Does anybody use this Offy manifold?

[Argess]

Yes, I sort of think it's more the cam, but it can't be denied the intake isn't the best design, so it's a hard one to argue.

When I selected the cam, I spoke with Crane's technical support and the cam I wanted was the last cam up that would give me a decent idle. Crane did a computer profile of my engine and got 480 peak Hp. Next cam up would have been 540 HP. Personaly, I don't believe either figure as the software probably assumes perfect fuel delivery and perfect igntion timing. I figure I'd be lucky to get in the 425 hp range.

Now, looking at manifold comparison tests I've seen over the years, people get real excited when a manifold shows a 10-15 hp increase. Well, on a 400+ hp engine, this isn't a significant change for street driving, but it is for 1/4 mile times. And I've never really noticed much HP/torque difference in the low rpm range on any of these manifold comparison tests.

On ignition timing, I am working on that. Currently at 20 deg intial and 38 degrees max. At 28 intial, I have a problem, but I may be able to squeak 24 or 26 out of it. The 38 max will probably remain at 38 as the higher rpm range is fine. If this darned manifold would let me install a larger dist, I'd go for a vacuum advance unit. That could make a huge difference seeing how these cars demand part throttle (and hence part vacuum) in low gears to maintain control. Right now, I don't want to spend the money on another small dist with vacuum advance only to subsequently change manifolds and then go to a large diameter dist. Not that I'm cheap, but there's no reason to waste money either.

Sidenote: Building the car was fun. Driving it is OK, but tinkering is the most fun. If I ever get this car perfect, I probably won't drive it much. But that probably won't ever happen....in my mind, a kit car is "always a work in progress"

2nd sidenote: Public roads are horrible for doing test runs. Too much traffic around.......