proxlamus© Posted March 30, 2005 Share Posted March 30, 2005 http://www.zcar.com/forums/read.php?f=1&i=547816&t=547505#reply_547816 Read that thread above.. very helpful no.. an adjustable fuel pressure regulator... allows you to adjust the amount of fuel pressure (max for example) so.. you can adjust it to run up to 60psi at full throttle or what not... a Rising Rate Fuel Pressure Regulator or (FMU - Fuel Managment Unit) - [same thing just different names].. increases the fuel pressure in relation to the boost pressure... so you can buy an RRFPR or FMU with a ratio like 12 :1 ... which means for every pound of boost (psi) the fuel pressure goes up 12psi... an RRFPR or FMU is ideal for a turbo/boosted application... ADFPR is great for standlone FI... or N/A cars.. or turbo cars with low boost. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted March 30, 2005 Share Posted March 30, 2005 I'm running a BEGI RRFPR now set to raise fuel pressure to 70psi total when full boost comes on, and tuned on the dyno with a wideband. I found that, adjusting fuel pressure this way just moves the fuel curve up and down as a whole... and my goal was to get it so that the leanest point of the fuel curve was in the mid 12:1 A/F ratio area. Now, my fuel curve at 14psi (stock turbo), with an I/C and the 70psi of fuel pressure, looks EXACTLY the same it looked when I dynoed at 10psi on bone stock everything... that is to say, it runs really rich from 3000-4000rpm, then is just about ideal from 4000-5000rpm, then after 5000rpm it leans out a little and then fluctuates a bit, and actually afte 5500rpm it did start to richen up again to 6000rpm where I had them stop the pull. I can actually lay my 10psi bone stock run, and the 14psi, intercooled and 70psi fuel pressure runs right over each other and the fuel curves are almost EXACT, not just the shape, but the actual AFR numbers are VERY close all the way up the revs. By the way, using the standard equations for figuring fuel flow from increased pressure, my stock 260cc turbo injectors are flowing approximately the equivalent of 320cc injectors at 70psi (actually 56psi after you figure for 14psi of manifold pressure). Considering you're running 370's and a little bit of extra fuel pressure to boot, you shouldn't be running lean on that setup at all. Quote Link to comment Share on other sites More sharing options...
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