On the secondary injection I am curious how it keeps the AF charge even between cylinders? It doesnt appear to have anything to equalise flow so I would assume its gonna spray to the rear of the plenum?

 

If it works i think you will see huge gains. But your right on a forced induction i can see it being a problem with even distribution. On a N/A car totally different story. But we shall see it does look beautiful!

Chris

 

That type of setup positions each injector directly above the orifice of each intake runner. I've seen it used both with and without a plenum (the latter requires alpha-n engine management).


If it is used with a plenum, why would it matter if the engine is FI or NA?

 

Good Point! Just my backyard mechanic theory would be that the the air being forced into the plenum is going to hit the stream of fuel in the plenum and throw it more towards cylinder 3 and 4. But like i said i could be totally wrong. On a N/A car i was thinking individual throttle bodies with the secondaries hanging right above the velocity stack not really thinking plenum but thanks for opening my eyes.

Chris

 

Don't think of air being forced into the plenum or into the engine. That isn't really what's happening. The turbo is just acting as an air compressor - increasing air density inside the plenum. The engine still depends upon vacuum and inertia to get air into the cylinders, just as it does NA.

But if turbulence inside of a plenum (turbo or NA) can affect fuel metering, I cannot answer. In a way, it is somewhat remniscent of an old TBI setup.

 

The manifold looks really nice, but a top feed FI setup on a side fed plenum can be very problematic... Even NA setups will struggle with this.

 

The plenum volume is adjustable. So is runner length.

Here's the concept; the plenum lid will be cast extra huge. Let's say 10" from top to bottom (this is not including the base, the base is a separate piece completely). You could start off with a 4" plenum lid and have 6" of material left for spacers - (1) 2" and (3) 1" lengths for example (we need some material to machine o-ring grooves in the top & bottom of each spacer). Add/stack the spacers to vary the plenum volume.

The plenum base bolts to the top of the manifold casting. It too, will have o-ringed spacers that go between the base and manifold casting to vary runner length.

We have some tests on the horizon, we'll see what happens....

 

Wow, Thanks for the description, That's pretty wild. Can't wait to see how your testing pans out.

 

To really see if there is fairly even cylinder to cylinder distribution of fuel, each runnner in the exhaust manifold ought to have it's own O2 sensor.

You would be surprised how different each cylinder's AFR's will turn out.

 

Which i already have. Keep us posted and i can do some testing. Something im sure Kinsler will do but why not have backup data.

Chris

 

This is too interesting a thread to tolerate ANY BS people... keep it clean. Even if this design does not pan out, it can pave the way for others from these people...

 

I would imagine that most guys that would consider running something like this monitor EGTs on every hole already.

 

The reason I mentioned the injector location is the manifolds that have done this had equalised flow in the plenum (like the HKS), used a restrictor, and were as a result airflow limited anyway.

I have it on excellent authority that moving the injector to the topside of the plenum on a FI car without something to keep airflow even ends up being problematic. Maybe this one wont be, I am not prejudging it, but thats why I asked.

 

Aaron, I find it difficult to accept that info at face value. Top mount injectors have been used for FI applications for years, including turbo F1 engines from the 80s and earlier without issue. This would also imply that speed density would be problematic with an FI engine, and that doesn't hold water either.

 

There may have been other modifiers to the issue this is true. I dont think the comparison to Speed density is exactly even though as it measures relative pressure for a load reference.

What I was told (I did not do the test personally) is that the car was inconsistent on the dyno and when the location of the secondary injectors was moved back to the runner the issue was resolved.

I have seen the Renault V10 video for instance (as well as numerous other injector setups where they are above the runner) and it worked just fine. Since in a plenum the flow characteristics shouldnt change with an increase in pressure (I am visualising a paxton styled box for this illustration) I would have agreed with you if it wasnt for the information to the contrary I had been presented with.