MACE 25mm Insulator

[Ventmaster]

Yes, you get new bolts in the proper lengths .

[TJ91]

I completely lost interest in this thread since I thought it wouldnt work with the VR (thread was depressing to me) But anyways, would any of the sizes work with the VR?

[Mach]

Originally Posted by bmorecam

Mach, where are you buddy have you been able to work the 25mm with vararam yet?

Sorry for the delay. I just got back from vacation. I'm gonna wait to get into my dad's shop prob in the middle of this month to get the vararam mace thing going. I hate to do this kinda stuff in my garage because my car is my only driver and I don't want things to go wrong.

[gwbates3]

Very Interesting! Keep up the quest!

[BowtieBelle]

K, so what are the gains from the 8mm? I have a chance to buy one...

[bmorecam]

Originally Posted by BowtieBelle

K, so what are the gains from the 8mm? I have a chance to buy one...

mace insulator come in 6,12 and 25mm. The gains so far is around 14hp/tq. Tracy's insulator showed higher gains so far but confirmation dyno are about to be performed by jdp and mike Norris. you might want to wait for that if you are leaning towards tracy's.

[BowtieBelle]

Originally Posted by bmorecam

mace insulator come in 6,12 and 25mm. The gains so far is around 14hp/tq. Tracy's insulator showed higher gains so far but confirmation dyno are about to be performed by jdp and mike Norris. you might want to wait for that if you are leaning towards tracy's.

The gains are the same for all the different sizes?? That doesn't make any sense, why not just offer one size then?

[bmorecam]

Originally Posted by BowtieBelle

The gains are the same for all the different sizes?? That doesn't make any sense, why not just offer one size then?

The design and orientation of the intake manifold is a major factor in the volumetric efficiency of an engine. Abrupt contour changes provoke pressure drops, resulting in less air (and/or fuel) entering the combustion chamber; high-performance manifolds have smooth contours and gradual transitions between adjacent segments.
Modern intake manifolds usually employ runners, individual tubes extending to each intake port on the cylinder head which emanate from a central volume or "plenum" beneath the carburetor. The purpose of the runner is to take advantage of the Helmholtz resonance property of air. Air flows at considerable speed through the open valve. When the valve closes, the air that has not yet entered the valve still has a lot of momentum and compresses against the valve, creating a pocket of high pressure. This high-pressure air begins to equalize with lower-pressure air in the manifold. Due to the air's inertia, the equalization will tend to oscillate: At first the air in the runner will be at a lower pressure than the manifold. The air in the manifold then tries to equalize back into the runner, and the oscillation repeats. This process occurs at the speed of sound, and in most manifolds travels up and down the runner many times before the valve opens again.
The smaller the cross-sectional area of the runner, the higher the pressure changes on resonance for a given airflow. This aspect of Helmholz resonance reproduces one result of the Venturi effect. When the piston accelerates downwards, the pressure at the output of the intake runner is reduced. This low pressure pulse runs to the input end, where it is converted into an over-pressure pulse. This pulse travels back through the runner and rams air through the valve. The valve then closes.
To harness the full power of the Helmholtz resonance effect, the opening of the intake valve must be timed correctly, otherwise the pulse could have a negative effect. This poses a very difficult problem for engines, since valve timing is dynamic and based on engine speed, whereas the pulse timing is static and dependent on the length of the intake runner and the speed of sound. The traditional solution has been to tune the length of the intake runner for a specific engine speed where maximum performance is desired. However, modern technology has given rise to a number of solutions involving electronically controlled valve timing (for example Valvetronic), and dynamic intake geometry (see below).
As a result of "resonance tuning", some naturally aspirated intake systems operate at a volumetric efficiency above 100%: the air pressure in the combustion chamber before the compression stroke is greater than the atmospheric pressure. In combination with this intake manifold design feature, the exhaust manifold design, as well as the exhaust valve opening time can be so calibrated as to achieve greater evacuation of the cylinder. The exhaust manifolds achieve a vacuum in the cylinder just before the piston reaches top dead center.[citation needed] The opening inlet valve can then—at typical compression ratios—fill 10% of the cylinder before beginning downward travel.[citation needed] Instead of achieving higher pressure in the cylinder, the inlet valve can stay open after the piston reaches bottom dead center while the air still flows in.[citation needed][vague]
In some engines the intake runners are straight for minimal resistance. In most engines, however, the runners have curves...and some very convoluted to achieve desired runner length. These turns allow for a more compact manifold, with denser packaging of the whole engine, as a result. Also, these "snaked" runners are needed for some variable length/ split runner designs, and allow the size of the plenum to be reduced. In an engine with at least six cylinders the averaged intake flow is nearly constant and the plenum volume can be smaller. To avoid standing waves within the plenum it is made as compact as possible. The intake runners each use a smaller part of the plenum surface than the inlet, which supplies air to the plenum, for aerodynamic reasons. Each runner is placed to have nearly the same distance to the main inlet. Runners, whose cylinders fire close after each other, are not placed as neighbors.
"180-degree intake manifolds"....Originally designed for carburetor V8 engines, the two plane, split plenum intake manifold separates the intake pulses which the manifold experiences by 180 degrees in the firing order. This minimizes interference of one cylinder's pressure waves with those of another, giving better torque from smooth mid-range flow. Such manifolds may have been originally designed for either two- or four-barrel carburetors, but now are used with both throttle-body and multi-point fuel injection. An example of the latter is the Honda J engine which converts to a single plane manifold around 3500 rpm for greater peak flow and horsepower.
"Heat Riser"....now obsolete, earlier manifolds ...with 'wet runners' for carbureted engines...used exhaust gas diversion through the intake manifold to provide vaporizing heat. The amount of exhaust gas flow diversion was controlled by a heat riser valve in the exhaust manifold, and employed a bi-metallic spring which changed tension according to the heat in the manifold. Today's fuel-injected engines do not require such devices.

^^^^^ this and every persons specific need such as maybe a vararam user needing to use 6mm to make it work.

[Mach]

So this is why using a smaller insulator may have a bigger hp effect? It's all to do with the helmholz principle (resonance/air pressure). And a 6mm or 9mm might just be right for our intake manifolds.

[Blacktip]

Originally Posted by Mach

So this is why using a smaller insulator may have a bigger hp effect? It's all to do with the helmholz principle (resonance/air pressure). And a 6mm or 9mm might just be right for our intake manifolds.

[bmorecam]

Originally Posted by Mach

So this is why using a smaller insulator may have a bigger hp effect? It's all to do with the helmholz principle (resonance/air pressure). And a 6mm or 9mm might just be right for our intake manifolds.

But I doubt this is the case here. I believe they all produced about the same power on holden which is the same exact 3.6L LLT in AU as it is for the v6 camaro here in the states. Again, not sure how Tracys numbers were so high. Mike Norris did state that he think he will see about the same gain as mace when he test Rx insulator so I guess we will just have to see.

[MACE_ENG]

As noted, the main reason the spacers work is not so much that they keep they manifold cool (which they certainly do) but is the fact that change the savaging properties of the manifold. In that the manifold is working more efficiently base on the engine's operating limits. This is based on Helmholtz resonance principle.

To put things into perspective, they could be made out of aluminum and still reel off similar figures on a dyno. Sure repeatability and power consistence on the other hand would fall but that is a different characteristic which is certainly influenced by material properties (thermal conductivity) of the spacer.insulator.

As for what size spacer? We have 3 sizes to give people options (6,12 and 25mm), primarily based on fitment consideration for various firewall, bonnet, intake constraints.

Thickness of a spacer/insulator with regards to runner length, is usually directly proportional to the gains down low, which is inversely proportional to the top end. Generally the latter isn't an issue at all, unless you plan on increasing the factory rev limit or consistently spending your time upper RPM band for competition work or fixated about peak power figures.

If your car is a daily driver, predominately spending most of your time in the lower to mid rev range then you would probably want to consider running the largest spacer/insulator you can.

Understandably we can be seen as being biased (however we do sell three different sizes), but the physics indicates that "optimal" lower RPM manifold scavenging is achieved with longer runner, while the inverse is true with short runners. Both with the same diameter runners of course

Hope this helps
Steve

[bmorecam]

learn something new everyday. that's what I figured. its old school rule. reason why some mfg's incorporate variable manifold which work in this exact principal. its a fact that longer runners will produce the best torque and power down low. same reason why old school hot rodder used to run with 3 ft open intake manifold shooting through the Hood.

good explanation steve

[Mach]

Good explanation Steve! I agree that very little power increase is coming from the fact that the intake manifold is kept cool by the insulator. If this were true my engine would feel much more powerful when first started (bc the intake manifold is cold) but it doesn't. Prob 90% of the power comes from the tall insulator and the taller the better.

Cannot wait to get my 25mm Mace insulator in!