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Posted by: zeezee Feb 19 2009, 09:57 PM

The PO connected both fuel lines together > filter > pump > carbs.

I'm assuming one line was originaly a fuel return line - so it is now drawing crumbs off the bottom of the tank ... not thru the tank strainer.

Is this a safe setup? Should I be concerned about pluggin up a carb jet?

The filter seems clean. I don't have a problem with fuel flow. POR-15ing the tank is on my to-do list.

Posted by: McMark Feb 20 2009, 01:54 AM

I usually plug unused fuel lines with a section of solid steel rod and a fuel clamp.

Get that tank cleaned up before it really fouls up your carbs. Yes, I know you have a filter. It's not enough. You'll be surprised what snuck by if you open up the carbs.

Posted by: 9146986 Feb 20 2009, 07:29 AM

You can run a return line, if you want, after a pressure regulator. You need to make sure the correct (strainer)supply line supplies the system and the return is actually the return.

I've only done this on one car, at the request of the owner. Unless you are racing with huge fuel delivery carbs, a single line works just fine.

Posted by: aircraftdesign Feb 20 2009, 07:37 PM

any suggestions on a good regulator for a carb conversion?

Posted by: sww914 Feb 20 2009, 07:49 PM

The Holley regulator works great. I've had mine on the car for years, it even survived a fire and it still works. I had to replace the gauge after the fire.

Posted by: McMark Feb 20 2009, 07:54 PM

Do not run this style regulator. No no.


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Posted by: 9146986 Feb 20 2009, 10:02 PM

There used to be a fuel pressure regulator that was self adjusting using intake vacuum. I don't remember what it was called, but I saw one in VW & Porsche way long ago, the reviewer said it was the goods.

Posted by: yeahmag Feb 20 2009, 10:11 PM

Just run the CB Rotary pump (or the like) and don't worry about a return.

Posted by: brant Feb 20 2009, 10:31 PM

returns are ultimately superior
may not always be necessary, but definitely superior for power.. and for racing.
I have 3 teeners right now.. all with returns
(2 carbed, and of course the one with f.i.)

I always run returns
there are many different ways to plumb the system
all covered in previous threads
b

Posted by: zeezee Mar 5 2009, 03:27 AM

There certainly is no shortage on talk about fuel pumps, regulators, etc on this forum.

I have read a ton of it and have desided my fuel delivery setup has several issues. (Like the facet clicker pump is mounted too high - next to the battery ).

So, my next project on the car is to redo the lines, filter, pump...



I plan on doing option E above (two IDF 44s on a 2.0L).

Regarding the return regulator (3ish psi ):

Brant, I can't find the cheapo facet regulator you've mentioned.
Not interested in $300 for a Holley return regulator.
Does it have to be a return regulator?
(Inexpensive) Regulator suggestions?

Regarding the pump:

The CBPerformance Rotory pump gets good reviews.

But I'm assuming I can't have a self regulated pump (at 3psi) AND a regulator on the return (at 3psi) ... then there wouldn't be ANY fuel circulation.

So, would the 5psi pump provide enough circulation?
If not, what kind of pump should I be looking at?




Picture credit to Eddie W - lifted from http://www.914world.com/bbs2/index.php?s=&showtopic=43028&view=findpost&p=562899

Posted by: 9146986 Mar 5 2009, 07:12 AM

The only way a Facet will work for you is up front, lower than the tank.

Posted by: rhodyguy Mar 5 2009, 09:42 AM

forget the facet. period. they're VERY noisy. even when isolated from the car's chassis. while the return line version may be a superior setup, i've never felt the need for one on my car. during VERY warm weather and only parked AFTER driving have i ever experienced what i would consider a "hot" fuel issue which quicky subsides after the restart.

with version E the return line is going to begin on the opposite side of the engine and return to where you've started. you will have fuel line running all over the engine compartment and the fuel sitting idle in the lines and float bowls is still going to get warm. where do you plan on locating the pump?

imho you're making quite a bit of work of this. cap return line @ tank, renew supply line at tank, renew line to filter, new line to pump, new line to 'T' in engine compartment, plumb to the carbs and be done with it. i like to keep it simple.

k

Posted by: John Jentz Mar 5 2009, 09:58 AM

Use the Mallory 4309 return regulator, $84.95 from SUMMIT. I'm going to use the stock FI pump up front like Fig E. Remember, pumps are not inherently high or low pressure, but volume against resistance. This regulator will handle a 140gph pump. I don't know what a D-Jet pump is rated at, it's got to be less than that.

Posted by: johnnie5 Mar 5 2009, 10:04 AM

I have run my fuel system in the same manner, except I have 2 filters. 1 up front with the pump , and a 2nd filter before the T. Works perfectly.

Posted by: rhodyguy Mar 5 2009, 10:08 AM

never mind.

k

Posted by: dinomium Mar 5 2009, 12:44 PM

Brant, I can't find the cheapo facet regulator you've mentioned.
Not interested in $300 for a Holley return regulator.
Does it have to be a return regulator?
(Inexpensive) Regulator suggestions?

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY-12-804&N=700+4294925239+4294839053+4294880914+400178+115&autoview=sku
27.95 from Summit racing... 1-4 lbs pressure...

Posted by: Rav914 Mar 5 2009, 02:37 PM

Does that Holley pump need to be adjusted? I know it says 1-4 psi, but would I need to fine-tune it down to 3.5 psi?

Sorry for the hi-jack but I just bought the same reg for my carb conversion.

Posted by: effutuo101 Mar 5 2009, 02:48 PM

I posted my thoughts on another thread.
Here is what I use:
http://www.aeromotiveinc.com/products.php
I am still in the testing phase, but have been impressed with the ease of use and accuracy thus far.

Posted by: brant Mar 5 2009, 09:58 PM

it doesn't have to be a regulator designed for return
I've used option E previously with the cheap regulator shown in marks post #6 in this thread. make sure you put a guage ahead of the regulator to see what kind of back pressure your building to.

also make sure you don't mount the guage on the motor or fuel rail where it will vibrate and eventually crack/leak. I helped put out a 911 on fire that was plumbed that way once.

I recently just upgraded my race car fuel pump yet again. I removed my pmo regulator (to save weight) and went with one of the decent rotary pumps with built in internal regulation. I'm using option B now, but with no regulator. My fuel pressure guage verifies this is working.

Here is the new aluminum mounting bracket we fabbed, along with the new smart bar:


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Posted by: zeezee Mar 6 2009, 01:02 AM

Option B would be easier ... but I don't get it. The fuel free flows right back into the tank... there is nothing to build pressure against.

Is the return line considerably smaller than the supply side?

Posted by: brant Mar 6 2009, 10:18 AM

fuel injection is highly effected by fuel pressure
carbs are not. The only reason for regulation is to now blow open the seats
since they have their own bowls, all the fuel has to do is flow into and fill the bowls.
(think of the bowls as mini reservoirs)

with hydraulics you have to remember that pressure equalizes (a smaller return would effect volume more than pressure). So the bowls fill, and the extra runs back to the tank/cell

I've got a fuel guage near the carbs showing that I'm getting 3.5 to the carbs... the pressure on return isn't important.

the real reason for a return line in a carbed system is to just keep the fuel moving (not heating up while it waits to enter the carbs and sits over the engine soaking up heat) and thus cooler = more hp

option E is actually what the factory used on the 4's, Djet and is good for a fuel injection system where you want to build back pressure. I've used this on carbs also with good effect. I've got one (street) car right now with option E.

also as a side note. I measured output on 4 different used pumps and found 4 different outputs. (3 were facet spares I had) Thats the main reason I used a regulator with the facets... variability. Also the reason I switched pumps in my recent new plumbing job. (plus I saved weight)

Posted by: zeezee Apr 9 2009, 03:28 PM

Finally have this in place (option B ).

Several PO plumbing problems were cleaned up. The old facet was mounted so high it would run dry around half a tank.

Other than that there are no drastic improvements. The engine still runs - that's always a plus.

But I'm still not happy.

The replacement pump (CBPerformance Rotory - Carter P60504) is so loud I can hear it over the engine!

I've encased the pump in sound proofing and used rubber mounts. The sound is now tolerable - but not really an acceptable long term setup.

I guess I'll try a Mallory 4070LP - that's supposed to be "quiet".

Also tried a Facet Posi-flo (advertised as quiet) - I nearly had a heart attack when it powered up, it was so loud!

Lots of $$ getting tied up in fuel pumps here.

Posted by: rhodyguy Apr 10 2009, 10:16 AM

i can't figure out how you can hear the pump running over the engine. where did you mount the pump?

k

Posted by: biosurfer1 Apr 10 2009, 10:38 AM

Thats what I'm wondering too...my buddy Justin has the same pump mounted up front and you can barely hear it with the engine off

Posted by: zeezee Apr 10 2009, 11:22 AM

Mounted to the lower part of the firewall on the passenger side.
Physically it fits well and makes the hose runs tidy.
In retrospect - not the best place for sounds issues - since it makes the whole firewall resonate with sound.

I don't really see any other place to mount it back there.

I changed the mounting insulators and it's much better.