Air Filter/Intake rubber

[philip]

Anything rubber on a truck this old is bound to be cracked. The intake flex hose (red arrows) was no exception. The previous owner had gooped the growing cracks a number of times but ... the repairs failed.



I ran across (on sale) one of those washable filters for a cheap price. With a filter, a 2-1/2" ID, 90 degree coupler from an off-road shop, a 3" section of 2-1/2" exhaust pipe, and three clamps, here's The Fix.

[kassim503]

is it one of those k&n filters?

[philip]

is it one of those k&n filters?

It COULD be ... but it is not. This filter is not cotton gauze rather, a cellulose-like material that still has to be washed and oiled like a K&N.

Since this installation back in the summer of '04, I've washed this filter a half dozen times or so in hot soapy water and reoiled it. The filter has held up well and there have been no further dust accumulations on the throttle plate.

[asavage]

I COULD be ... but it is not. This filter is not cotton gauze rather, a cellulose-like material that still has to be oiled like a K&N

Plus you get that cool roar/drone when you step on the throttle -- and the SD22 does have a throttle (for those reading who didn't know).

I tell ya Philip, you ought to get some undercarriage neon for that thing

[philip]

Plus you get that cool roar/drone when you step on the throttle -- and the SD22 does have a throttle (for those reading who didn't know).

I tell ya Philip, you ought to get some undercarriage neon for that thing

Well Al, it's a TOUGH call. Should I buy the neon treatment or spend the money on a chassis dyno test? Wonder if they would even need chock the front wheels.

I got the air filter on sale here:

http://www.autobacsusa.com/

[asavage]

So . . . would you call your mod the "hot air intake kit"?

[g,d&r!]

[philip]

So . . . would you call your mod the "hot air intake kit"?

[g,d&r!]

Actually, I would not. There are two large holes in the sheet metal for the back of the headlamps. The filter cap has a 2" opening with more pleated filtering area, about 3" deep and sits only inches away from plenty of cooler outside air when the truck is moving. Remember, diesels shed heat in porportion to fuel delivery.

Now the Datsun is a "Vintage Rice Racer".

[asavage]

I'm sure that the airflow around those headlights is HUGE.

As you know from our previous conversations, I'm not a fan of these oiled-element filters. Their use will void several OEM mfgrs warranties, and for the "cone" style elements -- like yours -- the average intake air temp goes UP, not down for the "cold air kits". Kids are buying these things for the style, not the performance. The opened-up air intake makes more noise, and they hear that and think that it must be making more power.

[philip]

I'm sure that the airflow around those headlights is HUGE.

As you know from our previous conversations, I'm not a fan of these oiled-element filters. Their use will void several OEM mfgrs warranties, and for the "cone" style elements -- like yours -- the average intake air temp goes UP, not down for the "cold air kits". Kids are buying these things for the style, not the performance. The opened-up air intake makes more noise, and they hear that and think that it must be making more power.

Well.... rock and a hard spot. As shown, there was a big open crack in the OEM rubber that allowed (twice noted evidence) dirt to show up on the throttle plate VS. the arrangement shown which has prevented any recurrance of throttle plate dirt. BTW, there is no audible intake "honk" until the engine is well past maximum torque RPM and at full throttle.

I agree with you and somewhere on this computer, I have a document from an off-roader who documented a substantial increase in silica found in his engine oil after installing a K&N. That was (1)a cotton gauze K&N on a vehicle that was (2)being used off-road. The filter I have installed is (1)a finer material and (2)driven only on paved streets. The two oil analysis tests I posted here Oil Analysis I and Oil Analysis II indicated all levels well within acceptable limits for diesel.

Toyota TRD, GM, and Ford sell their own K&N filters with their names on the box for high performance applications. But I know of no manufacturer who uses these filters for their EPA spec'd road vehicles.

I would RATHER have the OEM paper filter system in place and it will be again when I find a suitable rubber coupler. I've examined two spring/wire reinforced air intake hoses ... they are made of weak material that would not injest well.

[philip]

I thought that for a NA diesel, warmer intake air actually helps achieve a more complete burn?

By "complete burn" do you mean best power or best emissions? When compensated, warmer intake air makes for lower emissions.

In diesel ... cold air (low or non existant residual cylinder heat) has the effect of maximizing "ignition lag" time ... as shown in the graph at the beginning of the thread titled Noisy Combustion. With high ignition lag time present, more pressure is present because the piston is closer to TDC and ... there is more fuel present at the moment ignition does occur than would be the case had ignition occured earlier in the piston stroke. Result is a sharp, audible combustion knock which will go away as the engine reaches operating temperature.

Having said all that, without question, my best MPG with this little oil burner has been during summer months at temperatures exceeding 90 degrees. [/gotopost]

[asavage]

We want turbos!

[ocd]

i did the same thing to my '82 720 w/sd22, minus the exhaust pipe corner, and it seems like the engine has lost some torque. from previous posts it sounds like air temp doesn't effect hp/torque so now i'm not sure the the proximity to the engine would be the cause. my first thought was that because of the drastic increase in air available the fuel air mixture was wrong and since there is no MAF no way for the engine to adjust itself -but i really don't know much.

any thoughts?

thanks

[philip]

i did the same thing to my '82 720 w/sd22, minus the exhaust pipe corner, and it seems like the engine has lost some torque.

The "same thing" meaning you have done away with OEM air filter cannister and substituted a high flow air filter fitted where the flex hose used to be? IF in fact your engine lost some torque or horsepower, have you also noticed less exhaust smoke during hard acceleration or continual full throttle loading?

From previous posts it sounds like air temp doesn't effect hp/torque so now i'm not sure the the proximity to the engine would be the cause.

I don't know how or where you could draw that conclusion. For power, cooler air means more power PROVIDED ... the Fuel Control Lever position is optimized for that cooler air. Otherwise, when the Fuel Control Lever position is optimized for 120 degree intake air but ... now the ambient air becomes considerably lower, the colder, denser air has the effect of leaning the air/fuel ratio. In this uncompensated diesel whose fuel delivery was optimised for 120 degree intake air, this colder, denser air simply lowers engine output. On the other hand, fuel economy is best with hotter intake air provided the fuel control lever positon is optimized for hotter air. See thread Smoke Setscrew

The reason I installed the 90 elbow is to get the air filter closer to cooler air coming in around the headlamps. But as nature would have it, the sheet metal intake pleum leading to the throttle body picks up heat from air having prevously passed through the radiator. I have checked the surface temperature of the plenum feeding the air throttle. See Thermal Trivia.

My first thought was that because of the drastic increase in air available the fuel air mixture was wrong and since there is no MAF no way for the engine to adjust itself -but i really don't know much.

Any thoughts?

thanks

Drastic? Was your paper filter really clogged up? Except for times of heavy throttle application, the air throttle itself flows less air than either air filter. When talking about flat out running above maximum torque, then the puny exhaust pipe becomes a power robbing factor. This was by design.

[ocd]

thanks for the schoolin'. i'v purchased 3 diesels in the last 6 months so the learning curve is steep. the my sister drives the peugot, my partner promptly wrecked the volvo(it just might be getting out of the shop soon after 3 months) but this one is mine. i just bought it and am really excited. efficiency and excellence make me happy so i search for ways to increase them. i was really pleased with the torque when climbing hills and driving around. while getting aquainted with this cool little engine found the same cracking rubber boot to the stock air box and thought i had a brilliant idea by just replacing that setup with an universal k&n filter right on the end of that powder blue sheet metal contraption coming out of the throttle body(and it went on so nicely) so when it didn't work out like i thought(more air=more power) i was dissapointed -especially after the clueless 2 hour fuel filter replacement fiasco in parts store parking lot the day before -so the lesson is research then do -even when it looks super simple

when the Fuel Control Lever position is optimized

where would i find this and how is it's position optimized?

Except for times of heavy throttle application, the air throttle itself flows less air than either air filter.

i didn't realize this engine breathed like that. i did notice the puny exhaust pipe and was looking into changing the exhaust system for somthing that breathed better. what are the pros and cons of changing the muffler to a high flow system?

thanks for your help

[asavage]

The OEM exhaust is plenty large enough, unless you plan on running it above the governed RPM. It looks small, but the engine never turns the RPM that a comparable gasser would -- the 2.2l gasser has to move up to 30% more air!

There is no advantage to replacing the muffer, other than to make it louder.

Properly operating diesels -- any diesel -- operate with an excess of air. One of the reasons you see visible smoke from a diesel is a miscalibrated IP -- often this is done intentionally by the owner, in an attempt to gain more power. You can squirt in more fuel, but without sufficient oxygen to completely combust it, what you mostly get is soot (visible smoke) and cracked exhaust manifolds from the overheat condition.

With some situational exceptions, adding more air to a diesel will not gain power. It will, however, cool the pistons, valves, and exhaust, and that can lead to longevity gains. The cone filter you describe may counter those benefits. The OEM intake tract does not pull underhood air into the intake, it gets air from in front of the hot bits (more or less). A cone filter right above the alternator is going to draw warmer, less dense air than the OEM system. That's not an improvement.