Has anyone modified the air intake system for more air or for a ram air effect on a 240? I have a K&N filter but the rest is stock.

I've considered repeating what i did to my Grand Am a few years back, that is, relocating the battery to the rear with 4 guage wire in an acid-proof tiedown (bolted) box... My mother worked at a Steel and Aluminum Shop. For $100 and my own help we (not me and my mother) fab'd a nice intake duct to accomidate a stainless steel Cool Box (K&N cone) and ran the initial throat towards the ground and used an expanded metal type covering to deflect road crud at low speeds... i opted out of cutting a 2 inch raised slit in the hood behind the head light like other GA HO's were being tortured with

All in all was it worth it?

Kinda... the low end torque was rewarded with the robust throttle response and it looked much less of a factory car

I mean Mercedes does this along with some Audi's I've seen... why can't we?

Tim

First, the original air box offers virtually no significant restriction to air flow, so using something other than a clean original-type filter will have no improvement. Remember that you've got a n/a 2.3 liter engine -- it doesn't gulp air like a 7 liter V-8, even at high revs, so the OEM filter is not the limiting step in drawing air into the engine. What measurable restriction in air flow there is happens to start at the throttle body -- and you can't enlarge that.
Also, if you haven't scrupulously oiled the K&N (and possibly even if you did), the K&N doesn't stop dirt as well as the OEM filter. Do you want the engine to last, like Volvos do?

However, I do suggest that you modify the air box anyway. Here's the problem -- there's a thermostat inside it that controls a flapper the switches between hot air from the pre-heat duct from the exhaust manifold (directing hot air into the intake duct) and cold air from another, harder-to-see snorkel in front of the radiator. Naturally we'd like colder, denser air! Moreover, that thermostat is a disaster waiting to happen -- when it fails, it fails in the mode directing hot air to the engine and blocking the cold air. Eventually, when it fails, that continuous hot air will cook and destroy your AMM -- big bucks!

What I and many on this forum have done is remove the thermostat and block the flapper (I removed it altogether, with a dremel) so that the hot air duct is permanently blocked, leaving cold air to enter the engine all the time. Your engine won't miss the hot air, believe me.

Best regards, and happy holidays.

Ken,
Thanks for the advise. You are also dead on with the Air box themostat. Mine fail and the total cost were over $1450.00. Local foreign car shop about $450.00, Volvo Dealer around $1000.00. Neighter one found the themostat bad and the flaper closed. I finally found it. You and other make the point that escaped me on the K&N. I do check it and reoil it but your right about about the restrictions and the filter is not the issue. I wished that I had known about this forum a few year and $1450.00 earlier. Thanks again

Happy Holidays
Greg

Look around on the 'net and you'll find some 'studies' which seem to indicate that the airflow capacity of K&N comes at the expense of good filtering. My junkyard prowlings have shown that the stock Volvo filter is substantially bigger than those on many 3-to-5 litre engines, so you are unlikely to get any benefit from changing to a 'high flow' unit.
--
Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD and 89 745 (LT-1 V8); hobbycar 77 MGB, and a few old motorcycles)

Also, get rid of the K&N filter. If you don't oil it, your letting dirt into the engine, if you do oil it, it flows less air than a stock filter. Use a stock air filter, you know, the old stock original high flow units!

jorrell
--
92 245 245K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently in pieces

I have read on this forum posts by folks who tested a variety of different snorkel/air filter mods and found no discernable benefit to messing with the air intake on a 240 at all.
--
'92 245 5-speed, '92 944 GL auto

I'll add a bit of gobbledy-gook to TwoFortyWagon's comment - I've read a number of the threads that deal with the question of air flow, and as TwoForty states, the consensus seemed to be that it was difficult to improve on the original set-up.

The reason for this is not entirely obvious, so I'll paraphrase what I've seen here (and elsewhere, and also a bit of my own accreted knowledge)...

Essentially, the question you ask is this: "How I can I get more air into the engine for an improvement in power?" (understood assumption - more oxygen in combustion chamber = better burn, thus more power. This is the intention behind an intercooler ~ cooler air is more dense, hence more O2 into the combustion chamber).

You've assumed that the issue is the air filter. (a reasonable assumption, and one that is probably true on a number of cars - maybe; read on ->)

In fact, it seems that air acts like a fluid in terms of fluid dynamics, which means that the real limitation could be anywhere along the line from the intake to the combustion chamber. If you have a larger pipe going to a smaller pipe, you get higher pressure on the back side of the diameter reduction. Simple test - go turn your hose on; now, hold your thumb over the hose-end, allowing only a small opening - you get high pressure delivery, no? But the volume is reduced.

Why is this important? Because the consensus of those who tested various apparati, was that the breather box/air filter in the Volvo was already essentially delivering the plenty of air to the intake - that the limitation in oxygen delivery appeared to somewhere further along the line towards the combustion chamber - the intake manifold, would be my guess, but guessing I am.

This means that any change to the breather box in terms of delivering more oxygen to the engine has minimal value, since it's already probably performing near/in excess of the capacity of the intake manifold.

On a philosophical note, one suspects that the engineers at Volvo gave this a more than passing consideration - while it may not always be the case, they seem to have given durability and performance considerable thought in the B23/B230F engine, IMHO. It's relatively strong for only 114HP, and will take a beating.

Disclaimer - I'm not a physicist or engineer specializing in fluid dynamics, so I may be wrong about all of this.