16-08-2022, 11:28 AM
Once again, thanks all for the encouragement and advice.
Dennis you are right in proposing a good bit of research before starting, and that is what I am doing at the moment. I’ve gleaned several formulae from the web and others. Most, if not all, are rather empirical and some not even dimensionally correct, the constant in the equation hiding a multitude of corrections! However I’m not a fluid dynamics expert and can’t comment on their veracity.
However it would seem that to extract the best from the manifold and exhaust on a Seven the pipe exit should be around 3 to 4 ft from the block. A 4 into 2 into 1 seems to give the best mid range torque but a 4 into 1 better at high revs.
All this may be interesting but I have the constraint of a fabric bodied car with doors, meaning realistically the manifold and pipes must run under the car. So at the end of the day my design may have more to do with what will fit…. than out and out performance. There is also my perception of aesthetics and a huge gargle of pipes under the bonnet just doesn’t look “period” enough for me
.
I’m quite taken by the Ulster style where pipes each feed into a cone tapered pipe but I can’t find any useful information on performance. Saying that anything must be better than the original cast manifold!
Cheers
Howard
Dennis you are right in proposing a good bit of research before starting, and that is what I am doing at the moment. I’ve gleaned several formulae from the web and others. Most, if not all, are rather empirical and some not even dimensionally correct, the constant in the equation hiding a multitude of corrections! However I’m not a fluid dynamics expert and can’t comment on their veracity.
However it would seem that to extract the best from the manifold and exhaust on a Seven the pipe exit should be around 3 to 4 ft from the block. A 4 into 2 into 1 seems to give the best mid range torque but a 4 into 1 better at high revs.
All this may be interesting but I have the constraint of a fabric bodied car with doors, meaning realistically the manifold and pipes must run under the car. So at the end of the day my design may have more to do with what will fit…. than out and out performance. There is also my perception of aesthetics and a huge gargle of pipes under the bonnet just doesn’t look “period” enough for me
.I’m quite taken by the Ulster style where pipes each feed into a cone tapered pipe but I can’t find any useful information on performance. Saying that anything must be better than the original cast manifold!
Cheers
Howard