Air intake duct lagging

[Teetertank]

Contemplating lagging the air intake duct to the plenum chamber.

Has anyone actually noticed/measured a difference in performance from doing this?

And what material did you use and where did you source it?

[Andy JB]

I have done this using standard heat repelling fibre glass silver matting - its flexible & can be tied with cable clips or use self-adhesive stuff available anywhere in lengths >1m. Ebay can be a good source if you know what you want in advance.

I can't honestly say its made a significant difference to power as theres a lot to begin with, however, you also know that the lovely cool air rammed in at the front isn't heating up under the high under bonnet temps and teh air enetring is as cool as it can be - it must make a difference

[spend]

Stick bubble wrap under the heat-shield for better insulation Makes big differences on RR's and maybe starting up after sat at traffic lights.... but on autobahns at light speed I doubt it is of much assistance?

[450Nick]

It's definitely worth doing. After I instlled the Emerald, I put an air temp sensor in the old location of the AFM. With an ACT induction kit, the temp in traffic reached something like 40 or 50 degrees inlet. I remember someone did a calculation of how much power you lose per degree and it was a significant amount. To combat this, I got some heat sheilding from Tim at ACT and sheilded all the way from front by the rad to the throttle on the plenum. Doing nothing else, the inlet temps dropped to around 20 -25 degrees in traffic - a huge improvement which I assume would give some power gain also. Not sure how much though... anyone want to do the sums??

[GreenV8S]

As a very rough guide, 1C drop in air temperature at the heads is worth up to about 1 bhp purely from the charge density increase. If you're knock limited and had to back the ignition off to stay out of knock then reinstating the advance could gain you even more.

[Chimjunkie]

I wrapped the whole of my smooth bore ACT hose with highly reflective sticky backed foil. Did a test with the stuff on a piece of 100mm dia black plastic pipe. Half covered with foil and half not. Held over a hob ring for a while and the foiled side was cool on the inside, the uncovered side was very hot!

[trackcar]

Those temps will plummet once out on the open road though, and the first time you plant your foot on the throttle.

I've been out with a car today with an emerald on and as you say temps up in the 40s/50s are common in slow traffic, but you don't want full power in slow moving traffic. Once out of traffic a swift prod of the throttle saw the temps down near ambient within seconds. However having said that, making sure your inlet air is as cool as possible is a good thing so it's sensible to take steps to insulate the inlet path as far as is practicable .

The heating of the inlet path is primarily radiated heat from the manifolds and a simple heat shield will take care of that. Any convection heating effects disappear as soon as you get cool air through the engine bay anyway getting rid of the hot underbonnet air.

Get a proper well filtered high flowing cold inlet, lagged/shielded piping along teh inner wing and something to isolate the plenum from inlet manifold heat and you've done as much as you need.

[450Nick]

Yup, done all of that! Plus added a supercharger and intercooler just to be sure Still only 5 degrees above ambient though!