Orifice calculation

Radius=D/2 r=0.055/2 r=0.0275 V= h × V=0.3 × π× 0.02752 V=7.13×10-4m3 Calculations above show the volume of the pipe which represents the volume flow of gas before encountering the orifices. Radius=D/2 r=0.021/2 r=0.0105 V= h × V=0.006× 0.01052 V=2.078m3 Calculations above show the volume of the pipe which represents the volume flow of gas after encountering the orifices.

Pressure gauge and Straight 4 inch diameter pipe

A back pressure gauge can be connected to the exhaust system one of several ways. By removing the oxygen sensor and connecting the gauge to the hole in the exhaust manifold by removing the air check valve in the air pump or plus air system, However on this design it is install on the pipe by drilling a hole just ahead of the butterfly to attach the gauge. On the rear end of the straight pipe, a (orifice) 2.1 cm or 0.021mmwasher is weld inside the diameter of the exhaust pipe in addition with two tiny 3mm tubes. The pressure one is measured by the tube that is fitted just ahead of the washer or orifice while pressure two is measured by the second tube which is located just after the air flow is restricted by the orifice.

make manometer

we pick up a piece of board from unitec and bought 4 meters 3mm tubes from miter10, then we made the manometer in the garage, it quite easy to make it, and also i bought a ruler to measure the reading

air flow

gerry give us some idea today, he said we need test the air flow in the pipe, but the problem is the air flow meter can not test the exhaust air flow, because of the hot temperature, it will melt the meter, we can made a manometer instead of the air flow meter,but the first thing we have to do is install a ring in the pipe, and weld another two small tubes on each side of the ring.

install the pressure gauge and welding the gasket&adapter

today we still working in the workshop, we weld the gasket to the pipes and join to the adapter, also we weld the tubes on the pipe to connect the pressure gauge. as you can see in the photo, i bought the gauge from rosebank road, it really different to find the gauge, at first we went to repco, but they do not have the gauge, then we went to the BOC gas, they have the different gauge that we can not used, after that i went the rosebank road there is shop called "black..." ,i bought a pair cost 76 dollars. i am so happy i can find the gauge.

keep going in the workshop

today we still keep going our project, we extended the pipe, and i use the exhaust high temperature silicone seal the gasket we made~

new semester coming

after the summer holiday we come back to UNITEC, times goes very fast,we will do the modification today. The modification was done by removing the auxiliary valve, 4 screws, all air valves, brackets, gasket and O-ring. A steel sheet plate has being used with a silicone paste to seal the hole as we only need a throttle lever, butterfly and TPS sensor. The butterfly is located between a 1meter long exhaust pipe and it is control by cable which restricted the flow of gas (air) when the driver releases the accelerator paddle.