After experiencing a few problems with some SR exhaust manifolds we decided to develop our own.
Key features are:
- Short runners with minimal curves to aid gas flow
- Runners from cylinders 1+4 and 2+3 are separated as much as possible with a divider in the turbo flange - this helps minimise any valve bounce problems at high boost and rpm, it also reduces turbo spool compared to some other manifolds. Works in a similar way to twin scroll turbos.
- Made from thick wall stainless steel to help minimise cracking
- Skimmed head and turbo flanges - carried out in the final stages of manufacture
Here are some pics:
Runners and skimmed flange:
Internal divider and skimmed turbo flange
We've done quite a bit of testing with these manifolds
The graph below shows an SR that was running another type of manifold and suffering from valve bounce problems. This was then swapped to one of our new manifolds - nothing else was changed.
The red lines show power and torque with another manifold - you can clearly see that the power drops right off at high rpm.
The blue line shows the power with the H-Dev manifold (with no other changes!) - 2 things are clear: less lag and more power all through the revs.
To order click here or give us a call on 01635 247477