SWEET!! These intakes are outstanding. the long runner variations remind me a bit of the Lancia Thema 8.32 manifold with the long runners and dual tbodys. the 8.32 engine had a conventional firing order so it didnt have the top end power of the 308QV, but the long runner design was more conducive to mid range torque and the fwd, 3.0L Ferrari powered Thema accelerates just as fast as the smaller 308! last pic is an EFI conversion. Can the clear manifold covers be used in a forced induction application? Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Does anybody know (roughly) what the change in power output would be using EFI & and suitable ignition system on an otherwise standard 308QV/328? How would this compare with using throttle bodies?
A lot! I'm not sure that I'm free to post details as it's Nicks engine, I think the specifics are on his site though. 3.5L conversion via larger bore and substantial head work, cams etc.. I'm actually designing an intake specific for that build and will tease a bit later with some rendering pics.
They can support boost if I can get it molded in the right materials, one problem is cost ok that is THE problem with that one. I like the Lancia style intake and have a couple designs similar to that, problem is that the 2V head mounts are 45* vs the 15* off plane tilt of the 4v head. This makes the cross over that much more difficult.
On the 2V the EFI conversion and ignition will net 25~30Hp increase over stock. That is also maintaining the stock manifold. The 4V head flows better and will have a bit more gains with the EFI change over. A note on TB's, the stock TB is LARGE, and in reality bigger than it should be for the engine. I've wondered why until I did flow calcs on the stock manifold. The stock manifold is horrid! the flow is beyond bad, add in dynamics and it reverses flow in cyl 5 & 8 and few points in Rpm. It's also not balanced, the large dia bore of the TB helps to offset the issue, however it's a balance act as further increase slows velocity down to where it stalls the air flow for bank 1~4. The ideal and best arrangement would be two smaller TB's or individual AKA weber. what the 2V needs is velocity! the longer the runner before the valve the better, min 10" for the stock motors with cis cams and ~11" for carb cam motors. beyond that it's a case by case for ideal, being that's it's not economical to do that compromise is made for an avg.
Hi there, Great work, a terrific thread to follow and thanks for sharing it with us. I have EFI on an internally stock 328 motor in a 308GT4. I have had this set-up running for a few years now and have posted various pictures in previous threads, but here is one picture to show what it ended up looking like installed in the engine bay. I used the stock plenum and throttle body (with an extension). Engine management is Motec. Dyno-tuned, runs beautifully smoothly and is definitely strong, but I feel like there is more to get out of it. Later I may do cams and pistons, but for now, especially after reading your comments above, I wonder if I could get more out of it by modifying the plenum. Any thoughts? Cheers, Grahame Image Unavailable, Please Login
The stock plenum is not helping, the gap between the trumpet and lid is too short. The runner length is a compromise due to space restrictions. So in reality any modification of the plenum would end up being quite invasive which is why I ended up designing a completely new one.
