Honda Conversion Exhaust Options

The Oily Bits S1 Specific Topics
1

Hi all,

I would greatly appreciate your advice, I am nearing the end of a long and arduous Honda conversion on my Exige S1 and need your collective thoughts on exhaust options.

There is of course the option of whether to go under subframe or over which I have decided to go over due to the better breathing and heat dissipation.

I have been in communication with Chris Tullett and he has suggested to ask for the experience of others on the following:

4:1 or 4:2:1?
Ideal Primary Lengths and Diameters?
Anything else to look out for?

My engine is NA and heavily modified, looking for an exhaust that can handle 250-300bhp (to accomodate future tweekings!)

Thank you all in advance.

Richard

2

yeah OTT is key

as for 4-2-1 vs 4-1, the former will give you a bump at mid range but legend has it the 4-1 helps breathing top end.

TBH if can really be arse I’d build something modular that hangs way out the back so you can play with tuning the lengths on the dyno, then fab up the final version once done. I think TDI did this with the yota cars

3

Yea, my thoughts were heading towards the 4:1, have researched it a bit and looks to be the best way forward.

Is that TDI North with the yota cars? Sounds like a good idea to test on the dyno but also expensive!

4

Also, the problem I have is that it is a totally new engine which will require running in before it goes anywhere near performance testing on a dyno!