Header Collector

[dq409]

I`m getting ready to replace the collectors on my headers and was doing some research,,,
Now I`m totally confused???http://smilies.sofrayt.com/%5E/h0/hollering.gif
I was just going to use a three inch pipe and add the flange but now it might be better to taper it down like the one thats on them now.

They taper down to 2 1/2 inches.

The part that confuses me is ,,, would I lose power by going with the 3' out to 3" dumps or would I gain power by using the tapered collector and using a 3' dump?

Or use the taper and use 2 1/2 in dumps?

Mr. Walker?

[dq409]

Anyone ?? What ,,,no opinions ???? Can`t be,,,not on this forum !!!

[Va348]

OK Dq409 I will give my Opin

Can you put your cut outs right of back of collecter,Then taber down to 2 1/2 after cut outs.

Here a tip for you,Move your muffers has far back as you can. Will
be Quieter,make more power,move 40 to 50 lbs.from front to rear.

I am putting mine behind rear tire.

Here's a little story for you. In 66 I had a 65 409 with cut outs.State Trooper stop Wife Pregnant first child,Craw under and seen the cut outs,He going to take her to Jail. My Mom came by and talk him out of it, Because was with in 1/4 mile from Her house. So he gave her a ticket and follow to Mom's and said Car could not be move untill cut outs was taken off. My wife is still mad about that today. At Me for having them on there!


Dale

[fatride]

DQ, The taper is there to increase exhaust velocity at low rpm, it enhances scavinging at low rpm. I would say if you have big primarys and a tapered collector you would have the best of both worlds! As with every thing else in this world there is no simple fix. You still have to have every thing in the engine matched for power where you want it rpm wise. Huge collectors would kill your low end power, I would go for the taper. Unless you have a dyno handy it will be trial and retrial!
:cheers

[dq409]

Thanks fat ,,,Makes sence !!

Va,, I`m not using "cut-outs". What I have now are collectors that have a slanted port that goes off to the exhaust pipes and muffler and on the collector flange is 3" pipe to a race muffler with caps.

The collectors got beer canned after the exhaust shop installed the race mufflers without a hanger !!:cuss

I want to eliminate the port to the mufflers from the collector and move them to come off the 3" pipe going to the race muffler.

From all the reading on headers I believe that having them come off thye collectors is a bad idea.

Before I added the race mufflers I just had 3" dump tubes coming off the collector.

My ultimate goal is to have it setup so I can configure several set-up for street and strip.

1- Full exhaust with the capped dump tubes

2- Full exhaust with the race mufflers/dump tubes

3- straight dump tubes with the exhaust/mufflers removed

This way I can drive to the two strips with different rules.
One I always need to run the race mufflers and the other I can run open on certain races.

I`ll post photos as I figure this out,,,,dq

[dq409]

Here`s what I have now,,,,,

[dq409]

dunp tubes with race mufflers and spin-on caps,,,,,,http://www.348-409.com/forum/attachment.php?s=&postid=2765

[walkerheaders]

DQ:"I`m getting ready to replace the collectors on my headers and was doing some research,,,
Now I`m totally confused???"

BOB: Me too, so many different opinions, writings or views throws me into a tailspin everytime. especially on my golf swing.

DQ:"I want to eliminate the port to the mufflers from the collector and move them to come off the 3" pipe going to the race muffler."

BOB: I would agree and i would build the competition part of your system out of 3" stuff and make a 2-1/2 tap as far rearward as possible for your primary street system and as Dale said, mount the mufflers under the rear seat area.

Yours is a cool idea DQ, i like it. please have the guy tig weld the parts that will be seen by the public. you wont regret that extra touch for the appearance.

if all else fails, tack it up and send it here, i will make it pretty and low cost for you.

[dq409]

Thanks Bob,,,,

Let me get this right,,,,,

I should run a 3" non-tappered collector to 3" exust pipe then put the 2 1/2" tap as far back as posible.


Thanks for the offer !!http://smilies.sofrayt.com/%5E/_950/friendship.gif
If I can`t get it tiged by my welder I`ll send them !!,,,dq

[Va348]

Dq409

Walkerheaders Has it right! I would go one step more and put Muffler behind rear tire if you are going to run them out the back.

The pipe is easy to Oval to get by wheel & spring.You get it rig up
like this you will not see as much diff as you would think,running open & thru muffler. Not like it used to be.

JC whitney Has bends mandrel bent Any size,I make all my EX .right here.

Dale

[TomO]

Dq409 – Just a suggestion. Have a 02 sensor fitting welded into your collector of your header so you can use an air/fuel guage to tune up that 09. I used the same fitting to test the back pressure of the exhaust system. The mufflers on my car are under the rear seats. A guy by the name of Jim Hand (Pontiac guy!) did some testing/experimantation on the placement of the mufflers and the size of exhaut tubing needed. A quick search on the web will being up the articles written by Jim – it is good reading.
TomO

[dq409]

So what happens to that O2 sensor with leaded fuel ?

I guess I could just run super/Etyel/HiTest with a booster for the test EH?

I`ve also considered running full 3" exhaust,,,,,