It is currently Thu Mar 28, 2024 11:56 am

All times are UTC [ DST ]




Post new topic Reply to topic  [ 12 posts ] 
Author Message
 Post subject: FAO: RsPaul
PostPosted: Mon Oct 06, 2003 11:19 am 
Paul,

As we seem to be the only ones doing this different tank mod I thought I'd run this by you...

My setup as you know is a 5psi facet feeding a 1ltr swirl pot from a 13ltr tank! A return is connected from the swirl to the tank. The return from the engine goes into the swirl. The high pressure feed comes from the bottom of the swirl.

At the moment my swirl connections look like this:

- Return to tank
- Return from fpr
- Feed from tank to swirl
- Feed from swirl to high pressure pump

Now I seem to be having a problem that if I leave the low pressure pump running it goes mad and creates huge pressure which fills the swirl pot, feeds the high pressure feed, fills the return line all the way along to the fpr and then starts overfilling into the tank. - However this doesnt allow the fpr to return fuel to the tank.

One solution that might work is to change the connections on the swirl to:

- Return from fpr
- Return to tank
- Feed from tank to swirl
- Feed from swirl to high pressure pump

But im not sure if this will work or not? Any ideas? And how were you / are you plumbing yours?

Cheers,

Dave.


Top
  
 
 Post subject:
PostPosted: Mon Oct 06, 2003 12:06 pm 
Offline

Joined: Mon May 26, 2003 11:13 am
Posts: 187
I have thought all this through prior to designing the system for the mk2...and I think i can see your problem:

Basically its because you have an open circuit with regards to the swirlpot.
The facet is a 5psi (i take it its a silvertop?) self-regulating pump, what you've got to remember is that it was designed to feed a carburettor setup.
I dont know how much you know about carbs, but the pump feeds into the float chamber, when the foat chamber is full it closes off the feed using a needle valve (or similar) attatched to a float within the chamber.
Hence when the float chamber is full and the valve is closed, the facet builds up to full pressure in the feed line, senses this, and cuts out.

However, if you using a return from the swirlpot, you will never get this pressure build up as it is an open circuit, so the facet will simply fill the swirlpot then piss fuel back down the return to the tank.

For this reason, as i said in the other thread, my setup is as follows:

TANK - (feed line) - FACET - (feed line) - SURGE TANK - (gravity feed) -RST PUMP - (feed line) - RR REGULATOR - (return line) - TANK.

In your case you are left with no option but to follow the above design, because if you want the facet to regulate itself then you need to remove the return from swirl to tank, however if you do this you must also re-route the return from the reg, cos if you leave it connected to the swirl without the return from swirl to tank you will get a massive pressure build up and summat with go bang.

My method should work perfectly, as is it a closed circuit, and its also in my opinion, preferable to the in-tank swirlpot method as you can mount the surge tank wherever you want in the car, thus making it easier to gravity feed the pump (i fear i may have problems with this in the mk1, as the car is so low and the rst pump has to be below tank outlet level! :? )

Hope this helps you mate, not that you really deserve it!... :wink:

-Paul


Top
 Profile  
 
 Post subject:
PostPosted: Mon Oct 06, 2003 12:19 pm 
Ah well yes your system would certainly solve the return problem but your then asking a 5psi pump to keep a resovior full for a 100psi pump!

Which it should do just fine, for all of a mintute.

Cheers anyway mate and good luck with your system! :lol:

Dave.


Top
  
 
 Post subject:
PostPosted: Mon Oct 06, 2003 12:23 pm 
Offline

Joined: Mon May 26, 2003 11:13 am
Posts: 187
Its not all about pressure mate...but never, mind i've got my system sorted, good luck with yours.

-Paul


Top
 Profile  
 
 Post subject:
PostPosted: Mon Oct 06, 2003 12:33 pm 
I dont have flow rates to hand but i doubt the facet will flow nearly as much as the rst either!

Dave.


Top
  
 
 Post subject:
PostPosted: Mon Oct 06, 2003 8:58 pm 
Paul,

My new layout as described worked very well! No fuel coming out the return line at the engine side at all now where as it was out under full pressure before!

The car starts and runs too now without having to hold the metering unit down an inch!

So it seems to be perfect now! Id reconsider your system to copy mine!

Here is a diagram of it:

Image

Dave.


Top
  
 
 Post subject:
PostPosted: Tue Oct 07, 2003 12:32 pm 
Offline

Joined: Mon May 26, 2003 11:13 am
Posts: 187
Well done mate, glad to hear your car is finally getting sorted.

I'll just have to wait and see what happens with mine, i'll keep you potsed on how well it works.

-Paul


Top
 Profile  
 
 Post subject:
PostPosted: Tue Oct 07, 2003 1:48 pm 
Offline

Joined: Wed May 28, 2003 12:56 pm
Posts: 33
My original XRT from '97 ran this system but without the "Low pres pre pump filter" not sure what the purpose of that is?

And on the Notes section... does that mean you need to keep swaping between teflon and rubber depending on the length of your journey?

_________________
Buy a Reno and enjoy cheaper tax :)..
[img]


Top
 Profile  
 
 Post subject:
PostPosted: Tue Oct 07, 2003 2:13 pm 
It takes fuel from the tank into the swirl pot Andy! We're talking about alloy tanks in the car not under car steel fuel tanks.

Yes you have to swap between teflon and rubber, bit of a job each time! :(

Dave.


Top
  
 
 Post subject:
PostPosted: Tue Oct 07, 2003 4:34 pm 
Offline

Joined: Wed May 28, 2003 12:56 pm
Posts: 33
Dave wrote:
It takes fuel from the tank into the swirl pot Andy! We're talking about alloy tanks in the car not under car steel fuel tanks.

Dave.


I know.. but I'm refering to the one that is inbetween the swirl pot and the high pressure fuel pump but it doesnt matter as I've realised its not a pump but another filter !

I think I should retire from this board :?

_________________
Buy a Reno and enjoy cheaper tax :)..
[img]


Top
 Profile  
 
 Post subject:
PostPosted: Tue Oct 07, 2003 4:38 pm 
Yeah but your ok Andy because that diagram is 100% accurate, its taken from some SDB website that puts 2ltr 16v engines in novas!

The low pressure filter should infact be infront of the low pressure pump, as i have mine! Then just a straight connection from the swirl to the high pressre pump with the high pressure filter being as close as possible to the engine!

Dave.


Top
  
 
 Post subject:
PostPosted: Tue Oct 07, 2003 5:38 pm 
Offline

Joined: Fri May 23, 2003 7:18 pm
Posts: 2027
lol, thought that ive seen that diagram before- ive got it saved for when i can afford to do mine ;)

rolls


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 21 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  


Powered by phpBB® Forum Software © phpBB Group