design issues

[K-Star Automotive]

I am having some problems with my bench and wanted to get some thoughts on it.

The bench it self it a mercdog design. I had the cabinet built and changed my mind and went with a audie set up. So there is no orfice plates in it.

I calibrated it with Bruces plates, the 150 plate went 148 and the 300 plate went 297. I also ran those plates across AFD's bench and his across mine. Everything was with in 2 or 3 cfm.

Now, here is the issue. I had a head that went 285 @.500 on AFD'S bench. On my bench it only went 261 @ .500.

ON my bench it makes a real funny sound, kind of hard to explane. half way beteeen a wistle and a horn, if that makes any sense.

My chamber right below the top plate is only 4" down. Could that some how be making the air turn to hard??? For lack of a better way to put it.

If i slide the calibration plate towards the rear of the bench it makes a sound that will almost put you on your knees. If i pull it foward the sound really settles down, but it's still not real smooth.

I am about to tear it all apart( i am thinking this is going to really suck) and raise the top plate like 6", giving me 10" to the divider plate, but if thats not enough then i need to re-think/engineer the bench.

Not sure if pictures would help?? but i can get some if needed.

Keith

[coulterracn]

Kieth

If you have pictures it will help the Gurus here in advising you what changes to make.

I'm thinking the bench you have is similar to the MSD which was built to replicate a superflow bench. From past experience the bench may need an upper plenum built on top of the existing bench top. This may help with some of the turbulance your experiencing.

I'm sure someone here has seen this before or has better advice to offer.

Ray

[bruce]

Keith,

My thoughts . . . build a PTS bench, sell the Audie parts. You've seen my bench in-person and you know what it can do. I'm 30 minutes away if you need any support.

Go with a PTS DM since you and I have already discussed this and you would like the 3rd sensor, this will also cure the velocity problems you are having with your water gauge.

Just my opinion . . . but then again, I'm biased

PS I might even be interested in building the cabinet?



Edited By bruce on 1246105482

[larrycavan]

Your MSD bench could have been made to work very well with a couple of easy mods. It probably still could.

If you post some pics of the bench so I can see what you've done to it, I could probably help you.

Sell the Audie setup and buy a PTS or FP1. Both work great. I have used them both on my modified MSD bench and get repeatable, accurate numbers every day...

Larry C

[K-Star Automotive]

I don't think i am ready to push it off a cliff yet.


I'll get some pictures soon as i figure out how to post them.

Keith

[K-Star Automotive]

Ok this is the back side of the bench

[K-Star Automotive]

This is the front side

[K-Star Automotive]

This is looking in the bore, Notice the plenum is only about 4" down

[K-Star Automotive]

This is a side shot just to show the 2 divider loactions. The top of the top piece of tape is the 1st one down. The top of the bottom tape is the second one down.

[49-1183904562]

[larrycavan]

That cabinet looks perfectly fixable to me.

I would add a top plenum, a baffle, install a port hole door and use removable orifice plates with the cabinet you have now.

I also know someone in your neck of the woods who could do the mods.....You do too The question is will he do it? You might have to take the bench to his place to get it done....

[K-Star Automotive]

Larry, can you explane what all those mods will do??

This is my first bench. I don't have all the knowledge about what makes a bench work/or not work

I am having a hard time with the fact that it will calibrate fine. The thing sat for almost a month and when i check it again the numbers with the orfice on it were dead nuts. If the calibration numbers were all over the place then i could see a need for a mass change, but since it calibrates fine i am not so sure.

[larrycavan]

[K-Star Automotive]

I see i left out some crucial information. Sorry

My bench has no orfice plates in it. I use a motor control to speed the motors to get my 28". It's all digital , no manometers. The one in the picture is used just for air speed.

The head was flowed on a bench that has the exact same stepped bore adapter as mine.

I calibrated it with the head adapter on it. I guess in my way of thinking you would want the bench calibrated in the "AS USED" condition. But i can say that before i had the head adapter built my bench was running and i checked it with the calibration plates ( they are all bruces)that way also and it has the same numbers as when the adapter is bolted on.

Last night i flipped the head and got the intake valve as close to the front of the bench as i could. The sound it makes changed, alot, and the flow numbers went up.

I am convinced that it's a seperation/shear issue. I just can't think of anything else that would cause that sound. I know on the SSR of a head if you get it under a 15 deg turn you start having issues. I am thinking that the enter/exit port on the back of the bench is less then 15 degrees below the bore in the top plate.

Last night when i was messing with it i stuck the velocity probe down in the center of the 300 calibration plate. I was holding onto it by just the end, when i got it about 3" down it strated spinning circles...

Back when i just got the bench running i used another set of calibration plates(50,150,300 cfm,all bruces) from the bench i flow the head on first. They matched my numbers, and his bench. I can't get my mind around that we could both be so close and it's a electronics /data collection issue.

Keith

[larrycavan]

Keith,


If your bench has no orifice, then it's a pitot bench. I have no experience with calibrating one of that type. I thought that Audie setup used an orifice inside a pipe.