I am very interested in reading an equally well explained answer !

 

Technology is always progressing and Spicer's test caught the eye of K&N. They didn't improve their filter, but maybe someone else has.

 

My truck has dynoed over 500 hp and just a click shy of 1000 ft lbs pulling through a stock filter in a stock box/intake. The only change I made was to cut out the front of it as described on Kennedy's website.

 

Mark,

"I keep trying to get your input of this post but I keep missing you. This post is not adversarial but I do raise some issues that should be faced head on.

I agree that the HP increase with an aftermarket intake is mininal and I base that on all the dyno tests power adder manufacturers conducted a couple years go. They found little if any change in HP at all when they were dyno testing, regardless of the intake--which included testing with no intake at all. At that time they were routinely seeing 400-440RWHP. I would imagine at power levels in excess of 450-500 RWHP an intake may indeed be needed, but that is just a hunch."

As I have said hundreds of times the intakes should NOT be pruchased for HP gians as it is small at best. The worst way to dyno an engine is with no intake as well, in most cases you'll get less HP than with a stock filtrations system. The AFE uses velocity stack designs and others don't and it makes small differences in HP.

"I think the vast majority of EGT reduction an afternmarket intake provides is due to sealing off the hot underhood engine air. I just recently pulled of my Edge Attitude, but for a couple months I ran it with intake air temp displayed. There seems to be a direct correlation between air intake temp and EGT. I installed a Tex Christopher CAI (cold air intake kit) on my stock airbox in order to seal out hot underhood air, and the cold air kit keep the EGTs lower during "city" driving. However, there is little difference in EGTs with my LB7 at freeway speeds with the intake sealed vs unsealed."

The lower EGT's you get are due to adding MORE air volume AKA CFM, you add fuel you need to add air to get complete combustion and to utilize the BTU function of the fuel. Otherwise no one would ever buy a supercharger, turbo, nitrous or other oxygen adding devices. Lower air temps make a difference but very small and is so variable due to ambient temps at any one point in time.

"I am not convinced there is a real difference in turbo spool-up time with an aftermarket intake. The first thing I did when I bought my truck was to install a K&N Aircharger. The Air Charger seals off the hot underhood air. The first thing I noticed was a lot more turbo noise, and the reason for the increase in noise was most likely due to the removal the the factory resonator. "

Most all customers report quicker spool up time, easy to see and feel even without gauges. Most report an increase in boost pressures at max and partial throttle.

"I agree that an aftermarket intake certainly feels like it is giving better throttle response, but I am sure much (if not all) of that impression comes from the increase in turbo noise. I drag raced for 9 years, and one thing I learned was "seat of the pants" impressions are not a reliable indcator of actual performance. I think the noisy turbo feeds the impression that the vehicle has better throttle response, but I have not yet seen any empirical measuremnt that shows one way or the other."

Your comment that it certainly feels like it has better throttle response is what is showing a better spool up on the turbo as well. Only you can decide if you are capable of feeling or just hearing the difference in throttle response. All I can tell you is I have installed systems on every truck I have ever had and seen higher boost pressures, and better spool up.

"I don't know how you could measure throttle response. You can't use 60' times at the dragstrip, because for a dragstrip launch you stall the engine against the convertor to get the turbo spooled up. You could try to launch from idle, but I'm not sure that would show anything either."

60 foot times on a 8000 LB street truck will be very hard to prove even if you added 30-40 HP, look at the weight ratio to HP amount.

"We also have to be careful about using mpg gains to evaluate a new intake. These engines take 18-20K to break-in, and my mileage constantly improved during that time and I already had the Air Charger on. When I learned of the oiled cotton-gauze air filters propensity to let grit into the engine, I changed to an Amsoil (oiled foam) in a swiss-cheesed factory air-box. There was no diffference in mileage though turbo noise was reduced. I also didn't "feel" a change in throttle response, though feeling sin't worth much."

Newer diesels break in way before 18-20K, go back to the old 7.3 or even earlier yes, but crosshatch depth and ring desings aren't like that today. 5-10K at most. Your MPG improved because you worn off the new feeling of putting the pedal down to feel the fun of 8000 LBS accelerating after 5 K break in miles most likely. A foam filter used to be the standard as far as stopping dirt in an aftermarket product, but the patented PG7 way out flows it clean or dirty as evidenced by the test and the foam clogs way faster too. If your turbo noise was reduced then you also had a reduction in flow. Slow moving streams are quiet, while fast moving ones make noise, air is the same way.

"When I saw the air filter test (http://www.duramax-diesel.com/spicer/index.htm) and learned that aftermarket air filters flowed nowhere near double the stock paper AC Delco filter (as K&N has clainmed), learned the Delco filters better, holds more dirt, and plugs up 2.5 to 3 times slower than the K&N, Amsoil, and AFE--meaning that the Delco only flows less when all the filters are new--I changed to the stock Delco paper filter. I saw no change in mileage."

No one can quantify your MPG, so many variables, summer or winter, clean filters (fuel) or not, driving style or towing more or less. Broken in engine or not. Used up the "new feeling" as I mentioned earlier etc etc. What are your methods of MPG calculation and how to you guarantee the results are correct each and every time?? Again so many variables. The AC was 99.93% efficient, the AFE PG7 was 99.23%. That is 1/2 of 1% difference (0.5%)when clean, by my views that is next to nothing and not worth worrying about. The AFE PG7 flowed 4.99 while the AC was 6.23 a difference of 19.9% in favor of the PG7. The AC held 574 grams while the PG7 held 233 till each one reached 10 inches of water, while that is in favor of the AC if you're not into doing maintenance the PG7 still flowed 19.9% better when it was clean and I suspect it flowed more as well up to a specific point as it got dirty, then at that 10 inches of water it still flowed at the same level of the AC. Plus remember the PG7 still didn't let the dirt thru even when loaded with 233 and at 10 inches of water, this is VERY important. We are all into performance or we woudln't be doing this for a living or hobby so cleaning a filter more often to get nearly 20% more flow is worth it to me and others I suspect. Dirt passing was 0.4 for the AC while the PG7 was 1.4, but the Baldwin (it is a comparable quality paper filter) passed 1.1. Why I do not know, but in any case the 1.4 difference is still very very small and in the life of an engine not much to worry about.

"I am now running a 500 RWHP race tune on my truck. I may actually be able to use a better flowing intake, but I still haven't seen any tests that conclusively show ANY aftermarket intake flows better. It makes sense to me that they should flow better, but I have not seen the kind of test that would conclusively settle the issue. Regardless, I won't run anything that doesn't filter as well as a stock filter because I am sure mileage and power will really take a nose dive if excess dirt gets into the engine and causes premature wear."

This is something I can't help you on, you have to make the decision if it is worth it to you as a individual. I can tell you they do flow more, per the AFE tests on their own in house flow bench. Could they be fudging yes, do they, not in my opinion. I have been out to there factory and they are as honest as any manufacturer I have seen in my 20+ years in the aftermarket industry.

"Now the AFE filtered better than any of the other aftermarket filters tested, but it still passed over four times as much dirt in less than half the time vs the Delco. Maybe that it not a significant difference, and maybe under normal driving conditions it doesn't make any difference at all. Oil analysis from trucks with aftermarket filters--even with the poor filtering K&N--driven in normal conditions showed acceptable silicone levels."

See above concerning dirt and levels of restriction info.

"The AFE also plugged over twice as quickly as the Delco. The only advantage to the AFE was in it's flow when new. It flowed 20% better, but the only way to keep it at the 20% higher flow rate would be to clean the AFE very frequently. How frequently is hard to say, but if a Delco filter would run 6,000 miles before reaching "dirt saturation", then the AFE would need to be cleaned every 2,400 miles. Perhaps the 20% flow advantage of the AFE lasts for 20% of it's "dirt saturation" level, meaning the AFE would need to be cleaned every 480 miles to maintain it's flow advantage. All that is just a guess."

See above info on maintenance intervals and such.

"I admit the AFE seems to be the best of the aftermarket air filters evaluated in the test and htere may be an advantage to the AFE system for high HP trucks if the filter is kept clean."

I totally agree.

"However, I cannot see any emprical evidence indicating that anything other than a Delco paper filter in a factory airbox--sealed with a cold-air kit if needed--has any advantage for guys who are running under 400-450 RWHP. That would be the vast majority of DMAX owners."

I feel the lower EGT and quicker spool up and higher air availability is well worth it to mildly modded truck owners and they get better BTU efficiency for the fuel used. Plus if you're doing dyno or competition these guys basically could care less about EGT's or dirt, they are after the biggest numbers or the longest pull. More air flow will not make much more HP as I have said before, but it will for the "normal" user lower EGT's, spool up faster and potentially provide more MPG. Combine an intake and exhaust and there are a lot of members here that have seen MPG increases from nothing but increased air flow thru the engine to raise it's efficiency level.

"Now I am very open to empricial evidence showing otherwise. I would buy an AFE intake system if it had been tested to show it filters at least as well as the Delco paper filter and maintains it's 20% flow advantage over it's " dirt saturation" life.

"

You'll have to get with Spicer and see if he is willing to do a re-test and get the point/number where the amount of flow decreases vs the extra dirt added to decrease it. I think you'll find the AFE PG7 will have a higher flow somewhere in the 80-90% range, then when the extra 10-20% of dirt is added to hit 10 inches of water you would be in the negative flow level as compared to the AC filter. This is where extra maintenance will come in and you'll have to make a decision if you're willing to clean more often or not and just use a throw away paper filter. Again the key here is the AFE PG 7 stopped the dirt whiel otherss let dirt thru earlier and more quantity as well.

Keep in mind too that we are comparing a stock sized drop in filter to a same sized AFE PG7. If you install a Stage II system with a much larger filter that has a lot more square inches of filter media than a stock drop in the flow rates increase and the time to dirty when they slow down increases a lot too! We sell a lot of drop in filters, but if you're looking for an EGT drop, spool up increase, and CFM advantage then the Stage I and II are the ones that really make a difference. Spicer's test was a test to see which filters passed dirt as compared to a stock filter, not which intakes system flowed the most air. This is something the membership tends to forget when they are looking at this well documented info that Testand Corp. and Spicer did. When you compare a drop in filter to a intake system the whole deal is off except which filters let thru dirt and which ones don't.


Hope this helps, and remember this is my opinion backed up by Spicer's independent test info. I have a 10,000 dollar engine in my truck too, that I use this info on to decide if it is worth it to me, I choose yes and have the same potential for problems as the rest of the membership. I am not made of money so I will NOT do something to my engine that will cause me a large expense for the benefit of a more air either.

Mark @ DPPI

 

Mark,

Thanks for the response. I almost missed much of your response because it wound up showing in the same "quote box" as my post to you. Could I talk you into editing it to make it easier to read?

Thanks

 

afp1,

Probably not, I am about as bad as it gets on computers, much better with tools!! Basically what I tried to do is put my responses after your questions which I put in quotations!! Try it that way and it will make more sense to you, maybe!!

Mark @ DPPI

 

My truck has dynoed over 500 hp and just a click shy of 1000 ft lbs pulling through a stock filter in a stock box/intake. The only change I made was to cut out the front of it as described on Kennedy's website.

My 2005 remains the same except I chose a Uni filter for better filtration and longer service life. My 2002 had a Uni and I switched to the AFE PG7 with sock for the increased silicon levels and improved airflow.

As for air flow ratings, the AFE does flow more, but it's nothing monumental...

 

John,

What is your take on turbo spool up with the AFE vs stock?

 

Blaine, good write up.

I think this is interesting. While I bought my AFE stage 2 kit expecting to see some results either turbo spool up, mileage, or increase in power, my own seat of the pants meter registered exactly at zero. I like my kit but it is a royal PITA to keep clean. Not only that, the metal box is rusting. I also thought that the exhaust made the turbo alot louder than any air CAI will.

 

Mark,

Here is a reformat of your response to make it easier reading. Your responses are in bold italics.

Mark,

I keep trying to get your input of this post but I keep missing you. This post is not adversarial but I do raise some issues that should be faced head on.

I agree that the HP increase with an aftermarket intake is mininal and I base that on all the dyno tests power adder manufacturers conducted a couple years go. They found little if any change in HP at all when they were dyno testing, regardless of the intake--which included testing with no intake at all. At that time they were routinely seeing 400-440RWHP. I would imagine at power levels in excess of 450-500 RWHP an intake may indeed be needed, but that is just a hunch.

As I have said hundreds of times the intakes should NOT be pruchased for HP gians as it is small at best. The worst way to dyno an engine is with no intake as well, in most cases you'll get less HP than with a stock filtrations system. The AFE uses velocity stack designs and others don't and it makes small differences in HP.

I think the vast majority of EGT reduction an aftermarket intake provides is due to sealing off the hot underhood engine air. I just recently pulled of my Edge Attitude, but for a couple months I ran it with intake air temp displayed. There seems to be a direct correlation between air intake temp and EGT. I installed a Tex Christopher CAI (cold air intake kit) on my stock airbox in order to seal out hot underhood air, and the cold air kit keep the EGTs lower during "city" driving. However, there is little difference in EGTs with my LB7 at freeway speeds with the intake sealed vs unsealed.

The lower EGT's you get are due to adding MORE air volume AKA CFM, you add fuel you need to add air to get complete combustion and to utilize the BTU function of the fuel. Otherwise no one would ever buy a supercharger, turbo, nitrous or other oxygen adding devices. Lower air temps make a difference but very small and is so variable due to ambient temps at any one point in time.

I am not convinced there is a real difference in turbo spool-up time with an aftermarket intake. The first thing I did when I bought my truck was to install a K&N Aircharger. The Air Charger seals off the hot underhood air. The first thing I noticed was a lot more turbo noise, and the reason for the increase in noise was most likely due to the removal the the factory resonator.

Most all customers report quicker spool up time, easy to see and feel even without gauges. Most report an increase in boost pressures at max and partial throttle.

I agree that an aftermarket intake certainly feels like it is giving better throttle response, but I am sure much (if not all) of that impression comes from the increase in turbo noise. I drag raced for 9 years, and one thing I learned was "seat of the pants" impressions are not a reliable indcator of actual performance. I think the noisy turbo feeds the impression that the vehicle has better throttle response, but I have not yet seen any empirical measuremnt that shows one way or the other.

Your comment that it certainly feels like it has better throttle response is what is showing a better spool up on the turbo as well. Only you can decide if you are capable of feeling or just hearing the difference in throttle response. All I can tell you is I have installed systems on every truck I have ever had and seen higher boost pressures, and better spool up.

I don't know how you could measure throttle response. You can't use 60' times at the dragstrip, because for a dragstrip launch you stall the engine against the convertor to get the turbo spooled up. You could try to launch from idle, but I'm not sure that would show anything either.

60 foot times on a 8000 LB street truck will be very hard to prove even if you added 30-40 HP, look at the weight ratio to HP amount.

We also have to be careful about using mpg gains to evaluate a new intake. These engines take 18-20K to break-in, and my mileage constantly improved during that time and I already had the Air Charger on. When I learned of the oiled cotton-gauze air filters propensity to let grit into the engine, I changed to an Amsoil (oiled foam) in a swiss-cheesed factory air-box. There was no diffference in mileage though turbo noise was reduced. I also didn't "feel" a change in throttle response, though feeling sin't worth much.

Newer diesels break in way before 18-20K, go back to the old 7.3 or even earlier yes, but crosshatch depth and ring desings aren't like that today. 5-10K at most. Your MPG improved because you worn off the new feeling of putting the pedal down to feel the fun of 8000 LBS accelerating after 5 K break in miles most likely. A foam filter used to be the standard as far as stopping dirt in an aftermarket product, but the patented PG7 way out flows it clean or dirty as evidenced by the test and the foam clogs way faster too. If your turbo noise was reduced then you also had a reduction in flow. Slow moving streams are quiet, while fast moving ones make noise, air is the same way.

When I saw the air filter test (http://www.duramax-diesel.com/spicer/index.htm) and learned that aftermarket air filters flowed nowhere near double the stock paper AC Delco filter (as K&N has clainmed), learned the Delco filters better, holds more dirt, and plugs up 2.5 to 3 times slower than the K&N, Amsoil, and AFE--meaning that the Delco only flows less when all the filters are new--I changed to the stock Delco paper filter. I saw no change in mileage.

No one can quantify your MPG, so many variables, summer or winter, clean filters (fuel) or not, driving style or towing more or less. Broken in engine or not. Used up the "new feeling" as I mentioned earlier etc etc. What are your methods of MPG calculation and how to you guarantee the results are correct each and every time?? Again so many variables. The AC was 99.93% efficient, the AFE PG7 was 99.23%. That is 1/2 of 1% difference (0.5%)when clean, by my views that is next to nothing and not worth worrying about. The AFE PG7 flowed 4.99 while the AC was 6.23 a difference of 19.9% in favor of the PG7. The AC held 574 grams while the PG7 held 233 till each one reached 10 inches of water, while that is in favor of the AC if you're not into doing maintenance the PG7 still flowed 19.9% better when it was clean and I suspect it flowed more as well up to a specific point as it got dirty, then at that 10 inches of water it still flowed at the same level of the AC. Plus remember the PG7 still didn't let the dirt thru even when loaded with 233 and at 10 inches of water, this is VERY important. We are all into performance or we woudln't be doing this for a living or hobby so cleaning a filter more often to get nearly 20% more flow is worth it to me and others I suspect. Dirt passing was 0.4 for the AC while the PG7 was 1.4, but the Baldwin (it is a comparable quality paper filter) passed 1.1. Why I do not know, but in any case the 1.4 difference is still very very small and in the life of an engine not much to worry about.

I am now running a 500 RWHP race tune on my truck. I may actually be able to use a better flowing intake, but I still haven't seen any tests that conclusively show ANY aftermarket intake flows better. It makes sense to me that they should flow better, but I have not seen the kind of test that would conclusively settle the issue. Regardless, I won't run anything that doesn't filter as well as a stock filter because I am sure mileage and power will really take a nose dive if excess dirt gets into the engine and causes premature wear.

This is something I can't help you on, you have to make the decision if it is worth it to you as a individual. I can tell you they do flow more, per the AFE tests on their own in house flow bench. Could they be fudging yes, do they, not in my opinion. I have been out to there factory and they are as honest as any manufacturer I have seen in my 20+ years in the aftermarket industry.

Now the AFE filtered better than any of the other aftermarket filters tested, but it still passed over four times as much dirt in less than half the time vs the Delco. Maybe that it not a significant difference, and maybe under normal driving conditions it doesn't make any difference at all. Oil analysis from trucks with aftermarket filters--even with the poor filtering K&N--driven in normal conditions showed acceptable silicone levels.

See above concerning dirt and levels of restriction info.

The AFE also plugged over twice as quickly as the Delco. The only advantage to the AFE was in it's flow when new. It flowed 20% better, but the only way to keep it at the 20% higher flow rate would be to clean the AFE very frequently. How frequently is hard to say, but if a Delco filter would run 6,000 miles before reaching "dirt saturation", then the AFE would need to be cleaned every 2,400 miles. Perhaps the 20% flow advantage of the AFE lasts for 20% of it's "dirt saturation" level, meaning the AFE would need to be cleaned every 480 miles to maintain it's flow advantage. All that is just a guess.

See above info on maintenance intervals and such.

I admit the AFE seems to be the best of the aftermarket air filters evaluated in the test and htere may be an advantage to the AFE system for high HP trucks if the filter is kept clean.

I totally agree.

However, I cannot see any emprical evidence indicating that anything other than a Delco paper filter in a factory airbox--sealed with a cold-air kit if needed--has any advantage for guys who are running under 400-450 RWHP. That would be the vast majority of DMAX owners.

I feel the lower EGT and quicker spool up and higher air availability is well worth it to mildly modded truck owners and they get better BTU efficiency for the fuel used. Plus if you're doing dyno or competition these guys basically could care less about EGT's or dirt, they are after the biggest numbers or the longest pull. More air flow will not make much more HP as I have said before, but it will for the "normal" user lower EGT's, spool up faster and potentially provide more MPG. Combine an intake and exhaust and there are a lot of members here that have seen MPG increases from nothing but increased air flow thru the engine to raise it's efficiency level.

Now I am very open to empricial evidence showing otherwise. I would buy an AFE intake system if it had been tested to show it filters at least as well as the Delco paper filter and maintains it's 20% flow advantage over it's " dirt saturation" life.

You'll have to get with Spicer and see if he is willing to do a re-test and get the point/number where the amount of flow decreases vs the extra dirt added to decrease it. I think you'll find the AFE PG7 will have a higher flow somewhere in the 80-90% range, then when the extra 10-20% of dirt is added to hit 10 inches of water you would be in the negative flow level as compared to the AC filter. This is where extra maintenance will come in and you'll have to make a decision if you're willing to clean more often or not and just use a throw away paper filter. Again the key here is the AFE PG 7 stopped the dirt whiel otherss let dirt thru earlier and more quantity as well.

Keep in mind too that we are comparing a stock sized drop in filter to a same sized AFE PG7. If you install a Stage II system with a much larger filter that has a lot more square inches of filter media than a stock drop in the flow rates increase and the time to dirty when they slow down increases a lot too! We sell a lot of drop in filters, but if you're looking for an EGT drop, spool up increase, and CFM advantage then the Stage I and II are the ones that really make a difference. Spicer's test was a test to see which filters passed dirt as compared to a stock filter, not which intakes system flowed the most air. This is something the membership tends to forget when they are looking at this well documented info that Testand Corp. and Spicer did. When you compare a drop in filter to a intake system the whole deal is off except which filters let thru dirt and which ones don't.

Hope this helps, and remember this is my opinion backed up by Spicer's independent test info. I have a 10,000 dollar engine in my truck too, that I use this info on to decide if it is worth it to me, I choose yes and have the same potential for problems as the rest of the membership. I am not made of money so I will NOT do something to my engine that will cause me a large expense for the benefit of a more air either.

Mark @ DPPI

 

Now that I have my original post and Mark's response little easier to read we can continue. I hope this thread helps guys think through this stuff, regardless of what they do.

First off we are in agreement, and have always been in agreement, that an aftermarket intake--at least up to the 450 RWHP level--provides no significant advantage in HP. This is important for guys to realize, especially those new to the DMax. Of course, we are going to have to keep saying that because almost every owner new to the DMax that wants to improve performance is going to assume there is significant HP in the intake system.

No doubt more airflow lowers EGTs. However, since the stock airbox flows enough for 400+ RWHP, it seems unlikely that an aftermarket intake is allowing more air in at part throttle settings. I think the same thing is true at with lower HP tunes at WOT. A freer flowing intake does not "force" more air into the engine like the turbo, it just allows more air into the engine when the engine is demanding it, and the engine does not demand the increased flow until higher HP levels.

Having said that, when the turbo "wants" more air but cannot get it, EGTs will be higher. Based on the dyno results, my guess is the turbo doesn't want more air until that 400-450 RWHP range. However, this one is easy to test. All we have to do is check EGTs over a specific stretch of road--trying to keep conditions the same as much as possible--then add the aftermarket intake and check again. I don’t suppose you know anyone who has gone to that level of trouble?

I think keeping the air going into the intake cool will keep EGTs cooler. I am currently living in AZ. In the last three months I have seen temps from mid 40s to low 100s. There is a direct and measurable correlation between intake temp--as displayed on the Attitude--and EGT. My EGT gauge shows a 25 - 50 degree reduction in EGT between about 90 degrees OAT and the 60s, which corresponds to intake air temps of around 75-110 degrees. That is not as controlled a test as I’d like, but it is certainly much more reliable than a seat-of-the-pants feel.

My results lead me to believe that sealing off underhood air will reduce EGTs. We also know increasing airflow into the engine reduces EGTs. What is less clear is how much affect a free-flowing intake has on actual airflow through the engine at lower HP levels and part throttle situations. It would be an interesting test, both in the lab and on the road.

Now my boost valve—which does allows the turbo to spool quicker (based on boost obtained vs accelerator travel) and adds 4-5 PSI more boost (as shown on the gauge)—does lower EGTs under hard acceleration. I have checked this several times and over the same stretch of road under similar conditions. Again, this is not as controlled as we need it to call it a scientific test, but it is superior to a seat-of-the-pants feel.

I am still unconvinced that the freer flowing intake increases part-throttle turbo response. Your comment about whether or not I am capable of hearing or feeling the increased turbo response bears some scrutiny. I have been a USAF pilot for almost 24 years. I can promise you I am very attuned to the “feel” of any vehicle I operate. You get that way when such perceptions can have a major impact on your well-being. I even have measurable data showing the quality of my own hearing and vision. I am currently hearing a “hiss” in my truck that happens at higher boost levels. This is some kind of airflow related hiss and is very faint. I have not yet come across anyone else who has experienced it. My bet is this hiss is common, it’s just that most folks do not pick it up. A similar thing happened to me with a raw diesel smell and a secondary fuel filter. I have had two different types and they both gave off this smell, it’s just most guys don’t pick up on it.

Fine-tuned senses aside, “feeling” is not proof of anything. We need to see it and measure it before we know if there is a real change. I know taking off the resonator makes the turbo louder, but a noisier turbo is not the same as a quicker responding turbo. What often happens is we spend our hard earned $$ on something for our truck. This “thing” is supposed to be an improvement. When you factor in a wife’s objections to “fixing something that isn’t broke”, all of a sudden we have a real motivation for our new “thing” to work as advertised. When we are in such a frame of mind it is easy to convince ourselves of improvements that may not bear the scrutiny of actual measurements. I guess I said all that to say a guy who says the turbo is spooling more quickly, especially in a truck that has no gauges, is just not a reliable source of data. Ideally we need controlled measurements. At a minimum we need careful recording of how we are deciding if something has changed.

The MPG improvement on my truck did not being with the installation of the K&N Air Charger. I bought the truck and the next day installed the Air Charger. My mileage improved for the next 18,000 miles. Regardless of how I drove the truck, the mileage improvement was NOT the result of the freer flowing intake. Also, changing back to a swissed-cheesed stock intake with an Amsoil and then later to a Delco paper filter did not affect the MPG. My mileage has always been hand calculated and the results are from several tanks of fuel with the style of driving annotated. I can confidently state there is no significant—if any at all--MPG difference between any of the intake/filters I ran on my truck.

Regardless of all that, until we can get some carefully controlled tests, all we are doing is comparing once anecdotal experience with another are hostage to the quality of each others perceptions—even though mine are better than yours.............. I’d like to see flow tests at 700+ CFM as well as flow tests of intake systems. I’d like to see oil analysis results for the same truck run in the same conditions with different air filters. While we all know the Delco filters significantly better than the rest (the AFE passed over 3X as much dirt as the Delco), what we don’t know is what that translates to in terms of actual dirt in the engine. Silicone levels obtained with the AMSOIL, Uni, K&N, and Delco suggest they all filter fine under most conditions.

 

Nick,

Did you get he PM I sent containing the link to Spicer's test?

 

i have been reading this since it started and i enjoy the professionalism in it.


there is one thing that both of you have failed to mention in you threads. that is the turbo is a centrifugal pump. thus meaning the you can adversly change it output ei (flow/boost capacity) by restriction on both the intake and discharge side of the turbo.

there are three principles that relate/govern a centrifugal pump/turbo.
suction head- http://www.pumpworld.com/Flooded Suction.htm
it would be a postive flow of air into the turbo ie something like an unrestriced air pickup in the wind while the truck in moveing down the road. the more air that is push into the compresser wheel the most the turbo can put out inadition the normal output.
suction lift- http://www.pumpworld.com/Suction Lift.htm this is directly related to the amount of restriction the turbo has to suck the air through ie filter, intake tube thus decreasing the out put of the turbo.
total dynamic head http://www.pumpworld.com/Total Dynamic Head.htm
this is the pump/turbo's ability to suck and push air/fluid through a restriction. i personally have experience the diffrence between the stock and a pipe intake pipe i am currently use 4" pipe compare to the roughly 3.5 stock pipe. the same throttle postion that barely made boost with the stock pipe now make roughly 5psi of boost sucking through the same swiss cheese airbox the the stock pipe did. i all so notice that i start making boost sooner in the rpm band with the 4" pipe @ roughly 1500rpm vice the 1800-1900 that the stock allowed. and in moderate accelerating were i normally see 10 pounds i know see 15 pounds. this measurement is done on a auto meter 0-60 pound boost gauge. the filter element is a fram pletted paper with 13k on it. and turbo spool is quicker along with sooner in the relation to rpm of the engine

so did i make more power dont know???? maybe it could be measure in a 20mph-60mph accel run. what i do know is that the 30 dallors woth of PVC pipe has allowed me to get more of the available power soon and made my truck more of a joy to drive in city traffic.

another thing to notice
CFM= CID(402) * RPM* VE.9(VOLUME EFFECIENCY)/ 3456 auto math 101
314 cfm @ 3000 rpm with no boost.
now here is the kicker at 30 pounds of boost our engine are effectively 3 times their size. then it would look like this 402(no boost)+402(@15#)+402(@ 30#)= 942 CFM and that is if it maintan a 90% effeciency, 40# would be 1168 CFM.
stock @ 20# pulls 650 CFM at 90%VE
@30# with VE @ 100% it is 1046 CFM

with that stated all filter created create restriction/ vacuum with the ac delco creating 6.23" of H20 this alone with seriourly decrease turbos abilty to move air. then they took the inital restriction and add 10" of h2o for the limit on the Accumulative Capacity test at 350 CFM that would make over 16" h2o of vaccum
now let me remind you 30" of HG (mercury) is perfect vaccum. i am sure that 16" of h2o is is over 10"hg given that mercury is heavier that water......i dont know the exact conversion for 1"h2o to 1" HG is.
so with that said i agree with afp1 and i would like to see the test done at 700CFM plus.
"However, if a filter is using "better airflow" as their marketing tool, remember this....Does it flow better? At very high airflow volumes, probably. BUT, Our trucks CAN'T flow that much air unless super-modified, so what is the point? The stock filter will flow MORE THAN ENOUGH AIR to give you ALL THE HORSEPOWER the engine has to give" quoted from spicer. as i stated earlier these test were done on the assumstion the the Dmax does not use more that 350CFM i just prove that a bone stock Dmax uses nearly double the CFM under a full load
now will it increase power level overall probly not will it make the engine more effecient yes. thus making the truck funner to drive.
on filter wise i am goning to go with a filter that was in the middle of the test like a AFE, Baldwin or Wix

just MHO

 

Is there a way to use a 4" intake pipe with the stock airbox? If so, how?

I think Spicer's idea that the stock airbox allows enough airflow is based on dyno results. 500 RWHP is available with the stock airbox. However, the dyno tells us nothing about turbo spool time.

 

Nick,

Did you get he PM I sent containing the link to Spicer's test?

I did Blaine and I've read it before. Thanks. I'm tradin my truck in for an 07 here next week. My air system will be staying stock. Since I saw no real gain with anything, I'm convinced that its nothing but a waste of money. Maybe down the road I'll be going with EFI live and once the current stock tranny fails, I'll be upgrading. Again, good write up.

 

Were you were going to make that link a sticky?

 

afp1,

Hey thanks for fixing it!!! As far as you're flying history don't take offense, my point is I don't think anyone can tell a 20 HP change in an 8000 LB truck even on a dyno it'll be hard to see and repeat consistently too!

As far as making 500HP on a dyno with a stock intake that's great! But how many folks do that or plan to do that and is that really important anyway. Making HP with any intake is easy so long as you can supply enough fuel, the intake provides it's benefits when towing and such on grades as it does supply more air and that provides the max air the particular amount of fuel being requested to run up the grade in question at a specific speed per the drivers desired speed level (not WOT like a dyno run). The extra air makes that amount of fuel burn at a more efficient level so you get more BTU use of it. On a dyno a ton of the fuel is wasted as smoke, the run is short and doesn't look to use the fuel, only to make the max HP possible. Intakes for a dyno deal are a waste of time, espeically for those guys that are on the fringe of the most HP no matter what. Now take that same turck and go up the famous Grapevine with 12,000 K trailer and the intake does as advertised.

This will always be a debatable deal as there is no way to do a truly 100% accurate test with and without and get 100% of the variables out of the test data.

Mark @ DPPI

 

Well we can at least get guys to research what they do before just bolting on what looks good..............

 

Spicers study is great but it shows nothing about an aftermarket intake. All it shows is the filtering element itself. An aftermarket intake could make more or less power and it wouldnt be shown in spicers study.

I saw a solid 15 HP increase and an increase in boost on a dynojet dyno with a stage 2 AFE with standard element vrs a swisscheesed airbox with a paper filter. I saw a gain that was within the range of acuracy of the dyno between a factory air box with paper filter and a factory airbox with no filter. Since this was on a dyno jet with a very short sweep the AFE spooled just a hair faster so it showed a gain? I dont know.....

I do know I saw no gain at the track. All this was done back to back at the track or dyno, swaping between the 2. Never ran with no element at the track though.....

Made lotsa cool noise though, thats about what I noticed SOTP I dont think I could tell one way or another on spool time, lowering EGT or milage improvement.

wonder if anyone else has any back to back testing they want to share? Maybe some runs on a load cell? That would be interesting.

 

Also how much filtering do we need? Is the factory filter overkill?

I just tore down my 03 Duramax. Its got 280,000+ miles on it, approx. 250,000 of them with an S&B CAI. We run CAI's primarily for the ability to clean the air filter vs. replacing it, and the fact that we do see a small increase in MPG.

I saw absolutely no signs of insufficient filtering in the motor. Nothing that would indicate that I had "under filtered" it. The big crack in the piston kinda sucked though.):h

 

After reading (and skimming) this post and other related articles pertaining to aftermarket intake systems, I have learned, 1:Most of this high-tech stuff is beyond my ability to comprehend (hopefully I'm not alone here), and 2: If you want lower EGT's, there is no quantifiable evidence that an aftermarket CAI will get you there. The reason I am interested in this IS for lower EGT's. My Juice/Attitude gives me all the performance I seek. I added Cool Duals last spring (thank you Mark Craig), and saw a slight reduction in EGT's, but since this is a cat-back system, I don't realize the full advantage. So, I'm looking for other options. There was mention of an over-sized intake system that will provide more flow somewhere here. Is that something I should consider? I am an average Joe with moderate demands on my truck other than towing a 10,000 lb. trailer 8-10 times a year. My point is, a higher capacity filtering system that maybe doesn't filter the air quite as good as the OEM may not be a big concern for me. Also, losing the kitty isn't an option for me at this time. Anyone?

 

Is there a way to use a 4" intake pipe with the stock airbox? If so, how?

here is how i did a 4" pipe from the stock filter box to the tubo intake. i believe it is not the air box itself that is the most restictve part but the stock piping form the box to the turbo(which meandors through the engine bay). as i have stated in another thread air flow has been increase. air does not like to turn preiod neither does water. though not lab proven i do get an average of 5 psi more (via a auto meter 0-60 boost gauge) during the same load conditons than with the stock tube. in addition to that i was never able to through an over boost code with the stock tube.
i belive the stock air box can handle 1200-1300 cfm easily

this is a pick of a 4" pipe next the stock pipe 3 to 4 flex coupling, 1 4 to 4 flex coupling, 2 45* elbows and about 9" of 4" PVC pipe.. i have since take the mounting plate for the air box completely out. the PVC pipe is strong enough to hold the 1-2 pounds the air box weighs

this is pick of a 4" flex coupling to the stock air box

 

I question the accuracy of Spicer's filter test. Our filters normaly see the dirt buildup over a period of time, say 12 months or 12,000 miles, etc.. He introduced the dirt within a short period of time, didn't he? (9.8 grams per minute) That's like taking my vacuum cleaner bag and dumping it onto my air filter and expecting none of it to get sucked through..

Also, for those of us with cold air kits, a Used Oil Analysis will show if particulates are getting through the filter. If not, then there is no need for extra filtration.

 

i re-read the testing and test results. they only tested the filters them selves not the intake system. the filter is only going to flow as much air as the housing it is in. that is the main reason why i went and put a 4" pipe on. when the air flow meter go red with a new filter i will change the air box. i have 15k on my fram filter yeah its dirty but the airflow gauge hasnt moved

 

i re-read the testing and test results. they only tested the filters them selves not the intake system. the filter is only going to flow as much air as the housing it is in. that is the main reason why i went and put a 4" pipe on. when the air flow meter go red with a new filter i will change the air box. i have 15k on my fram filter yeah its dirty but the airflow gauge hasnt moved

If you're serious about testing this you might try a true vacuum gauge hooked to the intake tube at the engine. That might tell you in inches of vacuum what restriction each intake tube is putting on the turbo.