Flame arrestor vs. K&N air filter..proven by the dyno!
 

Just thought I should let ya'll know what I learned from the dyno. Just had my new 509ci HP500 carb built and dynoed by Bruce.

The only real standout was flame arrestors. My eyes are now opened!:eek:

results: only changes here were what's on top the carb

Velocity stack(hat) 565hp@5400

stock(8"x3") HP500 flame arrestor 544hp@5300 -21hp

Gaffrig (8"x5") SS screen arrestor 557hp@5400 -8hp

K&N (9"x5") K&N element 565hp@5350 -0 hp

I will be using the large K&N filter arrestor!!

I don't have dyno sheets in front of me yet. As soon as I do I'll post more results.

Thanks, Eric

One thing I should add....the Gaffrig and the K&N both had a slightly raised base plate that had a "bell" style flange. I think that is one of the contributing factors here.

The stock HP500 arrestor didn't have any type of "bell". It just sits flat on the carb flange. I think that really disturbs the incoming air. The other factor is size. The stock one is just too small.

Eric

Pretty interesting numbers there Eric. Cool.
Looks like the K&N gave you the same HP as the open stack, but at 50 rpm less. Hows that? Be curious to see what the torque numbers were with those changes.

Wonder what my Gaffrig 10x3 arrestor is doing? We only ran the stack when we did mine.

Jerry

Thanks for posting the numbers. I hope to have Bruce build some motors for me next season. I'd be curious if there is a difference between a round K&N and an oval one. Some of these oval billet air cleaners are sweet looking.

Dan

K&N also makes a an air horn for the 4150/4160 style Holley. I have one mounted under my K&N flame arrester. I wondered if it is actually doing any good or harm. Any have dyno info on them?

Tom Earhart has done simular tests and only saw a 3hp differance' that was between a large K&N(with a stack) and no cleaner at all. We pulled SuperV's with the real ****ty looking plate type flame arrester like comes on a 7.4 and it made as much HP as nothing but a large velocity stack, we did'nt have a K&N along for comparison but it would have been interesting....
Don

i wonder how the stock flame arrestor with only the last screen mesh in works?

Dredge, We did remove all but the last layer of mesh from the stock HP500 arrestor. It still had the 21hp loss. Anybody want to buy it??

I think the difference between a round and an oval would be not much. I think Im going to order a K&N custom 66 oval. The one with the flames. With 5" element hieght.

The #'s on the big Gaffrig and K&N were given to me by Bruce over the phone. I'll get more details when I get the dyno sheets.

Jerry, Id say that your 10" x 3" is costing you some hp. If you have room maybe get a taller one. As for the 50 rpm, I don't know.

talk more soon! ERic

One of the automotive mags recently did a comparison between the different sized K&N filters. They were all identical in HP-virtually no loss. I think that K&N's size recomondations are bases off of a dirty filter. Because marine motors don't really suck dirty air, you can get by with the smallest of air filters.

Are those numbers back to back dyno pulls...same day, weather, etc. ?

Intolerant, The dyno #'s (1st day)for the comparison between the velocity stack(hat) and the stock arrestor are back to back pulls on the same day.

The #'s(2nd day) between the big Gaffrig and K&N are back to back on the same day.

I got my K&N assembly today. It's 11 7/8" x 8 1/4" oval w/4" element height. Looks very cool too!:D

Eric

OK--- How much for the k+N and where do you get the best price?

www.knfilters.com
 

Check out the web site. Pick the one you like and right down the part #. OutlawMark here on the board may be able get it for ya. He'll probably get on here soon.

Part # on the one I got is 66-1520 in the "custom 66" page.

Eric

CheckmateF1, That is pretty impressive #'s. WOW I just looked at K&N's site. That assembly you bought looks great. I am buying a Whipple from Bruce and we haven't even talked about filters. 502 EFI
Hmmmm, I wonder if the whipple comes with one.........If not, I am sure going to order one. I ordered the billet throtle body which only gives about 30 hp, but it cost I think $500 or $600.
VERY interesting!

Are the Custom 66 models approved for marine use and how much are they?

Sean, the assembly I got does not have a CG approved stamp. I paid $125.00 for it.

Eric

Eric, thanks for sharing your dyno results. My hatch doesn't permit a taller flame arrestor than the 8 x 3" Barbaron I'm using now. Because it has a flat base, rather than a short curved horn like the Gaffrig, I installed a K&N stubstack like Intolerant 1 mentioned. My carburetor has the choke horn milled off, so I used K&N model 85-0500 Stubstack that is designed for square bore Holleys. It is a full radius design that helps increase the airflow of the carb, and holds down the flame arrestor base. In order to use this, I had to disassemble the flame arrestor to place the Stubstack inside. This was easy with the polished stainless Barbaron because it's held together by silicone. A little gentle prying separated the top plate.

I'll bet you can't wait to try that new lab finished 27" Hydromotive with your new engine! Likewise, I'm ready to try your old Bravo 1.
Randy

How are ya Randy!? I was wondering if you got a chance to try that prop yet. Yep the 27 is ready and waiting. I did cut the diffuser off of it though. I hope to put the motor in this week!

My right hand twitch is starting to get worse! ;)

Eric

ps..what happend to "stroker"?

i had been eyeballing the k&n filters in jegs for 4 or 5 months. i just ordered one. much cheaper than any one else's super filter.

Eric,
I'll run my own engine upgrade and new prop Memorial Day weekend. Michigan is still cold, especially up at Lake Charlevoix! I've got to put in 32 sections of dock just to get deep enough for the boat to float on the hoist with the lake levels still low.

My former "Stroker" name was a victim of the OSO conversion. I got tangled up trying to get re-established, so I just started over again with a new name (the name of my boat). Wish I could fit a 5" high K&N in my engine compartment. Tyler Crockett, who did my upgrade, says I'm fine with the flame arrestor I've got on my 464 HP 454.

Randy

Engines will typically develop slightly higher torque numbers with an air cleaner due to increased flow velocity-it is likely that is what caused the horsepower lower in the rpm range. The down side is the restriction from an air cleaner usually will restrict some air flow at high rpms at WOT.

Oh Yea!!!!
 

Got my motor today! I hope to be in the water in a week or so! Wish me luck. I'll try and post some pics of the finished product.

:D :cool: Eric

What is the best way to clean the stock flame arrestors on the HP500 Carbed? Mine look very dirty, and it is too late in the season for me to want to invest in the K&N setup.