Pod filter - does it need a heat shield?

Quicksilver · Postby **Quicksilver** » Sun Nov 15, 2009 12:34 pm

I'm thinking of putting a pod filter on my NB8A, just for bling and noise. Looking through past threads, most people seem to have made a heat shield to fit between the filter and the engine. I understand the reason for this (cooler air entering the system) but dont know if it is really necessary for a Sunday cruise car, not competing for lap times.

Second to that, there are heaps of pods and adaptors to chose from at Supercheap and Autobarn. They all look much the same to me. Any recommendations which to buy?

Hi 5 · Postby **Hi 5** » Sun Nov 15, 2009 2:25 pm

I suggest you get a Cold Air Intake.
Will cost more than an exposed pod but will look better and give cooler air to your engine.

I've got an exposed pod at the moment,came with the car and I reckon it sucks...obviously

NMX516 · Postby **NMX516** » Sun Nov 15, 2009 8:26 pm

It doesn't need a heat shield, but it's a good idea to have one. Cooler intake temps equal more power, or less power lost, and so at the very least will give you better fuel economy. The computer is programmed to pour more fuel in with hotter air temp. The air temp is measured by a sensor in the air filter box (needs to be relocated when you fit a pod filter). The cooler the air, the better. Throttle response is also sharper with lower intake temps.

As for brands of filter, well I use K&N. They have a very good reputation for performance/air flow and for filtering ability. I wouldn't use anything much else...

Hellmun · Postby **Hellmun** » Sun Nov 15, 2009 9:55 pm

An exposed pod filter can get you defected. Not likely unless you annoyed the cop but your giving him the option. That's another reason the heat shield is a good idea. Car will still work fine and make more noise with an exposed one.

SKYHI · Postby **SKYHI** » Mon Dec 07, 2009 1:22 pm

In my opinion the "heat shield" will be useless unless it is a fully enclosed and sealed compartment around the filter. Even then it would probably need a cold air intake from outside to be really beneficial. If you don't want to cut a hole in the firewall to create a Loch Stewart type intake, you might as well just keep any piping as far away from the headers as possible and place the pod filter in a high pressure spot in the engine bay, like the rear corner on the passengers side.

Then of course there is the debate about the correct length of the intake and it's effect on power and torque. For what it's worth, I've been told by a reputable engine builder and tuner in SEQ, that the optimal intake length is between 1100 & 1200mm.

Most of the Spec Miata racers in the US use something like this: