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| How to tell if you maxed out your fuel pump.. http://www.ladsm.com/forum/viewtopic.php?f=26&t=12025 |
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| Author: | cho [ Wed Oct 20, 2010 10:53 am ] |
| Post subject: | How to tell if you maxed out your fuel pump.. |
So I have a single hotwired denso supra fp installed in my car along with 660s. I know for a fact that the single supra fp is not enough to max out the 660s. Now i was hitting some type of hesitation/stuttering on the dyno on my high boost setting. I'm trying to knock out the possible culprits so i'm gonna be installing an ignition amplifier for any spark blowout issues, looking into w/m injection to minimize any detonation from heat and help the octane a bit. Now I have to look into the most expensive option, more fuel.. I wanted to know what are some symptoms for running out of pump? i didn't really wanna go BAP or twin walbros especially since the supra fp is brand new with less than 1000 miles on it. Another big reason to not go those options is that if i went twin walbros, i would feel more comfortable getting stainless lines to run over the old stock lines. The BAP is cool but obviously raising up the voltage will kill the pump faster. However the lack of power I'm making vs what i know I could make definatey wants me to figure out the next step. That way when I decide to make the jump, i'll be ready. Any thoughts? |
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| Author: | Black_gst [ Wed Oct 20, 2010 11:22 am ] |
| Post subject: | Re: How to tell if you maxed out your fuel pump.. |
was it running lean at WOT what did the wideband show??? |
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| Author: | fmedgsx [ Wed Oct 20, 2010 7:58 pm ] |
| Post subject: | Re: How to tell if you maxed out your fuel pump.. |
normally a lean condition that you can not correct no mater your adjustments and high injector duty cycles with low fuel flow |
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| Author: | Illeagle [ Thu Oct 21, 2010 12:03 am ] |
| Post subject: | Re: How to tell if you maxed out your fuel pump.. |
extremely high duty cycles and adding more duty cycle doesn't richen the car up. Thats when your pump is maxed out. Most cars its 1% fuel = 0.1 AFR. So if you are leaning out to 11.5:1 and duty cycles are at 90% currently, you add 5% to get your 11:1 and it still is at 11.5 and duty cycle is now 95%. So you go and add another 5% and your AFR is still 11.5 at the same RPM and your duty cycle is now 100%. You say fuck it, switch out to injectors that are twice the size. Which should bring your IDC back down to 50% right? So you do, start off at 50% and its still at 11.5:1. You say fuck it, im going to add 20% more fuel, richen the fuck out of it, and at 70% duty cycle on an injector twice the size, you should be at like a 9:1 AFR for sure. But you make the pull, and at the same RPM, you are still at 11.5:1. Why? WTF? Fuel pump is not flowing enough. Think of a garden hose, and the valve is opened up half way. There is a point in which putting a bigger nozzle on the end of the hose wont net you anymore water flow out of it. If you keep the garden hose analogy, how far the valve is opened up = fuel pump flow rating. ( ie. like cracked open barely = stock pump, half way is like a 255lph pump, and opened up all the way would be a dual 255lph) garden hose nozzle = injector size/duty cycle. Thats the best way I can explain it. |
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| Author: | cho [ Thu Oct 21, 2010 8:11 pm ] |
| Post subject: | Re: How to tell if you maxed out your fuel pump.. |
thanks sam.. it made sense. yay! unfortunately it sounds like I have a different issue.. boo! |
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| Author: | -red97rum- [ Fri Oct 22, 2010 10:24 am ] |
| Post subject: | Re: How to tell if you maxed out your fuel pump.. |
Sam has the best analogies! |
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| Author: | CaptainTonus [ Fri Oct 22, 2010 3:40 pm ] |
| Post subject: | Re: How to tell if you maxed out your fuel pump.. |
That Supra pump should easily flow enough to support 500-600whp. I use one on my car with stock feed and return lines and am supporting almost 500whp without problems. |
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