UrQ Fuel delivery fix challenge!

[John Cody Forbes]

Just to be clear, if you run a single pump the solution MUST be pre pump 
since the issue is with inadequate fuel delivery to the pump. Running two 
pumps with a swirl pot in the middle would remove the need to the fix to be 
pre-pump.

-Cody

--------------------------------------------------
From: <qshipq at aol.com>
Sent: Monday, March 29, 2010 1:28 PM
To: <benswann at verizon.net>
Cc: <urq at audifans.com>; <quattro at audifans.com>
Subject: Re: UrQ Fuel delivery fix challenge!

>
> Ben
> I never knock solutions that work!  I don't agree that the mounting of the 
> anti-cavitation tank *needs* to be pre-pump in the urq.  That would only 
> be the case if the fuel demand was a constant.  Can cavitation manifest 
> itself at a bad time?  Sure.  And I applaud you for finding a solution 
> with the noted challenge restrictions you self-imposed.  I don't see the 
> solution to such a fueling issues as a 200$ fix.  Not for my own cars, or 
> anyone elses.  Again, I'm glad you solved the problem, and did it with the 
> constraints you put on your own view of it.  That's just cool Ben.  That's 
> also not my view, nor the point of Peter's post.  I think we are both 
> pointing out this isn't a new concept, and has been addressed the same, 
> and differently, for many years.  If it solved the problem for you, that's 
> all you need.
>
> Cheers
>
> Scott J
>
>
>
>
>
>
> -----Original Message-----
> From: Ben Swann <benswann at verizon.net>
> To: qshipq at aol.com
> Cc: urq at audifans.com; 'Quattro List' <quattro at audifans.com>
> Sent: Mon, Mar 29, 2010 12:10 pm
> Subject: UrQ Fuel delivery fix challenge!
>
>
> Scott,
> WRT the conversion of the UrQuattro to an EFI system which has reduced 
> fuel pressure and greater flow, I'll issue a challenge, since folks seem 
> to be pooh poohing my solution I did over two years ago as not being 
> optimal.
> Regarding your comment regarding cavitation, space and mounting location 
> is the main concern on the Ur Quattro.  Once the fuel is fed either by 
> gravity or low pressure pump into a reservior with a large feed pipe, then 
> cavitation becomes virtually a non issue.  Having the return flow teed 
> into the surge tank pretty much eliminates negative pressure in the tank 
> and sometime the fuel flow could reverse back into the main tank - great 
> for keeping that sock clear of debris.
> I studied many variations on surge tanks, fuel cells, race delivery 
> systems, anti-slosh systems.  Many were simply a large tank in the trunk 
> with a small fuel cell in the engine bay.  Many of these systems were 
> applicable to dead head or low return flow applications - like carburators 
> mounted in Drag Race cars.
> In this case, the surge tank needs to come before the pump.  I considered 
> using a low pressure carburator pump to draw fuel from the tank and pump 
> into a surge tank, and I' tested it and it would have worked fine except 
> for drawback of space and more complex wiring and plumbing.  Everything 
> else was more expensive, too labor intensive, too much turnaround time, or 
> space constrained and/or combination of the above.
> Simplicity prevailed in the end - nothing fancy and works great.  So maybe 
> there is a better more effective way to solve the problem than what I came 
> up with.
> The challenge, if anyone wants to go through the mental exercise and 
> figure through all the caveats, is to have a fix to a constrictive fuel 
> pump feed of 3/8" diameter with a slight kink from a tank that has a 
> separate chamber at the bottom.  This feed essentiall starves pumps 
> especially when the fuel pressure is dropped for EFI.
> The UrQ tank has a separate cavity at the bottom underneath another main 
> bottom - so it is not a simple tank with one bottom, but a well integrated 
> in the tank bottom where the feed line goes out.  The 3/8"  main feed line 
> snakes into an 8" fine mesh sock located in the well chamber that is 
> sandwiched under a first bottom.  You can't see the feed line because it 
> is inside the sock and inside the well  - the hole to the well is about 2" 
> dia.  The return line goes into the tank in different location in the tank 
> than the main feed line - it diverges inside the tank.
> Well put some contraints on the challenge - these were essentially my 
> constraints :
> The job needs to be completed within 2 days - start to finish.  That is 
> the car can be out of service for two days max.
> There are no local welding shops that  will work on the tank and you live 
> in an area with high labor premium where the cheapest labor is $35/hour.
> You can do you own welding, but cost of welding materials needs to be 
> factored into the cost.
> You can use if on hand, a MIG welder  or torch, but no TIG unless 
> purchased inside the $200 price. (If anyone knows where to get a TIG for 
> $200 I'd sure like to know.)
> Incinerating or Blowing yourself up in process of welding does not count!
> Shipping a fuel tank is restricted as hazardous cargo.
> Fuel cell is acceptible fix, but must have 80% of the capacity of the 
> original 22 gal. tank.
> The fix needs to fit in the same space as the original tank and consume no 
> less trunk space.
> The fix needs to fit in trunk, engine bay, or  under the car in very 
> limited space, and have ground clearance higher than the max travel of 
> control arms and exhaust.
> Know that the feed lines from the stock tank are barely accessible - a 60 
> deg. Bend in 3/8" feed pipe that is only 4" long coming out of a 5" dia. 
> Hole in the trunk above the rear differential.  The return line is 
> smaller - 1/4" I think.
> The distance between the tank feed line and pump inlet is 15" and the path 
> is not direct - there is subframe, trans. Mount. Obstructing the original 
> line feed path from tank to pump, so existing plumbing take a convoluted 
> route..
> It needs to be safe - location can not be in proximity to any portion of 
> exhaust.
> Total cost of the fix needs to cost under $200 including parts and labor.
> Extra points to solutions that retain original tank and plumbing from the 
> pump to the engine bay connection fittings.
> Solutions that cost more will be considered too, since I would have paid 
> more if I needed to.
> I did it with under $100 parts and 8 hours labor with one day down time.
> Let's see what folks come up with.
> Ben
> [Date: Mon, 29 Mar 2010 12:09:37 -0400
> From: qshipq at aol.com
> Subject: Re: [urq] urq Digest, Vol 77, Issue 35
> To: audionly at gmail.com, cody at 5000tq.com
> Cc: urq at audifans.com, mdeltergo at hotmail.com
> Message-ID: <8CC9D715D08AF11-1F34-2A10 at webmail-d049.sysops.aol.com>
> Content-Type: text/plain; charset="us-ascii"
> I agree with Peter, cavitation can be addressed before or after the pump. 
> Actually anywhere between the tank and the fuel rail.  This 'fuel 
> capacitor' concept certainly can be mounted before the pump as Ben did it, 
> but every HP application of this concept I've seen, is in the engine bay, 
> regardless of pump location.  I would surmise the reason for this more 
> common application, is less of a need to modify fuel tanks, fuel line 
> diameter, and/or the risk of hanging a secondary fuel bomb under the car.
> Scott J]
> Original Post that started this all:
> [Date: Fri, 26 Mar 2010 12:21:43 -0700
> From: AF <afinn1 at gmail.com>
> Subject: [urq] More Weird UrQ Behavior
> To: urq <urq at audifans.com>
> Message-ID:
> <ed47d8be1003261221w2a4c5064v1f7af3a500956166 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> So, at the past 2 track events I've attended with my V8 UrQ I have had a 
> weird issue with engine cutout at high rpms, usually in 3rd gear, but on 
> the straightaways in 4th gear. They seem to occur during any throttle 
> position, like cresting a hill, or accelerating out of a corner, which is 
> somewhat unnerving. There are no fault codes thrown at all, which makes me 
> think it's a fuel supply issue. Here's the weird thing, I would say it a 
> fuel pump relay issue, but wouldn't the engine stall (that's what my old 
> UrQ and Coupe GT would do on the highway), but in this case there's no 
> power until I depress the clutch after slowing a little and downshifting, 
> then the power is all back. The engine never stalls and shuts off! I 
> confirmed it's not a rev limiter issue by redlining with moderate throttle 
> input and no issues occured. It's definitely at higher RPM though. Does 
> anyone have a thought? I thought about relaying the fuel pump, but 
> wouldn't the engine simply stall with no fuel supply, or will it simply 
> keep running with the car in motion and clutch out without shutting down 
> or turning on all the warning lights on the dash?
> Any help is appreciated. Thanks.
> Andrew Finney
> 1985 UrQ 4.2L ABZ]
>
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