Written by Jay from JHM (jaybquick):
What do they do?
They help bring your intake temps down by insulating the intake manifold from the heat coming from the cylinder heads due to combustion. Thus creating a cooler and denser intake charge which helps add more tq and hp, gear after gear! They also add a little more torque down low due to the slightly longer runner created by the spacer. All in all a great mod for the money. With JHMs testing we found a gain everywhere in the rev range from 2000 rpm to 7000 rpm. This was done with acceleration rate calculations in 3rd gear from logs. The BEST part is that we saw that the car didn’t slow down after repeated pulls due to an extremely heat soaked intake manifold bringing the intake temps up. Bottom line, the longer we beat on it the better it performed vs. the tests without the spacers.
[quote=Customer Question]jay any logs or anything on this showing gains. we had this same mod on the 1.8T…most considered snake oil. other than being able to put your hand on the manifold…i can’t recall anybody see gains from this. like perhaps an acceleration map…stock vs JHM?
[/quote]
Jay’s Response:
You are comparing apples to oranges. Turbo cars do best with excellent intercooling so intake spacers sometimes become a moot point. However they do help when you compare the data over time, pull after pull. I put intake spacers on a lot of B5s.
However, with a naturally aspirated motor you don’t have turbos or intercooling so there isn’t many other ways to get the intake temps down. This is a mod that you would never feel with the butt dyno, but most mods including chips with these cars aren’t that noticeable on the butt dyno. But over time you build the right combination of parts and you will finally have a really fast car. Example, full exhaust + chip + intake spacers + intake elbow heater delete + lightweight rotors + lightweight wheels + more parts as they come available.
Here is the RPM per second acceleration calculations on a mostly stock B6 S4 with just our tuning, 91 octane and only a cat back. It still had all 4 cats in the car w stock downpipes and everything else was stock. We have since done more mods and tuning and the car is substantially faster. We do this kind of math and keep the controls constant (ambient temperature, engine temp and using the same road in 3rd gear)
NOTE: The JHM V3 just indicates what version of our software this car was on at the time of the logging.
As you can see before the intake spacers it would fall off a lot quicker. The intake spacers did build some more torque in the mid range as well and over time made more top end vs. no intake spacers it was falling off. Unfortunately there is no magic bullet with these cars like with a turbo car (upping the boost) so we have to “piece together” our power with the right combination of parts.
Here is a write up I found that really relays the concepts well. I picked the ford 3.8L V6 since it is almost as big as our motor and it has the 2 length runners and flaps in the intake. I could have rewritten such a thing but why reinvent the wheel.
[quote]How Intake Spacers Work. . .
First off, let me try to explain how your intake manifold works. It’s more complicated than you think! Surely by now you’ve read enough posts that say longer intake runners are good for low end torque while shorter runners are good for top end horsepower. I know that, now you know that, and Ford knows it too. That’s why the 1999-2004 split port V6’s have short and long runners. At approximately 3500 RPMs your PCM (computer) will open up the short runners via a butterfly valve called an Intake Manifold Runner Control (IMRC - 2001+). The engine uses the long runners at low RPM for more torque and the short runners at high RPM for more horsepower.
“Resonance” is defined as a vibration. It’s the action of moving back and forth. Air in your intake manifold resonates or moves back and forth with the opening and closing of your intake valves. It does not move in a straight line from the air filter to the cylinder at all times as so many people believe. When the intake valve opens, air is pulled into the cylinder by the low pressure created from the downward movement of the piston. When the intake valve closes, the air in the intake is still moving forward towards the valve. There is nothing driving it but inertia at this point. It slams up against the closed intake valve and creates an area of high pressure. This high pressure is then reflected as a wave back up the runner away from the valve. When the pressure wave reaches the intake plenum (a common area shared by all the intake runners), it is then reflected back down the runner towards the valve again. If this pressure wave approaches the valve as it is open, then it will help flow more air into the cylinder. It will actually push more air into the cylinder than the cylinder could suck in by itself. The valve closes and the process repeats again. This whole process results in increased volumetric efficiency (more air entering the cylinders than normal). Since your engine is nothing but a large air pump, more air = more horsepower/torque. The intake runner must be properly sized (length and width) in order to enable the pressure wave to arrive back at the intake valve as it opens for the next cycle. The only drawback of this is that the “resonance tuning” is only effective in a precise RPM band.
An intake spacer will lengthen the runner which causes the air inside of it to have to travel a longer distance. The pressure waves also have a longer distance to travel. They travel at the speed of sound. This doesn’t change! Since they have a longer way to travel, they arrive back at the intake valve later. At lower RPMs, obviously, the valves are opening and closing slower. The intake valve reopens later and this can be timed with the intake pulse (with the spacer) in order to create more torque at lower RPMs.
Also, the intake spacer is made out of a heat resistant material. It doesn’t soak in engine heat as easily as the aluminum intake manifold will. Colder air = denser air. Denser air takes up less space which means you can fit more of it in the cylinder. Again, more air = more power!
A good intake spacer is made of a phenolic plastic material called G-10. There are other types but they are of a cheaper grade and won’t last for long under your hood. The thermal conductivity of aluminum is 2.165 W/cm-K. G-10 is 0.003 W/cm-K. I won’t bother explaining what this means in detail but the larger the number, the easier it is for the material to soak in heat. G-10 stays much cooler than your aluminum manifold. It resists heat over 700 times better than aluminum. Because the G-10 is in between the upper and lower manifolds, the upper won’t conduct the heat of the lower as easily. Ever notice your car “feels” stronger in the
[/quote]
And yes we make ours out of this material as well.
Hope this answers your question.