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  #31  
Old 06-17-2008, 05:06 PM
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Quote:
Originally Posted by lowriderdog37 View Post
I have actually studying that lately. I wasn't going to post about it until I had more definitive results, but since we are talking about it, I'll give you what I know so far. I have been doing all of this at 90-95* ambient temp, medium traffic on surface streets (red light to red light). I don't live in a city big enough to have to deal with gridlock, however I have been in it, and seen my car get SUCKED of power when it's hot and I am in the middle of traf****.

Engine bay: about 5-8* warmer than ambient. After sitting at a few consecutive red lights, temp was up to 110-115*. Temp was back to 5-8* above ambient after about 25 seconds.

Inside the u-turn: I start the car (when cold), and keep moving for about 15 mi before getting to traffic, doing this, the temp stays right at ambient. After a few red lights, temp soared to 125-130*. The temp was still raising, but I was out of traffic by this time, took a 12 mi drive on the freeway, and the temp only dropped to 109*. I have only been able to test inside the u-turn once, but I am still testing. I'll post more info when I get it.

I am hypothesizing that the temp will raise much higher in the stock filter setup before leveling out. I didn't think originally that the tin airbox would be able to keep the cold intake worth keeping.

I started working on this not to prove anybody wrong or to get better performance, but I wanted to get the best possible replacement for the stock box. My stock box vibrates and rattles on the side of the compartment, which pierced a hole in it. The u-turn also doesn't fit properly, I am sure it allows unfiltered air into the turbo.
Yeah, I've been thinking of doing something like dieselkid's original open element design but using black ABS plastic tubing and elbows instead of steel or aluminum - for the insulating properties of the plastic. I want to plumb mine to put the filter right into the front corner behind the PS headlight, and then install an "isolation panel" in that corner to box it in and provide a barrier between the filter and the rest of the engine comparment. That would make it draws all its air from around the headlight and not from the heated engine compartment.
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1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown
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  #32  
Old 06-17-2008, 06:28 PM
Craig
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Quote:
Originally Posted by ConnClark View Post
Actually a reduction in of the pressure drop across the air filter does help. It lowers pumping losses. It increases the excess air which increases the specific heat ratio of the combustion gases and reduces soot. Most importantly it drops the off boost manifold vacuum which keeps the ALDA from holding back the rack advancement as much on the IP.
Homework assignment; calculate the pumping power associated with the stock air filter on the inlet side of the turbo and determine how much additional exhaust back-pressure is associated with those losses. I do understand the theory, and I suspect you would gain more power by turning off your car stereo than playing around with the intake. Any power increase will be negligibly small.

If you are worried about off-boost power, just adjust your ALDA.
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  #33  
Old 06-17-2008, 06:55 PM
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Quote:
Originally Posted by Craig View Post
Homework assignment; calculate the pumping power associated with the stock air filter on the inlet side of the turbo and determine how much additional exhaust back-pressure is associated with those losses. I do understand the theory, and I suspect you would gain more power by turning off your car stereo than playing around with the intake. Any power increase will be negligibly small.
I suspect you may be right, but there is really no way to know without trying it.

Quote:
Originally Posted by Craig View Post
If you are worried about off-boost power, just adjust your ALDA.
OH NO! Don't go there - FI will be on you like white on rice! JUST KIDDING!

Seriously, off boost power isn't the issue so much as responsiveness - at least not for me. But then I'm less concerned with getting more power than I am with optimizing efficiency...
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1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown
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  #34  
Old 06-17-2008, 07:04 PM
Craig
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I don't know if you could noticeably decrease the turbo lag or not, but I suspect the turbo lag has more to do with the inertia of the turbo than the design of the inlet plumbing. I've pretty much decided that it is what it is, and I just patiently wait for the turbo to come in at 2K rpm.
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  #35  
Old 06-20-2008, 11:24 AM
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Quote:
Originally Posted by Craig View Post
Homework assignment; calculate the pumping power associated with the stock air filter on the inlet side of the turbo and determine how much additional exhaust back-pressure is associated with those losses. I do understand the theory, and I suspect you would gain more power by turning off your car stereo than playing around with the intake. Any power increase will be negligibly small.

If you are worried about off-boost power, just adjust your ALDA.
Actually I have measured a vacuum above 2 inches of mercury before. Thats about 1 psi and its enough to be significant and to induce turbo lag.

I also found a nice series of articles on reducing intake losses. This guy reduced his loss by about 1/2 a psi.

http://autospeed.com/cms/article.html?&A=0629
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  #36  
Old 06-20-2008, 01:53 PM
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Quote:
Originally Posted by ConnClark View Post
Actually I have measured a vacuum above 2 inches of mercury before. Thats about 1 psi and its enough to be significant and to induce turbo lag.

What filter setup was this measurement done on?


I tried to read that article, but sentences such as " probably don't have to tell you what a boost gauge is - but I will anyway cos unless you understand ..."

and "Positive boost makes cars go hard" turned me off.
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  #37  
Old 06-20-2008, 02:13 PM
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Originally Posted by bgkast View Post
What filter setup was this measurement done on?

I tried to read that article, but sentences such as " probably don't have to tell you what a boost gauge is - but I will anyway cos unless you understand ..."

and "Positive boost makes cars go hard" turned me off.
It was on my stock 85 cali filter system.

The article really has some useful information. Try to force your self to read through the rest of it and remember that its written in a way for rice boys to understand it
It gets much better in Part 3 of it. http://autospeed.com/cms/article.html?&A=0646
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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

http://ecomodder.com/forum/fe-graphs/sig692a.png
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  #38  
Old 06-20-2008, 05:58 PM
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Quote:
Originally Posted by ConnClark View Post
It was on my stock 85 cali filter system.

The article really has some useful information. Try to force your self to read through the rest of it and remember that its written in a way for rice boys to understand it
It gets much better in Part 3 of it. http://autospeed.com/cms/article.html?&A=0646
Ditto. Ever heard of Ebonics? Welcome to Xbonics.

It is written in a style meant to appeal to, and be understood by, GenX ricers, BUT I believe the principles and tech are solid.

I wish I had his differential Manometer to measure the pressure differential between the throat of the stock airbox and the inlet of the turbo. I think the pressure differential across those two u-turns would be a real eye opener...
__________________
1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown
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  #39  
Old 07-02-2008, 10:56 PM
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Quote:
Originally Posted by lowriderdog37 View Post
I have actually studying that lately. I wasn't going to post about it until I had more definitive results, but since we are talking about it, I'll give you what I know so far. I have been doing all of this at 90-95* ambient temp, medium traffic on surface streets (red light to red light). I don't live in a city big enough to have to deal with gridlock, however I have been in it, and seen my car get SUCKED of power when it's hot and I am in the middle of traf****.

Engine bay: about 5-8* warmer than ambient. After sitting at a few consecutive red lights, temp was up to 110-115*. Temp was back to 5-8* above ambient after about 25 seconds.

Inside the u-turn: I start the car (when cold), and keep moving for about 15 mi before getting to traffic, doing this, the temp stays right at ambient. After a few red lights, temp soared to 125-130*. The temp was still raising, but I was out of traffic by this time, took a 12 mi drive on the freeway, and the temp only dropped to 109*. I have only been able to test inside the u-turn once, but I am still testing. I'll post more info when I get it.

I am hypothesizing that the temp will raise much higher in the stock filter setup before leveling out. I didn't think originally that the tin airbox would be able to keep the cold intake worth keeping.

I started working on this not to prove anybody wrong or to get better performance, but I wanted to get the best possible replacement for the stock box. My stock box vibrates and rattles on the side of the compartment, which pierced a hole in it. The u-turn also doesn't fit properly, I am sure it allows unfiltered air into the turbo.
OK, I've finished enough research that makes me feel comfortable to share with the masses. What I was said before pretty much lasted through the trials. I will say, I didn't do this on a track with controlled conditions, but traffic is usually about the same, and the temps are pretty consistent this time of year.

As I suspected, I saw the u-turn with the stock air box get up to 137* when stuck in heavy (stop and go) traffic (for about 15 minutes). After 12 miles on the freeway the temp in the u-turn only got down to 103 (ambient temp was 96). This was the extreme condition, but the rest were comparable to the level of traffic I was stuck in. It's kind of funny though, as long as you keep moving, the temp stays the same, you actually have to be stuck in traffic for about 10 minutes for the heat to build, then it doesn't want to go away.

After this, I decided to make an el-cheapo intake with some stuff from Autozone (cost about $20). I had to use a cotton filter, but I truly believe that I get better filtration than the unsealed, un-fitting u-turn that was on there stock. Since then, I don't see the motor being drained from being stuck in traffic and getting REALLY hot air into the turbo. Since I put it on, I can't say that I have found any real performance gains, but I think the turbo spools up a bit sooner.

In the end, I believe it's worth the effort to change to a warm air intake, but only if you spend time in traffic. If you mostly drive on the freeway, I would stick with the stock setup. Honestly, I would like to see an IC that doesn't need much custom fabricating, but I'm not holding my breath.

*note, I don't have pyrometer yet, but it would be interesting to see what that shows in the same process.
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Last edited by lowriderdog37; 07-02-2008 at 11:29 PM.
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  #40  
Old 07-26-2008, 11:08 PM
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