Ok poeple Im tired of peopel saying you dont need any back pressure what so ever, thats LIE you need some to get the enige to run, too much is bad yes not enoupgh also bad, think of it in terms fo riding a bike,, Back pressure is the amount of pressure the pedeals give you to turn the chain and make the wheels turn,, if you had no back pressure you would just sit there spinnign the pedeals and the tires woudl nvee get movin,, if you had to much id be like pedealing but theres so much resistence that you cant even move the pedeal. I knwo everyone knows about trucks and engines ans what not, but backpressure is common sense we should all know about back pressure

 

Thus endeth the sermon.


Naw just kidding man thanks for educating us!

 

How do you explain AA fuelers with the short upswept pipes? Would seem to be no restriction there right?!

 

As for that, the tube diameter is small enough for the amount of air they produce that it provides sufficient backpressure. Remember, those are stroked, bored, supercharged, run on methenol, every trick you can think of. They produce way, way more air than any mortal engine could ever hope to.

 

Backpressure never helps power. What helps is proper exhaust tuning to help scavenge the cylinder. Higher back pressure hinders cylinder scavenging, but a system with higher overall back pressure may have low pressure later in the exhaust stroke because of proper exhaust tuning and thus perform better than an open header. Properly adjusted (which potentially could include cam revisions) an engine should be able to run without even an exhaust manifold--just holes in the block--, but that is undesireable for other obvious reasons. When it really needs the back pressure, during the power stroke, it has 100% back pressure because the exhaust valve is closed.

INLINE SIX POWER!
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!

 

many people think they need backpressure because they instal a new free flowing exhaust system, but they use too big of a pipe, this causes them to loose low end power, with the correct sized pipe, they will make more power all around , for example, a stock 84 f-150 with a 302 with dual 3 inch pipes and no mufflers would loose alot of power below 3000 rpm over a stock muffler with single 2 1/4 inch pipe, now the same motor with 2 inch duals and stright pipes would make more power all around than either one of those setups, add mufflers (more backpressure) to that setup and you will loose power

 

Where are you guys getting all your information? Back pressuers on any
device that has driven components down stream have are engineered to
the volume applied times inside diamater squared. Anything installed after the turbo will have an affect on gas flow. If you restict the
gas flow say, reduce pipe size from 4" to 3.5", you will loose performance. You already have a restricting devise in the systeme so
why add more? So, the more your turbo can get the burn't gases out, the faster the turbo will recover the intake charge. If you want thrust then restrict the exhaust side of the turbo. I don't see that happening. Use some logic, There is inherited restiction on any turbo charged engine. If you don't want to restrictions, take your turbo off and throw on a blower. The only restictions there are air filter, and the blower empellers. What are you going to do?

 

"The Scientific Design of Exhaust and Intake Systems"
by Philip Smith, John Morrison