Thread: Why no boost unless under load??
02-18-2010, 02:57 PM #1
Why no boost unless under load??
I was wondering if someone could explain why the boost guage doesn't show boost when the ski is reved up on the trailer.
02-18-2010, 05:35 PM #2
What kind of gauge are you running??Mechanical or electric???Does it show boost when riding??Your motor doesnt produce boost until around 6000 RPM..Until then your motor is under vacumn..
02-18-2010, 06:04 PM #3
if you watch the manifold when you rev it ...you can see it expand and contract ...your guage just may not read that fast...it amazes me they dont pop ...well more often ...they do at like 18 20 psi
02-20-2010, 06:06 AM #4
The gage may be damped so it doesn't bounce and/or it may read after the butterfy valve in the throttle body-inlet chamber just before the valves. Those are the only reasons I can see if I were a guessing man.
02-20-2010, 12:12 PM #5
you only have to crack the throttle body for the engine to reach high rev's while out of the water in no load.
Load on the engine would require more air and fuel to get the engine to the same point in the rpm range. The engine is having to do more work to get to the same point due to the load. The more work requires more air and fuel, timing, and more throttle position and more boost.
02-21-2010, 06:21 PM #6
- Join Date
- Aug 2006
- Gonzales, La
dav has got it.
"Load", "throttle angle", and "manifold pressure" are almost interchangeable words with NA and supercharged engines. If you're not holding the throttle close to the grip, it's not going to make boost in the plenum. Turbo is a different story...
02-21-2010, 07:06 PM #7
02-21-2010, 10:07 PM #8
02-22-2010, 02:43 PM #9
- Join Date
- Jan 2006
- Rydal, Georgia U S A
I've got a picture in my mind of a ski on the trailer being rev'ed to the moon.................... with no booost as it goes CLANK......clatter, clatter and goes dead.
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