MAF spacers, intake manifold spacers, and other possible nonsense

I've come across a few products lately claiming to increase performance and I can't tell if they are legit. With stuff like this it seems like there's a layer of internet smoke obscuring their true value so I'm coming here to ask you smart folks about it. 
 

There's a certain name brand company selling a MAF spacer that claims to increase fuel economy and power just by pulling the sensor out of the stream a little bit. I can grasp how this might work but it seems like it would mess with emissions and fuel trims and such and that can't be a good thing. The OEs spend a lot of time on those things. 
 

The second is an intake manifold spacer that increases the runner lengths almost 2". Same company and they are claiming dyno gains of ~7% in HP and torque. The car they would go in has almost no other power options so this one is intriguing. They recommend mid grade or premium fuel with this mod which I don't understand. Liability? Runner length wouldn't affect predetonation would it? 
 

Lastly, voltage stabilizers. This for sure sounds like a load of horseE36 M3. But maybe? I think these were popular in the early 2000s before I was in the scene and now a decade in I'm just coming across them. Is this a real thing? 
 

All of these seem like simple parts that the OEs would have already incorporated if there was any real value so I'm skeptical but I'm open to being wrong. 

A TB spacer can help by increasing plenum effective volume or tuning runner length, but I doubt 7%.  1-2 hp maybe, and it would depend on how poorly the OEM engineered it to start with.

Messing with a MAF filament probably reduces the amount of air the engine THINKS it's getting and a corresponding reduction in fuel being injected, but is it worth 2mpg for a loss of 20 hp?

spandak said:

There's a certain name brand company selling a MAF spacer that claims to increase fuel economy and power just by pulling the sensor out of the stream a little bit. I can grasp how this might work but it seems like it would mess with emissions and fuel trims and such and that can't be a good thing. The OEs spend a lot of time on those things.

Pulling the sensor outward will reduce the measured air flow under most circumstances. This will cause the ECU to reduce fueling and advance timing. Depending on how much it does this, your exhaust might end up with more oxides of nitrogen, or more chunks of piston. This is the EFI equivalent of drilling your carburetor's main jets with a hand-held power drill: A very large and badly measured change in a situation that calls for finesse and precision.

The second is an intake manifold spacer that increases the runner lengths almost 2". Same company and they are claiming dyno gains of ~7% in HP and torque. The car they would go in has almost no other power options so this one is intriguing. They recommend mid grade or premium fuel with this mod which I don't understand. Liability? Runner length wouldn't affect predetonation would it? 

Longer runners would normally move the engine's powerband down, adding more torque at the expense of high RPM.
 

Lastly, voltage stabilizers. This for sure sounds like a load of horseE36 M3. But maybe? I think these were popular in the early 2000s before I was in the scene and now a decade in I'm just coming across them. Is this a real thing? 
 

All of these seem like simple parts that the OEs would have already incorporated if there was any real value so I'm skeptical but I'm open to being wrong. 

On voltage stabilizers, the OEs already stuffed one into the stock ECU to stabilize its internal voltage. If you've overloaded it, you have other problems. The ECU is then able to measure outside voltage and adjust operating parameters as needed. So adding more stabilization generally won't do anything.

Miscalibrating the MAF is 100% a way to screw with fuel trims. That's what they're doing, purposefully making it report bad data.

There's a lot of high-end computing that goes into intake manifold/port/combustion chamber design. If this spacer requires higher octane fuel to avoid detonation, that means it's also completely jacking up the airflow that allows the car to run at a certain mixture without detonation. I can see how maybe it would provide some power gains, but I would want to see independent dyno proof.

I thought we gave up on the big grounding and voltage juju kits 20 years ago. Have you also come across the hydrogen generators?

Seems like my skepticism was justified. 
 

Not those lol not yet but reddit has a lot of interesting stuff that's for sure 

You forgot magnets on the fuel lines....

Or Brown's gas generators.  Needz moar HHO.

forget that stuff. You can get the fuel mileage and power upgrades pretty easily with this, for less money...

Wasnt there a semi legitimate electric turbo kit floating around a few years ago? If I recall the applications were the Miata and frisbee twins. That was cool

In reply to spandak :

That's a thing, but given that it adds load to the alternator to compensate for its power draw, exhaust driven turbos are more efficient. Having a motor pre-spool your turbo a la the current F1 powerplants isn't something I've seen trickle down yet.

There's reason to believe a phenolic manifold spacer could keep your manifold colder, which would net a tiny bit of power. Moot if you have coolant going through the manifold though. Similarly a throttle body spacer would effectively add plenum volume.

Electric turbo

Cactus said:

In reply to spandak :

That's a thing, but given that it adds load to the alternator to compensate for its power draw, exhaust driven turbos are more efficient. Having a motor pre-spool your turbo a la the current F1 powerplants isn't something I've seen trickle down yet.

Turbos increase exhaust backpressure, which results in less cylinder scavenging, more hot exhaust gases left behind in the chamber, and does a bang-up job of getting the exhaust valves really hot.  The latter two increase the likelihood of detonation, or at worst, preignition.

Not saying that a proper electric turbo might not have its own issues (mega power requirements being the biggie) but it's not all cupcakes and ice cream with the traditional exhaust driven unit.

There's reason to believe a phenolic manifold spacer could keep your manifold colder, which would net a tiny bit of power. Moot if you have coolant going through the manifold though. Similarly a throttle body spacer would effectively add plenum volume.

What modern engines don't have plastic intake manifolds?

This is GRM, where the 15-year-old NC is a "new" Miata. And has a plastic intake manifold :)

Problem with an electric turbo is that it needs a big chunk of power. This means it's only available in really short bursts and then you have to recharge the battery. It's like the concept of using your AC to cool the water in an air/water intercooler. It's been done and it does kinda sorta work, but it's not really effective. Much more efficient to simply add the electric power to the drivetrain via a motor.

Intake plenum spacers definitely can definitely shift the torque curve, and depending on airflow dynamics may increase torque at some point in the RPM, which all has to do with the runner length.  The increase in runner volume likely does not impact airflow delivery at all.   The OEM parts may have been designed for peak power at a certain RPM, and increasing runner length shifts the powerband lower.  Like these parts for Nissan 4.0L as an example:

https://extremetruckperformance.com/?page_id=37

Keith Tanner said:

This is GRM, where the 15-year-old NC is a "new" Miata. And has a plastic intake manifold :)

Problem with an electric turbo is that it needs a big chunk of power. This means it's only available in really short bursts and then you have to recharge the battery. It's like the concept of using your AC to cool the water in an air/water intercooler. It's been done and it does kinda sorta work, but it's not really effective. Much more efficient to simply add the electric power to the drivetrain via a motor.

What about using the A/C evaporator as the heat exchanger?  That's supposed to work great, as you're using the phase change right there.  At least one OEM has done this.