General: 850: - Volvo 850 Air Box Mod - Seriously GREAT Sound

BackInBlack · May 2nd, 2009, 13:23

Last week I cut 8 big holes in the bottom/side of my 850 air box with little enjoyment. When I put my foot down all I heard was a deep 'boomy' noise. That is NOT the noise I'm after. I am after that 5 cylinder growl (I'm sure you know what I'm on about).
So I got under the hood, removed the air box and cut smaller holes but more, more & more. I remember reading on the net (after cutting the large holes) that the bigger the hole the more 'boomy' the sound. Okay my mistake for the first try. But now.... Yeeehaaa.... All I hear is that fiery beast under my hood wanting to escape. (Under heaver acceleration) Insane!!!
The acceleration feels more responsive, no extra gains in higher gears but certainly in 1st, 2nd & 3rd. It feels like it really wants to move now.

This seems to be the best and safest way I could do this. As you can see in the pictures the pipe coming from the air box to the front has been removed, this is only because I cut off the snow-guard (As shown in this forum before) and fear water getting in.
So far after driving for a week in heavy rain there has been no sign of water even near the air box(good news). I have also removed the silver exhaust manifold heat pipe. I wouldn't need that silver pipe as the y shaped plastic piece housing the air box flap has been completely removed...Not needed at all.

So today I thought I would take a few pictures of my 'holy' air box and share my enjoyment with the 'world'.

Enjoy....

I take no responsibility if you decide to do this modification. I doubt you would be unhappy, but you may not be happy in the end... YOUR CALL, NOT MINE!! You have been warned. ONLY MODIFY THE AIR BOX UNDER THE AIR FILTER, NOT ABOVE... Again take your time and be careful.

warthog · May 2nd, 2009, 14:21

Hi,

glad you like the sound.

Not to p**s on your BBQ, but what you have almost certainly done is actually reduce your engine's power. Flow analysis of the airbox and ducting shows that it will flow far more air than required by the engine with minimal loss as standard. (Ref. various posts over the last few years). However, by drilling holes in the box and removing the ducting bringing air from the front of the grill the engine will now be breathing hot air from under the bonnet. Hot air = Less dense air = less Oxygen = reduced combustion efficiency. One source I found stated a 10% decrease in density with every 60deg C increase in temp. This is why turbo'd cars have intercoolers - to reduce the air charge temperature and increase the density after compressing it.

Cheers

BackInBlack · May 2nd, 2009, 15:33

Quote:

Originally Posted by warthog

Hi,

glad you like the sound.

Not to p**s on your BBQ, but what you have almost certainly done is actually reduce your engine's power. Flow analysis of the airbox and ducting shows that it will flow far more air than required by the engine with minimal loss as standard. (Ref. various posts over the last few years). However, by drilling holes in the box and removing the ducting bringing air from the front of the grill the engine will now be breathing hot air from under the bonnet. Hot air = Less dense air = less Oxygen = reduced combustion efficiency. One source I found stated a 10% decrease in density with every 60deg C increase in temp. This is why turbo'd cars have intercoolers - to reduce the air charge temperature and increase the density after compressing it.

Cheers

You see.... I thought that too, and totally believe the science behind it as well BUT < and that's a big BUT, I don't care.

My car is the 2.0Ltr Non-Turbo so I wouldn't be gaining anything anyway. The way I see it is, if its not a turbo you have nothing to loose (under certain circumstances). I bought the car for under £400 and it is a perfect runner. I have no problems with the car aside from the coolant slowly draining away (really slow leak from radiator fan area).

I can still attach the y piece and the front pipe to gain more air but wasn't to sure about water being sucked in.

Would you think that because there are loads of holes in the airbox, if water did get in, it would quickly drain away rather than bounce off the plastic inside the air box and get sucked up?

Don't forget this is not a performance modification. I didn't intend for it to be one. Merely a sound enhancement.

YOU CANT PUT A PRICE ON FUN!

lanciak69 · May 2nd, 2009, 15:55

mabey you will get it going a little faster ( less weight you got rid of all those round bits o plastic) LOL

BackInBlack · May 2nd, 2009, 16:43

Quote:

Originally Posted by lanciak69

mabey you will get it going a little faster ( less weight you got rid of all those round bits o plastic) LOL

That's the spirit...

BackInBlack · May 2nd, 2009, 21:49

To increase cooler airflow... Why don't I add the front pipe that goes from the air box to the front grill?
I am sure this would increase cooler airflow to the 'holy' airbox.

What do you think?

SUBURBAN KID · May 2nd, 2009, 22:05

Quote:

Originally Posted by lanciak69

mabey you will get it going a little faster ( less weight you got rid of all those round bits o plastic) LOL

Too many holes, I never thought I'd say that.

When it gets hot under there, I think you may see a real perfomance drop. I wonder would a Nova sound better with this mod?

tjts1 · May 2nd, 2009, 22:26

LOL

The quick and dirty NA 850 intake in 3 easy steps

Install an early 960 throttle plate.
http://www.matthewsvolvosite.com/for...p=80951#p80951

Fix the airbox thermostat.
http://www.matthewsvolvosite.com/for...p=82880#p82880

Get a 3.25" dia piece of flexible tubing.
http://www.matthewsvolvosite.com/airbox.php
http://www.matthewsvolvosite.com/for...p=59606#p59606

The OP would have to start with a new lower airbox. The swiss cheese thing is beyond repair.

BackInBlack · May 2nd, 2009, 22:35

Quote:

Originally Posted by tjts1

LOL

The quick and dirty NA 850 intake in 3 easy steps

Install an early 960 throttle plate.
http://www.matthewsvolvosite.com/for...p=80951#p80951

Fix the airbox thermostat.
http://www.matthewsvolvosite.com/for...p=82880#p82880

Get a 3.25" dia piece of flexible tubing.
http://www.matthewsvolvosite.com/airbox.php
http://www.matthewsvolvosite.com/for...p=59606#p59606

The OP would have to start with a new lower airbox. The swiss cheese thing is beyond repair.

There's always black duct tape

mario850 · May 2nd, 2009, 23:25

hi there sorry to s**t on your parade but you will def of lost power volvo spent thousends if not millions on designing this car to get the best performance/economy ratings and you go and waste all of there time by drilling loads of so**ng holes in the air box

i have a 855 2.0 N/A and i too cut the snow gaurd to allow better flow into the air box and that worked really well better throttle response and i dont suffer from water in it so its all good

to be honest i would have just got a sports panel filter banged that in and to get a better growl just fit a polly top mount and you get all the growl you will ever want

May 2nd, 2009, 14:21	#2
warthog VOC Member Last Online: Oct 30th, 2021 14:51 Join Date: Dec 2001 Location: Bristol	Hi, glad you like the sound. Not to p**s on your BBQ, but what you have almost certainly done is actually reduce your engine's power. Flow analysis of the airbox and ducting shows that it will flow far more air than required by the engine with minimal loss as standard. (Ref. various posts over the last few years). However, by drilling holes in the box and removing the ducting bringing air from the front of the grill the engine will now be breathing hot air from under the bonnet. Hot air = Less dense air = less Oxygen = reduced combustion efficiency. One source I found stated a 10% decrease in density with every 60deg C increase in temp. This is why turbo'd cars have intercoolers - to reduce the air charge temperature and increase the density after compressing it. Cheers __________________ Brian '96 T5 Estate Auto

May 2nd, 2009, 21:49	#6
BackInBlack Junior Member Last Online: May 9th, 2010 22:07 Join Date: Apr 2009 Location: .	Cooler Airflow To increase cooler airflow... Why don't I add the front pipe that goes from the air box to the front grill? I am sure this would increase cooler airflow to the 'holy' airbox. What do you think?

May 2nd, 2009, 23:25	#10
mario850 Vovlo lover Last Online: Oct 19th, 2016 12:02 Join Date: Feb 2009 Location: Nottingham	hi there sorry to st on your parade but you will def of lost power volvo spent thousends if not millions on designing this car to get the best performance/economy ratings and you go and waste all of there time by drilling loads of song holes in the air box i have a 855 2.0 N/A and i too cut the snow gaurd to allow better flow into the air box and that worked really well better throttle response and i dont suffer from water in it so its all good to be honest i would have just got a sports panel filter banged that in and to get a better growl just fit a polly top mount and you get all the growl you will ever want __________________ past-> F reg 245 glt 2.4 past-> M reg 855 glt 2.0 20v past-> 51 S60 2.0t Past-> L Reg 945 2.0 HPT Wentworth.

May 2nd, 2009, 15:55	#4
lanciak69 give me a 850/v70 anyday Last Online: Jul 2nd, 2011 19:00 Join Date: Sep 2006 Location: ormiston	mabey you will get it going a little faster ( less weight you got rid of all those round bits o plastic) LOL

May 2nd, 2009, 22:26	#8
tjts1 New Member Last Online: Jan 7th, 2010 17:23 Join Date: Jul 2006 Location: San Rafael	LOL The quick and dirty NA 850 intake in 3 easy steps Install an early 960 throttle plate. http://www.matthewsvolvosite.com/for...p=80951#p80951 Fix the airbox thermostat. http://www.matthewsvolvosite.com/for...p=82880#p82880 Get a 3.25" dia piece of flexible tubing. http://www.matthewsvolvosite.com/airbox.php http://www.matthewsvolvosite.com/for...p=59606#p59606 The OP would have to start with a new lower airbox. The swiss cheese thing is beyond repair.

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