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#1
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Fuel pressure dampener install with Sniper
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.
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"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
#2
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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.
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1968 Firebird IAIIa 522 340 E-heads Northwind with XFlow TBI 4L80E 3.50:1 Rear |
#3
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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. |
#4
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Quote:
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.
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"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
#5
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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 |
#6
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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. |
#7
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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.)?
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"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
#8
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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. |
#9
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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?
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"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
#10
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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
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'65 Tempest 467 3650# 11.30@120.31 |
#11
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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. |
#12
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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.
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"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
#13
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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.
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'65 Tempest 467 3650# 11.30@120.31 |
#14
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Instructions say that the fuel pressor sensor is supposed to go near the tank...if it's close to the throttle body the controller ends up chasing slight changes in pressure from the injectors opening and closing. Though I may move it tomorrow and see what happens.
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"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
#15
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I used a Radium Pulse Dampener after talking with some of the folks over on the Holley EFI support forum. I 'm using the Sniper Quadrajet version with the 12-303 in-tank fuel pump/regulator/return in the stock tank on my '70 GTO in a dead-head configuration.
The addition of the dampener was vital as I was retaining the stock steel fuel line. The only rubber line used was from the fuel filter (which was mounted to a custom fuel pump block-off plate) up to the throttle body. I wanted to maintain a stock-ish appearance with the dual snorkel air cleaner too. Here is a link to the post: https://forums.holley.com/showthread...raJet-Question Post #7 shows pictures of my completed installation.
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Larry |
#16
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Quote:
Like I mentioned, I have no experience with these GM pump setups. I assume they are pressure regulated back at the tank and your sensor is obviously back there too. I've always plumbed a car with a regulator as close to the carb, or EFI unit, as possible with a full length return line to ensure accurate fuel pressure regulation is at the source that feeds the engine. It removes the possibility of other potential feed issues that can arise running a dead headed line 25 feet through the car. That's a lot of line with injector pulsation. Maybe it matters or maybe it doesn't. Other guys that run dead head systems that have more experience with EFI may be able to comment. Scott??? I know many guys don't want to run another line for what ever reason but it keeps the dead headed portion of the line at the EFI unit very short. I'm guessing much easier to control injector pulsations. Not to mention keeps cool fuel circulating at all times close to the engine, something I've found beneficial living in Arizona. That's how I plumb mine anyway and with the Radium dampener, and a short 2 foot run of deadhead line from the regulator to the EFI unit, the pressure is rock steady. |
#17
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Quote:
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"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
#18
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Does the vaporworx use a second input besides fuel pressure? Map or tps, or maybe rpm? I studied their stuff briefly, but don't remember now. My general take away is that returnless is the most difficult way to go for a retro fit. And though my most desirable way to go would be closed loop PWM returnless, I've avoided it because I can't find a way that seems like it would work well in my retrofit application. I hope the OP can get it sorted and report back what works.
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'65 Tempest 467 3650# 11.30@120.31 |
#19
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Quote:
I do them all with a return style setup. |
#20
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Quote:
__________________
"If the best Mustang is the Camaro, the best Camaro is actually the Firebird" David Zenlea |
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