Engine/Transmission (1998.5 - 2002) Value of "special" aircleaner ducting...

[Gary - K7GLD]

Oops sorry Nick just got caught up in all the post. I think the cooling down the temps is really in the intercooler more than say the air cleaner. Someone chime in on this for me for what I am about to say. It's the turbo it's self that raises the temp from the sheering of air when it hits the impeller up to 300 degrees or more someone chime in? I think we need to look more after turbo than before, but we do need to get cooler air to start with. We need to get more air to the intercooler to cool down intake temps. But you got to start were you can and that is the air cleaner first. I had the Scotty II, mega canon, and a stock air box with a k&n with 3 two inch holes cut in the bottom. I will say this out of all 3 the only one that lowered my egt's the best under full power and loaded with an 8500 trailer was the Scotty II. I will say that in all my test or playing around that it only lowered my egt’s by 45 to 47 over the other setups. This is no bull and I can prove it. I did not check this out in the hills yet.

I too had a well-drilled airbox and K&N - it was vastly better than the stock setup - but when I recently went to the BHAF, I immediately saw an additional 150-200 degree drop in EGT.



As far as reduced EGT is concerned, I suspect any of several approaches will improve over stock - and so when guys make a move from stock, to say, a Scotty system, no doubt a big improvement over the stock setup they just came from, and they are understandably impressed.



What I am curious about, is any who went from a properly setup BHAF to something like the Scotty or similar type outside ducted system - what no-doubt-about-it added gains were seen then?



Believe me, I'm NOT trying to pick on Scotty or similar setups - just trying to nail down what's worthwhile, and what isn't!

 

[Walt-L]

Just a quick note on air induction hoods. When I used to belong to the 6. 5 Chevy TD crowd, they kicked that idea around big time since the 6. 5's were not intercooled. And in the end it was a bad idea because if you brake the hood seal in any way to let air into the engine compartment, you inadvertantly reduce the natural vacumming effect of the rushing air under the front end there for reducing the passive movement of air through your rad / coolers. The air induction would have to target intake air inlet only and not engine bay. THAT air must only come in through the rad opening.

 

[Todd T]

One is to put the insulation over the hole when maximum egt reduction is not needed. Not a great fix but still a fix for some.

Translation: You have to stop and manually extract this piece of insulation from the cowl area before proceeding to work the engine hard.

Two is to put a Turbo air Guide on.

Translation: You need to dish out another $159-$199 for this attempted reduction in the increased sound levels you created by neatly sawing a 4. 5" opening in your firewall.

 

[Todd T]

SO, where do all those radical claimed power improvements with the ducted intake systems come from? If it isn't actual cooler air, well, damn, it must be that vast amount of pressurized air from the cowl area, right?



We'll see!



It's rather easy to install a water-column sensor down in the cowl area where the air intake mods usually drill that access hole, and get the ACTUAL down the road pressure buildup - and then we'll see how much pressure there REALLY is down there to "pressurize" the engine intake tract...



So, all you critics get your objections and preconceived notions ready, and line up for the NEXT round!



QUOTE]



Gary, a few years back I had performed the above prescribed tests using two MAP (Manifold Absolute Pressure) sensors and a simple volt meter with correlating readings charts and conversion charts from Pascal to PSI.



The first (#1 sensor) was installed in the cowl area where the air is drawn from for the cowl type system. The second was mounted in the intake tract ahead of the filter (dirty side). As I did, you should also find that you'll consistently see, at all road speeds nearly zero pressure readings in the cowl area (a few spikes of pressure (. 5) but nothing sustained). Additionally, under light boost levels (6PSI and above) a slight negative pressure (vacuum) from this sensor (about those of the small pressure spikes (. 5-3/4 but a bit more measurable during a boost condition). This will also be supported by actual vacuum levels measured by the #2 sensor in the dirty side of the intake tract (this reading will be consistently about 4PSI lower than a boost gauge installed in the intake manifold and level off just before boost starts to level out (drop)).



These tests were performed first with the HVAC system in the off position, next in vent mode and third in recirculation mode on the A/C cycle.



Using a cowl induction system (CIS)* that utilized only the 4. 5” cowl hole, I theorized that the HVAC system with its series of vacuum operated doors do not allow for a good enough seal to actually hold pressure in the cowl area also the seal around the cowl and CIS area is not enough to hold back pressure.



Secondly, with a CIS that uses both a cowl hole and factory fender hole you cannot sustain pressure due to the obvious factory hole leaking it by. So basically, with either system the air flow to this area was pushed out of the area through numerous leaks including those not related to the HVAC system. Fresh air? YES, Ram air: NO! Louder turbo whine: YOU BET YA! More than my family could tolerate during extended towing.



*Note: Not claimed to be a benefit of the either type system, just an observation that pressure is not detected or sustained with either system in place.



Ram air? Id rather call it Cold Air Induction. The trouble with 'ram-air' systems is that often they aren't. Ram-air, that is. By the time you collect enough air and shove it into the airbox, negative pressures lurking around corners in the intake duct and at its entrance have probably assassinated the pressure gained by the forward movement. Plus, how d'you know that the place you're trying to pick air up from is under positive pressure anyway? With proper CAI siting on our trucks you can easily equal out the intake tube and filter restrictions of the intake system under a no boost condition and that would certainly help, but i still wouldnt call it 'Ram air!'. I don’t have data for our 5” tube or the BHAF or K&N type filters but would speculate the siting would need to be just about dead center on the trucks grill at the bumber line area similar to DF's location.



The true benefit of cold air intakes (CAI) or cowl air induction is to eliminate the draw of under hood air at take off and provide plentiful clean cold air during operation however the effects on under hood air temps at speeds greater than that of a regualar surface street (35MPH) are nearly identical to those you’ve reported already. IMO void and null, when compared to the trade-offs (louder turbo whine or risk of water ingestion) There’s radiant road heat to think about here on take offs too. but we have forced induction and aftercoolers. do you really think its a DMDPC (Dwyer Magnehelic Differential Pressure Gauge) measurable difference? or better yet, the ol' S. O. P. meter detectable faster spool up? like i said void to null IMO.



As with any non-factory intake system utilizing a larger filtering surface element you will see reduced EGT’s and freer air flow to the engine resulting in better performance be it cooler EGT or better MPG's or both.



Conclusion: Aftermarket air filters that provide a greater filtering surface to that of the factory element will result in better performance and reduced EGT’s. So pick your poison fella’s. Me? I have twins and a nice K&N stuffed under the hood drawing in nice hot air and spitting out piston melting performance. come and get you some, is all i can offer! loaded or not.



For Diesel Freak’s idea: Its REALLY nice, wouldn’t work for a twin setup but NICE! Also not something I’d want mounted up if following a Semi tractor or two in a heavy rainfall with 10K behind me and sucking enough air to sustain 18-20PSI of boost! so maybe we should think about a vacuum solenoid to shut off the front intake in adverse conditions. Just a thought – DF?

 

[Gary - K7GLD]

"Ram air? Id rather call it Cold Air Induction. The trouble with 'ram-air' systems is that often they aren't. "



YUP - my conclusion as well - and the chances are, there is precious little "cold" in that cold air induction, since you are limited to whatever ambient outside air is - on a 100 degree day, that outside "cold" air will still be 100 degrees!



Thanks for the insight and additional research-based info it really helps!

 

[Gary - K7GLD]

OK, Just returned from about 1200 miles of RV towing from eastern Oregon to the Oregon coast - several decent mountain ranges and grades involved. But as mentioned previously, typical actual time and distance on those grades was a pretty miniscule percentage of the total miles involved.



So how did underhood temps read?



Well, the VAST majority of the time and miles, underhood temps ran about 5 degrees above outside ambient temps - that's right, *5 DEGREES!*



Toss in some rolling terrain, and a slow rise to 10 degrees.



Fairly long climbs at 60 MPH or so delivered about 20 degrees rise - and that was IT!



Of course, once hills were crested, underhood temps quickly returned to the lower ranges - and while coasting downhill, usually approached ambient outside air.



Turning on the A/C while maintaining 60 MPH only raised underhood temps by about 1 degree, if that.



Just to try a "worse case scenario", I tried purposely artificially loading the engine up a 7% or so in overdrive long grade to see what temp rise I could generate - running at about 1800 RPM, EGT at 800 degrees, and boost at 28 PSI generated about a 45 degree underhood rise in temp - and that MIGHT represent RVers with heavier rigs than my 7000 lb. setup - or guys whose engines must work harder than mine. My power mods REALLY make it hard to stress my engine other than the above deliberate lugging abuse.



I *really* love and appreciate the recent power upgrades I had done - the 1. 6 injectors and full 4 inch exhaust, combined with the free flowing BHAF REALLY make this a delightful tow vehicle - during this trip I rarely used the Edge Comp - and when I did, it was on 1x1 to turn power DOWN, rather than up - all the rest of the time, it was off since I had all the power I needed - other than another burst on 5x5 up another 7% stretch to see what would happen.



Let me tell ya, those big Oregon pines started flying by REALLY fast, before I ran out of road and grade!



SO, let the reader judge for himself the need or value of "special" ducting to lower air delivery to the Cummins - I've already made my decision, and where I'm at is where *I* will STAY!



As an additional note, any members feeling the need for additional info from me personally, my subscription to TDR is up, I'm sorta burned out, so I don't plan on continuing for the time being - so if desired, I can be reached via Email at:



-- email address removed --



Best wishes to all...

 

[darkhorse]

Happy trails, Gary. I have appreciate the information in your posts.

 

[JR2]

Its a little late to chime in here, but I have seen temp differences of over 100 degrees before. Granted the outside temp was -20 but the underhood temp was 130 F. In this case the ram air would bring in nice cool air.

 

[rweis]

Gary, thanks for everything, and especially the testing and reporting.



I put some ideas over in the VP temp thread you might enjoy reading.



I will email you the results.



So long and HAPPY CAMPING Oo. Maybe we will have the chance to do a little RV'ing somewhere along the future



Bob Weis



The OA project is ongoing, the VP project is ongoing.



I might use my Scotty II cowl hole to vent the underhood temps (bilge blower) or source air to cool the VP44 after shutdown with a bilge blower and put in a BHAF instead.

 

[NIsaacs]

Gary,... . not trying to start something... . but the 800* pre turbo egt's seems kinda low. As a long time owner/operator of large and small ctd powered trucks, I have noticed low egt's usually means a defective pyro. The direct wire type seem to be the most tempermental. Again, just a thought that maybe... ... ... . ?





"NICK"

 

[Gary - K7GLD]

Gary,... . not trying to start something... . but the 800* pre turbo egt's seems kinda low. As a long time owner/operator of large and small ctd powered trucks, I have noticed low egt's usually means a defective pyro. The direct wire type seem to be the most tempermental. Again, just a thought that maybe... ... ... . ?





"NICK"

Nick, I've been down that road before, no, nothing wrong with my pyro or probe - been checked, and it CAN be made to go higher - just not a normal situation with my truck setup and loads unless I *really* force it...



The 4 inch exhaust and BHAF have reduced my EGT's a good 200 degrees across the board as compared to same loads, same routes of travel...

 

[Lsfarm]

Towed today

I towed my car hauler today, was running late for the event, so I was running pretty fast. OAT 75*, was pulling 15-20 psi boost continously, EGT's 1100-1200* A/C off.



My trailer is 22' and with my car weighs about 10-11K it is streamlined like a brick, all square corners and flat front. My truck weighs 7400 GCVW 17-18K



I was running around 80mph for an hour and pulled into a rest area, popped the hood and measured a few locations.



Temps were measured with Laser thermometer. I pulled into the closest parking spot I could in the rest area to get as close to cruise conditions as I could.



Fan blades, 150

Thermostat water neck, 167 [I run a 180 thermostat]

front of block and valve cover 167

air filter to turbo inlet rubber duct. 121

Air filter neck at rubber duct junction 119

Surface of airfilter 117 both on turbo side and fender side

[ I have an aluminum shield between turbo and air filter]

The 117 was with the engine running, after I shut it down the

filter surface rose to match the duct temp at 121

top of VP44 127

Fuel filter 117

air inlet to head 121



So on a pretty cool day working the truck a bit, I was seeing a 40* temp rise after a declerate, park and pop the hood measurement. 117-77=40



The EGT's were 500 on the gauge when I parked and the turbo ex housing read 485 when I lasered it after I opened the hood, The truck was idling for the very first readings since it was too hot to shut down. And I wanted as close to highway readings as possible. Once the EGT's dropped below 350 I shut it down to take the rest of the readings.



I'm sure the under hood temps were higher when I was running 20 psi boost, but I did not have any under hood gauges to take readings from when the engine was under load. I did not let the engine idle with the hood closed which would have given higher readings



From the readings I saw there is less under hood temp rise than I thought, but I shudder to think what the temps are like when it's 95* OAT and I'm running the hills with 30 psi boost 1250 EGT engine coolant showing a rise and only 55-60 mph. I'm sure the temp rise is at least 80-100. I have seen 200* coolant temp when really working the truck under extreme conditions.



From Gary's readings and mine I tend to believe that for a fairly light load and moderate driving a BHAF or an AFE are adequate. But for a heavy load, hard driving, long hills and low airspeeds, I believe it would be advantagous to have some sort of extra outside air getting to the airfilter. Of course a person could just back off a little... . nah, never mind :-laf



Gary, thanks for taking the time and effort to get some real-time on the road readings, I may try to find a similar temp gauge so I can do the same. Unfortunately I won't be towing very much for the forseeable future.



Greg L

 

[rweis]

And the REAL problem is when you get to 350* egt and shut it down the heat soak gets out of hand and the VP goes up about 30* - 40* ( 157* - 167*) and the circuit board gets a heat cycle.



Good information though, more data is always good. Helps define the problem.



Bob Weis

 

[Lsfarm]

Heat cycles

Hi Bob, I've been following the other thread about trying to keep the VP44 computer cool. I've been trying to keep it cool on my truck with a simple air duct.



I question that a heat soak after shut down is causing failures. I believe you took readings off of the ECM as well as the VP computer. Both had significant heat rise after shutdown. But we have virtually zero ECM computer failures.

I believe that the computer is just poorly designed.



Certainly the heat cycles aren't helping anything, but it seems that the ECM is designed to be bolted to the engine block and recieves the vibration and heat cycles and survives.



I'd be very curious to see what the VP's computer temperatures are when the lift pump is failing. There have been numerous VP failures on trucks that have plenty of fuel pressure [fuel cooling] and that have not been run out of fuel. I hope that there will be an improved computer for the VP some day.



I keep my fuel level above 1/4, 3/8 most of the time, have had a pusher pump and good fuel pressure since 12K miles, and I still lost my VP at 50K. It is just a poor design in my opinion and experience.



There are plenty of VP's in hot climates failing, and plenty in cold climates failing, in fact I believe the VP powerd trucks in Alaska have a high failure rate because of the winter fuel up there. [poor lubrication from #1 fuel]



How about a poll to track the climate of failed VP trucks??



If the heat cycles are the cause of the VP computer failures, shouldn't there be a trend to show higher failure rates during the summer, and especially in the hotter climates in the southern states?? I would think that the VP's would be failing all over the place in LasVegas, Tuscon, etc. ??



I'm just frustrated by the whole reliability issue. I had believed that what I do to keep fuel supply to my VP should have kept it alive, but it didn't. I had dead pedal, 0216 code and failure to idle. At only 50K miles. I know that the 'diaphram' in the VP has been redesigned, and this should help reliability, time will tell.



Oh well I guess a $1000 pump every 50K isn't too much to put up with.

 

[rivercat]

. I do not have the box completely sealed yet. I do have a relief port/valve in the bos just incase something pluggs the main intake on the bumper. One thing I have noticed is the effect on EGT at speds under 35-40 MPH.

Whould the effect you speak of be positive or negative.

meaning either the avoiding high underhood temps at slow speeds or creating extra vacum with the system at slow speeds when there is no ram air effect?

 

[BDaugherty]

but a cowl hole makes you want to put a bullet in your skull after a few hours of driving!!!!!

I know that this is an old thread, but I just want to say that the PSM system with the "cowl hole" is MUCH quieter than the K&N intake system that my truck came with.

 

[dknoch]

Hi fellas! I quit reading at page 5 but I will say I have a cold air intake from PSM Buick and when I went to install it, I needed to run to the store to get a hole saw to cut the hole in the fire wall. I left the truck in 5th gear and checked my EGT from 40 to 70 or 80 MPH, (I can't remember). After the install, The turbo is louder inside the cab, very noticable with the windows up and the vents on. However, that same day, after the install, doing the same "test", I saw a 50 to 75 degree drop in EGT and the outside temperature was hotter. Hope this helps. Dan

 

[Gary - K7GLD]

Hi fellas! I quit reading at page 5 but I will say I have a cold air intake from PSM Buick and when I went to install it, I needed to run to the store to get a hole saw to cut the hole in the fire wall. I left the truck in 5th gear and checked my EGT from 40 to 70 or 80 MPH, (I can't remember). After the install, The turbo is louder inside the cab, very noticable with the windows up and the vents on. However, that same day, after the install, doing the same "test", I saw a 50 to 75 degree drop in EGT and the outside temperature was hotter. Hope this helps. Dan

All well and good - AS LONG AS it's noted that apparently the comparison is vs a STOCK intake setup, not one of the cheaper BHAF-type, filter only solutions - as usual, the biggest gain of the "system" was undoubtedly due to the new and better flowing air filter element.



But congratulations on an improved intake setup - anything that efficiently improves engine breathing is a GOOD move!

 

[darkhorse]

as usual, the biggest gain of the "system" was undoubtedly due to the new and better flowing air filter element.

[/QUOTE]



I wonder dknoch's signature lists a AFE filter but not the PSM intake mod. Tell us dknoch. was that big temp drop due to just the cowl intake addition or did you add the AFE drop in filter at the same time?

 

[Gary - K7GLD]

as usual, the biggest gain of the "system" was undoubtedly due to the new and better flowing air filter element.

I wonder dknoch's signature lists a AFE filter but not the PSM intake mod. Tell us dknoch. was that big temp drop due to just the cowl intake addition or did you add the AFE drop in filter at the same time?

Yeah - that would be interesting if that's the case - I've never seen the element in the AFE - what might they be equivalent to as compared to a BHAF or the Amsoil 4510, I wonder...



I'm still interested in seeing results in EGT average in going direct from a properly installed BHAF, to something like being discussed here. When comparing to the stock OEM filter, LOTS of aftermarket "systems" look good - I improved EGT by 150-200 degrees simply going from the OEM to the BHAF, and the later 4510, sorta doubt I'd gain another similar significant reduction just with external ducting...



BUT, newer stuff keeps hitting the scene...