well, well, well!
what a day!
to save writing it all again, here is a copy of the email i just sent Dave, technical director of Brunswick Motorsport whom i met on Saturday, and along with Rodger, gleaned much info from, including the dimensions he would love to see on a manifold.
Well, what a day!
An Early start, a long day, a reasonable finish, but boy was it worth it!
Thanks to all the info we gathered from your good self, Rodger, and his Ansa fast Road system, i think we’ve come to a really good Fast Road / Race system, pretty much suitable for any of the motors, and immediately adaptable for any specific requirements.
We managed to pretty much get your wish list of measurements into the build, so the manifold we’ve built to finish on my own 16v 33 is as follows.
Primaries in 1.5”, minimum length 650mm, longest 700mm, so a good balance, and its the shorter tubes we could stretch slightly to get more disc clearance on the inboard versions if necessary, so these could get even closer to equal.
Secondaries in 1.75”, pretty equal at around 345mm each.
Third final pipe in 2”, and on my own car i’ve continued in 2” pipe only, all the way to a single oval rear silencer, with 2” perforated baffle and glasspack, exit in 2.5” rolled back tip.
Obviously, the system size can be upped to 2.25” or even 2.5” for your fire breathing beasts if you want, but 2” as on my own should be good for 200bhp quite easily.
I’ve tested it with a DB meter, and whilst still in the mouth of the workshop, it tested at 90.9 db at 4000rpm, and took 5000rpm to get to the magic 95db, so gets well in for even keen scrutineering, and does sound lovely!
Still got that Alfa Rasp, but sounds a tad like Fiat twin cam or even a hint of Mexico thrown in, clearly the equal header length is working, the pulses sound so much more defined and clearly ring through the stainless tubes.
I’ve only drove it around 8 miles home, mostly in traffic, but on the occasion where i had some road, it got some WOT and feels notably better pulling above 3500, but i didn’t rev anything like high at all, as i have developed a rattle!
Sounds like water pump bearing to me, and i can feel some lateral play on the pulley, so until investigated further or cured i’m a little limited for testing.
Anyway, let me know your thoughts to the info, figures, and pictures, and if you have a water pump lying around! Ha ha!
To put that into comparison, the Ansa system measured up far from equal length, varying as much as 140mm difference between the shortest and the longest primary, so we're very much improved on that score.
We've also managed to get about 10mm better ground clearance over the Ansa, so although is always going to be a concern, it should now be more in the back of your mind rather than a permanent worry.
8V fitment should be easy, just rotate and adapt the smaller flanges from an 8V gasket, but a donor car would be good again just to double check, and Sud and Sprint gearbox users with in board disc arrangements are almost catered for with this build already. We managed to get some room where this would be neccessary already, and have a plan to get some more if needed, so again a donor car to perfect and check would be good.
But all in all, we're there, its built, and it looks, sounds, and feels very very good so far, no negatives, and no compromises needed.
what do you reckon chaps?