...found and interesting thread on another forum..

DIY Digital Compression Tester

http://www.illstreet.com/forums/show...9552#post39552

sometimes the server is really slow...

 

I've thought about this many times before...

Making a DIY compression gauge would be pretty danged simple. All it takes is a sensor, a fitting/adapter, a DAQ card, and a laptop. I already have a DAQ card and laptop (pretty nice and flexible USB DAQ cards could be had for ~$100). Digikey has adequate sensors for pretty cheap (much less than the $103 one this guy was looking at). A little time at the lathe would give me a plug-to-sensor adapter. Voila!

Hasta,
Shad

 

very c0ol

eric e

 

Kick ***! I'm all up in that!!! I've been wanting a Mazda compression tester for a while, and this is much cheaper .

Thanks!
Dale

 

Where do you get the software??????

 

I believe the data acquisition unit comes with the software. Could be mistaken.

BTW, the pressure transducer is an Ametek P207. It's in stock at various other places, but for $190 or more. Ack! I might have to see if our local Grainger stocks that part.

Dale

 

i currently run something similar to a digital compression tester and there may be some crossover....

i log exhaust manifold pressure EMP (backpressure). that'd be between the engine and the turbine.

i use a Honeywell Pressure Sensor Monolithic Signal Conditioned. 4000PC Series

catalog number 4040PC150G4D w Packard connector or G5D w leadwires.

i bought and use 2 of them (fuel pressure logger) on Ebay for $40 total.

as to logging/recording pressures digitally.............

they key is to have lots of samples per second as the compression is dynamically always changing and your sample only reads for a very small time period. i see this as i review my EMP readings.

granted the engine will be cranking at only approx 250 rpm which helps a bit.

the sensor runs off 5 volts so you can get a feed from, your MAP sensor if you wish.

probably an easy thing to make.

howard coleman

 

I recently built one and it works well.



I got the inspiration from Fdjunkie’s thread;

https://www.rx7club.com/showthread.p...1&page=1&pp=15

The wave pattern shows a small “wiggle” at the valley, is this from the ports opening and closing or from the shape of the chamber?

 

https://www.rx7club.com/forum/showth...44#post4748244

Here is a Pressure Transducer for Sale to build your own tester under 100 dollars

 

oh man I gotta build one too