Northstar Engines and System Technical Discussion Discussion, Anyone want to compare MAF readings? in Cadillac Engine Technical Discussion; Looking at the OBD2 reader I've got hooked up, shows a peak airflow of 236 g/s air from the MAF, ...
Looking at the OBD2 reader I've got hooked up, shows a peak airflow of 236 g/s air from the MAF, working out to about ~80.4% volumetric efficiency at peak RPM (6300). Anyone? Induction system in good shape, reasonable shape, or needs a cleaning? (I've no issues or complaints, I'm just curious...)
The standard automotive airflow calculation uses a VE of 80% - most wonderful for a stock engine.
I'm not going to post it all - Google "automobile engine airflow calculations" and do the math yourself.
3 years ago I screwed around with a mechanically modified MAF - JET Performance - and got exactly nothing worthwhile. This was done over two 821 mile round trips from MD to FL and I actually lost a half mpg, set mixture codes, and introduced a low speed/off idle stumble.
So..........In answer to your opine, your engine and intake system is just fine..............but go ahead and work out the formulae - you'll convince yourself that the MAF/throttlebody modification idea is pretty useless on these engines: they already have a cold air intake tract and panel filter which flows more air than a 279 c.i. engine can handle as-is.
Huh? I'm not interested in modifying it, but it could perhaps be an early indicator of exhaust cam wear for the pre-2000 engines. The only way to get more suck (without a blower) is to get a tuned (variable length) intake along with finding space for a bigger crossover pipe (there is no space), and that's not happening
get more suck (without a blower) is to get a tuned (variable length) intake
Your engine already has a tuned intake manifold with 8 variable sized individual intake runners coming off the distribution log. Everything before the center lower distribution log is designed for maximum cold air flow.
.........not saying you're looking at modifications - just that a few of us have been there, and there isn't a gain to be had from fooling with the intake. You would have to have some pretty severe intake manifold sludge buildup before there would be ANY performance losses there - but a clean air filter and throttlebody is of prime importance.