Drilled Airbox

[tt82]

Originally Posted by hyvää

Cold air = denser = more fuel required
warm air = more volume = less fuel required

If you can live with 20MPG, pull the warm air pipe off that comes from the manifold into the lower airbox and drill a few holes. This should replicate cone filter performance levels.

Did that a couple of months ago, thinking the valve might be stuck and i was sucking warm air in all the time, not made any difference.

[Dog_Book]

the hot air valve is for only when the engine is cold anyway its supposed to shut when warm so doing away with the whole set up wont hurt :P

[HandsomeRob]

Erm. Either I am blind as a bat, or I couldn't see any warm-air inlet.

Has anyone sussed what the 'add on' box bit is for yet by the way?

R

[960kg]

Originally Posted by HandsomeRob

Erm. Either I am blind as a bat, or I couldn't see any warm-air inlet.

Has anyone sussed what the 'add on' box bit is for yet by the way?

R

.......you don`t have a warm air inlet on a turbo!!...

...i believe that "add on" box is something of a resonator to help even out the air flow before it goes through the filter....

......just to add the standard intake setup on the T4 is good for up to 250bhp before you need things altered , you may be just messing things up and get problems further down the line......with just the foam removed as i have done it is a fair bit louder, but now it gets on my BL nerves....maybe it`s the age thingy!!!

[HandsomeRob]

Ace, cheers. The resonator box baffled me (no pun intended) as it only adds about an extra 20mm of depth, if that.

Performance (Pipercross) panel filter has arrived, so will try that out later and report back!

R

[m1tch1987]

The OEM intake system will be finely tuned after much research by Volvo, an example is a wierd resonator tube within the OEM Mazda MX5 mark 1 intake system, if you change the OEM pipe for a straight bit you lose some torque, which is why for OEM intakes I would keep it as OEM, Volvo would have tried different setups and found the most optimal to run with the engine and OEM mapping etc.

[twinturbo]

Intake design on naturally aspirated cars is a lot more important than blown cars. removing resonators on NA cars can affect power and torque adversley. Turbos are less of a problem as they just eat whatever they can get

TT

[popuptoaster]

Cold air feeds are also only really important for wide open throttle apllications where you need the maximum volume of air you can squeeze in, for normal driving you get better torque and engine response at partial throttle openings with a warm air feed, cold air feeds will compromise mid range tractibility for slightly more power at WOT, so you need to decide if the trade off is worth it.


Its also worth noting that on the 940 turbo, the high pressure version has extra holes in the otherwise almost identical airbox compared to the low pressure variant.

[960kg]

Originally Posted by popuptoaster

Cold air feeds are also only really important for wide open throttle apllications where you need the maximum volume of air you can squeeze in, for normal driving you get better torque and engine response at partial throttle openings with a warm air feed, cold air feeds will compromise mid range tractibility for slightly more power at WOT, so you need to decide if the trade off is worth it.


Its also worth noting that on the 940 turbo, the high pressure version has extra holes in the otherwise almost identical airbox compared to the low pressure variant.

.....i see you have applied the science of it which is great.......i had the Volvo 940 2litre HP turbo which had the similar box.....

[cseventy]

Drilling the airbox without extra cold air feeding in, is probably going to reduce performance when the engine bay gets hot - you may get some extra noise, but it simply isn't worth it.

Do some proper modification like an uprated intercooler, race cat etc. if it's anything like Trionic, the Volvo ECU will knock back if you have inadequate cooling available.