Question for the Tuning Shops??????

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ChiefMC

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Has anyone tried to run twin stock turbos with larger injectors instead of switching to a modified VGT turbo or a non VGT turbo?

I am just making the assumption that if you can keep the vanes shut for a longer period of time it would eat up some lag and give you double the air flow, thus being able to clean up say 190 or 225 injectors, instead of having to use nitrous. I think the driveability would be ok as well especially if you factor in the advances in FICM tuning.

Can you split the signal from the computer to run both turbos correctly at the same time.

I know you could modify both the CAI and the intercooler to accept twin inputs or you could converge them into one.

Tuners let me know......
 
not a good idea. It has been tried and with very little success.

Back pressure is high enough with one charger, let alone two. You also wouldn't get the cfm you needed, just the boost pressure. Remember, boost isn't the same as cfm.

two well tuned non-vgt turbos will outflow any two stock VGT's anyday. Heck if you do it right, a non-vgt with some great programming will help clean up the larger injectors.

The problem with larger injectors isn't just air flow from charger. there are other issues that nitrous can clean up.
 
Computer only has one pressure feedback to control the control loop. Did you want to try to put one stock turbo on each bank and have them see 3.0L of air each? If so you could try to use one pressure to try to controll both. But its just got a big housing to try to clamp down for a 3.0L. I'd be willing to try it. Convert the mass air to blow through. And see what happens.
 
I'd be curious to see if the VGT driver has enough current capacity to handle a dual VGT system. You'd also have to be careful how you handle the feedback from the solenoid... you'd either have to use one and let the other float, or get creative, and design something to put both inputs together, average them, and feed that back to the computer. I would think theory wise it should be doable, but the lag time might be a bit much, agreeing with PSD, since you're only seeing 3L each. Would be a neat project though.

What is the feedback from the VGT, a frequency signal, or a resistance signal? Making an averager for a resistance signal would be a lot easier to tackle than a frequency converter...
 
I can tell you the GM guys are doing it. They make a kit that offers a second nonvgt turbo and pipeing to the stock VGT style turbo. I dont know anyone who has tried it on a FORD Powerstroke. Just alot of people saying you cant.

I know a guy who wants to try it and may do it soon. We call him Magiver
 
hpprose said:
not a good idea. It has been tried and with very little success.

Back pressure is high enough with one charger, let alone two. You also wouldn't get the cfm you needed, just the boost pressure. Remember, boost isn't the same as cfm.
two well tuned non-vgt turbos will outflow any two stock VGT's anyday. Heck if you do it right, a non-vgt with some great programming will help clean up the larger injectors.

The problem with larger injectors isn't just air flow from charger. there are other issues that nitrous can clean up.
Click to expand...

You would get double the CFM but at the same pressure ratio of a single,running them parrallel.
 
PSDPlayer said:
Computer only has one pressure feedback to control the control loop. Did you want to try to put one stock turbo on each bank and have them see 3.0L of air each? If so you could try to use one pressure to try to controll both. But its just got a big housing to try to clamp down for a 3.0L. I'd be willing to try it. Convert the mass air to blow through. And see what happens.
Click to expand...

Correct, I am thinking a true turbo twin turbo system instead of a compound situation. 3.0L of air is enough to feed each turbo. Would there be some lag, sure, but it should be minimized with proper tuning. On the issue of the stock charger having a big exhaust housing for 3.0L, wouldn't this be offset some by keeping the vanes closed for a longer period of time? As for the computer side of reading and controlling the solenoid, I think the tuners could come up with a way of controlling both turbos from a single signal. I think a blow through would work. I also think having the exhaust manifold coated and a turbo blanket would help with spool up.

What about reversing current methodology of putting a larger compressor wheel on a VGT and putting a smaller compressor housing and wheel to minimize some lag but still get a good amount of air flow?

Grotman....You are correct about the amount of airflow and back pressure wouldn't be an issue.....
 
You should be able to control both turbos in a similar fashion as the dual cp3 kits control each pump.
Also the turbos will be more responsive if they were mounted right at the end of the manifolds.
 
How friendly do you want the setup to be? Do you want to be able to change the oil with out a cluster ****?
 
From the little looking around in the engine bay I have done, I think off a log style header you can mount the turbo's down low in the back or up top in the front so changing the oil shouldn't be too crazy.

Now I am thinking about a whole different strategy of using a roots style blower, ala a Kenne Bell or a twin screw like a Whipple in place of the turbo.

Even more extreme would be to add the Kenne Bell and then compound it with a big single charger in the place of the stock charger. Say an 88mm turbo.

The intake and the heads are such a limiting factor though.....
 
GRotman said:
You would get double the CFM but at the same pressure ratio of a single,running them parrallel.
Click to expand...


???
You have the potential for double the airflow but if your running the same boost pressure then CFM will remain the same be it single or twin setups.
Pressure Ratio X Naturally aspirated CFM = Forced CFM
twins triples or quad turbos makes no difference unless its being compounded.
 
ClintJ said:
???
You have the potential for double the airflow but if your running the same boost pressure then CFM will remain the same be it single or twin setups.
Pressure Ratio X Naturally aspirated CFM = Forced CFM
twins triples or quad turbos makes no difference unless its being compounded.
Click to expand...

Not sure I follow you here... each half of the motor is seeing a turbo designed around a 6 liter air flow. With the turbo being the restriction point, the motor now has twice the flow capacity.

By the way, on compounded compressors, you're not increasing flow, you're increasing pressure, assuming each pump is the same size. Now if you have progressively larger pumps, that's a different story.
 
Kleetus said:
Not sure I follow you here... each half of the motor is seeing a turbo designed around a 6 liter air flow. With the turbo being the restriction point, the motor now has twice the flow capacity.

By the way, on compounded compressors, you're not increasing flow, you're increasing pressure, assuming each pump is the same size. Now if you have progressively larger pumps, that's a different story.
Click to expand...

The math doesnt lie.
Pressure Ratio X NA CFM = Turbocharged CFM
If the pressure ratio(boost) remains the same then the turbocharged airflow will still be the same with the only difference being is compressor efficiency.

As for compound setups, yes the pressure will increase but so will the flow or otherwise there would be no advantage what so ever in this setup.

Look at it like this. Your truck is naturally aspirated. Is performance better or worse the higher in altitude you climb?
Ask that question again but now your truck is turbocharged?

At sea level your performance will be at its best because of higher air pressure but as you climb it thins out and performance deteriorates. This is still the same but not as noticable with the turbocharged engine.. The turbo is just working a bit harder at higher alt to achieve the same boost pressure.

Lets compound the turbocharged engine with 1bar in front of the std turbo.. How much easier is it now for that std turbo to breathe with 1bar being fed to it..

So to cut a long story short flow will increase as long as the pressure increases. Thats why we turn up the boost in search of more power.
 
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