Secondaries: Vacuum or Mechanical?

[SeaSlut]

Thanx for the input, I guess it gets down to tuning.
We did some skiing under the full moon and the old girl has never ran better.
Maybe I should leave well enough alone. Nah!

[flat broke]

SeaSlut,
I'm not sure if your last post was to indicate that the boat ran better at night. If so, it sounds like you could probably tinker with the jetting during the day. Depending on the lake or river, air temps could vary as much as 40 degrees between High and Low temps. If this is the case and the boat ran better at night than during the day, I might try going 1, maybe 2 jet sizes leaner to see if the boat wakes up any during the day. Just a thought, and of course all based off of assuming that you meant that you were running better at night.
Thanks,
Chris

[Cas42]

SeaSlut,
Chris is right, try leaner jets. The night air is usually heavier/thicker than it is during the day. It sounds like your running a little too much gas during the day for the amount of air that's available. If you lean it out a tad, the air/fuel ratio will be much better for the thinner air.

[Heatseeker]

Cas. You seem to have this volumetric efficiency thing down on a normally aspirated engine. What about on a blown engine? When I bought my BDS 8-71(which STILL! sits on the bench http://free.***boat.net/ubb/frown.gif), I was told I would need a minimum of 1650 cfm(454bbc). Do you know the formula for figuring this out also? Also, has anybody had any experience with using VC carbs on top of a blower? I have a matched pair of Holley 850 VCs available to me. I was leaning toward a pair of Demons, as I hadn't had much luck with Holleys back in my hot rodding days. But if the VCs will do, I could spend my money on bottom end stuff(which would speed up the installation and get my wife off my back). Plus, I might get a bit more from a tank of gas http://free.***boat.net/ubb/rolleyes.gif.
[This message has been edited by Heatseeker (edited September 08, 2001).]

[jroos]

After you use the CFM formula, always add 100 cfm to your answer. You`ll be glad you did. Trust me!

[Cas42]

Heater,
I have very little experience with carburetion and blowers, none personally, just things I've heard from others. You might want to talk to KenA on the NorCal board, he's been blown for quite a few years with very little trouble.