Internal Wastegate control: single port/vs two port

[sutol]

Hello,
I wanted to hear some opinion of the benefits of running two-port internal wastegates (IWG75 by turbosmart) vs a single port, and 4-port MAC valve vs 3-port one correspondingly.
I have an ecoboost 2.3 engine, and I am keeping stock turbo but using GDI4 ECU. My car is very light and traction-limited. Boost target max is 1.7Bar. Exhaust is pretty well flowing with no catalyst, and 3" downpipe, so I don't expect much backpressure.
I have not programmed the wastegate control before, however very willing to learn, even if SCal wastegate setup looks frighteningly complex

[RICE RACING]

I personally use Phase + Anti Phase control on IWG (and EWG) cars, gives a wide control range.
Hardware needed 2 x 3 way valves, can be a mixture of different types (IE: Pieburg OEM type + a common MAC on anti phase) is not an issue

[sutol]

Thank you,
that would probably allow me to use a low pressure spring right? I actually have a stock valve and a MAC one, so could already make that combo.
I have heard advice not to connect the pressure sources with a T but to run two separate hoses to the intake plenum...? (So I could try to repurpose the the fitting on the turbo to be a temp/pressure sensor)

[RICE RACING]

Yes you can run a lower spring, its determined though by the size of the WG flap cross section and basic P=F/A taking into account the TIP and the counter forces provided by the anti phase at 100% duty as to how much you can physically hold shut while the phase is fully bled off.

In regards to the T supply, or even the valves type and distance from the WG the line size and valve flow has impact on cars that have very fast transients, EG: say you have a car with 6 speed and higher rear end gear and 1000bhp that will do > 2 seconds in any gear below 200kph, then the speed with which it can fill or empty the relevant area's becomes an issue. Not in your case but have seen this in a twin EWG manifold used on a single turbo inline engine application running single Pieburg valves not being enough to do the job, for those cases you use bigger lines and larger flowing valves

[stevieturbo]

The only thing you can do is try it, run a light spring and if you struggle to achieve top end boost with that spring plus full duty applying pressure to blow the gate closed, then yes you'll need a stronger spring.

A 4 port is one option, but you can pretty much do the same thing with a 3 port solenoid too with the only caveat to add a very small bleed hole to the chamber or line to the chamber that blows the gate closed. This just makes it a lot easier to get stable control everywhere, with only a very small potential reduction in max boost available.

2 solenoids as per phase/antiphase is another option which will give you more control options...but probably is not needed.

[sutol]

Thank you mates for the advices!

I have some stuff to play with, so will give it a try.
I have 35 series MAC valve with three ports, one similar volvo unit that is stock on the motor and two GM units, that are supposed to be very responsive.
If even the benefits would not be really perceptible, I still would like to use two 3-port ones and run phase/anti-phase. I guess I would start with GM, or would you say that one GM and one MAC is better? MAC flows more, but probably for the two-actuator setup probably that is not important as much as when one actuator does all the job?

The waste-gate actuator is Forge two port one and they gave me a bunch of springs to play with. Right now the car is very far from firing, the ECU wiring hasn't even started (I hope to make a thread here once I begin the electronic side) so I am doing the plumbing.

About plumbing... RB racing is advising (with reference to Pectel) to run the source to intake plenum, not to compressor outlet as I see done usually, and to run two separate lines instead of a T joint.
https://www.rbracing-rsr.com/sq6m_wastegate.html
Why? would you do that?
The third port of each solenoid i just leave open into air or it would be a good idea to join them and run into compressor inlet?

Thanks!

[sutol]

Anyone has inputs about the boost lines?
I am going to use two thre-port GM solenoids – one for lower and one for upper can of IWG actuator.
https://www.rbracing-rsr.com/sq6m_wastegate.html mentions that the boost source (metal port on my solenoid) is plenum, not compressor as I used before for single solenoid setups. Also they advise not to T the source for two solenoid but to run two separate lines... Why?
Also the vent line, do you normally have it VTA or you plumb it back somewhere?

Thank you!

[thisguy]

Having read pretty much all of the RB Racing articles, they have a theme of "We do this because of some data, testing, failure info that we have gathered from the 40 years or something of racing that we have done.". To say that anything they say should be followed to a "T" (lol) is a bit excessive. I personally believe in using compressor pressure for wastegate reference. I would rather have the extra 1-3psi over MAP to control the wastegates. I cant see why this would be an issue. They must have had some type of issue or failure or it may be the type of wastegate strategy they run.

Now for running separate reference points to the solenoids, I have never done this but, I can see where a single failure can effect the total boost control can result in engine damage. If you are running a Phase/Anti-Phase boost control with separate pressure references a single fittings or hose failure would result in some boost control.

If you are running some type of MAF or metered air flow system you would want to run the vent of the solenoid back into the pre-turbo intake. if you are running anything else it makes no difference.

[RICE RACING]

Bob is a nice bloke, but his way is just one, same for his articles. The boost control stuff is a basis or simplistic description, and does not cover all permutations.
If you search here on the topic you will see 'good' information from pat who knows all there is to know on this, so no point me retyping it.

Same if you need someone to set it up (don't want to waste time, money, stress), give you diagrams etc, send me a message, not free but it will be right

[T04GTR]

what peter said,
mine works quite well. even with my lack of fine tuning. 10 psi springs,iwg75's efr7163's x 2 ~1000hp at wheels. vq35hr. have been up to 35 psi with room to go higher. i used 4 old apexi smc mac style valves. (changing to perrin bullet valve units)
4 ports do work, but i have found that they have a very narrow window. ie :10-20% duty range between lowest boost and maximum boost. (your fine tuning in closed loop has to be on point to make them work, and you cant tailor they way it works re: phase vs anti phase duty curves.
basically you kind of want to be able to manipulate the way each valve is driven independently to compensate for system characteristics.