Exhaust manifolds
Discussion
There are three original production variants of the speed six engine - 3.6L, 4.0L and 4.0S (Tuscan and Sagaris) if I am not mistaken. What I would like to know is what differences, if any, were there in different exhaust manifolds supplied with the different engines ??
Surely the more tuned/more powerful 4.0S engines would have needed slightly better flowing (larger bore?) manifolds than the standard 3.6L/4.0L, and consequently larger twin pipes travelling back from the Cats ?? People (incl TVR Power) state that the Tuscan does have a better flowing exhaust than all the others
Also, as Racing Green now advertise 'equal length, optimised' exhaust manifolds for Speed Six engines, why didn't TVR do that in the first place?? Can't have cost that much extra to have the optimum manifold design from day one for a performance engine??
Finally, any particular reason why the 4.3 and 4.5 TVR Power engines don't have any exhaust changes, as Dom does say that the Tuscans will have more power because of better exhaust characteristics ?
Cheers
Surely the more tuned/more powerful 4.0S engines would have needed slightly better flowing (larger bore?) manifolds than the standard 3.6L/4.0L, and consequently larger twin pipes travelling back from the Cats ?? People (incl TVR Power) state that the Tuscan does have a better flowing exhaust than all the others
Also, as Racing Green now advertise 'equal length, optimised' exhaust manifolds for Speed Six engines, why didn't TVR do that in the first place?? Can't have cost that much extra to have the optimum manifold design from day one for a performance engine??
Finally, any particular reason why the 4.3 and 4.5 TVR Power engines don't have any exhaust changes, as Dom does say that the Tuscans will have more power because of better exhaust characteristics ?
Cheers
Edited by RedSpike66 on Tuesday 12th April 13:24
Getsis said:
Manifolds are the same for all speed 6's. Changes take place at the cats, 'S' and Sags have a larger outlet from the cat and the transition pipes to the cans or the back box.
Tuscans don't have the 90 degree change in direction like the sags do which helps exhaust flow.
Not sure that's correct as my car came with Tuscan S headers which are larger than standard I am led to believe.Tuscans don't have the 90 degree change in direction like the sags do which helps exhaust flow.
What's wrong with the std manifolds? the cylinder grouping means each manifold sees 3 pulses at 240deg engine rotation apart. they're not seeing much pulse overlap so having the lengths approx equal is good enough. The RG manifolds don't look better in any way that I can tell .. does anyone have before/after engine dyno test results for their manifolds? They may be better but it's hard to see how.
Alan Kee said:
What's wrong with the std manifolds? the cylinder grouping means each manifold sees 3 pulses at 240deg engine rotation apart. they're not seeing much pulse overlap so having the lengths approx equal is good enough. The RG manifolds don't look better in any way that I can tell .. does anyone have before/after engine dyno test results for their manifolds? They may be better but it's hard to see how.
what he says, if there was any advantage to be had by improving the standard manifolds, believe me, I would have made some shiney stainless ones myself by now
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