I am looking at fabricating myself a really good looking alloy intake system similar to the thumbnail picture. I have the fabrication skills and equipment but not the airflow etc knowledge. Basically, does the actual volume/size of the plenum on top matter, can it be too big? I am definately going to go twin throttle bodies and am thinking not of putting on 2 x 70mm as I would believe 2 smaller ones would be more effective as smaller means faster airflow, am i correct? It is only a pre ecotech V6 but want to get as much as I can out of her before I crack the engine open, just for my own curiosity. I have seen the Mace Engineering, Hogan, Walker ones but just want to have a crack at my own one.
plenum volume is important as is runner length/size. unfotunatly on a buick V6 there isn't much you can do about runner length unless you fabricate a complete custom manifold. i believe the MACE buick manifold is just the standard manifold with the top machined off and then there new plenum/ twin TB bolted on the side. greenfoam was working on something custom for the V6 for a while before he got into the 5ltr stuff. he might have some more definite figures for you to work with if he sees this thread
I will be building a pre eco V6 manifold on day just to practise welding on really . It's really got to be twin throttle/twin plenum to have maximum go fast on the V6 so it's a pretty big job. David Vizard talks alot about plenum size and the virtues of dual plenum manifolds on V6's (which is the best motor for such a manifold) in one of his books "Carburetors and Intake Manifolds" worth reading about 10 times before you build one just so you've got the theory down. Throttle body size isn't important so long as they are big enough it's fine, the only time you need over the top silly sized throttle bodys on a single plane manifold is so you can sell stuff to kids that don't know any better. All the power comes from the runner length and the helmholtz resonance Helmholtz resonance - Wikipedia, the free encyclopedia in the plenum and plenum neck all of this is explained in the book
Thanks mate, great help. I have read some of David Vizards material for two of my past projects (a MkII Escort 2 Dr Turbo, 11sec 1/4 and a Cooper S mini circuit racer). He is a very smart man with REAL ideas and great reading material. I am pretty new to the efi/electrics side of things so this is good, cheers Kev
I can remember aloong time ago the fastest street car in Australia was a 2 litre Escort with a turbo, no, twin turbo i think! and it used to run deeep 9's. Awesome, D. Vizard is allways raving on about pintos in all his books too obsessed
Mine was a 2 Litre OHC (I think a TRUE Pinto is a 2.1, an English motor, dont quote me on that though) Garrett TO-3 and a LOT of engine work. Loved that car...Can I say that on a Commodore Forum lol? The reason I researched Vizard is because of his aka 'Pinto' experience. I am an ex Kiwi so cars in NZ are a little different. I will post a thread next week with all my old rides in it, some ppl might be interested, they include the following: *MK II Ford Escort - as mentioned *Ford Escort MKI - 13.4 sec 1/4 *Mazda 323 Turbo 4WD Familia - 14 sec 1/4 *Mini S Cooper - built for circuit - ran a 14 sec 1/4. *Hillman Hunter - 1725cc - for circuit - ran 13.6 sec 1/4 *Mazda 323 Wagon 1980, ex 4 cyl, 13B p port swap - 12.2 sec 1/4 The list goes on but they were my favs. I'll post pics and stats next week
ahhh, David Vizard "the Wizard" well worth reading his carby/intake book. i have it and consider it worth every cent. a old workmate used his books on mini's to build race winning cars here in the mini series (another mini nut) he now races in the open GT series i think and generally beats a lot of big HP 6 and 8 cylinder cars
