liam.mccaffrey
|
| posted on 4/5/05 at 01:34 PM |
|
|
Inlet conditions
what i want to know is the relationship between engine performance and certain inlet tract conditions for injection engines
i'll start with what i think i know, please correct me if i'm wrong
injector close to the port is good for torque, far from the port top power? Or is it the oother way round
1. what effect does the distance between the throttle butterfly or barrel from the head have, if any.
2. Are there any ads/disads for having n inlet manifold as oppossed to direct to head boddies.
3. what is the effect of having the injector before or after the throttle.
4. lastly inlet tract length, any views on this contentious topic.
many thanks
liam
Build Blog
Build Photo Album
|
|
|
|
|
NS Dev
|
| posted on 4/5/05 at 06:18 PM |
|
|
1) not a huge effect, but some delay in throttle response can be noticed if the butterfly is a very long way from the valves (due to the inertia of
the air in between)
2) Not really, but there might be! Depends on the manifold! On my VX 16v the slightly angled carb mnaifold with dcoe type jenvey bodies actually gave
slightly more torque low down than with straight shot bodies down the ports. (fully mapped each time) Supposedly a pulse reflection off the swan-neck
but who knows!?
3) Injector before the throttle would (assuming the throttle is some way from the valves) give a big fuel pickup lag, ok at high airspeed/full bore
but crap at low speed, not a good idea on their own (but more so if they are a second set of injectors supplmenting ones near the valves, where the
fuel doesn't have time to atomise properly and is just drawn in a big jet at very high airspeed/rpm)
4) Inlet tract length, to all intents and purposes, as long as they aren't too small a diameter, then as long as you can get them!!!
Scientifically, you can tune the inlet lengths to various rpm, but in the real world, the tuned rpm required is usually "ripping away from the
traffic lights" i.e. from a standing-ish start, and here you just want torque spread, so long as poss will work on anything used on the road,
and that is a fact, not theoretical billy bullcrap.
|
|
|
liam.mccaffrey
|
| posted on 4/5/05 at 09:32 PM |
|
|
cheers dev exactly what iwanted, thanks!
Build Blog
Build Photo Album
|
|
|
|
