Drivetrain HAI - still happy with it?
6th Gear
Joined: Oct 2002
Posts: 3,652
Likes: 6
From: Lansdale, PA
Exactly! Now admit that your PDA dyno may not have a direct correlation to actual output power. :smile:
Originally Posted by Ryephile
Bingo! Active admission that what you measured may not have a direct correlation to actual output power.
Originally Posted by andy@ross-tech.com
Exactly! Now admit that your PDA dyno may not have a direct correlation to actual output power. :smile:
6th Gear
Joined: Oct 2002
Posts: 3,652
Likes: 6
From: Lansdale, PA
Originally Posted by Ryephile
It does have a direct correlation, if you have the sense to trust the math. It also has an accuracy tolerance, mostly due to atmospheric deviation and operator error (which was substantial when I was learning to use it!)
Also, this was your post about the HAI (where you got your plot that you reposted in this thread):
https://www.northamericanmotoring.com/forums/showpost.php?p=477278&postcount=359
At the time when you did both the boost logging and "dyno" runs, you still didn't understand the effect of timestamps on plots or that the Unichip clamped the boost data. Was that all done while you were still learning to use it?
5th Gear
Joined: Jul 2003
Posts: 772
Likes: 0
Originally Posted by Ryephile
ROFLMAO! 
No Andy, you measured an increase in boost pressure, not air weight. Anyhoo, who's this "Ryphile" guy, and why wouldn't he try to sell a ton of these cheap K&N filters versus only a few of the much more expensive ALTA CAI?
No Andy, you measured an increase in boost pressure, not air weight. Anyhoo, who's this "Ryphile" guy, and why wouldn't he try to sell a ton of these cheap K&N filters versus only a few of the much more expensive ALTA CAI? Sorry, I couldn't resist.
I have a dyno day coming up in July. Who'd like to see stock vs HAI on a car equipped with 15% pulley, VGS, and el-cheapo exhaust? This will be done on an actual dynamometer. I reserve the right to change my mind, let it be known.
Marty
6th Gear
Joined: Sep 2002
Posts: 2,196
Likes: 0
From: Hampton, VA
Originally Posted by LombardStreet
snip...
* The CAI designs seem to be assuming the cowl vent is a high pressure zone. (And it would seem logical to assume the stock intake, inside the grille is also a high pressure zone.) But has there been any evidence to show that this is actually the case? Not trying to be argumentative here, just wondering.
* The CAI designs seem to be assuming the cowl vent is a high pressure zone. (And it would seem logical to assume the stock intake, inside the grille is also a high pressure zone.) But has there been any evidence to show that this is actually the case? Not trying to be argumentative here, just wondering.
Originally Posted by obehave
Sorry, realized I had posted this on another forum
Testing done with an Alta intake, lots of tape and plastic sheet(ask Randy) and a Magnehelic gauge. 2 runs each test in 2 diffferent directions and average to minimize any effects of the wind (which was < 10MPH that day)
In a nutshell.
You don't see a pressure differential until 50-55 MPH. It's almost .035 psi at 70MPH.
This was obtained by taking a bag( 2 gal trash bag) and taping it in place where the cowl opening is. Inserted the gauge lead in under the cowl grill and driving.
Remove the bag and just run the lead in and repeat. Readings are slightly lower. Remember this gauge is in .035 psi increments so you have to kind of trust my judgement. (This is THE reason I never really posted this info since I didn't want to take a beating from the **** test monkeys out there. You know who you are
Run this 3 different times with the lead in 3 different places. Results are indistinguishable from each other. One with the lead right next to the filter.
Now the biggie.
I use plastic sheet and a friggin ton of tape to isolate the air box, close to what the OEM air box would be like. Rerun the tests.
Pressures are slightly, approx 1/4 psi, lower than with the open cowl being used.
For me that's all I really needed to see.
Note:
Max reading for the day was right a .06125 psi during an 80mph sprint.
I'm sure there's some cool mathematical ratio to explain the pressure rise. Like this:
45mph nuttin
55mph close to .0175 psi
70mph .04375psi
80mph .06125psi
One thing I didn't test but wanted to that's relative to this thread is; are forward or rear facing scoops better? Just couldn't figure an easy way to make test scoops. As upright as the MINI windshield is, I'm thinking rearward.
Testing done with an Alta intake, lots of tape and plastic sheet(ask Randy) and a Magnehelic gauge. 2 runs each test in 2 diffferent directions and average to minimize any effects of the wind (which was < 10MPH that day)
In a nutshell.
You don't see a pressure differential until 50-55 MPH. It's almost .035 psi at 70MPH.
This was obtained by taking a bag( 2 gal trash bag) and taping it in place where the cowl opening is. Inserted the gauge lead in under the cowl grill and driving.
Remove the bag and just run the lead in and repeat. Readings are slightly lower. Remember this gauge is in .035 psi increments so you have to kind of trust my judgement. (This is THE reason I never really posted this info since I didn't want to take a beating from the **** test monkeys out there. You know who you are
Run this 3 different times with the lead in 3 different places. Results are indistinguishable from each other. One with the lead right next to the filter.
Now the biggie.
I use plastic sheet and a friggin ton of tape to isolate the air box, close to what the OEM air box would be like. Rerun the tests.
Pressures are slightly, approx 1/4 psi, lower than with the open cowl being used.
For me that's all I really needed to see.
Note:
Max reading for the day was right a .06125 psi during an 80mph sprint.
I'm sure there's some cool mathematical ratio to explain the pressure rise. Like this:
45mph nuttin
55mph close to .0175 psi
70mph .04375psi
80mph .06125psi
One thing I didn't test but wanted to that's relative to this thread is; are forward or rear facing scoops better? Just couldn't figure an easy way to make test scoops. As upright as the MINI windshield is, I'm thinking rearward.
"I'm sure there's some cool mathematical ratio to explain the pressure rise."
the dynamic pressure varies as the square of the speed, for instance twice the speed gives you 4 times the pressure...BUT as obe wan's numbers show THE RAM AIR EFFECT IS LESS THAN 0.1 PSI (which you could also figure out by looking up the dynamic pressure of air at the temperatures and speeds we're dealing with.)
the stock intake trapezoid isn't really in the airstream anyway, so the emperor has no ram air.
given these numbers, andy's pressure drop measurements, and measurements from other auto intakes, it's hard to believe the 10-12 hp improvements claimed by assorted intake vendors.....
the dynamic pressure varies as the square of the speed, for instance twice the speed gives you 4 times the pressure...BUT as obe wan's numbers show THE RAM AIR EFFECT IS LESS THAN 0.1 PSI (which you could also figure out by looking up the dynamic pressure of air at the temperatures and speeds we're dealing with.)
the stock intake trapezoid isn't really in the airstream anyway, so the emperor has no ram air.
given these numbers, andy's pressure drop measurements, and measurements from other auto intakes, it's hard to believe the 10-12 hp improvements claimed by assorted intake vendors.....
Well, I'm sorry to have opened up an old argument, really didn't mean to. But I installed the HAI and I think its great, at least compared to stock. The engine revs up faster and pulls noticeably harder over about 4000rpm. My only other engine mod is the 15% pulley, and my gut feel is that going from stock to HAI is about 20% of the gain from the pulley. For the money, it can't be beat. There is slightly more SC sound, but nothing objectionable, so I don't think I'm being seduced by the sound. After driving to work, I immediately popped the bonnet and the K&N didn't even feel warm. I really think many people would be ahead using the HAI and putting the money saved towards some other mod.
Thanks, Andy!
Thanks, Andy!
HAI, One-Ball and MTH, lowest entry fee!
Originally Posted by inimmini
I really think many people would be ahead using the HAI and putting the money saved towards some other mod.
Matt
I still vascillate between AGS and just massaging the TB-SC runner. Depends on the checking account balence on any given day.....
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