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| nitroxr |
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Hello all.
Got a couple of questions about my nitrous setup. Ive got it on a 5L Windsor (EF XR8). Now my problem is when i hit the nos button my fuel pressure drops about 7psi (from 32 to about 25) is this normal? or do i need a stronger fuel pump?. We noticed that there are two fuel lines coming up from the fuel tank and thought maybe each one is for 4 injectors, so we connected the fuel lines together so that the volume of of fuel was higher and would maintain same pressure. However the car now does not start. Is the second line just a fuel return line to the tank?? How can i keep the fuael pressure up when applying the nos? help would be much appreciated Cheers, Luke |
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| xr8ute |
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One of those lines will be the return line.
Is it a wet or dry nitrous setup? Maybe your fuel pump is not up to scratch...? |
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| nitroxr |
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cheers thought so aye... after it didnt work. Its a wet system. so it injects fuel and nos in same jet in intake plenum. The fuel to the jet is supplied from a pressure test port near where the fuel line goes into the fuel rail.
i rang some guys about fuel pumps and they said they can get +100 hp and +300hp pumps in... does this meen more pressure or fuel volume? Also... after pressing the nos button it goes down to 25 but after about 3 secs it goes back up to 32. |
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| ebs_4l |
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yea, deffinatly need bigger pump, the pressure is controlled by the reg, so a bigger pump wont increase pressure (unless it flows more than the reg can return) but will allow a s**t more flow
_________________ EB 4L, 8.4:1, R154, GT4202r, 4in exhaust, Greenslade Engineering exhaust manifold, plenum chamber, 90mm throttle, Garrett W2A cooler, Surecam custom, autronic SM4, Bosch 120lb, Crane HI-6, LX-92, LM-1, Turbosmart Reg, 2x bosch 044, turbosmart 48 gate. 470kw+ @ 18PSI |
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| xr8ute |
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Yep, def bigger pump. There are really 2 ways to go about it....
You can replace the in-tank pump for something with larger capacity, like a Walbro GSS-341, which is a 255lph. I paid $160 for mine. Or you can add an in-line pump to assist the stock in-tank pump. These are like the Vortech T-Rex pumps that come with supercharger kits, and are rated on their own at 190lph and can sustain that flow at high fuel rail pressures. Can't remeber what CAPA sells them for, but 2nd hand ones seem to go for ~$100... The in-line are arguably less messy to fit, but you need at add another 12v relay to power it. If you can do it yourself, I reckon a larger in-tank Bosch or Walbro pump would be the go. |
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| nitroxr |
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cool, cheers for the info aye.
What would these pumps be rated at? +100HP? +300? Wheres best to buy one of these pumps? |
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| xr8ute |
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I am not sure what the stock pump size/rating is for the EL XR8?
Some good info on fuel pumps at these links, http://www.stealth316.com/2-fuelpumpguide.htm http://www.motorsportsdigest.com/tech/perform4.htm Walbro GSS-341 for $164 on eBay, http://cgi.ebay.com.au/WALBRO-GSS341-60 ... dZViewItem |
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| nitroxr |
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Thanks for the info. Having a look. looks like GSS-341 and GSS-342 are almost the same but have the outlet 180 degrees off from the inlet on the other side. I wrote a email to a shop on ebay and the said that the GSS-342 would fit mine. Is this correct or dosnt it matter?
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| EDXR8 |
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Stock pump flows around 90l/hr whereas the walbros flow 255l/hr which equates to around 5-600hp. The GSS-340, 341 and 342 pumps will all fit but the 341 is probably the easiest one to fit as it has the inlet/outlet on the same side of the pump like the factory one but any will do fine.
Technically you should not really need a new pump while still on factory injectors (although its never a bad idea especially if its a bit old). I would also check fuel pressure regulator as you should see a fairly significant increase in fuel pressure when you hit the nos, but probably starting with fuel pump is the best idea and take it from there. Just be carefull, I wouldn't be running any nos through it until its sorted as those head gaskets wont hold on for long. |
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| nitroxr |
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So your syaing the standard fuel pump assuming its in good condition handle the nos kit ? Rmemebering that the nos kit injects alot of extra fuel?
Also.. i thought the 341 was the one with the outlet on the other side. lol man this is so much work |
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| EDXR8 |
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The pump is boarderline but should still outflow the injectors. Still having a decent fuel pump in there will make sure pressure is maintained but IMO, a decent fuel pump along with some 24lb injectors is a minimum for a nos setup (depending on how much nos you are running).
And yes sorry, the 342 has the inlet/outlet on the same side, while the 341 is offset. |
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| nitroxr |
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ok. Cheers once again for the info. I might check the basics first like fuel filter and regulator before getting a 342. Its also only running a 100 HP shot.
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| ebs_4l |
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dude, is this a wet nos kit?? the extra fuel isnt coming through the injectors... so the pump is supplying the injectors plus the fuel nozzle/s, thats where his pressure drop is coming from...
dont fit larger injectors, youll create more probs.... absolutely no need, since the nos has it's own fuel system, the injectors dont have to supply any more fuel than normal.... UNLESS of course, you run a dry system and use injectors for extra fuel
_________________ EB 4L, 8.4:1, R154, GT4202r, 4in exhaust, Greenslade Engineering exhaust manifold, plenum chamber, 90mm throttle, Garrett W2A cooler, Surecam custom, autronic SM4, Bosch 120lb, Crane HI-6, LX-92, LM-1, Turbosmart Reg, 2x bosch 044, turbosmart 48 gate. 470kw+ @ 18PSI |
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| ebs_4l |
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EDXR8 wrote: I would also check fuel pressure regulator as you should see a fairly significant increase in fuel pressure when you hit the nos. what the?? please explain how this pressure increase occurs
_________________ EB 4L, 8.4:1, R154, GT4202r, 4in exhaust, Greenslade Engineering exhaust manifold, plenum chamber, 90mm throttle, Garrett W2A cooler, Surecam custom, autronic SM4, Bosch 120lb, Crane HI-6, LX-92, LM-1, Turbosmart Reg, 2x bosch 044, turbosmart 48 gate. 470kw+ @ 18PSI |
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| EDXR8 |
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The pressure in the nitrous lines is plumbed to the vacuum line of the regulator which increases the fuel pressure. Not sure how much pressure is actually supplied to the reg, but for every 1psi of pressure applied to the reg vacuum line, the fuel pressure also increases 1psi. Its a cheap and fairly effective way of making the factory system supply the extra fuel that nos requires.
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