thats a monster mini part by ABDracing they r' big in V-dub tuning (VW)

check them out abdracing.com

 

Attempting the HAI as my first mod. I found that there are two vacuum lines attached to the air intake on my MCSCa. As I will need to "tee" them to a separate air filter....does anyone know the size of these lines?

 

FYI, I just installed a temp probe inside the air filter. The temperature of the air going into the throttle body levelled off at about 20F over ambient while I drove around town (stops and starts, 40 mph tops). That's a 3% difference in absolute terms, and equates to about a 1% difference once you take into account the ~70% efficiency of the intercooler. I don't have data for the stock intake or others, but I doubt the stock setup does as well or better.

 

3% difference from what?

Any delta readings from sustained driving?

 

Ambient temp was 80F according to the OBC, its sensor is behind the lower bumper grille. Air temp levelled out around 100F. That's 548 -vs- 568 Rankine, or a 3% difference. Since the intercooler removes about 70% of the difference in temp between ambient and charge air pressure, that 3% contribution only becomes 1% once it leaves the IC.

 

Somthing seems not quite right about this. I think the amount of heat the IC removes is beside the point. As the inlet air temp increases, the SC moves fewer O2 molecules for a given rpm. The fact that the IC might cool these fewer O2 molecules by the same % temp differential can't make up for this.

 

My testing has shown that the intercooler efficiency is between 60% and 80% across a variety of running conditions. I used 70% as the rough midpoint. So, 70% of the difference between the charge air temp and ambient is removed by the IC and dissipated to the atmosphere.

Now, it's true that the amount of heat added by the supercharger varies due to several factors, but looking just at the charts like these:



At 10 psi (about stock) and about 14,000 rpm (about stock), temp gain is about 180F. So at 80F ambient:

Situation A (ideally air temp going into the supercharger is exactly ambient):

80F + 180F = 260F out of the supercharger
(260F - 80F)*(1 - 70%) = 54F delta after intercooler
54F + 80F = 134F into the engine

Situation B (air temp going into the supercharger is 20F over ambient):

80F + 20F + 180F = 280F out of the supercharger
(280F - 80F)*(1 - 70%) = 60F delta after intercooler
54F + 80F = 140F into the engine

134F is 594R and 140F is 599R, a difference of only about 1%.

If I can locate all the stock intake parts, I'll try to do some comparison testing this weekend with the temp probe stuck through the rubber elbow above the throttle body so it is in the same location as it is with the HAI.

 

BTW, here's two sets of test data that I did in cold weather and warmer weather at the same speed/rpm/etc:

ambient= 22 C,ic in= 87.3 C,ic out= 34.9 C,RPM= 4000 ,Speed= 100 mph Gear= 6 Boost= 12.5 psi
Delta = 65.3 C
ambient= 8.5 C,ic inlet= 73.4 C,ic outlet= 23.5 C,RPM= 4000 ,Speed= 100 mph Gear= 6 Boost= 12.5 psi
Delta = 64.9

ambient= 21 C,ic in= 103.1 C,ic out= 43 C,RPM= 5000 ,Speed= 100 mph Gear= 5 Boost= 14 psi
Delta = 82
ambient= 6.0 C,ic inlet= 90.7 C,ic outlet= 31.1 C,RPM= 5000 ,Speed= 100 mph Gear= 5 Boost= 14.0 psi
Delta = 84.7 C

It's in Celcius so shouldn't be related to the testing I did today in Fahrenheit. My point is that temperature increase due to the supercharger is fairly constant, regardless of the temp of the air coming into it.

 

How does it make sense to use absolute zero as a base point? Should it not be the lower of the two as base (looking at deltas, anyway)?
e.g. 140F is 6F (4.5%) higher than 134F.
Given that our engines will operate in a range far closer to 0F than -365F, using the larger scale minimizes any % differences in temps.

 

What are the implications regarding all the hoopla about the different air intakes that were recently tested? Splitting hairs? Also, what would be the theoretical basis for the claim of one manufacturer that their product would work best on a car that already had significant modifications? I presume they imply at least a ported/polished supercharger. Thanks...

 

The math for thermodynamics really only works if you use the absolute temperature scale (Rankin or Kelvin). When everything in the equation is deltas you can use either the absolute scale or degrees Farenheit since you're working with, well, deltas.

You can get a better understanding of why absolute temperatures matter by reading this at The Straight Dope website:

http://www.straightdope.com/mailbag/mtempscales.html

/gary

 

is that the absolute temp scales are proportional to molecular concentration, while the others are not.

Matt

 

As gmcdonnell mentioned, absolute temps are what you use to calculate conditions like these. PV=nRT uses absolutes.

IMHO, "heat shields" may be a waste of time, energy, and money when you have a forced induction engine with an intercooler. You can make more power if your intake air is:

1) Higher pressure (less restriction in the intake)

and/or

2) Lower temperature

If you make a change to your intake that makes the air cooler but causes more restriction in the process, you may be taking one step forward but two steps back. That's why testing is important.

 

One of the intakes workes after the TB. If the TB is the limit, then changing something after the TB won't really shine until after the TB is enlarged. This is purely speculative, but the underlying principle is sound, and is just one example of how this type of effect can work.

It's also a restatement of a very, very good approach to modifications and tuning, take a full system, balancled approach to the project, so you get all the bits working together..... It's the cheapest way to get reliable performance.

Matt

 

Bingo!

% Undaunted by Lisa's skepticism at dinnertime, Homer starts his
% search for Lincoln's gold. He carries a pickaxe through the White
% House hallways as he carefully counts off his paces. Marge follows
% him.

Homer: ... fourscore four, fourscore five, fourscore six,
fourscore and seven paces. [swings the pickaxe into the
floor]
Marge: Wait! How do you know this is where Lincoln buried the
gold. You just started counting from an arbitrary place.
Homer: I just started what from a what?
Marge: Your plan makes no sense. http://www.snpp.com/episodes/BABF13

 

Got a check engine light today. Car is 6 months old with 6k miles. I don't think the 3 month old HAI had anything to do with it, but do you think I should return it to the stock intake when I take it back to the dealer?

-Andy

 

Yep.

Btw whats the verdict on the HAI? good to go? ive got the alta on.. wouldnt mind trying the HAI out of curiosity

 

It's cheap, and sounds great. You can really hear the supercharger at high revs, and a lot of gas. Other people will know you have a blower. It's no more than 30 minutes to install, probably less. I can go back to stock in less than 30 minutes I bet, so I guess I might as well do that just to cover my butt.

-Andy

 

If it is worth taking the HAI off and going back to the stock airbox when taking the car back to the dealer with a CEL, is it worth doing the same when going back for the free oil change and some other miscellaneous warrenty work (the battery is leaking, for example)? Would the dealer look any more askance at the HAI versus all the other aftermarket intakes?

The HAI is absolutely great bang for the buck, and it's not obnoxiously noisy. I'd be interested in your observations comparing the Alta and HAI.

 

The one remaining clue after you put the stock box/plumbing back on would be the *possible* loss of the OEM clamps. Those things are hard to put back on by design and a lot of people give up and end up using the screw-type ones instead. Those could be easily seen if they knew to look.

 

skuzy , i had a alta on order then canceled it after installing the HAI .I'm very happy with the out come .

P.S Thanx Andy, job well done sir

peace out
mikie

 

It will give you some information, and you can check the BS that occationally comes from the service guys.

Matt

 

I just got done making my heat shield. I made it out of a sheet of plastic. The size is 14x5.5 with a eage missing 1.5 sq to clear intercooler. I can deffently feel more power. I measured the temp of the back of the intake with only 1 degree more in temp then outside air. I have it mounted on the left side of old air box using 2 factory mounting points and 2 metal brackets.
I measured gtech pro 0-60 times before (7.6) after (6.7) heat shield install.











-Tim

 

Interesting. Got a pic?

 

that piece of plastic shaved 1 sec off your 0-60 time?