Aftermarket In Tank Fuel Pump Question

[Jason Weaver]

Hey guys, anyone have any experience w/the aftermarket fuel pumps? I have looked at the Paxton unit. Does anyone have any suggestions on others or this unit? Also, while I'm asking, would a bigger in tank fuel pump cause a rich condition at idle and or everyday driving? I assume the ecu would still be controling everything to keep the A/F right at all times. I am trying to beef up the fuel system for a small increase in my NOS setup. I don't want to create a rich condition under normal driving etc. It's a small investment for the saftey of the extra fuel. (or the capicity if needed). Thanks for any info.

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Jason

 

[David]

I am using a Paxton 'blue', but I no longer have the stock ECU. There are a couple of Honda aftermarket in-tank pumps and I would think one of them would fit an NSX.

FYI - You could eliminate this concern by using a wet NOS system.



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Don't no nuttin 'bout no NSX;
Don't no nuttin 'bout birthin' no babbies.

 

[sjs]

David, does the Paxton pull though the stock one? Assuming not, how did you eliminate the stock unit and keep a proper pickup?

BTW, I've been thinking that a small fuel cell mounted low in the front would be a neat place for race gas. At the track, leave the main tank close to empty and run from the front cell for better weight distribution. Not a big difference perhaps, and you'd need to fill every session, but an idea.

 

[David]

David, does the Paxton pull though the stock one? Assuming not, how did you eliminate the stock unit and keep a proper pickup?[/QUOTE]

The Paxton is a puller. I threw away the stock pump and fabricated a plate with a bulkhead AN fitting that fit on the gas tank where the stock plumbing is. If you go with an external pump, the plumbing is just common sense. Use a regualtor at the far side of the fuel rails to set the pressure and run a return line back into the tank (you can just T back into the main line) so that fuel and vapor can bleed off.

A Paxton 'blue' is way more than you would need, but there are a lot of different size pumps.

You might also look at using a small secondary pump that only comes on at WOT.

------------------
Don't no nuttin 'bout no NSX;
Don't no nuttin 'bout birthin' no babbies.

 

[winreboot]

Can you use a fuel computer controller such as Apexi ?? This fulls the MAP signal and will give more fuel but I guess the pressure will stay the same

Is the in tank fuel pump any louder then stock ??

I had a BOSH external fuel pump in my x 97 turbo prelude and that pump WAS laud !

 

[sjs]

Originally posted by winreboot:
Can you use a fuel computer controller such as Apexi ?? This fulls the MAP signal and will give more fuel but I guess the pressure will stay the same

The problem with my stock one is a lack of pressure at the necessary capacity, or vice-versa depending on how you look at it. I can get plenty of pressure at lower flow rates, but it drops off as demand increases. Anyway, no amount of fuel control will change that, but I do have the Rebic IV with two 550 cc auxiliary injectors.

 

[NSXTC]

I think you are wasting your $$$. The Stock in-tank fuel pump is actually rated by its manufacturer as a 24-volt unit. Why don't you consider doing something along the lines of what comptech does with their supercharger kit...that is boost the voltage to the pump under boost. If you are running stock injectors, you may also want to consider increasing the fuel rail pressure by changing out to an adjustable FPR that can react to either a boost / vac signal or triggered by the NOS system.

Originally posted by sjs:
The problem with my stock one is a lack of pressure at the necessary capacity, or vice-versa depending on how you look at it. I can get plenty of pressure at lower flow rates, but it drops off as demand increases. Anyway, no amount of fuel control will change that, but I do have the Rebic IV with two 550 cc auxiliary injectors.

 

[sjs]

Originally posted by NSXTC:
I think you are wasting your $$$. The Stock in-tank fuel pump is actually rated by its manufacturer as a 24-volt unit. Why don't you consider doing something along the lines of what comptech does with their supercharger kit...that is boost the voltage to the pump under boost. If you are running stock injectors, you may also want to consider increasing the fuel rail pressure by changing out to an adjustable FPR that can react to either a boost / vac signal or triggered by the NOS system.

Hey, I don't want to waste $, too many other things I want! I didn't realize that the stock pump was rated at 24v. If that's true, it's GREAT news. I have already bypassed the resistor so it runs at full system voltage, and I have a "rising rate" regulator, but It's not enough.

Anyone know where to get a suitable DC-DC converter?

Thanks!

 

[sjs]

David, do you still have your stock pump? Can you look to see if it indicates the rated input voltage range and the rated amps?

I'm finding it very tough to locate a suitable up-converter. Zahn has one rated at about 4 amps, but I'm not sure that's enough.

 

[David]

I pulled my stock pump out a couple of years ago and no longer have it. Sorry.

Just a reminder to those looking at fuel system upgrades for NOS that converting to a wet system solves the problem.

------------------
Don't no nuttin 'bout no NSX;
Don't no nuttin 'bout birthin' no babbies.


[This message has been edited by David (edited 03 September 2001).]

 

[SpeedDemon]

Originally posted by sjs:
Anyway, no amount of fuel control will change that, but I do have the Rebic IV with two 550 cc auxiliary injectors.

SJS - Glad to hear you replaced your old unit with the Rebic 4/550 combo. What do you think? If you'd like, drop me a line and we can compare programs, I wonder how close our settings are..

As for the fuel pump/pressure.. In addition to my Rebic 4/550's and rising rate FPR, I also utilized a Kenny Belle Boost-a-pump.. This allows you to up the voltage to the pump (adjustable), and includes a Hobbes switch so the juice only bumps up during boost. You can find these for $209 - $249ish, depending on which model you go with. I went with the 15amp ($209) version.

I don't have a fuel pressure gauge but as far as A/F and EGT's go, it seems to be doing the trick. A/F stays consistently fat, and EGT's don't rise above the point I have them set for.

Marc
97 NSX-T Twin Turbo

 

[sjs]

Originally posted by SpeedDemon:
SJS - Glad to hear you replaced your old unit with the Rebic 4/550 combo. What do you think? If you'd like, drop me a line and we can compare programs, I wonder how close our settings are..

If I ever get the thing sorted, I'll do that.

Actually, I keep getting distracted from it but I need to finish the darn thing. Thanks for the boost-a-pump tip. I've been looking for a DC up-converter and figured I would trigger it from my spare boost switch, but they are not easy to find. Also, I'm told that more volts means less life, which makes sense because it means more RPM for the pump. Mine is already pretty old, and a Walbro in-tank pump is less than $120 shipped. There isn't a direct replacement but I'm pretty confident I can make one work since all the kits use the same pump with minor small part differences.

I'll let you know how it works out.


[This message has been edited by sjs (edited 04 September 2001).]