By request, a CJM Stage 0 System.
03-12-2009, 01:16 PM
#23
You should definately have improvement in cold starts. The vacuum during cranking will lower pressure and assist in the cold start. Cold start does take extra fuel... But with the stock ecu already handling that, the larger injectors compound that factor and over-do it. The reduction in pressure while cranking will take care of a portion of that
03-12-2009, 01:48 PM
#24
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The stock system runs constant fuel pressure. One problem with this is when boost rises in the intake plenum and fuel does not you have less fuel to deal with. For example, assuming stock fp is 52 and boost of 20psi, you have 32psi of fuel pressure to work with. Continue now, and take it to the extreme... 52psi fuel pressure and 52psi of boost... no fuel would be injected 
With a fuel return system (including boost-referenced fuel pressure regulator) you get an extra 1psi of fuel pressure for every 1psi of boost 
There is no hard limit where 'you must have a fuel return system' in my opinion as there are a number of ways to setup fuel on a car.
With a fuel return system (including boost-referenced fuel pressure regulator) you get an extra 1psi of fuel pressure for every 1psi of boost There is no hard limit where 'you must have a fuel return system' in my opinion as there are a number of ways to setup fuel on a car.
Thanks for the explanation, Hal.
03-12-2009, 05:36 PM
#26
Correct, an NA car wouldnt need a RFS for increased capacity and what not... however it doesnt still have a slight advantage in the fact that you can tune your fuel pressure!!! this can aid in tuning, and can aid in slight adjustments as climates change and what not. i would often tweak my fuel pressure a psi here or there if my car was running lean or rich for the night.
03-15-2009, 09:00 AM
#27
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Wow, Charles this is exactly the answer to my thoughts of "Holy Crap I gotta drop $1K on a fuel return system when I MAY not need it for a basic Vortech build." This is awesome and I'll definitely be getting a Stage 0 now when I go Vortech in a month or two. Thanks!
03-18-2009, 07:34 PM
#31
I just noticed this on JWT's website suggesting that the fuel rails be drilled out for high HP applications - http://www.jimwolftechnology.com/wol...UEL_SYSTEM.pdf
Would you suggest this with the Stage 0 setup? Is there no point to this if you only need to support 400 hp?
Would you suggest this with the Stage 0 setup? Is there no point to this if you only need to support 400 hp?
03-19-2009, 08:03 PM
#33
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I just got it installed and I must say, it is a lot easier than I imagined - even when I messed up the install the first time lol.
Charles answered all my calls but I think we were both on vacation or something so I can't expect him to make this promise to everyone.
I got a used FPR I bought to troubleshoot my post-install problem (which turned out to be a swirl jet hole size), if anyone wants it - Charles can sell you a kit without an FPR to make it cheaper.
Anyway - I turned my psi way down to fix the hot start problem and this definitely wasn't possible without this kit. I'm doing 44psi without the vacuum line going to the plenum and tuning it that way.
If it's not obvious already, turning down the fuel psi will definitely affect your tune.
My hot start problem is close to 90% gone, I'm sure the last 10% is due to my UTEC 0% column numbers.
Charles answered all my calls but I think we were both on vacation or something so I can't expect him to make this promise to everyone.
I got a used FPR I bought to troubleshoot my post-install problem (which turned out to be a swirl jet hole size), if anyone wants it - Charles can sell you a kit without an FPR to make it cheaper.
Anyway - I turned my psi way down to fix the hot start problem and this definitely wasn't possible without this kit. I'm doing 44psi without the vacuum line going to the plenum and tuning it that way.
If it's not obvious already, turning down the fuel psi will definitely affect your tune.
My hot start problem is close to 90% gone, I'm sure the last 10% is due to my UTEC 0% column numbers.
03-19-2009, 08:11 PM
#34
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I just noticed this on JWT's website suggesting that the fuel rails be drilled out for high HP applications - http://www.jimwolftechnology.com/wol...UEL_SYSTEM.pdf
Would you suggest this with the Stage 0 setup? Is there no point to this if you only need to support 400 hp?
Would you suggest this with the Stage 0 setup? Is there no point to this if you only need to support 400 hp?
So the real question is, without bypassing the dampener - will there be a point in opening up these rail orifices ?
BTW - the stage 1 bypasses this completely
03-19-2009, 08:17 PM
#35
glad that the problem was just the jet size!
for those of you that didnt know, when you use a walbro 255lph pump, you need to enlarge the opening in the yellow venturi shown here:
if you do not, your regulator will not be able to adjust fuel pressure where you want it at idle.
for those of you that didnt know, when you use a walbro 255lph pump, you need to enlarge the opening in the yellow venturi shown here:
if you do not, your regulator will not be able to adjust fuel pressure where you want it at idle.
03-19-2009, 08:46 PM
#36
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glad that the problem was just the jet size!
for those of you that didnt know, when you use a walbro 255lph pump, you need to enlarge the opening in the yellow venturi shown here:
if you do not, your regulator will not be able to adjust fuel pressure where you want it at idle.
for those of you that didnt know, when you use a walbro 255lph pump, you need to enlarge the opening in the yellow venturi shown here:
if you do not, your regulator will not be able to adjust fuel pressure where you want it at idle.
03-19-2009, 11:19 PM
#38
how low are you able to get the pressure at idle now with that size? i would figure mid 30s if not lower
i should add that 5/64 to the how-to for the walbro, since a lot of people have PMd me with trouble finding a bit since i list it in decimal
i should add that 5/64 to the how-to for the walbro, since a lot of people have PMd me with trouble finding a bit since i list it in decimal
03-20-2009, 12:32 PM
#39
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(not my car)
I see a lot of you guys running a small fuel pressure gauge on an adapter under the hood. I've been thinking about doing that to see what my fuel pressure is.
I looked on the CJM site, but couldn't find a search tool or a fuel pressure gauge. Will any fuel pressure gauge work? I'm thinking the vibrations and heat might be pretty hard on a gauge mounted directly to the engine.
Any recommendations?