K&N Stubstack

CobraEd · #1 (**permalink**) 10-22-2001, 07:01 AM

Just a quick tip on cheap HP.

This weekend I installed a K&N stubstack on the carb (650 double pumper). It only cost $35 and adds about 30 additional CFM of flow. The main claim though is that it straightens and smooths the airflow into and thru the carb to provide better fuel metering. I can tell you that there is a noticable gain in throttle response and low end torque. Top end RPM hp feels the same. This thing is incredibly well made and fits beautifully.

So, hot rodders, . . . for $35, and five minutes of work, its a good addition to your Cobra.

Ed

JAM1775 · #2 (**permalink**) 10-22-2001, 07:28 AM

I have one new in a box . I never used it because I wound up later getting a new Race Demon. Duh. They do smooth out the older Holleys very well and swirl the air down the intake.

dalola · #3 (**permalink**) 10-22-2001, 07:37 AM

Ed,
Does installing one of those raise the height of the air cleaner? How much clearance do you need inside the air cleaner, height-wise?
Just curious.
Dave

CobraEd · #4 (**permalink**) 10-22-2001, 07:56 AM

The stubstack raises the overal height of the carb inlet inside the air filter by 3/4 of an inch. K&N indicates that you must have a minimum of 1 1/2" clearance above the top of the stubstack.

I have the Edelbrock ProFlow 1000 air filter which breathes thru the top, not the sides, so it works out very well and the 1 1/2 is a non issue.

Ed

dalola · #5 (**permalink**) 10-22-2001, 10:59 AM

I was afraid that would be the case. Just don't have the clearance to get it in there, and still have 1.5 above. I wonder what the substack and no air cleaner would do? I know when I run with out my air cleaner now, it feels like another 50hp! Most all Cobras I've seen are WAY restricted in the air cleaner department....just no room. The K&N catalog has a neat formula for figuring cfm requirements. I'm just a little more than half of what I should be, and my air cleaner is bigger than most I've seen.

Oh well...

CobraEd · #6 (**permalink**) 10-22-2001, 11:12 AM

Dave,

Do I have a deal for you! Get yourself one of these top breather air filters from Edelbrock. They are rated at 1,000 cfm, and flow air in directly thru the top. Perfect for the scoop on a Cobra. But throw away the foam element that comes with it, and get the open cell foam that Sears sells as filters for its dehumidifiers! Just cut it to fit.

This is what I use. The air comes into the hood scoop and directly down into the filter. Plus you can use the Stubstack and not have to worry about top clearance like with a traditional air filter that has a lid. And if all this is not enough to get you excited, the cost of these filters is only $16.99 in Jegs.

http://www.jegs.com

Once you are at the site, just do a search on air cleaners. Its the Pro Flow one by Edelbrock. You can also get the Stubstack there. Just search on the name.

Ed

dalola · #7 (**permalink**) 10-22-2001, 01:06 PM

Well, Ed, I hate to keep asking questions here, but you have me intrigued with this.
1) What is the overall height of this a/c as measured from the carb flange?
2) What is the advantage of the dehumidifier foam over the supplied foam? Did you try both to see if performance was affected?
3) Have you compared running with and without the a/c to see if there is any difference?

Thanks so much for all the info. This is something I may try, if overall height is in range. I have about 3" total to work with.

Can't beat the price, either!

Dave

P.S. Also, what engine are you running, and what is your estimated HP?

CobraEd · #8 (**permalink**) 10-22-2001, 01:32 PM

Not having it in front of me, I can't say for sure, but I would say the total height is roughly 2.5". The air filter is supposedly rated at 1,000 cfm, but the foam that comes with it as the filtering element seems very restrictive. I never used it. The foam I get at the Sears parts store is a very open grain, and flows about as much as no element at all. It is only good for keeping out stuff about the size of a grain of sand or larger. Dust will go right thru it.

Hey, for $16 try it. If you don't like it, throw it away or sell it to someone else. It is a cool looking high flow filter, someone will want it. Not everyone has the space problems that us Cobra owners have.

Ed

JAM1775 · #9 (**permalink**) 10-22-2001, 05:43 PM

Cobra ED !!

I did EXACTLY what you did using my Edelbrock Pro Flow and changing the element for a Home Depot DH unit .
I then mounted the Edelbrock on to a Moroso Air Pan (JEGS) which looks like a cookie pan with 5" high very dense foam around the edges. I trimmed the foam on a downward angle forward to seal all around my air scoop. With my hood closed it is a tight Ram Air effect which I felt immediately on the highway.
In the winter I resort back to a plain old Edelbrock Pro Flow
(I have two) without the Air Pan because if the temps get near 40 degrees I have formed icycles in my carb throat and my car will not run properly. In the summer, my motor is hot but when I remove the air pan the carb throat is chilly to cold. On the dyno my AF was leaner and 8 HP was gained just sitting still and pulling the outside air in to the carb as opposed to engine compartment air w/o an air cleaner. I believe the ram air
makes more power when the car is moving at speed.

jgrice · #10 (**permalink**) 10-22-2001, 07:38 PM

I have thought about sealing my turkey pan to the scoop with foam.

What type of foam did you use and how did you secure it to your pan?

Thanks.

Jeff
SPF #186

dalola · #11 (**permalink**) 10-22-2001, 09:00 PM

Ok, Ed & Jamm, you've convinced me. I'm gonna give it a try. I like the idea of sealing a "pan" against the hood scoop.

The nice thing is, I'm only 1/2 hour from Jeg's!!

When I get it all together, I'll post back here with the results.

Thanks, guys. This site continues to amaze me with all the knowledge and experience of the members.

Dave

CobraEd · #12 (**permalink**) 10-23-2001, 06:00 AM

Jam, I like the idea of sealing the whole thing to the scoop. I'm gonna have to give that a try. Pretty creative!

Ed

JAM1775 · #13 (**permalink**) 10-23-2001, 06:57 AM

The Moroso air pan is featured in JEGS on the website.
After www.jegs.com enter Air Pan as a search then click Moroso air pan. The pan for single carb comes in two parts and can be 24" in length . One side has the carb hole. You slide them to desired length cut off the excess or just rivet them together.
The foam is 6' long.. You glue in around the edges then cut and trim. I did it in many stages, shaving off layers with a razor, until my hood sat firmly while making the seal and looking aligned with the body. I used a small light inside the engine compartment in a dark garage to check the seal. Replacement foam is $10 is you make a mistake. I do not know where to get the turkey pan seals. Perhaps Cobra Restorers or Finish Line. Marine supply stores also have a wide selection of various edgings and rubber moulding/sealers which you buy by the foot.

dalola · #14 (**permalink**) 10-29-2001, 09:20 PM

Guys,
Bought all my parts Saturday at Jeg's...air pan, air cleaner, substack. The bad news is, don't have the hood clearance needed for the Pro-Flow. So, I'm working on fabricating a "mini filter" to mount directly on top of the substack, using the humidifier material. Put the air pan together, and it fits nice. Need to glue and trim the foam next. Hoping to get a test run Thursday, when it's supposed to be 70 degrees here in Ohio! I'll post results and pix when I have it all set. So far, it looks like it will work well!

Dave

CobraEd · #15 (**permalink**) 10-30-2001, 07:00 AM

Good luck! Keep us posted.

Ed

JAM1775 · #16 (**permalink**) 10-30-2001, 09:59 AM

If you need more info on the Pro Flo dimensions or filtering
substitutes their number is 800-416 8628.

CSX 4027 · #17 (**permalink**) 10-30-2001, 12:15 PM

The only problem I have with the Edelbrock is that the element can deteriorate with a slight backfife and get sucked in to the motor. The K&N open top is constructed to not allow that to happen. It's a bit more money but will save your motor and fits in the turkey pan and under the hood. The Edelbrock design has been around for about 30 years and is just that when it comes to technology

John McMahon · #18 (**permalink**) 10-30-2001, 12:27 PM

Steve,

Are you talking about the K&N Extreme Filter Top?

If so, it can't be beat, got one on McStang. Got one on the 289 too.

CSX 4027 · #19 (**permalink**) 10-30-2001, 01:14 PM

Yes.
The stub stack is actually better if you can fit it with a 14"x 3" regular top air cleaner.
Theory: The air wants to swirl its way in from the sides as in the bath tub drain effect as opposed to the straight in the top thing.
BUT, The K&N open top on my motor made 25HP more than the closed top Stellings with a K&N. It is the lesser of the 2
"Evil doers"!!!!

dalola · #20 (**permalink**) 10-30-2001, 07:46 PM

ok, guys, here's a coupla pix of where I'm at. Got the air pan cut and fit together(used rivets and silicone sealer), and modified the substack slightly to fit over the BG carb. I then attached the substack to the pan with a couple small screws where the thick ribs are cast into the stack. Next, I sandwiched a piece of the humidifier filter between two pieces of 1/2" gap welded wire mesh, and attached it to the top of the substack with some steel reinforced vinyl edging. Easy to remove for filter cleaning! Next, I will glue on the foam seal, and trim to the hood. I'm counting on the pressure of the hood against the foam to hold everything down tight. Once the hood is open, everything will lift right off, no hardware, no tools! I have about 1.5" - 2" from the top of the stack to the bottom of the scoop. Not a lot, but sufficient I hope. I'll post some more pix when the foam is in place. Thanks again for everyone's help!
Dave