The computer was working very hard to get the big singles to idle. It had an idle surge of what I would guess to be about 1500 RPM. At the time the scheid guys didn't seem too interested in programming and were playing with the spring pressure in the injectors to get them to run. I can only assume nothing ever became of it since I've heard absolutely nothing about it since then.

Completely agree. In this case his arguments are wasted on me, but that doesn't mean I don't respect the effort.

I've run no less than 5 different intake configurations on my truck, and the 6637 gives me the best throttle response and lowest EGT's of the bunch. If it's filtering abilities are a tick lower than some of the others, I can live with it....I know it flows better, doesn't make a lick of difference to me what the numbers say.

The only knock I have with the 6637 is it's getting too expensive to change twice a year. It's more than $30 at fleet filter now. Thinking about trying one of the giant AFE filters that Brandon is running.



Seems like that would be the best of both worlds. Plenty of air flow and reusable.

 

Seems we think alike on some things. I should have already had one.

 

Let me answer the washing the engine bay statement... I'm probably a little more **** that some folks here about keeping it clean. I do it at least twice a year not because it's filthy, but because I CHOOSE to keep it that clean. A lot of us do. I fail to see what that has to do with anything here. Unless you just wanted to point out my bone-headed move of leaving the bag on the filter when I started it.

 

When I hunted on base a lot a few years ago I noticed a serious amount of dust in the bay. More than 2x cleanings would not satisfy for my analness. That is why I bought my Bushwhackers for those gravel roads with talcum like powder. Go off road and things change. I am talking off paved roads of course.

Nevertheless, I have yet to dust a turbo and have been running the 6637 for years. Let me put it this way, after lurking here in 2001 and on, I did the CCV and 6637 mods. Yeah, I lurked for a few years with overseas deployments.

 

Yeah.....but "just over 400hp" in your sig wouldn't draw as many comments

 

That's why I called it out for what it was... it had absolutely NOTHING to do with the issues in this thread's discussion.

Besides, you're in good company.......we've all seen the threads with numerous and sometimes hilarious bonehead moves that MOST of us have been party to at some time or another.

followed by , and then normally followed by !

 

Because you previously told me you had it and at one point we discussed how much effort would be required to temporarily re-install it and hook the hose from your restriction gauge to here...



...where I had my gauge hooked to my AIS so that we could compare the restriction readings between the two setups and this is where you need to hook it for testing the stock air box.

The wife is cranky and the market is back down right now so I'm not raising the subject with her but "ideally" I could offer up enough "inducement" to dyno your current 6637 setup, change to the stock air box and dyno that, and then dyno the 6637 again later before the day is done.

I'm assuming each session on the dyno is 50 to 75 $ and ideally to benefit my dyno analysis of run to run variance all 3 runs for each of the 3 sessions should be done in the same chip setting. Then of course there's the beer money to consider to pay for the help you'll need switching setups etc... but I think I can swing up to say $300 for the effort.

NOTE... you had the number 0.076 lb/ft^3 written at the top on your compressor map? That's the air density at 14.7 psi and 60 F but the maps are measured at 13.95 psi and 85 F where the AD=0.0692 lb/ft^3.

Compressor maps are tricky to work with because the flow they give needs to be corrected to actual operating conditions or vice versa! I'll post what I'm doing a little bit at a time so you can chime in and help me refine the approach before I go to the effort of trying to recalibrate my computer model for your new turbo. If you have any BP vs restriction data please post it along with the RPM if you noticed that.

You have a unique advantage because you can measure your actual restriction and then go to the "updated" 6637 curve below...



...and get the estimated CFM flow through the filter and into the turbo and from that calculate the actual MAF from the actual AIT at the filter. Then from the corrected MAF I can get the TPR and from that the BP.

Of course to get the BP I need to consider the PD across the IC and the PD due to the air filter and turbo inlet tube. Do you have any estimate of your IC restriction vs CFM? If not see if you can find one because I'm on a cell. I previously used a 2 psi ICPD at 700 CFM number that I'd come up with for my early 99 IC. Installing a second BP gauge on the hot side is the only way to know for sure!

Just to make things easy and to get an absolute maximum performance baseline I'm going to first analyze an "open" turbo inlet with no air filter and no turbo inlet tube and a perfect IC with a 0 psi PD!

Don't worry unless a "moderator" pulls my plug I'll continue to post exactly what I want to when I want to!

Well I do have a stake in the sense that I don't like to see members misled into thinking that the 6637 mod is a "slam dunk" (where have I heard that before?) and if I direct them to some of my reference posts on the 6637 at least they'll see there's two sides to the story!

 

Please be advised that you et al can save yourselves an awful lot of wasted ft-lb of typing ENERGY by not repeatedly asking me to respond to "nitpicking" comments!

BTW each 1 ft-lb of ENERGY that you waste in this manner is equal to the 1 ft-lb of ENERGY that's required to hoist a full 16 oz can of beer to your mouth!

 

Not unless you're like me. I'm typing and drinking a beer right now at the same time. Leinenkugel's Sunset Wheat is especially tasty at the moment. Hey, it's just a little after high noon here!!!!

 

I can both agree and disagree with you, Mike.

As for "running him off", I have no interest or goal there, but for the benefit of us all, NONE of us should sit quietly by and let half-truths get quoted without offering the audience an opportunity to hear the rest of the story and then think about it while being FULLY informed.

I, too, believe that Gene really wants to help, but the fact that he doesn't have a dog in this hunt doesn't make him any more subjective than any of the rest of us. And you're right, too, in that he seemingly has nothing to gain or loose from taking either position...
... - 1) trying to help with valid science and good engineering principles, or
... - 2) simply looking for an audience to continue bashing a product he doesn't personally believe in.

The fact remains that Gene loses credibility when he will not acknowledge his mistake or retract his comments when presented with the full context of his misapplied quotes - and this is especially true when the full context does NOT support his position. By his own admission in his last response to Curtis, Gene calls what has been shown by several people to be "the rest of the story" nothing more than "nitpicking comments", and further said that these nitpicking comments are not worthy of a response from him. Can any of us really consider that kind of attitude as being consistent with the kind of intellectual responsibility Gene wants to demand from the rest of us?

Why does Gene ignore these posts of more complete information? Is that because when his quotes are taken in context and end up NOT agreeing with his position, he just doesn't know what to do? Is it because he just doesn't read most people's responses to his posts? Is it someother reason? I honestly don't know and will not assume to know, either, but it is quite disturbing that he apparently DOES read at least some of these posts and just brushes aside their truth as being "nitpicking".

So, when Gene accuses folks of keeping their heads buried in the sand because they don't want to hear "the truth" ... well, I don't need to say any more about the obvious reality here.

Concerning the 6637... if it really sucks the big one, yes, I want to know that. But again, I can't walk away from the context of its hugely popular use with virtually no negative side-effects being documented in the real world for virtually all of our daily-driver applications (outside of a lab, calculator, or computer... neither of which being where our trucks are operating).

 

Pete, all I can say is

 

Disregard.

 

All I can say is just sitting around waiting for Jeremy and Kyle to get here. Actually I have some things to do, but then it's on.

 

If one filter isn't good enough, 2 should do the trick right?



NOT my photo, I borrowed it from southmike at powerstroke dot org.

 

The difficulty in analyzing exactly how Air Flow + Fuel Flow = HP is accomplished in a turbo diesel is caused by the "turbo" itself because the turbo connects the Air Flow to the Fuel Flow so to simplify this discussion I'll "disconnect" the Air Flow from the Fuel Flow in this following "thought" experiment. Disconnect the up-pipes and install a dual exhaust and then disconnect the downpipe and attach the output shaft from a variable HP electric motor to the turbine drive shaft so that the compressor wheel is now powered solely by the adjustable electric motor.

Before we do some "thought" experiment dyno runs with this configuration lets measure the turbo's compressor map by disconnecting the boot from the turbo outlet at the CAC tube end and hooking the boot to a pipe with a throttle butterfly in it so that the opening from the turbo outlet can be "throttled" from fully closed off to wide open. This in fact is how a "cold" bench test is done to measure turbo compressor maps.

It's easier to follow this discussion by referring to the "generic" turbo compressor map below which I'm using because it's well labeled unlike the actual compressor map for a GTP38R turbo which I'll of course be using in the actual analysis of Tenn's new restriction data.

The electric motor delivers a constant rpm drive HP in the exact HP amount that's required to maintain the compressor wheel at a constant rpm as the airflow is varied with the throttle. Start with the throttle wide open and adjust the electric motor for an rpm of 84,200 rpm which is the compressor wheel rpm line in the center of the efficiency island and with the throttle wide open you'll be at the intersection of the 84,200 rpm curve and the 50% efficiency curve at an MAF=30 lb/min which is in the "chocked flow" region of the map.

Now start closing the throttle and as you do the TPR increases, the MAF decreases, and the compressor wheel blades stall at about a MAF=14 lb/min where the 84,200 rpm curve hits the "surge line" at a TPR=1.8 and where the efficiency is about 63%. At each point along that line the outlet pressure and temperature are measured so that the TPR and efficiency can be calculated.



Since these calculations are based on the standard reference conditions of 28.4" Hg=13.95 psi turbo inlet pressure and 545 R=85 F turbo inlet temperature you need to "correct" your actual MAF to what it would be if you were actually operating at these standard values and then use that "corrected MAF" to see your turbo's compressor performance on the map.

There's some interesting physics relating to this compressor map correction business and I'm pretty sure none of the "compressor map" sites understand it because they just present the correction formulas, mumble something about air density, and then wave their hands as if it should be obvious to all why corrections are needed and how and what they're really correcting for!

The pressure correction seems straight forward but the temperature correction involves the square root of T instead of being proportional to T as would be the case for a straight forward correction to air density at the turbo inlet. However if you'll note in the example map the compressor wheel rpm is also corrected by the square root of T.

Some of the best information I've found on this subject is from jet engine sources where it seems to do in part with the Mach number at the compressor blade tips and sure enough when I did a calculation of the tangential linear velocity of the tips of the compressor blades for both a stock 99.5 wheel and for an early 99 wheel I got numbers approaching and or exceeding Mach 1 depending on wheel rpm.

Now before moving on I've got a few words to say about what "causes" turbo surge because those who think it isn't caused by the compressor blades stalling have some more homework to do! At the outer leading edge of the compressor blades the relative Air Blade Angle ABA, which is the angle between the incoming airflow and the compressor blade leading edge, is given by the arc tangent of the ratio of the tangential linear velocity of the blade leading edge to the velocity of the incoming airflow.

If the ABA exceeds a critical value the incoming airflow separates from the blade surface and the blades stall just like the wing on an aircraft stalls at too steep of a relative angle to the airstream!

Now consider moving in a slant 45 degree direction from lower to higher MAF along a line that's parallel to the surge line and towards increasing compressor wheel rpm and increasing TPR. As the compressor wheel rpm increases the tangential linear velocity of the blades increases and because you're moving towards both higher MAF and towards higher TPR the inlet CFM needs to increase to meet both the increased MAF and to generate the increased TPR at the higher MAF!

This "double whammy" combined effect for increasing inlet CFM causes the velocity of the incoming airflow to increase in direct proportion to the increasing compressor wheel rpm and this in turn causes the respective velocities to increase about equally and this tends to keep the ABA at about a constant relative angle so that the blades don't stall as the higher TPR is being generated at the higher MAF!

Now consider moving in a vertical direction from lower to higher TPR but at a fixed MAF. Say you move straight up the map at an MAF=20 lb/min. Now as the compressor wheel rpm increases the tangential linear velocity of the blades increases as before but since you're moving upwards on the map at a constant MAF the inlet CFM only increases just enough to generate the higher TPR and this doesn't cause the velocity of the incoming airflow to increase nearly as much as before and as the surge line is approached the ABA gets larger and larger until finally the blades stall at a TPR=2.2 and you get surge!

Surge means that the compression can no longer be maintained and that the previously compressed air now flows backwards through the compressor wheel blades placing a torque reversal fluttering strain on the turbo shaft bearing! If you're still applying the "diesel" throttle the compressor blades once again get a "bite" on the air and recompression is achieved that is until the rpm of the compressor blades once again gets high enough relative to the air flow to cause a second stall and then these repetitive stalls keep occurring at a rapid rate until the driver either backs off the throttle or the turbo destroys itself!

Now back to the "thought" experiment dyno runs so reattach the turbo boot to the CAC tube and now the airflow out of the turbo outlet is limited by the demand of the engine which is controlled by the "diesel" throttle instead of by the "butterfly" throttle but since the compressor wheel is being powered by the electric motor the turbo isn't "aware" of the change so it will continue to perform just like it's previously measured compressor map says it will and this is where I'll pick up in the next installment assuming the "nitpickers" stay at arms length and don't distract too much from the proceedings.

Now I don't mind at all responding to questions where someone points out something they don't understand in the above and then I'll try explaining it some more using a different approach. However I will no longer respond to any replies whatsoever which simply post that my stuff is silly and wrong unless the poster at least makes an attempt to highlight a particular segment and also makes an attempt to demonstrate that their version of that segment is more correct than mine is and just claiming that they are correct doesn't count and they can say I'm wrong as many times as they want but they'll get no response from me unless they prove I'm wrong and I accept their proof as being correct!

Of course everyone should always feel fee to post anything they wish to post on any thread they want to post it on but that doesn't mean they should feel entitled to be getting any replies from me and I don't care how many names they call me while trying to get a reply because it just won't happen!