I forgot to mention in my post, they make exhaust backpressure testers. You unscrew an oxygen sensor (or pressure port bung/flange) and screw in tool, then go road testing (dyno, or whatever). No oxygen sensors? No problem, get a few of these:
Make sure you get the screw in plug with them (as pictured, above), so they can be capped-off after testing. Place one after headers (or header collector) or somewhere before catalytic converter(s) – if using cats, that is, one after cat but before muffler, one after muffler but before any other restriction (tube downsizing), etc.
If there might be a possibility of using oxygen sensors in the future (fuel injection) then you might as well get the sensor flanges placed in a position as recommended by system manufacturer. Otherwise, get the flanges/bungs placed into easy to reach location(s).
The flanges/bungs and plugs are, for the most part, universal as far as the threads go. The design of how it attaches to exhaust does vary from manufacture to manufacture. A very good possibility your favorite exhaust shop may have his own to use.
There are several websites that talk about backpressure, like this one: http://www.tuneruniversity.com/blog...st-backpressure-for-smarter-exhaust-upgrades/ . the above website does a good job explaining things – but also gets into “buy this” and “buy that” so you can disregard that aspect of it.
Keep a log of the different pressures at different ports. Sense the needle does jump around some, I go by the highest-pressure mark. Might not be the best, but easier to figure out than trying to average the needle movement.
If you have enough hose, and hose(s) routed in a manor not to get melted or damaged, you can go on road test with a passenger to record your readings in real life conditions. Even better, have several pressure gauges to see all pressures at once.
I’ve used pressure sensors many a time, mainly to test catalytic converters for stoppage. Today’s cars (built sense ’96) automatically test the cats for efficiency (via engine computer), but the older cars don’t.
One (or more) cats on my ’86 Fifth Ave are (partially) stopped up – but I’m not quite to point to get them fixed, yet (got other plans in mind).
BudW
Make sure you get the screw in plug with them (as pictured, above), so they can be capped-off after testing. Place one after headers (or header collector) or somewhere before catalytic converter(s) – if using cats, that is, one after cat but before muffler, one after muffler but before any other restriction (tube downsizing), etc.
If there might be a possibility of using oxygen sensors in the future (fuel injection) then you might as well get the sensor flanges placed in a position as recommended by system manufacturer. Otherwise, get the flanges/bungs placed into easy to reach location(s).
The flanges/bungs and plugs are, for the most part, universal as far as the threads go. The design of how it attaches to exhaust does vary from manufacture to manufacture. A very good possibility your favorite exhaust shop may have his own to use.
There are several websites that talk about backpressure, like this one: http://www.tuneruniversity.com/blog...st-backpressure-for-smarter-exhaust-upgrades/ . the above website does a good job explaining things – but also gets into “buy this” and “buy that” so you can disregard that aspect of it.
Keep a log of the different pressures at different ports. Sense the needle does jump around some, I go by the highest-pressure mark. Might not be the best, but easier to figure out than trying to average the needle movement.
If you have enough hose, and hose(s) routed in a manor not to get melted or damaged, you can go on road test with a passenger to record your readings in real life conditions. Even better, have several pressure gauges to see all pressures at once.
I’ve used pressure sensors many a time, mainly to test catalytic converters for stoppage. Today’s cars (built sense ’96) automatically test the cats for efficiency (via engine computer), but the older cars don’t.
One (or more) cats on my ’86 Fifth Ave are (partially) stopped up – but I’m not quite to point to get them fixed, yet (got other plans in mind).
BudW