Supercharged guys...what fuel pump are you running?

zelement · 05-03-2004, 09:36 PM

I am confused on the setup of my fuel pumps and I hope someone can help me understand.

I have an external in line Mallory Drag EFI pump just outside my fuel tank, I also have a bosch in tank pump. From what I understand, the Mallory pump only works with the supercharger, and the Bosch pump only turns on when the nitrous is activated, so when I am running nitrous on top of the charger both pumps will be working at the same time.

However, I have talked to serveral people and they all have told me that my setup is running both pumps all the time, with or without the nitrous, and no matter how big the Mallory pump is, it is only going to pump what the Bosch can support. Is that true? So does that mean both pumps run at all times?

The Bosch pump is only rated up to 550hp. The reason why I am asking this is because sometime under WOT at over 6000rpm the motor shuts off, it feels like I have hit a rev limiter.
I didn't do the work on my car so I don't know exactly how it is setup. I was wondering if there is anyone else on here that have a similar setup as mine.

Bruce,

How is yours setup?

TIA,

Paul

[Modified by zelement, 7:37 PM 5/3/2004]

[Modified by zelement, 7:37 PM 5/3/2004]

TONYDEE64 · 05-03-2004, 11:23 PM

I used two separate lines coming from the bottom of the tank....One aeromotive pump for each sump... One pump runs on an Aeromotive tranmission, and the second pump is rpm activated...

I'm not sure if this helps you....but it makes sense that two pumps on one line may help a bit... but may not provide the full capability if they were on separate lines... you may also run into restrictions on what the single fuel line will flow...Just my $.02

XTwinTurbo · 05-03-2004, 11:48 PM

I'm running a single Walbro HP 255lph pump. I removed my stock pump with Vortech inline add on. So far so good but I also have to add a Kenne Bell boost a pump to keep the voltage up.

The two pump setup you are running should be sufficient for most fuel needs. Some thoughts on why you are hitting a wall;

- possible voltage problems onto the pumps. Are you getting full voltage or are you losing power? A voltage drop will reduce efficiency at the pumps and they may be maxxing out. I.e. check out Kenne Bell boost a pump in search engine for details.

- Also could you be over reving at 6000 and hitting the fuel cut-off. I believe redline on our vettes is about 6000 (or was that 6200) rpm. If your tach is off you may be hitting the rev limiter on an LT1. Get a soft touch iginition rev limiter to help lower your limit. You don't want to be hitting the fuel cut off too often.

[Modified by XTwinTurbo, 9:51 PM 5/3/2004]

XTwinTurbo · 05-03-2004, 11:50 PM

PS: To answer your other question, most likely you are running both pumps at the same time all the time. Think about it, the inline pump would be a restriction on flow if it was powered off most of the time.

tjwong · 05-04-2004, 01:11 AM

I run a single Bosch in the tank pump along with a boost activated Kenne Bell boosta pump which is active when boost levels hit 3 psi which kicks effective pump flow to 150% of nominal flow.

Bruce · 05-04-2004, 01:18 AM

Paul
I am running a twin 255lph in side the tank and two -06AN feed lines thru the filters and to a Y into the external regulator inlet port and than a Y on the oulet port than both lines feed to the rails.

You should get rid of the external pump. Run a 255lph in tank pump along with a boost a pump this should easily support 650rwhp. If you are going to do like mine that can easily support 1000hp

zelement · 05-04-2004, 10:14 PM

Quote:

I'm running a single Walbro HP 255lph pump. I removed my stock pump with Vortech inline add on. So far so good but I also have to add a Kenne Bell boost a pump to keep the voltage up.

The two pump setup you are running should be sufficient for most fuel needs. Some thoughts on why you are hitting a wall;

- possible voltage problems onto the pumps. Are you getting full voltage or are you losing power? A voltage drop will reduce efficiency at the pumps and they may be maxxing out. I.e. check out Kenne Bell boost a pump in search engine for details.

- Also could you be over reving at 6000 and hitting the fuel cut-off. I believe redline on our vettes is about 6000 (or was that 6200) rpm. If your tach is off you may be hitting the rev limiter on an LT1. Get a soft touch iginition rev limiter to help lower your limit. You don't want to be hitting the fuel cut off too often.

[Modified by XTwinTurbo, 9:51 PM 5/3/2004]

Thanks for the replies.

Is it necessary to run the Kenny bell boost a pump?

I just got back from a test drive and I had a fuel gauge taped to the windshield it seems that the cut off is not fuel related. The fuel pressure stayed constant when it cut off.

I don't think it is the rev limiter because it is a 91 and I had Ed wright remove the rev limiter on the chip. The rev limiter is controlled by the MSD 6AL, it is set at 8000rpm.

Since I am running the stock HEI I have been told that they cannot spin over 6000rpm. I got a new distributor waiting to be installed tomorrow. Hopefully that's what it is.

Tom,
Where can I get a boost a pump? Do I have to boost the intank pump or the external pump. When I got the Mallory pump they told me it is good for 1000hp. The intank pump I have is the Bosch one from TPIS, good up to 550hp.

Bruce, How do you have two pumps setup in tank? Are they running off the same fuel line?

Paul

Bruce · 05-05-2004, 01:05 AM

Paul
I am running two 255lph pump in side the tank and two pick up and two feed line thru Russell filter and to external regulator and a Y both line feed to the rail. You can get Kenne bell BAP at kennebell.com I think is the web site. It is about $250.

Here is the link http://forums.corvetteforum.com/zerothread?id=811452

Bruce

[Modified by Bruce, 11:11 PM 5/4/2004]