Interesting take on ecoboom.

[1QwkEcoBoost]

From the dsm bolt on housings yes. If you were using an internal gate with a bolt on housing the gate port usually couldn’t flow enough to regulate boost well. Was mostly a problem with internally gated 16/18/20g turbos with mistu turbine housings.

Yeah I had a Big 16G on my gsx I got from RRE, had to port th hell out of the throat area near the flapper to control the boost creep. I miss my DSM’s at times...

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[Marvinmadman]

FP Red on my last 4G63 and it was internal WG. Same issue, boost creep at 7-8.5k

 

[Kjewer1]

The only issue I see is that back pressure on these cars is really quite good. I have a thread on here somewhere where I measured it. Having EMAP at 2-3 times higher than MAP is not unusual at all. If I remember correctly, our back pressure is only around 1.5x boost.

 

[ZenkaiRacer]

The only issue I see is that back pressure on these cars is really quite good. I have a thread on here somewhere where I measured it. Having EMAP at 2-3 times higher than MAP is not unusual at all. If I remember correctly, our back pressure is only around 1.5x boost.

Speaking of DSM's.... This guy right here may know just a little about them lol.

 

[TorqueMan]

If I remember correctly, our back pressure is only around 1.5x boost.

At what boost setting? The video was discussing modded cars at high boost using the stock turbo.

 

[Kjewer1]

Testing was done at all the boost the stock turbo can make. Actual numbers will be in that thread on back pressure that I started (sometime in 2016 I'm sure). Once airflow flatlines and boost is dropping you are generally compressor limited and at the mercy of whatever back pressure blows the wastegate open (internal gates usually don't hold a whole lot). My car even on daily street boost is in this situation above 4 or 5k rpm.

 

[TorqueMan]

Testing was done at all the boost the stock turbo can make. Actual numbers will be in that thread on back pressure that I started (sometime in 2016 I'm sure).

Found the thread here:

https://www.mustang6g.com/forums/showthread.php?t=50536

You reported 2:1 EMAP to MAP, but I couldn't tell if that was stock or after your modifications (did your mods include porting the head?). I would be curious to know the EMAP to MAP ratio on a completely stock motor.

You are correct that 3:1 EMAP to MAP ratios weren't unheard of with older turbo cars, but there is a factor with the Ecoboost motor that doesn't apply to those older cars: direct injection.

When manufacturers started using direct injection to improve efficiency contamination on the back side of the intake valve became an issue. Unless I'm mistaken, as part of its strategy to mitigate intake valve contamination Ford jiggered with valve/injection timing as well as valve overlap. The goal was to force some of the fuel/air mixture back past the intake valve to provide a detergent mechanism for the intake side of the intake valves--sort of an intentional intake air reversion. I don't know all the details (does anyone?), but it seems to me this factor would affect assumptions about acceptable EMAP to MAP ratios.

Am I out in left field here?

 

[Kjewer1]

No, you're definitely not out in left field. Certainly not too far out there anyway. As always, I don't claim to be an expert myself.

Whether the fuel is injected at the port or in the cylinder may not change much. But I'd have to think more about that.

Valve timing is definitely used strategically. It is now the source of all EGR, which is of course allowing exhaust gas back into the cylinder on purpose. Previously it was done with valving and actually rerouting exhaust (usually through a cooler of some kind, even if that's just a water cooled passage through the head) from exhaust manifold back to intake manifold. Now it's all done with valve timing and all of those other components have been eliminated. I would expect however that EGR is ignored at WOT anyway and valve timing is done as it would normally be done.

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