DIY VTT Double Shotgun Installation

doublespaces

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Oct 18, 2016
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What about this:
http://www.radiumauto.com/M14-Inverted-Flare-to-6AN-Adapter-P375.aspx
upload_2018-4-12_17-21-8.png


Or this:
https://store.034motorsport.com/14mm-inverted-flare-to-6an-adapter-fitting.html
upload_2018-4-12_17-20-56.png


Seems like there are more fittings once you search for "M14 1.5 bubble flare"
https://shop.boostinperformance.com/product-p/stm-6an-to14mm.htm
 

martymil

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The problem with most of these fittings the thread doesn't go far enough towards the bubble

And you end up only getting 1 two 2 turns on the thread because the thread on the pump is so short

Its a hit and miss with most of them

The speedflow one has the thread go all the way down to the bubble
 

doublespaces

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The problem with most of these fittings the thread doesn't go far enough towards the bubble

And you end up only getting 1 two 2 turns on the thread because the thread on the pump is so short

Its a hit and miss with most of them

The speedflow one has the thread go all the way down to the bubble

I was looking for a local source perhaps. Also is that speedflow fitting one continuous piece of metal? Seems like I saw a drawing earlier and it had something else going on that made it look like a two piece fitting with an oring.
 

amik

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Thanks for this write up! Completed my Double Barrel install last night and this guide was extremely helpful. Going to rework a couple fuel lines to clean things up a bit, but performance so far is great on full E85. Will have dyno results next Saturday.
 
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doublespaces

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Thanks for this write up! Completed my Double Barrel install last night and this guide was extremely helpful. Going to rework a couple fuel lines to clean things up a bit, but performance so far is great on full E85. Will have dyno results next Saturday.

I'm glad it helped you! Did you find anything wrong with it? I'm curious if it was different for other people.
 

amik

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Nothing wrong in the write up. My steering lines moved a little differently and I ran the low pressure fuel lines a little closer to the engine block, but I think that’s probably normal variation.

I do have some oscillation in the low pressure fuel sensor reading at WOT when the second HPFP kicks on. Looking at potentially moving the sensor ahead of the T feeding both HPFPs and at a FPR and a return line.

The oscillation doesn’t seem to cause any performance issue yet, but I’d like to get it smoothed out.
 
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doublespaces

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Nothing wrong in the write up. My steering lines moved a little differently and I ran the low pressure fuel lines a little closer to the engine block, but I think that’s probably normal variation.

I do have some oscillation in the low pressure fuel sensor reading at WOT when the second HPFP kicks on. Looking at potentially moving the sensor ahead of the T feeding both HPFPs and at a FPR and a return line.

The oscillation doesn’t seem to cause any performance issue yet, but I’d like to get it smoothed out.

Keep us updated on what you do. I have not activated the second pump yet so It may concern me as well.
 

amik

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Made 634 whp 609 ft-lb on the dyno today with the double barrel on E85. Will post logs and whatnot when I get some time this evening. This was the first shot at the tune so there are some issues that need to be sorted out but pretty pleased with the initial result.
 

doublespaces

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Made 634 whp 609 ft-lb on the dyno today with the double barrel on E85. Will post logs and whatnot when I get some time this evening. This was the first shot at the tune so there are some issues that need to be sorted out but pretty pleased with the initial result.

This is with both pumps active or just the one pump?
 

martymil

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Because the pump is switching the pressure valve on and off inside the pump so quickly you get oscillations

Port injection cars with large injectors do the same thing.

I moved the LPFP sensor next to the aftermarket filter under the car and it settled the oscillations quite a bit but still there.
I was thinking of putting a fuel rail dampener to see if it would help
http://www.radiumauto.com/Fuel-Pulse-Damper-Direct-Mount-Kits-P759.aspx
 
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amik

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Did you see the oscillation on the low pressure side only, or on the fuel rail as well? I see it in both places andnthe swings on the rail are more concerning. I’ve read a couple posts indicating that changes to the AIC R4 tables can help, as can a higher fuel rail pressure demand in the ECU map.

I have not tried either yet, but I did just receive a bunch of parts to upgrade the low pressure fuel lines going to the double barrel system, including return lines and a fuel pressure regulator. Hope to get them installed in the next week or so.
 

martymil

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From what ive seen the higher the pressure and smoother the hpfp rail is the more odcillations on the lpfp rail, i could be wrong its just an observation

I went out this afternoon and brought the fuel rail damper and associated fittings

Ill install it and report back if it made any difference

15245616736691105536460706786566.jpg
 
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Shane303

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I am getting oscillations between 2300-2500rpm with the single barrel. It affects both the low and high. I bumped the pressure to 7mpa in all low load cells and it seems to have helped slightly. What does everyone have set at low load? 7mpa= 1015psi
 

Erichale77

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From what ive seen the higher the pressure and smoother the hpfp rail is the more odcillations on the lpfp rail, i could be wrong its just an observation

I went out this afternoon and brought the fuel rail damper and associated fittings

Ill install it and report back if it made any difference

View attachment 10854
Are you running PI? I assume you're going to install that directly into fuel rail?
 

martymil

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No pi

I'm going to install it prior to the split in the lines for dual di and after the sensor to minimize the oscillations on the lpfp line