric pressure in the compressor outlet. Instead, both numbers are only .5 psi apart. Seems a little strange...

Sox: Same as above……

If you could post a graph with the measurement box showing values at idle, it may help clear things up.

Sox: see below

http://forums.pelicanparts.com/uploa...1583167730.jpg

I have looked at the WG to CV line, I put a gauge on this line and pinched it off to the CV so any pressure build up would be from the valve being pushed up by the exhaust.
At 22 to 25 psi Turbine inlet pressure there is an increase in the trapped air in this line.
Sox

How much pressure did you see in the WG to CV line without the line pinched off?

Also, another question about the last graph you posted:
http://forums.pelicanparts.com/uploa...1583167730.jpg

Your note says "Notice the fluctuations in the turbine inlet pressure with the engine power strokes" - each tick on the x-axis looks like 0.1 seconds, which matches the times in the measurement boxes. That makes the peak-to-peak time between the peaks in the turbine inlet pressure line about 0.5 seconds. If the engine is running at 778 RPM, that means that it's at 12.967 revs/second, which means that 1 rev = 0.077 seconds. A four cylinder engine fires two cylinders per revolution, so you should see peaks every 0.038 seconds, if it is matching the power strokes, right? Or is something else going on?

Yah you are correct...will do some more digging. It (turbine pressure) looks very erratic., maybe caused by the turbine spin up and idle coast in between ignition events? My rpm was steady and also when I took the line of the sensor I could fell the puff, puff coming out of it consistently, with the power strokes.
Will explore and post.
Sox

Haven't forgotten this thread...
Maddog is down with a clutch replace. Will resume after the car is functional again.
Sox

I am bored....hunkered down in my impenetrable bunker for 2 weeks or what ever, so here is an updated map showing the theoretical ability of the k26-6 attached to a 2.5 well 2.495 liter engine.
Sox

http://forums.pelicanparts.com/uploa...1585855836.jpg

Ok back on this project again. Since car is now running and in good shape.
Re-calibrated the 3 pressure measuring sensors, I can't get rid of the slight discrepancy between the car's boost gauge and other pressure sensors.
Anyhoo did a test the pic posted here is for change from 3rd to 4th gear and then WOT till traffic interfered. Line to WG was pinched off as I just wanted to test the WG's spring without the KLR bleeding the boost.
The compression on this page makes the data boxes too small to read so I posted them separately.
Sox

http://forums.pelicanparts.com/uploa...1599420601.jpg

http://forums.pelicanparts.com/uploa...1599420874.png

Another run, with CV enabled and a sensor attached to the CV to WG control line.
Looks like about a 4 PSI difference in boost. The sensor outputs have some smoothing done to get rid of the spikes.
Sox

http://forums.pelicanparts.com/uploa...1599672060.jpg

Data boxes expanded....

http://forums.pelicanparts.com/uploa...1599672450.png

that looks way more complicated than this one:

http://www.supramania.com/photobucke...psd06edf85.jpg

http://forums.pelicanparts.com/uploa...1599925396.gif

Well my WG/turbo is characterized now, so on to my target of 13 to 15 psi of boost.
Sox

Quick note, what I tried to do so far is to change the gain of the amplifier that the pressure sensor drives. So the signal coming out to the KLR processor is lower than the actual value of the boost.
This causes the KLR to delay bypassing the boost to the WG till a higher number is achieved. In my case the KLR thinks 13 psi is 10 psi. So it lets the pressure build up to 13 plus psi before actuating the WG. Of course at 13 psi the exhaust is already blowing past the WG valve. (See last couple of posts).
This works as far as getting higher boost from the car..There are two issues with this approach.
-1 the car's boost gauge reads low, no biggie as it is not very accurate anyway.
-2 the high boost cut off from the KLR becomes harder to set, because the sensor runs out of usable range at about 14.5 psi.
The low boost side continues to work, with the low boost fault getting set at a 3 psi higher point than before.
The rest of the KLR functionality is retained.
The above reads pretty convoluted...short version trick the KLR into thinking the boost is 3 psi lower than it really is.
Opinions, pitfalls etc. That I am not seeing ?
Sox

Correct knock retard for 3 psi higher boost pressure?

Mike G.

Knock retard will happen at the same place. The retard for high boost will shift by 3 psi.
Sox

i don't recall anyone trying to trick the KLR into thinking the boost is 3psi lower than actual, but if someone would know this trick it would be josh at rogue tuning because he basically reverse-engineered the whole thing. here we are 30+ years later and it's not a common hack so i'd be super surprised if it actually worked.
Rogue Tuning - Tuning freeware:

The 3 psi increase does happen. It's probably a path less taken as it required a redesign of the electronics in the pressure sensor.
If one has already de compiled the code and knows where to modify it...that would definitely be the better approach.
As I said this works, but to get the over boost protection I am going to use a sensor with a larger range, so it does not run out of "headroom".
Finally the KLR's native control of the CV is very jittery due to the processor getting reset at each trigger event. This causes spikes in the boost signal and erratic control of the CV.
I am designing a software based filter to read the output of the KLR and then use it to continuously modulate the boost control. The existing CV is not meant to be used for precise PWM.
This thread seems to getting tangled up in my KLR thread :)
Anyhoo will keep y'all up dated.
Sox

another issue contributing to inaccurate control of the wastegate is that the factory wastegate is a single port. converting to a dual-port wastegate improves control.

also, why not add some sort of physical restriction/control to the KLR boost sensor line to consistently reduce the pressure by 3psi? that seems easier than re-engineering the electronics.

It would be hard to do a consistent job..as the line to KLR does not have an outlet to be able to maintain a 3 psi differential.
I am moving this discussion to my KLR thread as the WG part is done.
Sox

Agreed..I am trying to do this with the existing WG. Hence the new control and PWM method.
Sox

I don't know what that means but what I'm saying is that the ign might need to be more retarded at this higher boost level for the same RPM vs WOT to reduce the chance of knock occurring.

Mike G.

sox, i have heard and read many have tried to control the factory single-port wastegate at higher boost levels and have either given up or converted to a dual-port wastegate. i believe the factory wastegate is mechanically incapable of providing the type of fine control you're seeking, regardless of how quickly/accurately you can control the cycle valve.

the solution for me was to go with a dual-port wastegate and an aftermarket solenoid (more accurate/faster than the factory CV) to control boost better.

i hope you succeed but hate to see you waste your time.

I think I understand what you are asking...The ignition retard vs boost and throttle position will change. It will move 3 psi higher, or pressure related retard will happen latter. I don't know if this is enough to cause knock that the knock sensor driven retard will not be able to overcome. Will monitor and report.
Sox

I am using a new PWM controllable solenoid instead of the factory CV, see my post in KLR part 2. As to the WG being unsuitable for more precise control, I don't see why a pressure/spring combination could not achieve better control. Will find out....being retired has it's advantages :)
Sox

Stolen form another site :D

http://forums.pelicanparts.com/uploa...1600275093.jpg


Mike G.

lindsey is a great knowledgeable guy with great tech articles, a lot are geared towards selling more products and providing product-specific information. as such, he only mentions in passing the dual-port dual-solenoid solution which provides the best boost control. all three examples show what's known as a two or three-port boost controller and leaves out the critical fourth (and best) configuration which uses a four-port boost controller that takes advantage of a dual-port wastegate. a manual boost controller can not operate as a 4-port controller because it requires constant variable on-the-fly adjustments, so you must get an electronic boost controller to take advantage of a dual-port wastegate.

honestly if anyone is going to use one of those three examples (with a manual boost controller!) they are wasting money buying a dual-port wastegate.

more details here:
https://dsportmag.com/the-tech/education/science-boost-part-1-solenoids/5/

and here is an example that takes advantage of a dual-port wg:
https://tier1motorsports.com/collections/mac-control-solenoids/products/mac-4-port-boost-control-solenoid-valve-for-dual-port-wastegate-46a-aa1-jdba-1ba

edit: a quick search on lindsey doesn't turn up any electronic boost controller so it looks like they only sell manual controllers, which explains why they only show the three boost control configuration examples and ignore the fourth.

here is the fourth and best configuration to control boost. this configuration also allows you to use lower spring pressure so if the controller fails it will default to practically zero boost, providing an additional failsafe against damage.

note the 951 factory cripple mode still gives some boost because it's a single-port and relies on higher spring pressure. increasing the factory spring pressure increases cripple mode boost and bypasses the failsafe.

http://forums.pelicanparts.com/uploa...1600357241.JPG
http://forums.pelicanparts.com/uploa...1600357241.JPG

Nize the 4 port you have posted above seems to be a on/off system...I am looking for proportional control in my solenoid.
if that is a proportional control solenoid can you post a part number ?
Thanks Sox

Ignore Nize..should have followed the links above.
Sox

I think its one of these guys

https://www.ebay.com/itm/NEW-MAC-4-PORT-BOOST-CONTROL-SOLENOID-VALVE-SENSOR-turbosmart-haltech-aem-apexi-/322993893903

Mike G.

Run with new KLR control system....no tweaking yet. WG is still orignal, no CV.
Sox

http://forums.pelicanparts.com/uploa...1600381574.jpg

Pic of the gauges
Sox

http://forums.pelicanparts.com/uploa...1600381810.jpg

just to clarify, the solenoid is on/off but cycles between on/off quickly, and controlling the cycle rate/pulse is how you control boost proportionally. :) this is the advantage over a manual boost controller.

trivia: the 951 factory cycle valve is called a cycle valve because that's exactly what it does. :)

Thanks Mike.
Sox

Nize, Mike et all would y'all go and look at my post in the KLR part2 and opine?
Thanks
SOx

So after doing the characterization of the stock WG and it's control, next was to to do a dual port with a 4 way solenoid control valve.
I have a Tial I am playing with but decided to see if a stock WG could be modified to become a 2 port WG. Much easier to install and no modification/fabrication to the exhaust system.
Short answer is not really....
First I welded the 4 vent holes in the stock WG. Then I put a crush washer to prevent leaks from the top chamber when it is reverse pressurized. Finally I put a 1/8 inch npt 18 barb into the side to introduce air into the bottom part of the WG to hold it closed against the exhaust pressure.
See pics.

http://forums.pelicanparts.com/uploa...1603211629.jpg

The copper crush washer did not work, it leaked as it was not large enough.

http://forums.pelicanparts.com/uploa...1603211752.jpg

Th aluminum crush washer worked to seal the chamber, and it held pressure in both chambers.

http://forums.pelicanparts.com/uploa...1603211853.jpg

Barb installed, notice the welds for the vent holes.

http://forums.pelicanparts.com/uploa...1603211964.jpg

So here is the problem, the piston that moves up and down inside the the WG,s body runs flush with the walls. So any protrusion into the chamber, like the threaded end of the barb interferes with the motion of the piston.
It may be possible to install a smaller barb into one of the vent holes, but did not look very feasible.
So chalk it up to a learning experience.
Sox

This is where the Tial 46 is ideal, except for the price!!! $500!!

Mike G.

sox; it looks like you have a tial wg sitting on your bench, but you're trying to frankenstein the stock wg? :) why don't you just use the tial!?!?

also, don't feel bad about failing to frankenstein the stock wg into a dual-port, many have already tried and failed, which is why the tial wg is the solution.

lindsey has a successful halfway-stock dual-port conversion but it costs almost as much as a tial:

https://www.lindseyracing.com/mm5/gr...-951-WG-1d.jpg

Nize cause it's more fun :)
Sox

also, make sure you don't get a counterfeit tial!
TiAL Sport - Spotting a Counterfeit TiAL

fake vs real how-to:
https://www.youtube.com/watch?v=__Jzk0XXvr4

fake vs real teardown:
https://www.youtube.com/watch?v=2nOPLxln5Ec