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austenw · Oct 5th, 2008, 18:48

Here is a reply i got back from Polestar touring car team who run volvo's

Sound like a nice engine you are building, much like the old super touring Volvo engine built by TWR. I´m sure you will meet your target power with that specification. I can not help you with all your questions but I can give some hints to some of your questions. First of all, our rules prevent us from using some of the things you are using. For example, our valve lift is limited to 10.5 mm so we have to design our camshafts in a special matter to optimize performance. How does cat cam measure the duration?

We are also limited to use a single throttle body so individual throttles can not be used. You could probably use individual throttles with approx. 42-44 mm effective diameter. I expect you will be running the engine between 7500-9500 rpm and I would suggest you to run a inlet length between 260-270 mm.

The exhaust system I would suggest you to run a 5-1 with approx. 800-850 mm primaries. 50.8 mm diameter into the collector should be good. For improved range you could try to run a cone after the collector, starting at 60 mm and ending at 76 mm, 300mm long.

Oct 5th, 2008, 18:48	#20
austenw Junior Member Last Online: Jun 28th, 2016 13:32 Join Date: Feb 2008 Location: Lincolnshire	Here is a reply i got back from Polestar touring car team who run volvo's Sound like a nice engine you are building, much like the old super touring Volvo engine built by TWR. I´m sure you will meet your target power with that specification. I can not help you with all your questions but I can give some hints to some of your questions. First of all, our rules prevent us from using some of the things you are using. For example, our valve lift is limited to 10.5 mm so we have to design our camshafts in a special matter to optimize performance. How does cat cam measure the duration? We are also limited to use a single throttle body so individual throttles can not be used. You could probably use individual throttles with approx. 42-44 mm effective diameter. I expect you will be running the engine between 7500-9500 rpm and I would suggest you to run a inlet length between 260-270 mm. The exhaust system I would suggest you to run a 5-1 with approx. 800-850 mm primaries. 50.8 mm diameter into the collector should be good. For improved range you could try to run a cone after the collector, starting at 60 mm and ending at 76 mm, 300mm long.