Sunday, February 19, 2012

Equal Length Long Tube Headers Continued

So, building motor mounts to stuff a ls1 into a 240sx seemed like a challenge, but it was actually a breeze compared to building headers and attempting to make the tubes equal length.  My first length attempt was 32" with the collector just behind the firewall, to maximize ground clearance, it worked great for the two cylinders to the front of the engine, but not so well when it came to the back two, I had to pick one or the other to make the 32" length, then the one that didn't get the length was going to be 4-5 inches shorter which just wasn't going to work.  So I went back to the drawing board and came up with some creative tube arrangement to shorten all of the tubes to 28" the shorter end of the recommended length from cone engineering.

Notice the front most tube, its tucked as tight to the block as I could get it and actually enters the collector above the next tube behind it to make it possible to make these headers equal length.

I decided to tuck the front most tube in very close to the block and take the straightest path possible towards the collector, inserting it into the upper opening (rather than the lower opening where it would typically go), tucking the second tube from the front underneath it.  With this tangled tube arrangement, I was able to get the first three cylinders within 1/2" of length of each other and the last one within 2", this is not perfect equal length, but I think it will do.  I could have squeezed a little more length to get it closer to the 28" goal, but I would have had to have much more aggressive angles, which didn't seem worth it in terms of loss of flow. 

Front View

Here's the underside view, there's another new tool under there, an adjustable V-channeled (angle iron) tube tube stand.  Between this and the collector holder these are some massively helpful tools.  I've built these with a lot of inspiration from Advanced Chassis's shop tools.

The passenger side is now ready for tig welding.  The driver side is coming up, so its decision time, I wanted to make it in such a way that it could be installed without removing the steering shaft, but with the difficulty of the passenger side I'm not sure if that will be a possibility.

No comments:

Post a Comment