just a quick question. has anyone seen or had dyno numbers with and without running an air filter. THIS IS FOR DYNO/TRACK PURPOSES ONLY!!!! i dont wanna hear how its stupid to drive around without a filter. almost everyone i see takes their filter off or always runs no filter on their setup for dyno/track runs

I would have to say it does make a difference as all the Big Boys run without filters and what looks to be a black hole attachment " I should patent that name for that purpose ha ha" 

I would have to guess anything over 600 hp is where bhaf will be struggling and I wouldn't put any other filter on.

2 hours ago, Dieselfuture said:

I would have to say it does make a difference as all the Big Boys run without filters and what looks to be a black hole attachment " I should patent that name for that purpose ha ha" 

I would have to guess anything over 600 hp is where bhaf will be struggling and I wouldn't put any other filter on.

Are you thinking of a velocity stack?

I can see for track or dyno purposes of putting on a velocity stack. Then when you are done with the fun I would toss the BHAF back on again.  

10 hours ago, cumminsVP2001 said:

Are you thinking of a velocity stack?

No not really, I never researched what them things are called. Just thought it looked like a black hole sucking stuff in if there is such a thing. If i would to make my own I'd call it that 

 

Edited July 28, 20186 yr by Dieselfuture

I dont have the dyno numbers you're after since I've never seen anyone do a run with and without air filter.  But nonetheless, I really cant imagine what benefit you'd get since most BHAF's are rated between 500-800 CFM.

 

Thats not me preaching about running without an air filter either but simply making the point that if your boost numbers are better with the filter off then you clearly have a CFM restriction.  But if boost is the same with the filter in place, EGT's are the same, and the exhaust color is the same,.....then you could assess that the BHAF isnt causing any power loss.

 

That said, if you have the filter minder in place or the ability to utilize one then you'd know in a hurry if the air filter was restrictive since the vacuum would suck the minder down immediately.

5 hours ago, Dieselfuture said:

I would have to say it does make a difference as all the Big Boys run without filters and what looks to be a black hole attachment " I should patent that name for that purpose ha ha" 

I would have to guess anything over 600 hp is where bhaf will be struggling and I wouldn't put any other filter on.

I haven't even looked, so I don't expect to be spoon fed but is there Dyno numbers between stock and bhaf? I honestly have been running no filter on my truck in the sig. Well, I guess a screen over my turbo is considered some sort of filter, just not a good one lol. But I also drive this truck about 500 miles a year. But it's starting to bug me thinking about the dirty *** air here getting sucked in my engine. I was looking into a velocity stack a couple weeks ago but again couldn't find any real world Dyno numbers, just claims of higher airflow/hp. Going to the track for the first time in 2 weeks!

Only thing a velocity stack would do for you is reduce the amount of turbulence of the air going into the compressor wheel, and speed the flow up (hence the name).  

Just now, trreed said:

Only thing a velocity stack would do for you is reduce the amount of turbulence of the air going into the compressor wheel, and speed the flow up (hence the name).  

Do you think they are worth while?

You might see a small gain.  There is only few percent difference in flow acceleration versus a pipe with a slight radius (stock, BHAF, etc) and a smooth radius.  A longer stack will net more gains than a short guy like this:

Edited July 27, 20186 yr by trreed

Sounds like you really need to get your truck on a dyno and report back with some findings.

5 minutes ago, KATOOM said:

Sounds like you really need to get your truck on a dyno and report back with some findings.

Who me? Lol I do plan on doing the Dyno at the event. 65$ for 3 pulls

6 minutes ago, trreed said:

You might see a small gain.  There is only few percent difference in flow acceleration versus a pipe and a smooth radius.  A longer stack will net more gains than a short guy like this:

I feel like I don't have any room to put a velocity stack straight into the turbo. My alternator is in the way. I know I couldn't put on my 45 degree elbow and air filter that I bought for it a few months ago to have the filter over by the passenger battery. Good thing it fit my 1st gen

Edited July 27, 20186 yr by cumminsVP2001

Not sure you're going to see much benefit from one.  

23 minutes ago, trreed said:

Not sure you're going to see much benefit from one.  

Probably not. But like anyone I went to squeeze every last bit of power possible. I've been doing some reading on the bhaf and I've seen people say everything from gaining 30hp using one to losing 10hp or so compared to stock box

BHAF has about 3 times more filter area compared to a stock panel filter. I really doubt there is any loss to BHAF but there is a limit of how far it will reach typically the boundary is around 600 HP (generally speaking). There are people that reached past this mark with good results too.

1 hour ago, cumminsVP2001 said:

Who me? Lol I do plan on doing the Dyno at the event. 65$ for 3 pulls

 

He who askith the question in the first place...

 

But I'm curious about the dual pyrometer set up you have.  Whats differences in temp do you see from the back three to the front three?

If the filter is sized correctly there shouldn't be any difference.

 

I'll bet there is more of a loss from pulling hot engine compartment air than cooler outside air. 

52 minutes ago, AH64ID said:

l bet there is more of a loss from pulling hot engine compartment air than cooler outside air. 

 

I'll challenge that bet and say that Stock Air Box will be the same IAT as BHAF. Being that IAT temperature is based 90% on the Intercooler and not where the turbo is sucking from. Yes, I've still got my stock air box.

 

Very easily prove that myth...

I agree with @Mopar1973Man.  The whole velocity stack idea works so much better on an N/A engine than a FI engine.  The process of compressing the air mostly negates the cold air intake theory (but cooler, denser air is always the answer), as the intercooler is going to bring the IAT value down, and you sure won't have laminar flow after going through the compressor wheel.  

Edited July 27, 20186 yr by trreed

Being there is IAT calculator that can, in theory, give you fuzzy math of the IAT with intercooler you'll find that normal highway driven Cummins typically has a very low turbo outlet temp close to the inlet temperature. Once it hits the intercooler it will be close to the outside temperature. So 90% of the temperature is based on the intercooler the inlet temperature really doesn't make a huge difference for highway driven trucks. Being I monitor IAT and Outside temperatures closely and rarely ever see a crazy IAT increase. Still pretty much always a +30*F IAT for 100*F weather. Even idling for 3 HOURS my IAT never rose over 135*F with the outside air being 103*F. Once I got rolling it dropped with air flow not a bunch but like 125-127*F. This is totally normal for 2nd Gen for summer temperature to range in the 100-140*F range. BHAF and stock air box will result in the same values. 

 

Daily driver. No real change will be seen for BHAF or Stock Air Box sucking from the fender. 

 

Now Racing... That is a whole new battle and rule set. Yes IAT has to be held down for EGT reasons...

Edited July 27, 20186 yr by Mopar1973Man

1 hour ago, Mopar1973Man said:

 

I'll challenge that bet and say that Stock Air Box will be the same IAT as BHAF. Being that IAT temperature is based 90% on the Intercooler and not where the turbo is sucking from. Yes, I've still got my stock air box.

 

Very easily prove that myth...

 

 

Based on the poor location of the IAT sensor on the 2nd gen I am not sure how much  you'll see. It's too heavily influenced by coolant temp. IIRC you often see 140° IAT's in the manifold. The only times I ever see 140° IAT's is when it's above 95° outside and I'm pulling grades at 80% load or higher, otherwise I run intake manifold temps of 6-15° above ambient. 

 

I do know that I can see pre (right after the air filter) and post turbo (intake manifold) IAT temps on my 05 and I have a CAI and WAI inlet to my stock box and depending on how I am pulling air I can see a pre and post temperature change. 

 

The foam that seals my stock box to the fender broke away and I ran about a year without it, when I added some insulation back in there my pre/post IAT's dropped again, so I was even getting warm air from the gap between the box and the fender. 

 

Basically if the pre-turbo temp goes up so does the post turbo temp, unless it's well below freezing outside. The intercooler is very efficient, but the temp into the turbo has a very noticeable effect on the final temp.