SoCal Jet Boats

Tech Talk => Jet Pumps => Topic started by: RTriebess on May 04, 2009, 10:25:48 PM

Title: tap location for suction housing psi
Post by: RTriebess on May 04, 2009, 10:25:48 PM

were do you tap at what psi should I see.

Title: Re: tap location for suction housing psi
Post by: IRRebel on May 04, 2009, 11:33:13 PM

Ummmm, Huh? maybe it's the beer, but why would you want to know a reading from there? 7 People read this and passed so I'll ask it.


Ray

Update: I guess I should clarify. You should read possibly flow there? or maybe vacuum? Not gonna get PSI from the suction side of the pump.

Title: Re: tap location for suction housing psi
Post by: GT Jets on May 04, 2009, 11:39:08 PM

Quote from: RTriebess on May 04, 2009, 10:25:48 PM

were do you tap at what psi should I see.

I have always heard half way up on the side of the pump, it ends up at the logo in most cases........As far as pressure, depends on the setup, speed, type of bottom, loader or no, yada yada yada...I've seen anything frome 10# to 40#...

GT

Title: Re: tap location for suction housing psi
Post by: propless on May 05, 2009, 01:28:08 AM

 This is a good topic.  I would like to tap my suction housing too.  I would think it would be better to tap it in 2 places (one high and one low) so you can try to balance the load on the impeller.   Anybody know the best places to do this ?

Title: Re: tap location for suction housing psi
Post by: SLCKREG on May 05, 2009, 02:20:20 AM

Quote from: propless on May 05, 2009, 01:28:08 AM

This is a good topic.  I would like to tap my suction housing too.  I would think it would be better to tap it in 2 places (one high and one low) so you can try to balance the load on the impeller.   Anybody know the best places to do this ?

This is pretty much the answer I got, mine are right behind the wear ring, at like 1:00 and 5:00, or as close as I could get to the top and bottom as I could get,(with the ride plate and clean out in the way. I've asked the "how much pressure Q? alot, and I'm always told different hulls respond/like different things. I've yet to see over 10psi on either tap, but I think that's the exception not the norm. Like proppy said, I've also been told it's to try to balance the shoe and the loader(top and bottom). I'd be curious to hear others suction housing #'s. I just trimmed my loader back we'll see if that makes both or either of mine go up.

Title: Re: tap location for suction housing psi
Post by: btnhtillidie on May 10, 2009, 05:36:37 PM

I have always wondered if I can Tap my "WJ" with a hose bib and hook the garden hose up to it and pump in water when running on the trailer. Of course it couldn't be the exact amount of water yo would get on the lake but i think it would help keep the WR lubed. Now this is all in theory.  ;D 

Title: Re: tap location for suction housing psi
Post by: Brad @ SCJB on May 10, 2009, 05:52:07 PM

how about tapping the suction housing AND the bowl....get readings from both ends.

Title: Re: tap location for suction housing psi
Post by: maddogg20 on May 10, 2009, 06:24:17 PM

what my friend and i figured out when we would run his boat on the trailer was to hook 1 garden hose to the engine and disconnect the water feed line from the jet and hook another garden hose to that too so we would have water going thru the jet and engine, seemed to work fine.

Title: Re: tap location for suction housing psi
Post by: Mr Plow on May 10, 2009, 07:08:03 PM

 :screwy: Are we talking about pressure readings or running a pump out of the water???? :screwy:

Title: Re: tap location for suction housing psi
Post by: beerjet on May 10, 2009, 08:18:41 PM

This should be kept on topic  :mad:
So I've heard 1:00 and 5:00 also.

From what I've gathered, it's to get a pressure reading in the suction housing high and low.
Lots of data needs to be gathered to make sure the pump is loading properly or not overloading.
I'm probably wAAAAAAAAAAAyyyyy off on this but I do know that the drag guys have been doing this for a very long time.
With great results.
Like I said though , it's not just suction housing pressure readings.
You should log RPM, MPH, to go along with all this other data your collecting.

-beerjet-

Title: Re: tap location for suction housing psi
Post by: propless on May 10, 2009, 08:33:25 PM

 OK, looks like the 1:00 and 5:00 placement is the place to be, so how far ahead of the impeller ?   I was thinking ( ::)), if there to close to the impeller it might give strange readings  ??? . 

Title: Re: tap location for suction housing psi
Post by: SLCKREG on May 10, 2009, 08:48:51 PM

Quote from: propless on May 10, 2009, 08:33:25 PM

OK, looks like the 1:00 and 5:00 placement is the place to be, so how far ahead of the impeller ?   I was thinking ( ::)), if there to close to the impeller it might give strange readings  ??? . 

You mean behind the impeller? They are suction housing/intake readings. Not that some peeps don't take bowl pres. readings too.

Title: Re: tap location for suction housing psi
Post by: propless on May 11, 2009, 09:06:20 AM

Quote from: SLCKREG on May 10, 2009, 08:48:51 PM

You mean behind the impeller? They are suction housing/intake readings. Not that some peeps don't take bowl pres. readings too.

 No I meant in front of / ahead of the impeller, in the suction housing. I was thinking if it was to close to the impeller it might get some kind of weird readings (pulsing or swirling) as the impeller turned.

Title: Re: tap location for suction housing psi
Post by: SLCKREG on May 11, 2009, 09:32:23 AM

Quote from: propless on May 11, 2009, 09:06:20 AM

No I meant in front of / ahead of the impeller, in the suction housing. I was thinking if it was to close to the impeller it might get some kind of weird readings (pulsing or swirling) as the impeller turned.

Maybe I'm confused, I was told to tap locations just before the wear ring. Wouldn't that be behind the impeller? Or maybe more even/level with the impeller? I've never taken a jet apart before, I'm just asking.

Title: Re: tap location for suction housing psi
Post by: beerjet on May 11, 2009, 09:52:50 AM

Quote from: SLCKREG on May 11, 2009, 09:32:23 AM

Maybe I'm confused, I was told to tap locations just before the wear ring. Wouldn't that be behind the impeller? Or maybe more even/level with the impeller? I've never taken a jet apart before, I'm just asking.

Thats in front of the impellor  ;)

-beerjet-

Title: Re: tap location for suction housing psi
Post by: Stevecat on May 11, 2009, 11:00:44 AM

This is what I THINK - but it's just my opinion and WTFDIK, I'm not Dr. Phil or anything!  ;)

Suction housing = inlet housing = gullet = big bent pipe where the water comes up and goes into the bowl.

From a standing start to full speed at WOT, the "pressure" inside the inlet housing will change from a slight vacuum to some amount of positive pressure. How much positive pressure will depend on the complex dynamics of each boat's hull, ride angle, impeller size blah blah. The reason it switches from slight vacuum to positive pressure as the hull picks up speed is because it isn't really a pump after the hull speed gets up around 30+ mph. It's some kind of weird hybrid of a pump + a no-bypass compressor. The inlet water isn't being sucked it's being rammed into the mouth of the impeller.

For the "average" boat that is under 60mph hull speed the maximum inlet pressure probably stays under 50psi - maybe way, way lower. For race boats the max pressure can be anywhere from 30 to 100-ish. I doubt there is even a consensus yet on what is good or bad value for pressure, but the race guys (or the ones who talk about it) seem to say that a successful boat will have a small amount of positive inlet pressure, but not too much. (Then again they could be handing out false info just like in a spy movie!)

There are various opinions on why you have to tap at two locations but on most boats, the pressure is not uniform at the impeller inlet. Some people think it is because of the "shadow" of the drive shaft blocking flow to the top of the inlet mouth. Others say it is because the water near the top of the inlet has a longer distance to flow than from the bottom. And there's the mysterious "boundary layer" which is the region of water near the surface of the hull which is flowing "past" the hull at less than full speed. So monitoring a single location will perhaps tell you the wrong story. If you are trying to use pressure info to "tune" loaders, shoes, ride plate, et cetera than you want to watch what is going on near the impeller mouth and at a "high" and "low" location.

Title: Re: tap location for suction housing psi
Post by: propless on May 12, 2009, 08:51:59 AM

Quote from: SLCKREG on May 11, 2009, 09:32:23 AM

Maybe I'm confused, I was told to tap locations just before the wear ring. Wouldn't that be behind the impeller? Or maybe more even/level with the impeller? I've never taken a jet apart before, I'm just asking.

 OK, some new info has arrived.
 Ive been told now (by two people) to have the taps about 2" in front of the impeller/wear ring.  How far forward are yours.  If I remember right you were getting some strange readings.

Title: Re: tap location for suction housing psi
Post by: SLCKREG on May 12, 2009, 09:06:47 AM

I guess a better choice of words on my part would have been to said my taps are BEFORE the impeller, not behind. when Omar typed "in front of" ,and I reread your post "ahead of " it dawned on me we were on the same page. I'll see if I can put up a pic of my taps tonite. On a side note, the gauges stay remakably steady, they dont bounce aroud hardly at all. 1st time out this year I had my loader way too low(about 3/8" below) and my pres. was almost non existent, like 5-7 psi on top, and zero on the bottom. I trimmed it back to what I thought would be level(still about an 1/8" under). Now my #'s are like 22 psi on top, and about 10 on the bottom. Curious to see what others are seeing for lake/river boats. I read once where Timminator said 19 or so were good #'s for his 21 daytona. I'm going to shave the loader back a little more and see if that helps level it out.

Title: Re: tap location for suction housing psi
Post by: propless on May 12, 2009, 07:15:03 PM

 Thanks, pics would be great !!   Sounds like your getting close now  ;D.  This is exactly why I want to do this, without the gauges I'm working blind in there.

 BTW, didn't you use a pair of mec oil pres gauges on yours for this ? I ask because I have a couple extras I was thinking about useing.

Title: Re: tap location for suction housing psi
Post by: Oldsquirt on May 12, 2009, 07:40:58 PM

Not my pump, but it shows the locations recommended by one of SoCal's premiere pump professionals. This is approx 1" ahead of the wear ring. If you go 2", you will have to move both taps a lot closer to the pump centerline, kind of working against the idea of a top and bottom pressure reading.

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.hotboatpics.com%2Fpics%2Fdata%2F500%2F3633PressureTaps.JPG&hash=c1838a86927d0d5daae1d024628a1b13840679da)

Title: Re: tap location for suction housing psi
Post by: propless on May 12, 2009, 08:06:35 PM

 Thanks Oldsquirt,

 That's exactly what I needed to see !!  I was just out in the garage looking at mine and I didn't think about the clean out hole, that would be a problem trying to do it at 2".  I'll go with the 1" spacing.  ;D

 Is that 3rd line for bowl pressure ?

Title: Re: tap location for suction housing psi
Post by: Oldsquirt on May 12, 2009, 08:11:30 PM

Quote from: propless on May 12, 2009, 08:06:35 PM

 Is that 3rd line for bowl pressure ?

Yes. This was a friend's dragboat and it was equipped with an Edelbrock QuikData unit.

Title: Re: tap location for suction housing psi
Post by: SLCKREG on May 12, 2009, 08:11:56 PM

Hopefully...here is a pic of mine(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi578.photobucket.com%2Falbums%2Fss230%2FH20MOFO%2Fpaul059.jpg&hash=04f265b10a6604b350dc0553fa7d5d38342d4799)

Title: Re: tap location for suction housing psi
Post by: SLCKREG on May 12, 2009, 08:16:47 PM

Let's see if I can put up a short vid??

[yt=425,350]<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/_jBCkcIzjdE&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/_jBCkcIzjdE&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>[/yt]

Title: Re: tap location for suction housing psi
Post by: propless on May 12, 2009, 08:35:05 PM

 Your killin me over here with that video bro  :mad: .  I've got to get this stupid little boat done so I can start on my Daytona, very cool !!  ;D ;D

Title: Re: tap location for suction housing psi
Post by: SLCKREG on May 13, 2009, 07:28:14 AM

Quote from: propless on May 12, 2009, 07:15:03 PM

Thanks, pics would be great !!   Sounds like your getting close now  ;D.  This is exactly why I want to do this, without the gauges I'm working blind in there.

 BTW, didn't you use a pair of mec oil pres gauges on yours for this ? I ask because I have a couple extras I was thinking about useing.

As far as the gauges...I ended up with 1 water pres gauge(0-35 psi), and one oil pres gauge. Seeing how I'm only hitting 10-25ish psi, I may swap the oil pres gauge out for a second water pres. gauge.