25-07-2012, 03:33 PM
(19-07-2012, 10:04 PM)Ruan Wrote: Oh no absolutely, I was more referring to petrol engines there... Diesels really don't suffer from valve overlap, however, if they have a restrictive exhaust, they cannot get the gas out fast enough... The more you de-restrict the exhaust, the more power you'll make... I was pointing out that on a Diesel, it really won't make any difference.
The only time you'll see gains is if you tune the exhaust so that at a certain RPM it'll help pull the gasses out - just like blowing over a bottle, you can tune it to a certain frequency... Same as the inlet... But naturally this is ALL pre-turbine wheel...
Yeah, some fancy manifold might help you out I suppose. The early manifolds on the Td's are a bit crappy really, they have like a big collector that then feeds to the turbo which can't do much good for anything but those were the days.
The later cast tubular type ones seem the best all-round compromise before you go for a fancy battery area mounted jobby
Dave