Sidepipe horsepower loss?

[Dwight]

my guess is the air filter is killing your hp.

I did the number on an 8" S&S filter (classic old Cobra air filter) on a 351W with 400 hp. At 4000 rpms he was losting 90 plus hp. Motor would not rev above 5300 rpms till we changed the air filter.

Dwight

[FUNFER2]

A friend with a chassis dyno has done some tests with air filters. The fabric type like the K & N was fine until they used the instructed amount of the supplied oil. The numbers fell down dramatically. The common paper type produced the best results. So, if you're gonna use the fabric type, keep the amount of oil down.

[RICK LAKE]

I run the same airfilter as rdc767 and it is worth 5-7 HP in top end of HP range. This is dyno check and proved. The bending of the air and smoothing it out helps over not running anything. Same applies for cutting the top choke housing on Holley carbs. For racing and high RPM's this works for low rpms it cost you HP. It's more about bending the air to get to the carb and fuel/air mixture than anything else.

If you like burning up exhaust valves and seats with running straight pipes, it's your motor and money. You can extend the life of the valves by running a motor richer or with a higher octane of fuel to a certain point. I have seen over the years race motor with burnt exhaust valves and seat. Exhaust gas has little to no oxygen in it. If slowed down to get out the the headers you get a little back pressure and this helps. Overlap is also important with how much and again helps cool off exhaust parts. I have seen power improvements with good exhaust and small amount of back pressure in an exhaust system. This is on a motor that runs between 1,000 rpms to 6,800 rpms. This is not a 1/4 mile car. You really need to find a dyno and install a gauge to the exhaust and run power runs and change exhaust until you find max power from your car and see what the numbers are. Again no 2 motors are the same and what works for 1 car will not produce the same power on another car. Rick L. Ps K&N oil air filter over time will hurt O2 sensors and cause drivablity problem and cause loss of MPG's Use little oil as possible after cleaning. I have changed my front O2 sensor and picked up 1.2gpm after replacement. I went back to paper with $110.00 O2 sensor per side.

[Bobcat]

If you really want to improve your exhaust , contact Burns Stainless about their merged collectors . That`s what is on mine now , along with their stainless 5 lb mufflers . Major improvement in the whole rpm range . Talked to Robert Pond who also runs their stuff and with open exhaust on his engine ( 427 in a `67 Fairlane ) , he saw 100 hp increase 0n the dyno . I`m probably in the 75 hp range with mufflers . However , you should probably be seated as they aren`t cheap !

[JBCOBRA]

Compared to what filter or no filter?
Curious, because I have seen these try and get sucked into the engine too.
There is no way I would use one of them,
rdc Needs a better filter.

[quote=RICK LAKE;1199138]I run the same airfilter as rdc767 and it is worth 5-7 HP in top end of HP range. This is dyno check and proved.

[JBCOBRA]

...additionally, a backfire from the carb heats/melts the cells in the foam and closes them up......

[RET_COP]

JBCobra, I use that same filter (Edelbrock 1000cfm) but I changed the element as there are bad stories like you said. I used a fiberglass type that keeps the stones and leaves out, I can change my thicknesses and it seems to flow much better then the foam and the engine pulls hard to 6500.
I had a nice K&N 8" billet aluminum oval with a 2" element. I called one day to get the CFM's it flowed. She came back after calculating it and said 384!!!!!!!!. WHAT 384. I quickly dumped that nice looking expensive filter and developed my own like I described.
Lou

[JBCOBRA]

Hi Lou!
Your filter idea is excellent.
Do you have any pictures of how you did it?
It would be helpful to a lot of guys
JB

[RET_COP]

If you click on my username and view public profile, to the right click on "Lou's Pictures" under the cobra, you will see the air filter on the carb. I used a quality furnace filter and layered it. I also put a flame to it to test it.
Lou

[DAVID GAGNARD]

Originally Posted by FUNFER2

A friend with a chassis dyno has done some tests with air filters. The fabric type like the K & N was fine until they used the instructed amount of the supplied oil. The numbers fell down dramatically. The common paper type produced the best results. So, if you're gonna use the fabric type, keep the amount of oil down.

+1

When I dynoed my SBF engine (472 hp), I brought along my air filter, open element 3" X 14" plain jane AC Delco paper element filter bought at Auto Zone, after the last pull, we took the "bell" off the carb and I put the air filter on, made a couple of pulls, lost all of TWO hp!!!!!!!!!!!!

David

[RICK LAKE]

JBCOBRA FI systems donot backfire if setup right. The filter base helps bend the air into the 1,200 cfm throttle body. If you sucked a filter into the carb, you could have had a couple of problems to cause this, possible too dirty, fuel inversion ate the foam, backfires. They tell you to clean and or change the filter every 2-3 years. it does get hard over the years. I like it because it keeps the big junk out of the throttle body and allows the air from the hood scoop to go directly into the throttlebody with out any bending. I don't oil this foam either. Rick l.

[JBCOBRA]

With all due respect Rick. Hoodscoops do not work at all on these cars.
No air goes in the scoop at all no matter how fast you go,unless you have a sealed system around the base of the carb to the top of the hood.

[xlr8tr]

sidepipe question: am I correct in assuming the sound reduction with a glasspack style muffler is primarily due to the glass packing, so more is better? I.e. a 3 inch core 5 inch body will be quieter than a 3 inch core 4 inch body, all other things being more or less equal? I'm thinking specifically of the 5 inch Jones glasspacks vs the 4 inch classic chambered style.

Doubling up: I'm considering using one of those 2 types of glasspack mufflers, then inserting one of the "auger" style spiral turbo baffles into the exhaust tip. Spiral Turbo Specialties:
Anyone tried something similar? I just think it will eliminate the straight through sound path, without blocking things up: you can use a 3 1/2 inch spiral inside the 3 1/2" tip, extending into the muffler body to the 3" to 3 1/2" transition.

[RedEye]

Bump. Also interested in thoughts regarding STS. Thanks!

[GT Bill]

Hope you ran away from STS ..
They are the worst bunch of Crooks !

[RET_COP]

Just an observation and more information. Remember when I posted that I use a furnace filter for my air cleaner on the Edelbrock triangle air cleaner. Well I added a Victor Jr and bigger header primaries. I thought I would put the foam element back in just to see how it performed with the better induction and exhaust. Well the car fell on it's face above 3500 rpms. At first I thought I had an ignition problem as I changed to a HVC coil and firecore50 wires. I brought the Cobra home and replace the foam with the fiberglass furnace filter and Bang! 6500 rpms.

Oh, those FireCore50 wires, love them. I can also listen to my radio without the RFI.

Just some information.