atljar

Is there any reason people arent using these on the low side systems? They are compatible with PWM pumps. Most of the charts show pretty massive flow gains.

Recent vendors have shown that the low side lines arent a restriction on ~8 to 900hp E85 cars. They are just putting add on pumps that attach to the factory lines and sending fuel forward.

The only down side is pump life at 17v/21v, BUT they would only be run there under boost.

atljar

No one has tried this?

HessViper

atljar

LOL. Right?

So there are 2 players here from that I found that work with PWM. Works by boosting input voltage to fuel pump module, which in turn goes to the pump. Seems like a bad idea to spike your module with high voltage but JMS tech hotline says NBD as does Kenne Bell Tech, with the disclaimer that their 17v kit can be run full time, but 21v can only be used on hobbs

Kenne Bell. Triggers off external Hobbs if wanted . 17v (75% advertised gain) or 21v(100% advertised gain) options. No ramp up algorithm. Tech says about 17% gains in pump output from each additional volt. Also works as a regulator to stabilize voltage if you have a bunch of boom boom stereo etc

JMS. Works with Hobbs, internal Hobbs, grounding switch or 5v trigger (could run off tps or map etc). 18-22v scale-able voltage output. Claims of 85% more fuel. Has a ramp up algorithm via time or via 0-5v voltage reading (ie 10% boost at 2.5v Map reading, 50% boost at 3.0v map reading, 100% boost at 3.5v map reading) That scaling would be amazing tied into a map sesor
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FYREANT

RoxyCarter

This is one of the more brilliant threads lately.

if GM is going to fix their cars, this will be the way they would need to go for cost effectiveness.

also, the part about the stereo. You have us reflecting on times the vehicles failed, which have the 3lz sub in the back... We are curious if the stereo being up loud on a song with bass causes the fuel pump to run weak and the limp modes to throw.

50f degree temp failures occurred, and every one at that temp was with the stereo blaring.

meanwhile, with the stereo off, we have gotten into the 30s and no failures sometimes.

you've found the last piece to the puzzle we think.

atljar

I doubt that any charging issues are occurring at WOT. My comment above is more pointed at a car with significant amounts of electrical drain at low rpm/idle where the alternator doesn't have full charging rpm. The pump blasters will help hold Voltage stable to the pumps so you don't get fluctuating output, which could cause your BLM to constantly be changing

RoxyCarter

1 volt is 17% flow. And we have known this long before your post actually. Just never put 2 and 2 together about the stereo being up loud.

half a volt is 9% flow.

This stuff matters in our case.

we will test again and let you know.

Mk3chris

Interesting thread. I have a family member that upped the voltage on a newer supercharged coyote motor and had success. I'm very interested in seeing how it works on our cars.

The OEM sub/amp is very efficient and draws very little power. I don't have the specs in front of me but I'd be willing to bet the current draw from just rolling up the windows is actually a larger draw on the electrical system than the whole stereo system at full volume.

Mr. Gizmo

RoxyCarter

could be that there is no impact.

people joking that a 1 volt drop would not matter... are not realizing, GM spent a lot of money to go to the zr1 in tank pump to flow a mere 20% more fuel.

17% in the wrong direction is a very big deal. 1 volt.

atljar

Mike... Just put a meter on the car (or watch voltage on the dash) . At idle, no radio on and at idle, radio as loud as you are listening to it. Then do the same test at like 4k RPM.

Now can we get back on topic..... Anyone, anyone at all that has done this in a c7? Only post I saw from a reputable source was from MTI that said it wouldn't work on PWM fuel pumps. Odd that the manufactures of the boosters say explicitly say it WILL work with PWM.

HessViper

they list a very specific booster for GM vehicles. I got to this one by selecting Camaro. Corvette takes a person to the same one. There is a special checkbox for GM Vehicles.

Perhaps someone who had bad luck with this product did not get the one specific for GM vehicles?

https://www.jmschip.com/electric-fuel-pump-p2000gmp2/

atljar

GM uses a B+ / always hot supply to their pump driver modules. Most other manufactures use a switched supply.

I assume the Gm specific version "may" have a switched turn on lead? Like a remote wire in the stereo world. Or it "may" just not have a status light that shows power like the other units do?

Either way, my guess is the only real changes to the GM specific unit are to address parasitic draw with engine off. EDIT: Also read that the JMS generic unit will regulate output to 14.5v when the unit is not boosting. On the JMS GM version, there is no regulation (Battery/system voltage output) unless the unit is in boosting mode. Also see there are 3 different GM versions, that all say they are constant B+ units.

PM-2000-GM is typically used on GM/DCX vehicles with constant power applied to the fuel pump driver module.

PM-2000-GMP is typically used on 2010-2015 Camaro, 2008-2013 C6 Corvette, and 2008-2015 Cadillac CTS-V with constant power applied to the fuel pump driver module.

P2000GMP2 is used on 2016-2017 Camaro with constant power applied to the fuel pump driver module.

(My note....C6s didnt have a driver module, they were on/off and a relay driven by the PCM, so?? Just looked at wiring diagrams to confirm. Also a 13 camaro has a dedicated Fuel pump driver like we do, where as the 16+ have the a chassis control module (semantics only?)


The more I read about the JMS unit, the more I like it. Their install instructions give some really killer insights into how the unit works and can be customized. https://www.jmschip.com/content/Powe...al_v11_WEB.pdf

HNK

davepl

I've done it to crutch a fuel system before but the version I had ran the alternator field up to 17V or whatever, so the whole car experienced it. I didn't care for that with modern electronics, even though they're likely briefly tolerant. At least that's my possibly-flawed understanding of it,

The problem with our cars is that the limitation isn't the low electrical side of the pump, it's the high side. And being positive displacement, it doesn't reallty matter how much the low side does. With an incompressible fluid like fuel, it can't store energy and it doesn't help.

atljar

Upgrading the low side has shown substantial power capability gains on a lot of cars. Dsteck, mti, cpr, weapon X etc are all boosting the low side to make power, at least initially.
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HessViper

correct, it presents itself in the high side via pressure drop p0089, but the real culprit is the low side. The stock programming allows for 10psi drop in the low side line BEFORE the p228c code ever throws (low side pressure loss)

71psi I believe is where it is supposed to be on the low side line, and below 61 psi is when the code throws.

If one maintains 71psi with NO pressure drop at all, that will allow the high side to flow much more than, say, if the low side is at 62psi (which wont throw the code on the low side, but the high side may/will throw the code p0089 first on certain vehicles)

Then theres the option of running even MORE psi in the low side, and then the high side picks up the ability to flow and support even more power as a result. 75 or 80psi when under WOT boost, with the twin in tank pumps from Fore for instance, and the stock high side system will impress you. Over 1000hp at the crank is possible with such a setup on 93, with perhaps (optional) minimal meth. Depends on your IAT and which blower you are running, if one can maintain 75+ psi on the low side line, while under WOT.

HessViper

Upon first start, the z06 we tested, climbs up into the 14.5+ volts in the first minute. Then it lowered back to 13.7-13.8 and stayed in that range, regardless what we did to the vehicle.

Take the stereo out of the equation for this discussion... our first question is "does the car have a computer program that is instructed to maintain this 13.8 volts?"

It seemed, whatever we did, the car maintained this voltage, even at higher RPM while driving in a lower gear, but not under WOT.

atljar

The voltage regulator is responsible for , eh, regulating voltage