Aux Fuel Pump: SMG/Hobbs Kit

[LS3_SPEED6]

Hey everyone,

Any users on here running the SMG aux pump kit? I know it uses a hobbs switch for activation. How has it been working out? Has it been reliable? Does the hobbs activation effect any tuning? Thinking of going that route. Thanks.

[RupertPupkin]

Originally Posted by LS3_SPEED6

Hey everyone,

Any users on here running the SMG aux pump kit? I know it uses a hobbs switch for activation. How has it been working out? Has it been reliable? Does the hobbs activation effect any tuning? Thinking of going that route. Thanks.

Why not run the DSX?

[Scott S]

I am running the SMG Aux kit with flex fuel and E85 no issues. It is a couple hundred cheaper than DSX kit also.

[LS3_SPEED6]

Originally Posted by Scott S

I am running the SMG Aux kit with flex fuel and E85 no issues. It is a couple hundred cheaper than DSX kit also.

Ok cool good to know!

[graf101]

I would steer clear of any SMG branded part. I happen to know the owner and guy who works for him. There is a reason why they both do not run their own SMG aux pump kit.

[JANNETTYRACING]

Originally Posted by LS3_SPEED6

Hey everyone,

Any users on here running the SMG aux pump kit? I know it uses a hobbs switch for activation. How has it been working out? Has it been reliable? Does the hobbs activation effect any tuning? Thinking of going that route. Thanks.

I would recommend DSX, His pump control system is far superior to Hobbs switch.

With a hobbs switch you will get a sudden hard surge in fuel pressure, which causes all kinds of tuning nightmares of which no one talks about or do not care that it happens.

When the fuel pressure swings wildly you get rich and lean surges that follow.

At the end of the day it is not the pump itself, it is the quality of the fittings hose and control system that sets them apart.

Never skimp on fuel system, most engine failures can be linked to lack of fuel supply.

Ted.

[AGP Turbo]

Originally Posted by JANNETTYRACING

I would recommend DSX, His pump control system is far superior to Hobbs switch.

With a hobbs switch you will get a sudden hard surge in fuel pressure, which causes all kinds of tuning nightmares of which no one talks about or do not care that it happens.

When the fuel pressure swings wildly you get rich and lean surges that follow.

At the end of the day it is not the pump itself, it is the quality of the fittings hose and control system that sets them apart.

Never skimp on fuel system, most engine failures can be linked to lack of fuel supply.

Ted.

Wow, I didn't even notice that till you mentioned it. Sudden on/off with no fuel pressure regulator. Seems like typical trash sold today with no thought or standards behind it. But it's cheap so they'll sell tons.

[IKILLEDSUPERMAN_ZL1]

Originally Posted by JANNETTYRACING

I would recommend DSX, His pump control system is far superior to Hobbs switch.

With a hobbs switch you will get a sudden hard surge in fuel pressure, which causes all kinds of tuning nightmares of which no one talks about or do not care that it happens.

When the fuel pressure swings wildly you get rich and lean surges that follow.

At the end of the day it is not the pump itself, it is the quality of the fittings hose and control system that sets them apart.

Never skimp on fuel system, most engine failures can be linked to lack of fuel supply.

Ted.

How does the DSX kit turn on the aux pump ? Does it not have a sudden surge of fuel like a Hobbs switch ? Is it activated progressively?

[JANNETTYRACING]

Originally Posted by IKILLEDSUPERMAN_ZL1

How does the DSX kit turn on the aux pump ? Does it not have a sudden surge of fuel like a Hobbs switch ? Is it activated progressively?

I do not have all the specific you might contact DSX for the details.

I do know they use a Map signal, and I believe a soft start system.

[Batmanntexas]

Originally Posted by JANNETTYRACING

I would recommend DSX, His pump control system is far superior to Hobbs switch.

With a hobbs switch you will get a sudden hard surge in fuel pressure, which causes all kinds of tuning nightmares of which no one talks about or do not care that it happens.

When the fuel pressure swings wildly you get rich and lean surges that follow.

At the end of the day it is not the pump itself, it is the quality of the fittings hose and control system that sets them apart.

Never skimp on fuel system, most engine failures can be linked to lack of fuel supply.

Ted.

Originally Posted by AGP Turbo

Wow, I didn't even notice that till you mentioned it. Sudden on/off with no fuel pressure regulator. Seems like typical trash sold today with no thought or standards behind it. But it's cheap so they'll sell tons.

So, as long as their is a pressure regulator in the system the rich/lean spikes wouldn't be that much of a concern?

[Greenhornet2]

Originally Posted by Batmanntexas

So, as long as their is a pressure regulator in the system the rich/lean spikes wouldn't be that much of a concern?

If you have a return system the regulator would keep it from a large pressure spike. The dsx aux pump system is advertised as being run with the stock non return style system. It's commanded on by boost pressure and unsure if it's also linked to the fpcm, or the fpcm just lowers the demand for the in tank pump.

[LS3_SPEED6]

Originally Posted by Greenhornet2

If you have a return system the regulator would keep it from a large pressure spike. The dsx aux pump system is advertised as being run with the stock non return style system. It's commanded on by boost pressure and unsure if it's also linked to the fpcm, or the fpcm just lowers the demand for the in tank pump.

The differences between the dsx and smg is just the way it is activated. DSX uses an electronic controller and turns on by using a MAP sensor at a certain psi (or kpa). It also has a prime function and override. SMG is by a hobbs switch hooked via vacuum line getting boost reference off the intake manifold. Can also very easily wire in an override.

I ended up talking to a handful of very competent tuners on this. Tuners that deal with this all the time, and have this platform down to the wire. Since the car has an FPCM, making changes along with other things will not cause any of these issues. You just have to know what you are doing.

[Greenhornet2]

Originally Posted by LS3_SPEED6

The differences between the dsx and smg is just the way it is activated. DSX uses an electronic controller and turns on by using a MAP sensor at a certain psi (or kpa). It also has a prime function and override. SMG is by a hobbs switch hooked via vacuum line getting boost reference off the intake manifold. Can also very easily wire in an override.

I ended up talking to a handful of very competent tuners on this. Tuners that deal with this all the time, and have this platform down to the wire. Since the car has an FPCM, making changes along with other things will not cause any of these issues. You just have to know what you are doing.

If that is the case wouldn't it cause a pressure surge in either case?

[JANNETTYRACING]

Originally Posted by Greenhornet2

If you have a return system the regulator would keep it from a large pressure spike. The dsx aux pump system is advertised as being run with the stock non return style system. It's commanded on by boost pressure and unsure if it's also linked to the fpcm, or the fpcm just lowers the demand for the in tank pump.

True, we have incorporated return regulators successfully.

If tuning with HPtuners we can get in to the FPCM and make adjustments to improve the pressure spikes.