C-5 Pilot

I just purchasee a 2004 c5 with a procharger D1-SC w/microtuner along with headers and Corsa exhaust. Is this a good thing and why did they have a boost-n-pump installed later? How does it work? What does it do? There is a adjustment **** under the dash--what should this be set on? There is only 7600 miles on the car. The shop has closed down and the previous owner doesn't know what it is.
Thanks in advance

Blown 346

Yes it is a good thing, The pump was installed to help get the fuel up to the motor without starving it for fuel. Im not sure what to set the setting at though.

BaneZ06

Its a Kenne Bell Boost A Pump

http://www.kennebell.net/accessories...boostapump.htm

Mr. Big

It increases the voltage to the pump under positive pressure. When you increase the voltage to the pump, you increase the volume it pumps. I always turn the **** as high as it will go, and tune that way.

keith954

mine is turned all the way up, thats how it was tuned do not turn it down or your car will run lean i wouldn't move the setting if you already did, i would take it to get retuned... better safe than sorry

C-5 Pilot

SteveDoten

you'll most likely see a Hobbs switch under the hood that turns on the BAP, the BAP then increases voltage to the fuel pump

often those wires are cutoff and soldered together for max voltage

FRCTony

Steve,

I thought the gain control is what is jumpered?

You are talking about the pressure switch?

SteveDoten

correct, in my reply the 2nd part was referring to the gain control, NOT the Hobbs switch, a bit misleading on my part now that I read it

Mr. Big

Not really true. If you remember, the regulator keeps the pressure at 58psi, doesn't matter if it is 12.5 volts or 17 volts, it is the same. If he starts to run out of fuel during boost, then more voltage would have pumped more fuel.

The best thing to do is turn it all the way up and forget about it. That way you get max effort all the time when your under boost.

Tuner@Straightline

We us the Kenne Bell Boost-A-Pump with every FI car we do, as well as tuning all our own tuning in house. If you have any questions please feel free to give us a call.

DSSA

Is this with a stock pump setup?

I'm just curious as to what level the stock regulator is good until, as on a large enough fuel system, the regulator can be over-run.

Mr. Big

stock pump, racetronix, lpe.. it works the same for all. Does anybody retune for fuel when they install the racetronics? NOPE it flows more fuel when needed, but it still keeps the same pressure in the rail. You only need to re tune if you change pressure or injector size.

I don't know what it takes to overrun the regulator, but if your using a pump big enough to do that, you should have a new rail and regulator too.

DSSA

Obviously.

I was asking at what level the regulator gets overrun though.

Mr. Big

Ok then, i will say there probably isn't a pump that will over run the regulator. If you find a pump that could do that... (aeromotive, magnafuel come to mind) there is no way to hook it up to the stock fuel system without major modification. And if you do all that without changing rails your not very wise.

So to run a pump that may be capable of doing this is nearly impossible on the stock fuel rail. Most pumps run a constant 100psi, doesn't matter which one. It is the regulators job to reduce this number. The only difference in the "larger" pumps is the volume it flows, not the pressure. If you find a way to use a large volume pump on stock fuel system, you can't pump enough to over run the regulator through the stock fuel system. The feed line becomes a bottle neck an makes your large volume pump not so large volume.

DSSA

See this is where you're losing me.

Pumps do not create *ANY* psi, and certainly do not "average" 100psi if they were to average anything.

Pumps create flow volume. The pressure is created by resistance against this volume's flow. On top of this, flow from different pumps can be completely different @ "X" psi even if their nominal rating (typically rated @ 40psi and 11.5/12V input) is the same. Bosch 044 pumps for example seemingly flow a lot less then a Paxton "Blue" pump when the data from the testing shows flow @ 40 psi, however, compare both @ 70+ psi on a forced induction car, and the results are somewhat surprising.

Are these rails *that* bad flow-wise or something? I've yet to play with the fuel setup on these cars (and typically stay away from return-less fuel systems), but it seems to me that most places that are selling in-tank pumps for these cars simply use the WalMart (Walbro) 255s which typically won't over-run any stock regulators short of ones on a smaller 4-cylinder (and then only some).

As far as I know, you're probably right with the aspect that no commonly used fuel pump will overwhelm the stock regulator (which unless you're running VERY restrictive lines, *Creates/Maintains* pressure, not "reduces" pressure. When the regulator (opened fully) is still a resistance past the fuel pressure you're trying to run, is what creates problems.

Is there some reason no one has used external in-line pumps and simply used the stock unit as a pusher pump on these cars?

Mr. Big

They do have inline pumps, i believe ECS has a kit with it.

AS far as the PSI...you are right, there is no set psi, but anytime you have resistance in a line, it will build pressure. There is resistance in every fuel system, that i why i use PSI.

Pumps themselves flow around 100psi if not regulated, and have ample resistance give or take 20lbs. Once 100 (or whatever number) is achieved, the pump meets to much resistance to flow more, so it can make anymore pressure

The lines and rail are both restrictive. You can get enough volume to the regulator to over run it given the lines.

I have had the entire fuel system out of the car, and a new one built, i spent countless hours with the system, it is good enough to around 500RWHP then needs upgrades, that is with a new intank pump..(walbro)

DSSA

Do you have any links to the ECS kit? Their website wasn't showing much on there.

As far as the fuel system, we redid the system on a '99 LS1 Firebird that we turbocharged a while ago. I'll have to look at the specs on what we did to that particular car, but we weren't even coming close to running out of fuel @ 698 to the wheels @ 7-8psi (I'd have to look it up to be sure of the exact figures---it was a while ago.

I just did some quick research on pumps for these cars (wrote the above 15 minutes ago).

Do you guys really pay $270+ for the Walbro pumps for these cars??

Mr. Big

Yes they are 260, and they are a complete rip off.

You won't run out of fuel if you have changed the pump out and upgraded the injectors. But by no means will the stock pump support anywhere near 698

I don't use an inline, i have a aeromotive eliminator pump, and i have no problems running out of fuel. But I also changed the feed lines to 8an and upgraded the fuel rail. Nothing is stock on the fuel system anymore.

I have also built fuel systems for ls1 f-bodys, and that is a completly different animal. Much easier to build a fuel system on an f-body since it only has 1 large tank.

When you get to the vette, you have to compete with a venturi system of switching between tanks, which means using the stock pump to keep the cycle going. It is a bitch.. pardon my french.

DSSA

No problem on the "descriptive terms" (I.E., "bitch") as I'm sure I'll use a lot worse as soon as I find a Z06 to play with.

Yes, we modified the stock tank, ran lines, and ran aftermarket injectors/pump on the Firebird.

I'm anxious to play with a C5 model though to come up with some setups to market. I'm used to building fuel systems that have to support 800-900 whp + on a 2.0 4 cylinder which is a PITA. (single rail, 1600cc injectors, lotsa flow (see: -10 lines or better).

I'm anxious to have one that I can experiment with as I refuse to use a customer car to play "trial-and-error" with.

Yes, totally agree on those pump prices. The price I pay for those things would make anyone who bought one from a "C5 Vendor" cry.