Hey guys,

Trying to find a bit more infomation on a setup as such. Seem to be alot of people with larger engines (supras etc) running this setup but have not found much on our 4cylinder honda engines as of yet.

The setup would be useing a single scroll manifold with a twin scroll turbo and a Quick spool valve (SPQSV).

Here is the unit



Wanted to know if anyone has any real life experience with a setup like this? Also what the pros and cons would be ? could this unit actually act as a restriction since all the exhaust is directed down a single side of the turbo? also any difficulties tuning, getting flatspots at crossover with your power band etc?


Cheers guys

 

I guess its that time of the year for another one of these. better get my

 

Please be sure you are talking about a Twin Scroll. not a divided housing.

In4shitstorm.

 

I have not any of my own experince but I have seen it being used by a shops bmw turbo. It worked great in the beginning and they gaind spooltime and low tourq but they desided not to sell them. They were not consistent and after some time it got stuck.

 

99% of all turbine housings that aren't single scroll are simply divided.... there's a huge difference between the two

now the valve does work, thats been proven.... what takes some time is determining wheen to have the valve open....

heres how i would do it.... do a complete pull with the valve closed, then another with it open.... where ever the torque curves cross is where i would switch the valve open... i do the same thing with the vtec crossover point

 

....id run the actuator referenced off of regulated drive pressure. have the actuator start to see pressure @ 1.5 x of desired boost pressure.... maybe. just my theory....
so if you want 20psi of boost, the spool valve will open at 30psi of drive pressure and maintain that drive pressure throughout the powerband. Regulate boost pressure with external gate.... dunno. try it. see what happens

 

Wasn't there just a thread about this?

 

has there been any unbiased dynos besides the one provided by the manufacturer?

 

Yes i apologies for this, after i listed my thread i actually just realised that another thread on the same topic was recently just brought back to life

 

pressure level shouldnt matter.... it should be where the power starts to drop off with the valve closed vs. it being open

thats why i would do it like setting the vtec crossover point...

where ever the open/closed power (or torque depending on your personal preference of more torque) lines cross is really where it should open, keeping it closed too long can cause excess backpressure and cause power loss or even reversion.

so it shouldn't be boost dependent but rpm dependent

 

Thats why it should have some sort of drive pressure reference (pressure seen inside the exhaust manifold)

 

again, not drive pressure.... any sort of pressure will open it, it stays closed with the absence of pressure, not even vacuum.
drive pressure has no correlation between spool, torque and pressure

thats why they say you can control it one of two ways, with an adjustable hobbs switch or through a pwm output with an ems.

the best way to utilize it would be to control it by pressure vs. rpm

so at cruising loads its open to minimize backpressure and maximize economy.... you don't want it closed all the time out of boost as the backpressure would be sky high and actually hurt engine performance.... but once you reach the positive pressure threshold (like 0.1psi) it closes until the predetermined pressure and rpm is reached. think of it like a boost controller... but with an added rpm requirement

you could even do it tps vs. rpm so its open all the time until you reach a certain tps value then it closes again until a preset rpm and opens back up to lower backpressure and maximize performance. so say above 60% throttle it closes.... or any tps value you would deem outside of the range of cruising throttle input.

but the best way to do it really is rpm vs. pressure.

now I don't know if you can open it under vacuum, that isn't covered in the video or anything I can find. The way to go would be put a dual port wastegate on it so vacuum can push it open... solenoid cuts off vacuum supply and it closes, then the pressure signal is sent to the top port to open it.