Modified LS400 header questions

[ethann]

Hey fellas,

I'm building a buggy with a 1uz. Had plans on building some custom headers, but the LS400 headers are going to work for me with some slight alterations.

Going to bring either the passanger side up over the bell housing (or vice versa, pics to follow) and join them into one.
http://i97.photobucket.com/albums/l...FE519D4-7360-000005CC5C58AEC1_zps2be5f39c.jpg
Now first question, will it be ok if I use 1" 5/8 while going over the bell housing? Or should I try to get something like 2.25 in there?
http://i97.photobucket.com/albums/l...29344E5-7360-000005CB88652A7F_zpsb5f07d79.jpg
Plans
The one on the right would be ideal, to help get the heat away from the drivers side. But wasn't sure on the 180 bend? I really want the exit point to be on that left point where the pink is.
http://i97.photobucket.com/albums/l234/etho91/EXHAUST_zps2826edae.png


Thanks, look forward to a discussion
Here's a pic of the buggy
http://i97.photobucket.com/albums/l234/etho91/IMG_6687_zps65de68a2.png

 

[LEXUSA]

Wow, that is pretty slick! What rpm do you use, low or WFO? I've perused many of JBrady's exhaust evolution posts and IIRC you need to run 2" between the headers/manifolds and the "Y" pipe. The most critical point seems to be when both banks merge into 1, the OE "Y" pipe seems to be unbeatable when it comes to making power, do you have it from the donor car?

What is that manifold off of? Did you modify it? Aren't the short little head pipes 1 5/8" OD? If low end power is what you are after then each step up in diameter is very slight, most aftermarket headers step up way too much.

I just purchased PipeMax, an exhaust design program. Not only can it design an exhaust system, it can also give you an idea how an existing header will perform or what rpm range it is designed for. I'm still trying to find some data for the 1UZ so I can input and calculate what a header should look like for it.

Seems like this website isn't nearly as busy as I once remember it being.