V8 Air intake ducting

[Deeman]

Hi Guys - I still have the manky old ribbed fabric ducting between plenum and AFM and AFM to induction pipe (the one with huge 45 degree elbows at each end!). Is it really worth upgrading to Silicone jobs, and what sizes did people use? ACT seem to do stuff for the Chim/Griff but it doesn't look the same shape/set up in the v8s. Saw Barky Choc stating there is a need to find a 80 to 70 converter. Just wondered what sizes people have used and which company, when they changed the ducting? Pete

[v8s4me]

You could do this....



Or chuck out all the plumbing and do this....



Much neater and no noticeable difference despite what the theory says.

[Scoobimax]

Best pic I have my new one is this.

[GreenV8S]

For several years I had a short air filter directly in line with the throttle body, boxed in so that it could only draw air from the gap at the back of the bonnet. This is a high pressure area when the car is moving so it gets plenty of nice cool air - intake temps do shoot up when the car is stationary, but it cools down within a few seconds of moving.


For the blower installation I have the main cooling rad fully ducted in and the air intake runs forward, wiggles through the gap between the wheelarch inner and the corner of the rad, and is fed by a K&N in the space in front of the rad. That sees cool air all the time. Here's a front view of that wriggle round the corner of the rad.




Here is a mockup showing how that would look with a standard intake.

[Deeman]

Max - you've got the same "Arkansas chug a bug" type of chimney stack intake pipe as I have, unlike Joe's curvy job - there is also a weird link between your plenum and AFM joe - a tornado arrangement perchance?. The "talk" seems to be about smooth air flow equalling torque and a couple of horsepower - does smoothing it all off really help? Some great shots Joe (and Green v8s - phenomenal engine!). Come back to where did you get the silicone and what sized bores - 80 to 70 converter in short space, seems an odd one.

[GreenV8S]

Those scarf joints don't look as if they'd flow very well. I don't know how much difference they make to power but I'd much rather replace them with smooth bends. Getting cool air in definitely makes a difference, so you want to make sure you're drawing air from somewhere cool and make sure if you have a long intake pipe that it's either well insulated, or the outside is protected from exhaust and general engine bay heat. I'm not sure, but I think the short intake Joe showed is fed from the front wheel arch which has been opened to the high pressure area in front of the rad so that is probably seeing nice cool air while the car is moving. Probably gets hot while stationary like my short intake did, but that's no problem as long as it cools down on the move.

I have two stage fueling for the blower and run mainly upstream fueling for idle and cruise conditions, and the evaporative cooling gets the throttle body cool enough to collect condensation on hot days and ice on cold days. The metal intake has a significant thermal inertia so it acts as a 'pre-cooler' at the start of power runs. It makes a really noticeable difference have the air pre-cooled to 20C below ambient instead of heated to 30C above it.

[v8s4me]

Deeman said:

..... Come back to where did you get the silicone and what sized bores - 80 to 70 converter in short space, seems an odd one.

Here or here or here or....loads to choose from. Mine were from ASH.