Tractorsport Flowbench Forum Archive

Posted: **Wed Apr 05, 2006 2:37 pm**

Hey all,

I have been gathering up bits and pieces for some time and am finally putting some of it together. I bought a couple of commercial type cabinets for $17.50 ea already laminated, with the intention of using one for a motor box and the other for the plenum. Since my interest are in 2 stroke and some flathead developement, my airflow requirements are somewhat low at this stage. Therefore I decided to incorporate most of the elements into one cabinet, with the ability to alter it at a later date if needed. It is based on a Meriam (filtered) LFE calibrated @ 100cfm @ 8". Basically I built a 10" x 10" x 28" plenum around the LFE, out of 1" plywood, salvaged from a dumpster of a local plant. I opened the bottom of the cabinet and inserted and epoxied and screwed the plenum in place with West System Epoxy. Please feel obliged to chime in with "what I would do's".....trader

Posted: **Wed Apr 05, 2006 2:58 pm**

What a goof... Bruce could you pls delete that pic as the "edit" would not let me...lets try again...

Posted: **Wed Apr 05, 2006 3:01 pm**

How LFE mounts in the box

Posted: **Wed Apr 05, 2006 3:04 pm**

How the plenum box loads into the cabinet...

Posted: **Wed Apr 05, 2006 3:07 pm**

Inside the cabinet, view thru back door...

Posted: **Wed Apr 05, 2006 3:11 pm**

Here the bottom hole is closed up and the stand pipe is placed in the LFE adaptor. The additional side pieces are epoxied in place for the vacuum chamber floor...

Posted: **Wed Apr 05, 2006 3:16 pm**

This is a view another view of the vacuum chamber and stand pipe. The stand pipe has 22 holes 1/2", and it buts against the vacuum chamber floor...

Posted: **Wed Apr 05, 2006 3:19 pm**

Close up of chamber. Everything is glued and sealed with West System Epoxy...

Posted: **Wed Apr 05, 2006 3:24 pm**

The chamber floor is laid in a bed of liquid nail and screwed and finished with epoxy,and all seams filled...

Posted: **Wed Apr 05, 2006 3:34 pm**

Here I have the 4 1/2" id closet flange in place. I will make an adaptor from the 1" X 8" X 8" to cover the PVC flange, and bore it to 4.500. It will have a top counter bore to 5" X .750" so that I can adapt different I.D. cylinder's, or whatever, to the head fixture...trader

Posted: **Wed Apr 05, 2006 5:14 pm**

Cool Bench!....The first LFE unit I've seen here. A couple of questions.

1. Why LFE over Pitot or Orifice?
2. How much was that LFE?
3. Is it bi-directional?

4. Anything else you care to share..feel free

Posted: **Wed Apr 05, 2006 9:35 pm**

I have built a couple of the Laminar benches.

One was about 600 cfm flow and one was 1000 cfm flow.

The weather corrections are VERY IMPORTANT.

You also need to pay very close attention to not getting any contamination in the stone filters at the laminar taps. I had a guy screw that deal up too. They are not cheap, by the way.

He had Merrium make him a scale that read in cfm from zero to full scale (40" manometer).

Most orifice benches are calibrated with a Laminar
bench or with a plate calibrated by the bench.

Extremely easy to get trash in the laminar element if proper filtering is not followed. A guy I knew found a dead mouse on the inlet side of his bench.
He was reading high, as the mouse was blocking some of the tubes and raising the delta P for the readings. He never bothered to retract his readings for the magazine articles though. LOL!

Good luck and nice work.

Tom V.

Posted: **Wed Apr 05, 2006 10:34 pm**

Thanks Larry,

I bought the LFE several years ago as a surplus item from the National Defense Department of Canada. It was listed as a Calibrator Set, Radiac, Air Sampler. Classified as restricted. ha Anyway cost out of pocket for the LFE as packaged including UPS freight to Texas was a wopping $83.00. Had a fresh calibration from Meriam. At the time I was doing some R&D on Rochester 2bbl carbs and boosters for circle track customers. I made a crude flow box and used a shop vac to power it. I have since retired, and play around with 2 stroke outboard motors. Most are in the range of 10 cu in per cylinder, so not much cfm needed. A good friend gave me a Ametek 114787, and I use a variac to control the speed. I also still like playing around with my old Ford flatheads. Another motor light on cfm. I will use the variac controlled 114787 as the main motor on this new bench, and probably another in case I need more flow. With a 2" vacuum hose to the LFE and the other end hand held against the bottom of the 114787 (crude) gave me a differential of 8.5" on the U tube, about 106cfm. Hooked to my 6.5 hp shop vac and I could only pull 4" differential and 52 cfm. This was using the calibration sheet from Meriam, but no correction factors. I did not have an absolute inlet pressure manometer in line, so I don't know about working pressure. I have a 6.4" Meriam incline, so will probably work at a lower pressure and do the math.

Would be interesting to use the LFE in conjunction with an X.000 orifice and use the LFE for the 0 - 100 cfm range. Only with electronics.........

I recently bought a new Dwyer DS 300-3 off e-bay for $16.00 and I am going to set it up in a tube and check against the LFE bench, when it is up and running. I will eventually use the pitot in another bench later.

I decided on the LFE at the time because of price and ease of use, and it worked in the cfm range I needed. I have learned so much from everyone here, that I wouldn't be afraid to build either style, but would lean toward a pitot.

It is not bi-directional. neither am I ha ha...trader

Posted: **Wed Apr 05, 2006 11:06 pm**

Tom,

We have cockroaches here that have run off all the rodents. ha I am building this unit to be insect free. The main concern here is dirt daubbers and mason bees. Since I will also house the vac motors in the cabinet, I will have to screen and mesh the back door for ventilation. Thanks for the advice...trader

Posted: **Thu Apr 06, 2006 9:23 am**

Trader

The price is certainly right for the LFE. The bench should suit your purposes well.

If you're into 2 stroke engines, get yourself a copy of Gordon Jennings "2 Stroke Tuners Handbook". I've seen the formulas duplicated in various software packages available on the Internet. The book is rather old now but the information is still quite valid. I've applied the formulas to small cc 2 cycle Yamaha engines and obtained very good results.

Years back there was a racing class for 50cc Yamaha PW. A guy approached me to build one for his boy. I used the formulas in the book to calculate port area / time area and RPM calculations. According to my digital hand held tach, I reached the high rpm I was after. According to the kids trophys, the engine made the power I was after. I got very into that project. It was such a cometetive class that every week you had to be searching for a way to squeeze a little more out of the bike. After a point, it became an exercise in finding creative ways to reduce rolling friction as much as it was finding ways to increase HP. Then it took on the atmosphere of parents at little league games and the fun went out of it.....

Tractorsport Flowbench Forum Archive

LFE Bench