header building blocks. (alternative)

[NASTYZEN]

Those plastic kits certainly look like they would help a lot in mock up. I just use an old vacuum hose and go from there.

Here's one from the past I made using the hose method.

 

[toddoky]

Those plastic kits certainly look like they would help a lot in mock up. I just use an old vacuum hose and go from there.

Here's one from the past I made using the hose method.

Looks good nastyzen, I've used the plastic block kit and although it looks promising it is in fact frustrating to use due to the discrete fixed angle of each block that lies somewhere in neighborhood of 30 degrees. If you want an angle of degree that is not the sum of any combination of these individual blocks then you are out of luck.

 

[ckpitt55]

Alright Chuck, to start this off I need to know more about the car itself and to keep it short and sweet just give me the following info the best you can:

Vehicle weight-
Transmission type-
Rear end ratio-
Rear tire size, will you be traction challenged?

Vehicle weight- ~3000 lbs
Transmission type- t56 magnum [2.66/1.78/1.30/1.00/.80/.62]
Rear end ratio- 3.91
Rear tire size, will you be traction challenged? 275/35/18. Yes I will be traction challenged.

 

[toddoky]

Vehicle weight- ~3000 lbs
Transmission type- t56 magnum [2.66/1.78/1.30/1.00/.80/.62]
Rear end ratio- 3.91
Rear tire size, will you be traction challenged? 275/35/18. Yes I will be traction challenged.

I'm working out in the garage today Chuck, but I'll post up a reply for you tonight when I get some free time after getting the kids to bed.

 

[1953mercury]

Mike,(1953mercury) that looks really nice!

Thanks for the kind words guys. Kind of a mish-mash of materials, but what was at hand at the time. Still running strong in my sons Galaxie after 5 yrs with no issues and a very nice exhaust note (428/TKO with Super Comp headers). Mike

 

[toddoky]

Vehicle weight- ~3000 lbs
Transmission type- t56 magnum [2.66/1.78/1.30/1.00/.80/.62]
Rear end ratio- 3.91
Rear tire size, will you be traction challenged? 275/35/18. Yes I will be traction challenged.

Thanks for the info Chuck. Based on the info you provided and your stated usage, I would target the header specs towards maximizing power at peak horsepower RPM rather than peak torque RPM. The fact that you have a fair amount of rear gear and a moderately light car that will be traction challenged by your tires means the mid to top end bias of the power curve will be a benefit to your goals.

I would use 1-7/8" tubing (yes, you will realize improvements in both average and peak horsepower numbers over using 1-3/4" tubing) and set the target for max primary length at 28". Do not spend much focus trying to get the primaries to be equal length as un-equal length primaries within 15-20 percent of one another will actually provide you with a broader usable torque band.

All of the above is assuming you are building 4 into 1 headers, if you have the means and skills to construct 4 into 2 into 1 headers, they will be of yet even more benefit to you with the trade-off being the increased labor and expense to build them.

In either case, you want to use the largest centerline bend radius possible and from what I've seen on some other BMW LS swaps that is probably going to be limited to 2.5" radius. once past the first bends out of the ports you can switch to larger 3",4" or 6" radius for successive bends. To determine how tight a bend you can use at the port, you can make/use cardboard or wood templates of various bend radii that you can hold up to the head flange to determine how large you can go.

Let me know if this helps you get started.

Todd

 

[nonhog]

Any alternatives that could do the same job?

I just stumbled on this build thread .... http://forums.turbobricks.com/showthread.php?t=282426

alternate idea on mock up. Seems to work for this guy ^

 

[1953mercury]

Have to be impressed with a guy who builds his own mufflers. Thanks for the link. Mike

 

[toddoky]

I just stumbled on this build thread .... http://forums.turbobricks.com/showthread.php?t=282426

alternate idea on mock up. Seems to work for this guy ^

Anything like this method that allows you to efficiently and inexpensive visualize your primary tube routing would be helpful to someone having their first crack at designing/building a set of headers. His method could possibly be cheaply duplicated if you have some dead-soft annealed aluminum or copper tubing lying around or access to it at a fair price.

 

[phill u7c]

Hey Nonhog that was a great link to find. Thankyou for sharing

 

[AussieDan]

I'm greatly humbled by your willingness to help, it's much appreciated sir.

To offer a little more detail without getting carried away - the engine is indeed a small block chevy - an ls1 that I blueprinted / assembled. Pretty much a maximum effort n/a engine on stock displacement - high compression, forged internals, milled heads, intake, the works. It's going into a non-gm vehicle - an old bmw m3 - which pretty much rules out off-the shelf headers due to space constraints in the engine bay. I've always wanted to get into tig welding so figured this would be as good of an excuse as any and I really look forward to learning.

I've done preliminary research (and have much more to do), but I was between 1-3/4" and 1-7/8" on primary size - favoring the smaller size at the moment to help keep velocity up. I honestly don't know whether or not a 347ci engine moves enough air to take advantage of or need 1-7/8" primaries, but many guys have had good results with them....perhaps you have experience with this. I'd like to try and make them as close to equal length as possible to take advantage of proper scavenging, and configure the primary / collector lengths to maximize area under the curve. I'm obviously limited by the space available to me in the chassis, but I'd like a setup that emphasizes a wide power band and good average power vs. something that is gutless down low and peaks up high. The car will serve as my DD in nice weather and also see road course / hpde / autox.

Any input / tips you could provide is greatly appreciated

You need to start a build thread for this immediately.

 

[spv]

good idea. never thought about that. where can you get it? you're talking about the bendy straw stuff right?

Sorry superspec, I only pass through here from time to time. I missed this one.

This is what I used to help me visualize and template the headers. I think I got it from the hardware store. Just some flexy down-pipe/drain pipe/vacuum hose. They hold their shape better than one expects. You could potentially wrap them in masking tape and fit them to the car for a test fit. If it does not help you, hopefully it saves someone else some time and $ avoiding those plastic fiddly blocks:

 

[ADSR]

Sorry superspec, I only pass through here from time to time. I missed this one.

This is what I used to help me visualize and template the headers. I think I got it from the hardware store. Just some flexy down-pipe/drain pipe/vacuum hose. They hold their shape better than one expects. You could potentially wrap them in masking tape and fit them to the car for a test fit. If it does not help you, hopefully it saves someone else some time and $ avoiding those plastic fiddly blocks:

That's great!! Thanks for posting them!

 

[superspec]

Thanks SPV

 

[rlitman]

I might just bite the bullet and order the master set. (1000 bucks)

Holy schmoley!. $1000 for those plastic parts?!?

If I were trying to replicate the same thing, I'd gun drill dowel stock, then chop it at the required angles and string it together with a bungee cord in the middle. Once I was happy with where I had something, I could use CA glue to stick pieces together while I move to another section.