Rick Engman's Exhaust Port Shape - Thoughts
02-22-2005, 06:35 PM
#23
Senior Member
Join Date: Apr 2004
Location: Highways of the Midwest
Posts: 896
Only thing id like to know about Yaw s website is what is the error on that flowbench, it could easiely been as high as 10% error, in which case a 12cfm change could just be their imagination.
*this comeing from someone who has no experience with flow benchs just some backround in technical lab type operations.
*this comeing from someone who has no experience with flow benchs just some backround in technical lab type operations.
02-22-2005, 10:46 PM
#24
Senior Member
Join Date: Nov 2002
Location: Honolulu, Hawaii USA
Posts: 925
Originally Posted by z8cw' date='Feb 22 2005, 06:50 AM
The only contrary experience is from owners with a T51r kai kit. The manifold is vband and the turbine housing is undivided and people love this turbo. It seems to spool up fairly fast for its size. You could possibly explain it that with this set-up the shape from exhaust port to turbine blade doesn't change. The pipes stay round all the way through. As for our typical application we go from round exhaust port exit to the square flanges and back to the round turbine housing. Maybe the consistent shape makes up for the larger diameter in the turbine.
It only comes in collected, and you're limited to their 1.00 turbine A/R.
It also helps that HKS makes a FD3S (and FC3S) kit for this particular turbo...if you can afford it.
Even with the collected 1.00 turbine A/R, this isn't overly large in terms of application to a 13B; the "lag" is due to the sheer size of the compressor wheel.
-Ted
02-23-2005, 12:18 AM
#25
Fabricator
Join Date: Jan 2004
Location: Central Ohio (Hebron) Zephyrhills Fla.
Posts: 1,322
Originally Posted by psyclo' date='Feb 22 2005, 04:35 PM
Only thing id like to know about Yaw s website is what is the error on that flowbench, it could easiely been as high as 10% error, in which case a 12cfm change could just be their imagination.
*this comeing from someone who has no experience with flow benchs just some backround in technical lab type operations.
*this comeing from someone who has no experience with flow benchs just some backround in technical lab type operations.
A bench with even a 1% error in repeatability would be next to useless. You would never know what you had done.
You can have a test piece for the size range that you are testing for, and run that test piece before and after each test to maintain your baseline.
The testing should be done with conditioned air. SAE tables are used to correct conditions to sea level after each test. It is fun at first, then after a long time it becomes a job, and is not so entertaining. You will learn more on a flow bench before 9:00AM than you will doing anything else the rest of the day.
Lynn E. Hanover
02-23-2005, 06:36 AM
#26
Senior Member
Join Date: Jun 2004
Location: Germany
Posts: 240
Originally Posted by l8t apex' date='Feb 22 2005, 05:28 AM
so wide it looks like there is little apex seal support. I did that on my 1st porting job and they cracked .
i think that's why some builders port the exhaust ports like the scoot one. before the seal finally arrives at the closing line, it gets pushed back smootly by the sides of the port.
02-23-2005, 09:18 AM
#27
Senior Member
Join Date: Oct 2003
Posts: 352
Originally Posted by Old Splatterhand' date='Feb 23 2005, 04:36 AM
i think that's why some builders port the exhaust ports like the scoot one. before the seal finally arrives at the closing line, it gets pushed back smootly by the sides of the port.
In The Book that's what Engman says about they're p-port intake port. The closing line is rounded to gently close the port and make it easier on the seal. For a high mileage 24hr motor he'd leave the port roof pretty much stock. For a shorter mileage sprint motor he'd square it up a bit but still leave a curve. Might be the same theory used by some on their exhaust ports? But evidently Rick doesn't feel it's neccesary.
02-23-2005, 10:34 AM
#30
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Join Date: Oct 2003
Posts: 352
Originally Posted by Old Splatterhand' date='Feb 23 2005, 08:04 AM
How To Modify Your Mazda RX-7 by Dave Emanuel and Jim Downing. Out of print. I picked up a used copy for $85. Lot's of good info but most of it is dated (1987) and common knowledge on the boards now.