shftn6
Viper Owner
When putting on smooth tubes on a 97 GTS is it better to keep the stock air box and just upgrade the filters or change the filters to the conical type?
Thanks for the help!
Thanks for the help!
GTS Intake Question
- Thread starter shftn6
- Start date
Ron
Enthusiast
For economics and function I'd stay stock. For looks, your call...
Bad Asp
Enthusiast
What he said.
GTSII
Enthusiast
Is it interesting/useful to "de-baffle" the stock box?
McGuireV10
Enthusiast
Conical filters **** too much hot air from the engine bay. Hot air = lost HP. The baffle question comes up periodically and if I recall correctly, verifiable horsepower gains have never been clearly demonstrated. If you drive in the rain, don't do it.
Viperzilla
Enthusiast
Like McGuire said, if you drive in the rain, or if there is a chance you may, you must retain the baffle. If not, and you encounter rain, you must park your Viper, or the engine will be flooded with water.
Ron
Enthusiast
De-baffling has no dyno advantage. In fact, removing the entire front of the airbox has no dyno benefit. I know as I've tried. 435RWHP with full airbox, smooth tubes & K&N's, 435RWHP without airbox front but with smooth tubes &K&N's.
You might think that sure, with only a slow fan blowing on the front a stationary car that may be the case, but what about 100MPH ram-air... will the de-baffled airbox now shine? Don't think so. Someone a while back posted an excellent explaination of why the naca scoop was primarily cosmetic though it does help in minimizing hot underhood air.
p.s. I have a de-baffled front airbox if anyone wants to buy it... (Guess I should have talked it up)
You might think that sure, with only a slow fan blowing on the front a stationary car that may be the case, but what about 100MPH ram-air... will the de-baffled airbox now shine? Don't think so. Someone a while back posted an excellent explaination of why the naca scoop was primarily cosmetic though it does help in minimizing hot underhood air.
p.s. I have a de-baffled front airbox if anyone wants to buy it... (Guess I should have talked it up)
GTSII
Enthusiast
Thanks for the information: no horsepower gain + no driving in the rain = baffle stays in and question laid to rest!
Matt M PA
Enthusiast
A NACA duct is an inlet (not a scoop) designed for no, or little drag. No drag...no ram air.
Viper Magazine, Sept. 1999 has an article on the NACA DUCT.
Dave Adkins
Enthusiast
<nerdmode = on>
'No drag' does not necessarily equate to no "ram" air. If the duct inlet were located in a better location, it could provide some ram benefit. For instance, the NACA scoop located out near the wingtip of a 747 (on the bottom side of the wing) which vents the wing fuel tanks pressurizes those fuel tanks + 0.5 psi over ambient in flight. The reason is because it is carefully located in an position that has a positive pressure coefficient. Of course, it has to go 400+ mph to get that kind of ram effect....
Having said that, note that the SRT/10 has a scoop that protrudes a bit up off the hood.
I'm actually planning on having a few coworkers help me to instrument my car to measure dynamic air pressure at a few locations on the car (front grill, just inside the NACA scoop, just in front of the windshield, etc.) to try and quantify what the NACA scoop actually buys a GenII in terms of 'ram' gains/losses......
</nerdmode>
'No drag' does not necessarily equate to no "ram" air. If the duct inlet were located in a better location, it could provide some ram benefit. For instance, the NACA scoop located out near the wingtip of a 747 (on the bottom side of the wing) which vents the wing fuel tanks pressurizes those fuel tanks + 0.5 psi over ambient in flight. The reason is because it is carefully located in an position that has a positive pressure coefficient. Of course, it has to go 400+ mph to get that kind of ram effect....
Having said that, note that the SRT/10 has a scoop that protrudes a bit up off the hood.
I'm actually planning on having a few coworkers help me to instrument my car to measure dynamic air pressure at a few locations on the car (front grill, just inside the NACA scoop, just in front of the windshield, etc.) to try and quantify what the NACA scoop actually buys a GenII in terms of 'ram' gains/losses......
</nerdmode>
Paolo Castellano
Enthusiast
Shftn6, I would go with the baffle removal. I felt a slight difference at higher speeds. I have an air box with the baffle removed already that i do not need as the Heffner airbox for his supercharger system replaces it. You can buy mine or just have Scotty "TOOFST" do it for you, he did mine. He is in Glenview, his # is 847-529-8322. Good luck.
BigCarrot
Enthusiast
I think the NACA duct is mainly made to induct cold air. The ram effect is pretty much stopped by the filters. Think about it. It's like hitting a wall. You might see a little gain if you took the filters out all together, but who wants to do that?
McGuireV10
Enthusiast
Sorry to say, the NACA duct doesn't do anything useful on the Viper -- a regular old opening would do just as well. Basically a NACA duct's purpose is to scavenge boundary-layer airflow without introducing additional drag. It does this by gradually creating a low pressure area using a ramped intake aligned with the airflow. The diverging sides of the duct simultaneously create small vortices and reduce how close the duct walls are to the air (the "charge") flowing into the duct making it harder for the charge to escape back out over the walls. The curved shape was basically determined to be optimal through plain old experimentation (in comparison to parallel walls).
In the case of the Viper's hood, the duct "hits" the air head-on, so there isn't anything for a NACA duct shape to do. There isn't an undisturbed airflow to coax a charge out of at that point on the car's surface. In fact, the curving sides of the duct walls simply create interference with what would otherwise be direct airflow into the duct opening, so the Viper's duct potentially does more harm than good relative to the opening size.
Although it does look damned cool and I wouldn't trade it for anything.
Why do I know this much crap about NACA ducts? I just happened to finish doing a lot of NACA-duct-related work last night, oddly enough. Mostly based on the original NASA study from 1947, which you can read at the URL below (funny to think it used to be classified material) :
http://naca.larc.nasa.gov/reports/1948/naca-rm-a7i30/
It's cool -- take all those calcs and figures, plug in your site requirements (max depth, run length, etc), and voila, out pops a NACA duct.
In the case of the Viper's hood, the duct "hits" the air head-on, so there isn't anything for a NACA duct shape to do. There isn't an undisturbed airflow to coax a charge out of at that point on the car's surface. In fact, the curving sides of the duct walls simply create interference with what would otherwise be direct airflow into the duct opening, so the Viper's duct potentially does more harm than good relative to the opening size.
Although it does look damned cool and I wouldn't trade it for anything.
Why do I know this much crap about NACA ducts? I just happened to finish doing a lot of NACA-duct-related work last night, oddly enough. Mostly based on the original NASA study from 1947, which you can read at the URL below (funny to think it used to be classified material) :
http://naca.larc.nasa.gov/reports/1948/naca-rm-a7i30/
It's cool -- take all those calcs and figures, plug in your site requirements (max depth, run length, etc), and voila, out pops a NACA duct.
Similar threads
