[Gator67]

I'm wondering if I can install a fuel pressure dampener between the unused ports on a base Sniper throttle body (front of the tb). My thinking is that this would be like installing a dampener on a fuel rail in a MPFI system, which is often done.

As background, I installed a Sniper/Hyperspark system. It's set-up to run returnless with an in-tank ZL1 fuel module, Vaporworx controller, and mostly 1/2" hardline. The car seems to run fine, I only noticed the fuel pressure fluctuations when I looked at the mechanical fuel pressure gauge (I verified the gauge). I installed a Radium fuel pressure dampener about 24" away from the throttle body (it's under the fuel pressure gauge in the photo), mostly because this was the easiest place to put it. This cut down on the fluctuations by half, but they are still there. I suspect I have to move the dampener closer to the throttle body, but I'm space limited (drop base air cleaner to clear hood). Thoughts about plumbing the dampener to those unused ports on the TB? Of course open to other suggested fixes.

[punkin]

Following...I too have a tight fit situation. I've considered a low profile carb hat and plumb cold-air duct. Curious what you come up with.

[Formulajones]

I run the Radium Engineering damper on both Holley EFI installs on our cars.

They are a pinch on the bulky side so they can be a challenge to hide or obscure.

From what I understand on how they work, and my short experience with them, they do work best closer to the injectors to dampen that pulsing affect they cause.

I'm not familiar with that particular Holley Sniper that you have with an internal regulator, I run Stealth units on both of ours that use an external regulator so my plumbing is a bit different. But if I'm not mistaken you could possibly loop the 2 unused ports in the front with the damper in between. Whether or not your air cleaner would fit over that would be another obstacle.

Another option since you basically have the inlet fuel line deadheaded to the unit. I also deadhead the Sniper Stealth units as that is how they are advertised to install so you can keep a "stealth" single fuel line coming up to the Sniper. I simply have my regulator hidden low behind the engine with a return line from there, keeping a stock appearance up top.

Anyway what I did in that instance was install the damper right at the fuel line inlet. Being a dual inlet I have the option of putting it in the line before the dual feed, or anywhere in between the dual feed, as long as it's close to the injectors. Once the air cleaner is installed you can't see it.
In your case it would be right at the inlet of your feed line. It would require a few fittings and re-bending that feed line to accommodate it. More work but it would be behind everything and less obvious.

I don't have any good pictures of how I did it but could take some. Being a Stealth unit I'm not sure it would help anyway but I'd still be interested in what you figure out.

[Gator67]

Originally Posted by Formulajones

I run the Radium Engineering damper on both Holley EFI installs on our cars.

They are a pinch on the bulky side so they can be a challenge to hide or obscure.

From what I understand on how they work, and my short experience with them, they do work best closer to the injectors to dampen that pulsing affect they cause.

I'm not familiar with that particular Holley Sniper that you have with an internal regulator, I run Stealth units on both of ours that use an external regulator so my plumbing is a bit different. But if I'm not mistaken you could possibly loop the 2 unused ports in the front with the damper in between. Whether or not your air cleaner would fit over that would be another obstacle.

Another option since you basically have the inlet fuel line deadheaded to the unit. I also deadhead the Sniper Stealth units as that is how they are advertised to install so you can keep a "stealth" single fuel line coming up to the Sniper. I simply have my regulator hidden low behind the engine with a return line from there, keeping a stock appearance up top.

Anyway what I did in that instance was install the damper right at the fuel line inlet. Being a dual inlet I have the option of putting it in the line before the dual feed, or anywhere in between the dual feed, as long as it's close to the injectors. Once the air cleaner is installed you can't see it.
In your case it would be right at the inlet of your feed line. It would require a few fittings and re-bending that feed line to accommodate it. More work but it would be behind everything and less obvious.

I don't have any good pictures of how I did it but could take some. Being a Stealth unit I'm not sure it would help anyway but I'd still be interested in what you figure out.

If the pulse dampener needs to be closer to the throttle body, the the simplest and most compact solution would be to run a direct mount pulse dampener directly to one of the front throttle body ports (through a couple 90 degree adaptors to get it below the air cleaner). The downside to this option is that I'd have to buy another pulse dampener (the one I'm currently running is the in-line version) and an adaptor or two. I'd go with this option if I were more sure that I could use the empty ports on the front of the throttle body this way.

My other options involve remaking the lines. Not the end of the world, but I'm not the best at bending 1/2" line and I end up wasting a lot of material (and time) before I'm satisfied.

[Formulajones]

I used the inline damper version on both sniper installs.
I just bought some AN fittings to make it fit the way I wanted, basically right at the inlet in the rear of the dual line setup.

Yes it costs a bit more with fittings and more finagling but I couldn't use one that bolted directly to the throttle body with a dual feed line (like a Holley carb if that helps paint a picture)

Fun making all this aftermarket stuff work huh, lol

[Formulajones]

Originally Posted by Gator67

If the pulse dampener needs to be closer to the throttle body, the the simplest and most compact solution would be to run a direct mount pulse dampener directly to one of the front throttle body ports (through a couple 90 degree adaptors to get it below the air cleaner). The downside to this option is that I'd have to buy another pulse dampener (the one I'm currently running is the in-line version) and an adaptor or two. I'd go with this option if I were more sure that I could use the empty ports on the front of the throttle body this way.

My other options involve remaking the lines. Not the end of the world, but I'm not the best at bending 1/2" line and I end up wasting a lot of material (and time) before I'm satisfied.

Looking at this more, if you wanted to run your inline damper on one of the front ports.....just thinking of ideas here.
Could you simply connect those 2 front ports with AN line with the damper in the middle?? Basically making a small loop that has fuel flow from both sides, that may have enough flex to stay below your air cleaner base and make the install look more uniform.
That is assuming both of those front ports have fuel flow?

That way you wouldn't need to mess with the rear line at all.

[HWYSTR455]

Originally Posted by Formulajones

... I also deadhead the Sniper Stealth units as that is how they are advertised to install so you can keep a "stealth" single fuel line coming up to the Sniper. I simply have my regulator hidden low behind the engine with a return line from there, keeping a stock appearance up top...

I missed where Holley instructions show to deadhead the Snipers/Stealth?

https://documents.holley.com/199r11971.pdf

Instructions and pic clearly show a bypass regulator.

Regular Sniper instructions:

https://documents.holley.com/199r11031r.pdf

Internal bypass regulator is used, return line comes directly from the throttlebody.

Many have had issues with the internal regulator, and the common corrective action is to install an external bypass regulator.

The psi issue has been addressed in numerous posts on the Holley EFI forums.

Just to say, in other non-holley installations, and in general, it is not recommended to run 2 dampers in series.



.

[HWYSTR455]

I'm not familiar with VaporWorx PWM pump controllers, but they generally vary voltage to the pump. Caution needs to be used when selecting a pump, and you need to understand the pump's operating voltage range.

You may need to adjust the pump voltage range within the VaporWorx controller to match the pump in use. If it is not adjustable, it needs to be within spec that VaporWorx recommends.

If voltage drops below X, and is outside of the low range of the pump, the pump just stops pumping. The sensor/transducer signals the controller psi has dropped out of range, and immediately increases voltage. If the voltage range is out of spec for the pump, it can cause an on-off-on-off rollercoaster.

Sensor/transducer also needs to be able to respond within a spec for the controller, and not have an error range outside of recommended for the controller.

.

[Formulajones]

Originally Posted by HWYSTR455

I missed where Holley instructions show to deadhead the Snipers/Stealth?

https://documents.holley.com/199r11971.pdf

Instructions and pic clearly show a bypass regulator.

Regular Sniper instructions:

https://documents.holley.com/199r11031r.pdf

Internal bypass regulator is used, return line comes directly from the throttlebody.

Many have had issues with the internal regulator, and the common corrective action is to install an external bypass regulator.

The psi issue has been addressed in numerous posts on the Holley EFI forums.

Just to say, in other non-holley installations, and in general, it is not recommended to run 2 dampers in series.



.

I probably didn't explain that clear enough. The Sniper Stealths purpose is to be able to run a single line up to the unit for a "stealth" appearance. They require a regulator as they don't come with one.

What I like to do is run the Aeromotive 13301 regulator, and I have it close to the engine, and run the return back to the tank. When I said dead head I was just simply explaining the very short run of feed line from the regulator to the EFI unit of about 2 feet.

The normal way to feed these EFI units would be the feed coming into the unit and the return coming out of the unit on the other side after it passes through all the injectors, similar to how a multi port EFI system would be done with fuel rails. But that defeats the purpose of having a "stealth" EFI system.

Running fuel through the unit and out the other side helps with the fuel pulsation issues that are most common with a single dead head type of line. Although the OEM's still usually incorporate a small dampener in most cases.

So in other words, any time you aren't running the feed through the Sniper and out the other side of the Sniper for continuous flow, or any other throttle body EFI, it's dead headed so to speak.

[Gator67]

Re-did the lines, replaced the fp gauge, moved the inline pulse damper closer to the throttle body, added a direct mount pulse damper to one of the unused ports. System pressurizes to 60psi with key-on engine not running. But with the car running, fuel pressure spikes to just under 80psi and fluctuates +/- 5psi or so.Is there any way the Sniper, O2 sensor, or the tune could be causing this, or is the problem have to rest with the fuel system (e.g., controller, pump, fp sensor, etc.)?

[Formulajones]

Is there a reason you wanted to try running 2 dampeners?

I've never tried running 2 dampeners like that, I'm not sure how well they would play together but can't imagine why it wouldn't work.

Are you regulating this back at the tank? Or are you trying to use the built in regulator on that Sniper?

I know the regulator supplied on those Sniper units have been a common fail point, either with dirt or just simply not working correctly.

[Gator67]

Originally Posted by Formulajones

Is there a reason you wanted to try running 2 dampeners?

I've never tried running 2 dampeners like that, I'm not sure how well they would play together but can't imagine why it wouldn't work.

Are you regulating this back at the tank? Or are you trying to use the built in regulator on that Sniper?

I know the regulator supplied on those Sniper units have been a common fail point, either with dirt or just simply not working correctly.

Running two dampers because the first one seemed to help, and from my reading, sometimes a second is needed to fully cure the problem. OEMs sometimes have two.

The GM fuel module (in tank) has a built in PWM type of regulator that is managed by the VaporWorx fuel controller.

I capped the port on the Sniper with the fuel regulator...this should take it out of the equation. It's still in there but should be non-op. Wonder if I should take it out altogether?

[HWYSTR455]

Originally Posted by Gator67

Re-did the lines, replaced the fp gauge, moved the inline pulse damper closer to the throttle body, added a direct mount pulse damper to one of the unused ports. System pressurizes to 60psi with key-on engine not running. But with the car running, fuel pressure spikes to just under 80psi and fluctuates +/- 5psi or so.Is there any way the Sniper, O2 sensor, or the tune could be causing this, or is the problem have to rest with the fuel system (e.g., controller, pump, fp sensor, etc.)?

Didn't realize you were running a mech gauge. Those things are junk, and wouldn't trust it.

Sadly, the base Sniper units do not have the ability to use a transducer, but maybe your digital gauge setup can support using a transducer.

Or, you can buy a stand alone gauge that supports transducers.

.

[Formulajones]

Originally Posted by HWYSTR455

Didn't realize you were running a mech gauge. Those things are junk, and wouldn't trust it.

Sadly, the base Sniper units do not have the ability to use a transducer, but maybe your digital gauge setup can support using a transducer.

Or, you can buy a stand alone gauge that supports transducers.

.

The Sniper will support a transducer for fuel pressure readings if you buy the "Super" Sniper, which is basically a Sniper that has extra inputs/outputs.

That's what I run so I can employ extra sensors for fuel pressure, oil pressure etc... and have that on the touch screen as well as datalogging.

[HWYSTR455]

Originally Posted by Formulajones

The Sniper will support a transducer for fuel pressure readings if you buy the "Super" Sniper, which is basically a Sniper that has extra inputs/outputs.

That's what I run so I can employ extra sensors for fuel pressure, oil pressure etc... and have that on the touch screen as well as datalogging.

Yes, the XFlow too. The earlier Stealth setups came with the HP ECU, not sure what they use now. With the HP ECU, you have an upgrade path to SEFI without having to upgrade the ECU.

Transducers are fast-acting, and very accurate. Datalogging is very granular.


.

[Formulajones]

Originally Posted by HWYSTR455

Yes, the XFlow too. The earlier Stealth setups came with the HP ECU, not sure what they use now. With the HP ECU, you have an upgrade path to SEFI without having to upgrade the ECU.

Transducers are fast-acting, and very accurate. Datalogging is very granular.


.

Honestly I'm not sure what they use now either. I've heard they separated the ECU's from the Stealth units on the later models. Not really what I wanted to hear but I guess makes it easier to service.

Yes those transducers are extremely fast acting. Took a bit getting used to vs an analog gauge. I actually compared the two, with good analog oil and fuel pressure gauges to the transducers at the same time on a running engine. Mainly to make sure they were accurate, but I found while the analog gauges were rock steady, the transducer readings do fluctuate around a few numbers back and forth extremely fast. Just normal I guess.
Did throw me for a loop on the fuel pressure though, related to this thread. I thought maybe the fuel pressure was fluctuating too much on the transducer so that's when I invested in a Radium dampener. I would have never noticed until the transducer was installed because the analog gauge was rock steady and I actually was driving the car for about a year before the switch to transducers and it ran perfectly fine. The dampener did calm down the transducer readings a good 90% but it still moves around back and forth a few PSI. Not a big deal. The big reason was so that I could datalog the fuel pressure during a pass and in a datalog I can look at any point of the run, so what I see fluctuating on the screen in real time doesn't really matter so much.

It's all pretty cool stuff when it works like it should.

[Scott65]

I'm curious if the root cause could be the frequency of the PWM signal to your fuel pump. I've never had to run a damper to have stable fuel pressure.(admittedly with a return style system) However I have experimented with PWM pump control, and the frequency that the pump is driven at makes a noticeable difference in the way the pump performs. Just an observation

[Formulajones]

As soon as I read your post I thought the same thing that Scott has just posted.

I have no experience with the GM PWM pumps but that sure sounds like something that would cause fluctuation readings on a fuel pressure gauge.

I think you're okay on the Sniper regulator, if it's capped and not a player you should be fine there.

[Gator67]

Just to check I removed the pressure regulator from the throttle body...no change. The Vaporworx controller is connected to a fuel pressure sensor just off the tank to adjust the voltage to the pump. Carl at VaporWorx has been super helpful, so pretty confident it will get sorted out.

[Scott65]

I'd be asking if the pressure sensor can be relocated to read from very close to/at the throttle body so it can be more accurate. Some of the OEM use a pressure and map sensor, or in Ford's case a combination sensor right at the rail to help provide good feedback for pressure control.