clubstylus

Finally got the car booked into MKEngineering (Some of you may know him as Martin Keenan) this week for a new stainless side exit exhaust manifold and silencer to replace the rattly, awful mild steel scaffold pipe and rear box.

He made me new manifolds for my old V6 locost several years ago so I know he does good work. Got a pic of StylusSprinters exhaust to show him how it would mount to the chassis and how much body might need cutting out to fit the 6" silencer in nicely.

The existing XFlow minifold is a 4-2-1. Should I keep this layout or drop to a 4 into 1 setup?

Any final tips or advice before I let him loose on the car tomorrow evening?

Best advice is to think forward ie -- you might not always have that power and silensors/repackables don't come cheap. If the pipe size and silensors through pipe is too small it will sap power on a more powerfull engine. Best to compromise your existing power plant with an eye to possible future changes ????
My through pipe was over large on 200bhp but is perfect for the 231bhp it now puts out at 2.75ins . Very important that each primary is the same length for optimum power .

Dave of Emerald will tell you to go 4 2 1 regardless of the engine size & use.

Cheers for the replies.

Does Dave give any reason why he says 4-2-1 is preferable to 4-1?

I've had a rolling road session on the old exhaust in Feb this year with the rear exit exhaust, it needs a bit of a tune up so will be back early next year to get it done again and will see what difference it makes, if any.

I think its to do with the flow. The exhaust gases are smoothed out. Therefore escape quicker.

Every engine make has it's own requirements . Dunnell says on Zetec's all primaries to be 1 7/8ths plus equal length but can be between 28 and 32 INS . Then 4 into 1 with a 2.5 INS through pipe and 6 to 7 INS repackable .
Crossflows will have their own requirement along with whatever bhp it has .

I've heard from several sources ...xflows 4-2-1 for road 4-1 for race and zetec 4-1 road and race. Don't know about any other 4 pot engine.