Ive got a fuel pressure gauge I wanna hook to my stock FPR, I want to know if i need to get an AFPR or not. Where do I hook it to? All the install directions ive seen are to hook it to an AFPR...
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I used to have a 420A...
'92 TSi AWD
11.8 @ 119mph 470awhp 405 ft/lb torque 30psi on E85 w/ Borg Warner S256 Turbo
#10059, "RE: Fuel pressure Gauge install question" In response to Reply # 0 Aug-18-04 11:41 AM by HybriDSM
In theory, you would want the AFPR with the FP gauge for the simple reason that there really is nothing to monitor unless it's adjustable in the first place. Oil pressure you can't adjust but want to monitor it regardless but fuel pressure is good to monitor once you start changing its value.
That being said, if you really want to install it, you might want to look into tapping in an AN fitting somewhere in the stock line that has a sender adapter built in. As far as moutning mine, it went in at the same time as my custom fuel line so the AN adapter was part of the process and was very easy to incorporate the FP gauge.
There are a couple of ways to do it, but generally you put in the FP gauge in conjunction with the AFPR as that is what you need the gauge for.
Here is a link to the SteveTek high flow line upgrade I did that explains some theory and installations things that may help you: http://www.stevetek.com/R-FuelSys.html
#10060, "RE: Fuel pressure Gauge install question" In response to Reply # 1 Aug-18-04 11:49 AM by Hult250R
well I want to put it in to see if I need an afpr. To see if my 255 is over running my stock FPR By "stock line" do you mean the fuel line that runs to the fuel rail? I could just get a fitting to hook in the gauge to that line no problem.
----------------------------------------
I used to have a 420A...
'92 TSi AWD
11.8 @ 119mph 470awhp 405 ft/lb torque 30psi on E85 w/ Borg Warner S256 Turbo
#10061, "RE: Fuel pressure Gauge install question" In response to Reply # 2 Aug-18-04 01:11 PM by HybriDSM
Generally, the stock line is super restrictive (The line that goes from tank to rail, a hard line to can trace under the car from tank, to fuel filter to fuel rail). You can run plenty fast on it but at a certain point it's just too small to flow enough fuel. Putting in the fuel pressure gauge won't tell you much since by default, you'll be running a very high FP to flow the fuel you need to keep you from running lean.
The stock FPR is notoriously limiting too as it does not increase FP with boost. It runs off vacuum but does not increase Fp to compensate for boost related fuel needs. AFPRs are generally a 1:1 thing increasing FP 1 PSI per 1 PSI of boost. This helps keep the fuel curve more managable.
Just think of it this way. When there is less volume in the line, you have to run a very high pressure to meet fuel requirements. Putting the gauge in will tell you what pressure you are running but since you can't adjust it, it's more window dressing at that point.
It's worthwhile, but it's moreso when you have adjustability.
#10063, "RE: Fuel pressure Gauge install question" In response to Reply # 4
The sender goes on the line before the rail to determine FP. That adapter I linked is an in-line piece that houses the sender and feeds the signal to the gauge.
#10065, "RE: Fuel pressure Gauge install question" In response to Reply # 6
Well not really. Jeff is running a stock FPR for a 12 second car. I wouldn't worry too much about it for now if I were you.
You can certainly use it for a long time, but it makes tuning more difficult in high horsepower applications due to it's limitations in regulating FP. It's just one of those components in the system that is a bottleneck over time. If you can install the FP gauge, go ahead. It certainly can't hurt.
#10066, "RE: Fuel pressure Gauge install question" In response to Reply # 3
Originally posted by HybriDSM Generally, the stock line is super restrictive (The line that goes from tank to rail, a hard line to can trace under the car from tank, to fuel filter to fuel rail). You can run plenty fast on it but at a certain point it's just too small to flow enough fuel. Putting in the fuel pressure gauge won't tell you much since by default, you'll be running a very high FP to flow the fuel you need to keep you from running lean. The stock FPR is notoriously limiting too as it does not increase FP with boost. It runs off vacuum but does not increase Fp to compensate for boost related fuel needs. AFPRs are generally a 1:1 thing increasing FP 1 PSI per 1 PSI of boost. This helps keep the fuel curve more managable. Just think of it this way. When there is less volume in the line, you have to run a very high pressure to meet fuel requirements. Putting the gauge in will tell you what pressure you are running but since you can't adjust it, it's more window dressing at that point. It's worthwhile, but it's moreso when you have adjustability.
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