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Bulletproofing fuel pump power...

 
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
Location: MI

PostPosted: Sun Jul 12, 2015 10:28 am    Post subject: Bulletproofing fuel pump power... Reply with quote

Reading a lot on how to tune CIS for performance I came across this..

"""""""""""""""""""""""""""
the best thing you can do for your CIS equipped car -
relay the fuel pump.

"""""""""""""""""""""""""""

Sounds like a good idea to me, he's pretty much talking about using you OEM FP relay power to turn on a separate/extra relay to power your FPs..

That means taking a really big load off of your OEM circuitry and placing your FPs load on a separate relay. This gives you more solid +12v to your FPs and giving everything else on the same OEM FP relay circuit more/better power because it doesn't have to compete with the FPs any more, like the frequency valve and whatever else the OEM FP relay turns on..

Make sense?

Here is my iteration...

DOUBLE relays... Oh yeah... Both are made in austria OEM BMW 4 pin relays..
Yep and double wiring for everything too.. Why not??
I could have went with 4 relays but that would be a bit much I think.. 2 should be plenty..
Blue=relays ground
Gray=additional FP ground
Red=relays direct battery power
White=OEM FP relay power in to new relays (to turn them on)
Red/Blk=power out to FP's
Also notice the hose I sliced and put over the chassis seam there to protect the wires crossing it..


Before taping...
Far left splice=OEM FP power, Blk/Grn wire
Middle splice=tapping into the middle of the OEM FPs ground to double it because I can..
Right splice=Power back from relays to FPs by way of its Blk/Grn wire

BTW those are ancient snap on "squid grip" side cutters, like 1940's or older, They rock even to this day they work and feel on level with knppix etc.. America needs to learn how to do things like that again instead of buy chinese ones that last a few uses.. I didn't do that on purpose but must comment on it because I'm passionate about high end tools new or old..


After taping to make it a "harness"... Well half way after taping, I taped a lot more after that once I tested everything..




That monster +12v battery lead is from the BMW also actually, its a beast, goes to the starter area and connects to all the wires that used to be up front in the battery box now tucked down between the firewall and engine down to the starter area..


Results??

My FP's and frequency valve sound much healthier, they all sound like they've just been given a new life, they just sound cleaner, I don't know how to explain that well..

Flame suit on..
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ideola  



Joined: 01 Oct 2004
Posts: 15548
Location: Spring Lake MI

PostPosted: Fri Jul 17, 2015 12:36 am    Post subject: Reply with quote

In general, I think this is a good idea if executed well. Not sure if that's your writeup or someone else's can you clarify?

Thoughts:
1. The intent is to make the system more reliable, not less so. Doing this adds more points of failure. Adding complexity increases difficulty of troubleshooting and could make life miserable for the next owner (how many times have you cursed the previous owners or your car(s)?!). All of that said, again, if this is well executed with high quality components and workmanship, it should ultimately improve quality of current/signal to the fuel pump.

2. I have already added an auxiliary fuse block with spade style fuses to run extra components on the Club Sport, and I plan to do so as well on the 941. What you describe above could be really nicely executed in conjunction with such an auxiliary fuse block.

3. I would not put the relays in the engine bay strapped to the positive cable as depicted. I would put them in the passenger compartment. For the Club Sport, because it is AC-less, my aux fuse block is on the footwell shelf on the passenger side. In the 941, it is / will be mounted to the back side of the AC kick panel. In the 941, I've hinged it for easy access. I have all of the PLX modules mounted there as well.

4. The spade terminals and all splices should be soldered and shrink-wrapped. When you're in a hurry, doing so seems like a huge hindrance. This is why I don't like tackling electrical projects off the cuff. I prefer to have it planned with a block of several hours so I can take my time, do proper soldering and shrink-wrapping. Makes a big difference to longevity and reliability. See opening sentence in point 1!
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Kenodog  



Joined: 25 Jun 2003
Posts: 2645
Location: Vancouver,B.C.

PostPosted: Tue Jul 21, 2015 11:13 pm    Post subject: Reply with quote

Marrette connectors Eddie ?! Not a good idea in a car. Good thing you have a fire extinguisher...

Not a flame post, this is about safety.


Leigh
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
Location: MI

PostPosted: Wed Jul 22, 2015 12:21 am    Post subject: Reply with quote

ideola wrote:
In general, I think this is a good idea if executed well. Not sure if that's your writeup or someone else's can you clarify?
That is my car in the pics. All words and pics are mine except whats in the quotes.

Thoughts:
1. The intent is to make the system more reliable, not less so. Doing this adds more points of failure. Adding complexity increases difficulty of troubleshooting and could make life miserable for the next owner (how many times have you cursed the previous owners or your car(s)?!).
It is double relayed in parallel and double wired in parallel also, if one fails I probably wouldn't even notice.All of that said, again, if this is well executed with high quality components and workmanship, it should ultimately improve quality of current/signal to the fuel pump.
It works excellent, I would think the austrian relays are of good quality.
2. I have already added an auxiliary fuse block with spade style fuses to run extra components on the Club Sport, and I plan to do so as well on the 941. What you describe above could be really nicely executed in conjunction with such an auxiliary fuse block.

3. I would not put the relays in the engine bay strapped to the positive cable as depicted. I would put them in the passenger compartment.
The battery, relays, and all wiring is in the rear passengers wheel well cubby in the rear hatch right over the fuel pumps, not under the hood.
For the Club Sport, because it is AC-less, my aux fuse block is on the footwell shelf on the passenger side. In the 941, it is / will be mounted to the back side of the AC kick panel. In the 941, I've hinged it for easy access. I have all of the PLX modules mounted there as well.

4. The spade terminals and all splices should be soldered and shrink-wrapped. When you're in a hurry, doing so seems like a huge hindrance. This is why I don't like tackling electrical projects off the cuff. I prefer to have it planned with a block of several hours so I can take my time, do proper soldering and shrink-wrapping.
Soldering and shrink wrapping would be better, except I cant solder to save my life.. Maybe I will go back and improve upon this. I didn't do this in a hurry, it took me a couple hours. Makes a big difference to longevity and reliability. See opening sentence in point 1!

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Last edited by Fasteddie313 on Wed Jul 22, 2015 12:42 am; edited 3 times in total
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
Location: MI

PostPosted: Wed Jul 22, 2015 12:33 am    Post subject: Reply with quote

Kenodog wrote:
Marrette connectors Eddie ?! Not a good idea in a car. Good thing you have a fire extinguisher...

Not a flame post, this is about safety.


Leigh


You mean wire nuts correct? They are what I had, I know they don't look the greatest and are a bit bulky/ugly but I figured they would work well, better than just twisting and taping, notice they are in pairs as its double wired. The whole thing is taped up with super strong cloth electrical tape and then taped into a "harness".

If need be I can/will go back and redo the connections in some other manner.
Would crimp splice connectors be better? I can go buy some of those to replace the wire nuts and I suppose I could shrink wrap over them before taping it into a harness..
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ideola  



Joined: 01 Oct 2004
Posts: 15548
Location: Spring Lake MI

PostPosted: Wed Jul 22, 2015 12:40 am    Post subject: Reply with quote

Fasteddie313 wrote:
You mean wire nuts correct? They are what I had, I know they don't look the greatest and are a bit bulky/ugly but I figured they would work well, better than just twisting and taping, notice they are in pairs as its double wired. The whole thing is taped up with super strong cloth electrical tape and then taped into a "harness".

If need be I can/will go back and redo the connections in some other manner.
Would crimp splice connectors be better? I can go buy some of those to replace the wire nuts and I suppose I could shrink wrap over them before taping it into a harness..


Recommended reading:
ideola wrote:
Automotive Wiring and Electrical Systems
By Tony Candela, CarTech, Incorporated, 2009
ISBN: 1932494871, 9781932494877
Comments: Picked this up to prep for my impending wiring harness and ECU installation. Very helpful book, should be on every enthusiast's bookshelf.

Mr. Candela describes a technique of twisted wire + electrical tape that is safer, quicker, more streamlined, and more reliable than wire nuts. It's best to solder them, but in some cases you don't have the working space to do so.
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Last edited by ideola on Wed Jul 22, 2015 4:02 am; edited 1 time in total
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
Location: MI

PostPosted: Wed Jul 22, 2015 12:44 am    Post subject: Reply with quote

Your link has a 404 error..

404. That’s an error.

The requested URL /books?id=pJjFNwAACAAJ was not found on this server. That’s all we know.
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ideola  



Joined: 01 Oct 2004
Posts: 15548
Location: Spring Lake MI

PostPosted: Wed Jul 22, 2015 4:03 am    Post subject: Reply with quote

Fasteddie313 wrote:
Your link has a 404 error.


Ahh, nuts, love it when Google changes their interface. Fixed the link, try it again.
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RC  



Joined: 25 Mar 2007
Posts: 2636
Location: Australia

PostPosted: Sun Aug 02, 2015 10:31 pm    Post subject: Reply with quote

What was your initial FP voltage, max current draw and particularly the voltage drop?

What was the voltage drop after your umm... modifications?

You did measure & quantify any benefits or otherwise, didn't you???
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Allan @ DTA wrote:
I have no issue with superchargers, they are for guys who want to drive a car rather than talk about horsepower with their baseball cap on backwards
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
Location: MI

PostPosted: Mon Aug 03, 2015 2:04 am    Post subject: Reply with quote

RC wrote:


You did measure & quantify any benefits or otherwise, didn't you???


No..

I didn't exactly get all scientific with it..

I did not need to do this modification (I think) but I am asking my fuel pumps for more than they would otherwise be in OEM configuration, providing more fuel to accommodate higher boost and at higher system pressure..

I read that when tuning CIS, not specifically Porsche, when you start expecting your fuel pumps to put out more flow at higher pressures it's a very good idea to make sure they get good clean power vs running on 15 feet of ancient OEM wiring. And 1 ancient spade connection for a ground on 6' of ancient wire? no.

My fuel pumps now have much shorter and bigger wiring, and are on much newer high quality relays likely capable of higher current draw than OEM but I haven't checked the specs..

I don't see how it could be anything other than as good or better than the OEM configuration. Plus relieving the rest of the OEM FP relay circuit of the fuel pump power draw thus making better + 12v available to the rest of it also. And providing a secondary grounding path for everything on the rear ground crown and relieving it if much of its duty..

It sounds good to my logic but I run much more off gut instinct than calculations so who knows, sometimes I am wrong..
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