Different manifold 2.5d and 2.25d ?

[henk]

Is there a huge difference between the exhaust and the exhaust manifold of a 2.5d and a 2.25d?

I have a 2.5d in my 88 but used the exhaust nd the manifold of the 2.25d

[Outrage]

The 2.5 manifold is larger diameter I think, to match the larger diameter exhaust off a 90/110. The manifold studs will not mate with the flange of a standard series 3 exhaust.

I used the 2.25 manifold to match to 2.25 exhaust on mine. I've noticed no power problems although others have suggested it will reduce the power output substantially.

Cheers,

Lee

[Phil Hancock]

Its just the flange dimensions that differ. The comments about power loss are due to the 2.25 exhaust pipe being a smaller diameter than the 2.5 pipe.

[Snagger]

I found that my 2.5 nad had temperature problems uphill despite a brand new cooling system with a 2.25 exhaust, even after a full rebuild with rebore, pistons, crank grind and new valves. Fitting a 2" exhaust cured the problem immediately. Though the overheating never enetered the red one, years of elevated temperatures led to cracked pistons, so don't be tempted to use a 2.25 exhaust on the 2.5 engine.