dual fuel pump question
09-19-06, 03:22 PM
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dual fuel pump question
Ok, I plan on running 2 nippon denso pumps and wiring them to the battery with 8 ga. wire, my question is can i use the stock 12v lead that normally feeds the pump as a trigger for the relays??
09-21-06, 01:59 AM
#4
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hmmmm i have that setup in mind... actually gonna get it started this weekend....
Wont one relay be better then two? less things to go wrong, but if it goes wrong all pumps will stop altogether rather then having the ex secondary relays pump quit on boost....
I had in mind of gettin a solid state relay SSR, and use just one for both pumps. I am using a 8 mm line lead to....
what the stand on the relays guys?
Cheers
George
Wont one relay be better then two? less things to go wrong, but if it goes wrong all pumps will stop altogether rather then having the ex secondary relays pump quit on boost....
I had in mind of gettin a solid state relay SSR, and use just one for both pumps. I am using a 8 mm line lead to....
what the stand on the relays guys?
Cheers
George
09-21-06, 10:17 AM
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I run 1 (40A)relay and 1 (30A)fuse with my dual walbros. Hasn't let go so far.
The race car runs the same relay/fuse combo and it has an A1000 + stock fuel pump.
The race car runs the same relay/fuse combo and it has an A1000 + stock fuel pump.
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09-21-06, 04:17 PM
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Any part numbers on the Bosch or any other automotive grade 40A relay? I went across the street to the local auto parts store and they didn't have a Bosch catalog. They did have a GP Sorenssen a/c compressor relay for the third gen but we couldn't figure out the amp rating on it. Are any of the stock RX7 relays 40A?
09-21-06, 11:43 PM
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I run dual 280 lph in tank nippon denso pumps and run them off a single 70 amp relay vs two 40 amp relays. I have it fused with a 60 amp inline glass fuse and triggered off a 12 volt switched source. I run 10 gauge wire on the heavy sides (battery and fuel pumps). Reason I didnt run two relays is because if one relay decides to take a crap, I wouldnt know and would loose fuel pressure under high boost=bad...vs. loosing all at once and car would just die...which it did because I was running them both off a 40 amp relay and trying to pull it through a 30 amp fused circuit, which it didnt like and melted things, lost all fuel pressure. So I rewired everything to handle it now. Each pump pulls about 25 amps Each at wot/full boost so makre sure if you go with a single relay, go with one that can handle the amps....this relay has really big power terminals to handle that kind of current, so you will have to find the right female wire terminals to fit.
Last edited by BLitzed33; 09-21-06 at 11:46 PM.
09-22-06, 08:11 AM
#11
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Originally Posted by EZFD
Ok, I plan on running 2 nippon denso pumps and wiring them to the battery with 8 ga. wire, my question is can i use the stock 12v lead that normally feeds the pump as a trigger for the relays??
It seemed such a slick thing to do but I wouldnt do it this way again. Find a good trip wire and wire the pumps right the first time.
09-22-06, 08:22 AM
#12
Perpetual Rebuilder
Originally Posted by BLitzed33
Reason I didnt run two relays is because if one relay decides to take a crap, I wouldnt know and would loose fuel pressure under high boost=bad...vs. loosing all at once and car would just die.
Cool thing was I just modified the FPR setting to compensate and drove home on one pump (no boosting of course).
I run two wired independently now and dont worry much about one failing and me not knowing it. There is always that "at WOT" possibility but I quit worrying about that.
09-22-06, 12:45 PM
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Im thinking of running dual walbro, and each pump supply a fuel rail. One going to the primary and one to the secondary.
Im thinking of running it off of one relay, 70AMP, stated earlier by BLitzed33. Please reconfirm.
BTW, Im thinking of fabbing up my own dual pump bracket. Are you guys using aluminum or stainless steel? Or does it matter.
Im thinking of running it off of one relay, 70AMP, stated earlier by BLitzed33. Please reconfirm.
BTW, Im thinking of fabbing up my own dual pump bracket. Are you guys using aluminum or stainless steel? Or does it matter.
09-22-06, 02:19 PM
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Originally Posted by Broken09
Anyone have a p/n for a 70A relay?
I'm currently running two 40A relays but want to switch to one relay. I use the 12V wire from the OEM fuel pump line as a trigger with no issues. I do have two batteries in the back PC680's, with thick gauge wire.
09-22-06, 03:01 PM
#15
Perpetual Rebuilder
I just used 2 clamps to hold the pumps together...No fabrication required.
I did end up getting the top welded for the wire passthrough. Dont have a pic of that though.
I did end up getting the top welded for the wire passthrough. Dont have a pic of that though.
09-22-06, 04:09 PM
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Originally Posted by BLitzed33
I run dual 280 lph in tank nippon denso pumps and run them off a single 70 amp relay vs two 40 amp relays. I have it fused with a 60 amp inline glass fuse and triggered off a 12 volt switched source. I run 10 gauge wire on the heavy sides (battery and fuel pumps). Reason I didnt run two relays is because if one relay decides to take a crap, I wouldnt know and would loose fuel pressure under high boost=bad...vs. loosing all at once and car would just die...which it did because I was running them both off a 40 amp relay and trying to pull it through a 30 amp fused circuit, which it didnt like and melted things, lost all fuel pressure. So I rewired everything to handle it now. Each pump pulls about 25 amps Each at wot/full boost so makre sure if you go with a single relay, go with one that can handle the amps....this relay has really big power terminals to handle that kind of current, so you will have to find the right female wire terminals to fit.
The only bad thing about this type set up is that if you get a short in just one of the wires gong to pumps or if you have one pump go bad and start pulling mega current its going to have to draw more than 60amps before ti blows the fuse. The wire will probably melt thru before the fuse blows unless all of the wires in the circuit all the way to teh pump is rated to handle more than 60 amps.
The best way would be to have a seperate power wire for each pump that goes all the way from the pump to the battery with the appropriate size fuse and relay to handle one pump on each line. You could also do a larger single feed from the battery with a 60 amp fuse then go into a distribution block and come out with 2 power wires (one for each pump), each with its own relay and 30 amp fuse....which is what I did.
The most important thing is to size up the capacity of the wire with the fuse. If all you have is a 60amp fuse on the entire circuit then make sure all the wire running off that fuse is rated to pull more than 60amps that way the wire doesnt burn thru before the fuse.
Stephen
09-22-06, 04:59 PM
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Originally Posted by SPOautos
The only bad thing about this type set up is that if you get a short in just one of the wires gong to pumps or if you have one pump go bad and start pulling mega current its going to have to draw more than 60amps before ti blows the fuse. The wire will probably melt thru before the fuse blows unless all of the wires in the circuit all the way to teh pump is rated to handle more than 60 amps.
The best way would be to have a seperate power wire for each pump that goes all the way from the pump to the battery with the appropriate size fuse and relay to handle one pump on each line. You could also do a larger single feed from the battery with a 60 amp fuse then go into a distribution block and come out with 2 power wires (one for each pump), each with its own relay and 30 amp fuse....which is what I did.
The most important thing is to size up the capacity of the wire with the fuse. If all you have is a 60amp fuse on the entire circuit then make sure all the wire running off that fuse is rated to pull more than 60amps that way the wire doesnt burn thru before the fuse.
Stephen
The best way would be to have a seperate power wire for each pump that goes all the way from the pump to the battery with the appropriate size fuse and relay to handle one pump on each line. You could also do a larger single feed from the battery with a 60 amp fuse then go into a distribution block and come out with 2 power wires (one for each pump), each with its own relay and 30 amp fuse....which is what I did.
The most important thing is to size up the capacity of the wire with the fuse. If all you have is a 60amp fuse on the entire circuit then make sure all the wire running off that fuse is rated to pull more than 60amps that way the wire doesnt burn thru before the fuse.
Stephen
09-22-06, 07:47 PM
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DAMN!! I havent looked at this thread in a few days and it really blew up!! Tons of great info here, thanks everyone! So it looks like 1 Bosch 70 amp relay, 2 separate 8 ga. wires from the battery each fused with a 30A fuse to each pump is gonna do it.
09-27-06, 12:29 AM
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I am also doing a twin in tank setup and was worried about one of the pumps failing. Do you guys see any problems with putting a pressure switch inline on the fuel line that would be hooked into a relay shutting down both fuel pumps if the pressure drops below a predetermined level? Just an idea.....I guess base pressure is much lower then it would at WOT making it difficult for it to read when a pump goes out.
09-27-06, 07:49 AM
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09-27-06, 08:53 AM
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Originally Posted by howard coleman
i suggest anyone reading this twin pump thread should check out a recent thread entitled "fuel system goodies from Dsport."
howard coleman
howard coleman
Good stuff!
09-28-06, 01:32 PM
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Originally Posted by willjs7
u might want to put some rubber between the pumps. i cant tell clearly from the picture if you had done so, but if you dont it will burn the pumps out.
