PPE Generation 2.0 header information thread

[TroyLotus]

Bane. My first thought was that you did not need to put the 2.5" on there or if you did I would just chop saw that bad boy off and put on a 3" flange. If you want to make one then that would be great and I would love to test it out for you. It can also make my life easer, just include the other side of the flange for me so I can weld up to what I will be making. I want the headers that are the best for flow so going to a 3" exhaust would be a big help. I will make the 3" exhaust with a Borla muffler (or other) and single tip outlet. It will sound nasty with this setup. Sign me up!!

Also by my math (please check me). If you have 1.75" primary's and they are about 1.5" inner diameter then you have 1.20375 of area. ((.75*.75)*2.14). Then multiply 1.20375*4 and you have 4.815 total area for all 4 primary's. So if you take 3" area you get 4.815 also. ((1.5*1.5)*2.14). As I see it the math works out perfect for a 3" exhaust after the header. Just cut that 4-1 flange at a point where it is exactly 3" so we do not have a bottleneck at all throughout the exhaust. FI engines love to breath.

On another note when I was planning on making my own I was going to do the same thing with 1.75" to a 3" flange. If you go with 1.875" a 3.5" flange would be right on assuming 1.75" inner diameter and 3.5" inner diameter for a total area of 6.55375.

Troy, thanks for the props... that means a lot coming from you  The header has a 2.5" outlet so it will bolt up to all factory/aftermarket muffler systems.

We've been wanting to build one with a 3" outlet for people with custom exhausts... Did you want to be that person?

[Bane]

Troy, you have PM.

Everyone else... we took what Troy said into consideration already. However, we found it was most beneficial for 95% of Lotus owners to stay with the standard sized collector. We didn't want to neck down the cat pipe. This was counter productive due to thermal expansion (necking down is a bad idea when gases are cooling and expanding), manufacturing, and cost reasons.

That being said... please keep checking back for updates to the entire exhaust solution

[GTsRasta]

Looks like it's coming together for you Troy! Good luck!

[elise/europa]

TroyLotus,

The exhaust diameter is not a question of surface area, the secondary pipe needs to be small enough to generate high velocity in order to sock the gas to the next cylinder to exhaust. A 3 inches pipe on secondary will reduce that capacity of the exhaust to extract gas. Maybe you will gain some HP in very top end, but the car can be slower. Bigger is not better at all.

I like to consider the exhaust made with primary section, secondary, and with a third section. The secondary pipe should be small enough to create good extraction, and around teh lenght of the primary, after that, go as big as possible.

My opinion, and I did a lot of trial in my life, with some impressive result.