nylen Posted September 4, 2021 Report Share Posted September 4, 2021 When I search for exhaust manifold I find that there at two different main types. From Racetorations and Revingtons the have the figure 6-2-1. This is also what Kas Kastner recommend in his book. Triumph Preparation manual. Both Phoenix types on Moss website has figure 6-3-1. Primaries joined together in pairs at 180 degrees interval. That make sense but I can not understand the principal for 6-2-1. Can anybody explain? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted September 4, 2021 Report Share Posted September 4, 2021 This was a good discussion at the time Quote Link to post Share on other sites
TRseks Posted September 4, 2021 Report Share Posted September 4, 2021 (edited) On 6-2-1 the pipes from the 3 rear cylinders goes in to 1 and the 3 at the front to another, then into 1. I got the Racetorations, no problems with clearances even with standard starter. I wrapped the starter in “heat shield material”, and made a heat shield under the carburettors as the heat is higher from the SS manifold. Magnus Edited September 4, 2021 by TRseks Quote Link to post Share on other sites
nylen Posted September 4, 2021 Author Report Share Posted September 4, 2021 Thanks but I still don´t understand the principal for 6-2-1. Quote Link to post Share on other sites
TRseks Posted September 4, 2021 Report Share Posted September 4, 2021 (edited) I did not fit the racetorations system because I have a highly tuned engine, my car is a US model and had the original single outlet pipe (not the dual outlet) and I wanted a SS system that would last a long time and with added nicer sound. The racetorations manifold is made of high grade 308 stainless steel and sounds great, big bore system with a phoenix muffler. I have heard the 6-3-1 is better for the TR6 as it gives a better “pulse from each cylinder”? and helps better at higher revs but it does not really matter as I hardly ever rev the engine up. I have not wrapped the exhaust either as this will probably make it rust. Magnus Edited September 4, 2021 by TRseks Quote Link to post Share on other sites
YankeeTR5 Posted September 5, 2021 Report Share Posted September 5, 2021 The principle behind the 6-2-1 is, I believe, is that there may not be much principle behind it (other than the simplistic things like packaging, ease of mfg and the fact that cars need some type of exhaust manifold). For the dual pipe exhaust using a 6-2-1 header you can almost make the case that each of the two branches would have its own exhaust pipe. The 6-3-1 at least has some thought re: resonance scavenging etc. that make sense. Basis some other comments....the beauty of the 6-3-1 is that the largest benefit to power is mostly on the lower end. Quote Link to post Share on other sites
nylen Posted September 7, 2021 Author Report Share Posted September 7, 2021 It is funny that no one ever made a test of a 6-3-1 system compared to a 6-2-1 system. For example- Phoenix race performance system against Ractorations or Revingtons. You have thousand of TR5/TR6 in UK and no one had made a rolling road test to compare!! Quote Link to post Share on other sites
DRD Posted September 7, 2021 Report Share Posted September 7, 2021 1 hour ago, nylen said: It is funny that no one ever made a test of a 6-3-1 system compared to a 6-2-1 system. For example- Phoenix race performance system against Ractorations or Revingtons. You have thousand of TR5/TR6 in UK and no one had made a rolling road test to compare!! I think people have but there are always so many different variations its difficult to compare directly. You would need to do it on the same car on the same RR on the same day etc. etc. Quote Link to post Share on other sites
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