math to building headers.

[FestYboy]

Nate, you should be in the 28-32" range depending on your redline.

[skeeters_keeper]

festyboy, whats that based on? An online calculator? Some equations you have? Just "rule of thumb"?

Just wondering, I enjoy knowing how my stuff works more than just having it work. Thats why I'd rather build a slow car into a fast car; there's no fun in buying something someone else made! I'd rather do it myself.

[FestYboy]

understood

while i was in school, i had access to performance equations, some involving header tuning. i based my calcs on a B6 with a 7500 redline and < 1" primaries. it netted 30.5" for a 4-1 header. now depending on the redline, primary size, and valve size, you're length will vary, but not that much. that's why i gave the range.

i'll try to find those equations again, and if you can give me some numbers, i'll crunch them and give you a better estimate.

[skeeters_keeper]

Well, I'm looking to use 1" conduit, which is equivalent to 1 1/8" pipe (1" ID), redline around 6.5, I'd like to make peak power around 5k. This is for B6 SOHC I'm planing on turboing with a small turbo (T25), a DD, not raced except maybe a few times down the strip, and perhaps daily if you call my driving style racing
I don't plan on running more than 5-8psi of boost. 2" conduit (2 1/8" pipe) for the down pipe and all the way back.

how much different is designing a turbo header than designing an NA header? I'd assume most of the same principles apply (exhaust pulse scavenging, etc).

[FestYboy]

ummm, in that case, i'd recomend an equal length shorty header (not log style), but in the same diameter. the goal here is to keep the gasses moving fast and as hot as possible before reaching the impeller. you may have to purchace specialty bends to build it, or if you're feeling adventurous, build a long tube design and place the turbo where the cat would sit, and wrap EVERYTHING.

[skeeters_keeper]

I'm thinking of a "ram horn" style header, haven't decided yet. I'll be cutting and welding my own pipe which may be a little tricky, but we'll see. Even if the "most efficient" size for the runner lengths becomes impossible, at least I'd like to have a number to shoot for.


this is the conduit I've been looking at, I may end up buying exhaust pipe though if I don't think this will be high enough quality (mostly worried about it not being perfectly round).

http://www.lowes.com/lowes/lkn?action=productDetail&productId=72274-15527-02-55543PE&lpage=none

I know a guy with an after-cat turbo on his stang... I'm not interested in going that route, but it is interesting! He's got his inter cooler in the hatch with 4 electric fans blowing through it... neat idea at least!

[NovaSS]

The conduit will not hold up in a turbo application , just too much heat and will burn out. Its also coated with zinc, makes funny fumes ( dont breath it) when heated or welded.


You are correct about design, what tends to work well in a N/A application works well in a turbo header, but with a turbo small design changes need for packaging will not effect the outcome as much.


For turbo applications use what is called black pipe or stainless in "schedule 40", this refers to the thickness of the wall. It comes in different "schedules", were the outside diameter is the same but as it gets thicker the inner diameter drops.

It can be found at just about any real plumbing / hardware store. Do a google for butwelded black pipe/ elbows or check out Mcmaster Carr ( GET a McMaster Carr catalog reguardless ! Its full of net industrial stuff that can be used in automotive projects and great prices, its a little harder to search /shop using their web page)



Dont forget if you want to go stainless it can can be stick welded.

Heres a great link...

http://www.sdsefi.com/techheader.htm

[solatare]

build a long tube design and place the turbo where the cat would sit

cat is under the car in a festiva, put a turbo down there and youll fry it since the oil return is by gravity. go back to my earlier post on page 2 of this thread, where i post suggestion of sch 80 pipe. i say 80 and not 40 because sch 80 is abit thicker for about the same price. thicker means it lasts longer. make a log type manifold and try to center the turbo on the log. looking at mine for a turbo it so far seems do able. also, these welds are critical to making the header last, and flow well. make sure you have a steady experienced hand put it together.

[FestYboy]

STS makes a turbo system that is placed where the muffler usualy sits. they use an oil return pump.

[sasquatch]

i got my headers done today and they sound amazing... i ended up going with a new design... i love them. ill post up some pics later and i have a copple vids of the new sound. it sounds much more like a race car

[canadianfestiva]

Sasquatch-
I want to see those things!!!!! Get somme pics up ASAP!! Thats awsome!

[sasquatch]

ok i got some pics. not many but you get the idea...

first i cut out the flange:



then i got the #1&4 tubes welded on:



then got #2&3 on, and tube extenders on too:



then i messed up and welded the tubes on the wrong side so they hit the oil pan, i beat it with a hammer and that did nothing...



so i cut off the 2nd set of bends and welded a pice of 2.5 inch piping in the same place:





then i welded some bungs in for my egt gauge and 02 sensor:



and they where done

[canadianfestiva]

Nice job!!! how does it run on the car? any issues? Powerband? notice improvements? or negative outcome?

Either way, They definately look better than stock!

P.S. What engine is that for? and how did you cut the holes in the steel plate? torches? plasma?

[sasquatch]

it runs good, some hp gains (i would say 5 to 8 hp at the top end and a little less torque at the bottom) and a wicked sound i used a plasma cutter for the big holes and a air dremel to smooth out the holes. if i did not weld the tubes on the wrong side the would have fit (still kickin my self for that...) and i think they would have sounded even better

[canadianfestiva]

Nice! I think when I go to do mine I'm going to try a 4-2-1... this way we can swap theories on torque/ hp gains seeing urs is 4-1....

Is that on a B6??