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Old 09-14-2008, 06:51 PM   #1
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Default Aeromotive FPR - SORTED!

i bought the one below from Aeromotive to dump the stock fpr and stupid vortech to cure my lean afrs after adding a starion FMIC.http://www.aeromotiveinc.com/products.php?prod=10
so took both the oem and vortech fpr out, installed the new unit, used a pressure gauge that plugs in one of the ports, took out the vacuum line, and set the base pressure at 43psi.

took it out for a spin after setting the wastegate to 4psi, and suprise, i'm even ******* leaner. 15 afr's.
open the hood, increased the base pressure to 60psi after 3 more pulls, and currently i'm doing 12.9 afr's when flooring it, and even after 4k, in open loop mode, not helping. I want to make at least 5/6psi, so here's my question:

the specs say:
"Fuel pressure rises on a 1:1 ratio with boost."
if base pressure is now 60psi, and 1:1 means 1psi of fuel pressure per 1psi of boost, that gives 64psi at 4psi of boost correct? i think the math i'm doing is wrong, because at 60psi base pressure, i am too rich off boost, so, dont think it will help increasing the pressure more.
Wallbro 255 is going in tomorrow.

Sould i increase it to 70psi base pressure and try again? wtf am i doing wrong???

thx in advance

Last edited by mx5dude69; 09-15-2008 at 01:25 PM. Reason: problem solved
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Old 09-14-2008, 07:01 PM   #2
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Hahaha. Sorry.

Your Vortech VPR is a rising rate regulator. it adds fuel X PSI of fuel pressure per pound of boost. That X value is more than 1. Probably like 6-8, but I dunno. Anyway, replacing it with a 1:1 rate FPR is the wrong move. Put the vortech back.

Oh, to cure your lean AFR's after installing an intercooler, you just need a different disk for the Vortech unit to add more PSI of fuel / unit boost.
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Old 09-14-2008, 07:08 PM   #3
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Originally Posted by patsmx5 View Post
Hahaha. Sorry.

Your Vortech VPR is a rising rate regulator. it adds fuel X PSI of fuel pressure per pound of boost. That X value is more than 1. Probably like 6-8, but I dunno. Anyway, replacing it with a 1:1 rate FPR is the wrong move. Put the vortech back.

Oh, to cure your lean AFR's after installing an intercooler, you just need a different disk for the Vortech unit to add more PSI of fuel / unit boost.
cant be that. with the vortech was leaner than now...
and i read here the 8.1 disk would be an overkill to the stock FP.
any other ideas?
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Old 09-14-2008, 07:19 PM   #4
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You need a tunable ecu my friend. Get a MS (or any other one, I don't care) and then keep the aeromotive fpr.
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Old 09-14-2008, 07:20 PM   #5
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Originally Posted by mx5dude69 View Post
cant be that. with the vortech was leaner than now...
and i read here the 8.1 disk would be an overkill to the stock FP.
any other ideas?
Of course, what was I thinking. I'm out of ideas.
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Old 09-14-2008, 07:34 PM   #6
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A few years ago I had an adjustable FPR that was a direct replacement for the factory FPR on my 94. It looked like the factory one except the adjustable part and bolted to the fuel rail. Ended up giving it to a friend. No idea what brand it was. Does anybody know of something similar?
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Old 09-14-2008, 07:45 PM   #7
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Originally Posted by patsmx5 View Post
Of course, what was I thinking. I'm out of ideas.
Dude, sarcasm doesnt help. what I mean is if the vortech gives more pressure, how exactly does that work, if this one is actually giving richer afr's?
I just dont know what 1:1 means. But obviously cant be 1psi of fuel pressure for 1 psi bost.

And I cant get a ecu untill I get the pinout for my ecu sorted. since I have a 96 euroland with imobilizer, this is proving to be a challenge.

Anyone else please?

Last edited by mx5dude69; 09-14-2008 at 08:41 PM.
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Old 09-14-2008, 08:08 PM   #8
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Quote:
Originally Posted by mx5dude69 View Post
dude, sarcasm doesnt help. what i mean is if the vortech gives more pressure, how exactly does that work, if this one is actually giving richer afr's?
i just dont know what 1:1 means. but obvisouly cant be 1psi of fuel pressure for 1 psi bost.

and i cant get a ecu untill i get the pinout for my ecu sorted. since i have a 96 euroland with imobilizer, this is proving to be a challenge.

anyone else please?
Dude, learn to use CAPITALIZATION! I swear I'll never help you again if you don't start using correct grammar.

Listen. I am about to repeat myself.

Quote:
our Vortech VPR is a rising rate regulator. it adds fuel X PSI of fuel pressure per pound of boost. That X value is more than 1. Probably like 6-8, but I dunno. Anyway, replacing it with a 1:1 rate FPR is the wrong move. Put the vortech back.

Oh, to cure your lean AFR's after installing an intercooler, you just need a different disk for the Vortech unit to add more PSI of fuel / unit boost.
Did you understand that? If not, reread it.

1:1 means the FPR adds 1 PSI of fuel pressure per 1 unit of boost.

2:1 means the FPR adds 2 PSI of fuel pressure per 1 unit of boost

4:1 means the FPR adds 4 PSI of fuel pressure per 1 unit of boost.

85784732328:1 means the FPR is gonna blow the fuel system apart at the first hint of boost if the FP is up to the task. Get the idea?

Get a standalone ECU or put the Vortec back on and get the next size up disk for it. You started running lean because the intercooler makes the air more dense, so each pound of boost now has more oxygen in it. So you need to compensate by adding more fuel per pound of boost to maintain a safe AFR. Does this make sense? Is it clear? I give up.
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Old 09-14-2008, 08:29 PM   #9
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I get that. What I dont get, is how a 1:1 fpr gives richer afr's than the vortech that as you said, delivers 6/8 per psi of boost. let me try to explain what I mean:
the stock FPR gives 50psi at 0psi.
-6*4psi= 24+43= 67psi at WOT. (assuming the vortech increases 6psi per pound)
-with the new unit. 60psi base+4psi=64psi at WOT. (assuming 1psi increase per pound)

you still up to help me or you give up on me?
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Old 09-14-2008, 08:34 PM   #10
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Edit your post and correct the capitalization issue and I'll explain. From now on try a little harder to do better.
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Old 09-14-2008, 08:39 PM   #11
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Quote:
Originally Posted by mx5dude69 View Post
I get that. What I dont get, is how a 1:1 fpr gives richer afr's than the vortech that as you said, delivers 6/8 per psi of boost. let me try to explain what I mean:
the stock FPR gives 50psi at 0psi.
-6*4psi= 24+43= 67psi at WOT. (assuming the vortech increases 6psi per pound)
-with the new unit. 60psi base+4psi=64psi at WOT. (assuming 1psi increase per pound)

you still up to help me or you give up on me?
If you are running a 6:1 disk, then your math is correct assuming 43PSI base fuel pressure. But as you said you now run lean with this disk after adding an intercooler. Perfectly normal.

You need to try a different disk, say an 8:1.

43 PSI base fuel pressure
4 PSI boost @ 8 PSI fuel pressure per pound = 32

43+32= 75 PSI at WOT That would be more fuel and would make the car run richer.

Thing is, with the stock ECU, you can not change base fuel pressure. It has to stay the 43PSI. That's why the new regulator you just bought and installed won't work. If you set it to 43, the car runs fine until you boost, then it's gonna be crazy lean and tear up your motor in short order. Or you setup the base fuel pressure really high and then it might run OK in full boost, but would barely run out of boost, smoke, waste fuel, could cause it to hydro lock, would flush out the rings, and other bad things.
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Old 09-14-2008, 08:42 PM   #12
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Done, so can you help me now please?
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Old 09-14-2008, 08:46 PM   #13
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Ok I got it. I was planning to buy a Begi afpr, but then decided to go with Aeromotive.
I cant believe this ****. All this work for nothing...

thanks
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Old 09-14-2008, 08:52 PM   #14
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Well, you could just buy a different disk for the Vortec FPR you already have. Cheap, and it would fix it. But you will need to upgrade your fuel pump some time, though. Not hard and about 100 or less.

Or, get a MS. But this will cost more, but ultimately be better. But, you will recover some of the cost by selling off your bandaids that are currently running the motor. So really up to you.
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Old 09-14-2008, 08:53 PM   #15
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Here is my 2 cents! Install the Vortec and Aeromotive FPR. Use the Aeromotive to raise your base pressure to 50-52psi and then the Vortec to get it up to 74-76psi (4*6psi). You will now be on the edge of what the stock fuel pump can produce.

While this may not be the optimal solution, you will find raising the base fuel pressure by 7psi will allow the car to still run okay.

The above is a trick I have done on Miatas and Honda setups in the past. Just remember that you will probably have to set base FPR to 43psi if you have to do an emissions test of some kind.

Lisbon - Portugal? Looks like I am visiting Portugal for 2 weeks next summer.. Can't wait!
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Old 09-14-2008, 08:56 PM   #16
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For example, I'm running MS2 and 550cc injectors. I bought a Mallory FPR, same thing you got really, just a different brand. It's 1:1 too. Reason why is so that when boost builds, the difference in pressure between the injectors and the intake manifold remains constant. Stock, my 99 runs 62 PSI fuel pressure, and that number NEVER changes as the FPR has no vacuum line going to it (FPR is actually inside the gas tank, lame). So If I were running 20 pounds of boost, I would really only have 42 PSI of fuel pressure! Despite the need for more fuel pressure at high boost, I would actually get less. Pretty lame.
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Old 09-14-2008, 09:05 PM   #17
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Originally Posted by [email protected] View Post
Here is my 2 cents! Install the Vortec and Aeromotive FPR. Use the Aeromotive to raise your base pressure to 50-52psi and then the Vortec to get it up to 74-76psi (4*6psi). You will now be on the edge of what the stock fuel pump can produce.

While this may not be the optimal solution, you will find raising the base fuel pressure by 7psi will allow the car to still run okay.

The above is a trick I have done on Miatas and Honda setups in the past. Just remember that you will probably have to set base FPR to 43psi if you have to do an emissions test of some kind.

Lisbon - Portugal? Looks like I am visiting Portugal for 2 weeks next summer.. Can't wait!

PM'd you about your visit.
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Old 09-14-2008, 09:06 PM   #18
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Originally Posted by patsmx5 View Post
Well, you could just buy a different disk for the Vortec FPR you already have. Cheap, and it would fix it. But you will need to upgrade your fuel pump some time, though. Not hard and about 100 or less.

Or, get a MS. But this will cost more, but ultimately be better. But, you will recover some of the cost by selling off your bandaids that are currently running the motor. So really up to you.
I have a Wallbro255 going in tomorrow. Will see if that helps.
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Old 09-15-2008, 01:24 PM   #19
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Default Aeromotive FPR - Help please - SORTED!

yeah... after fitting the wallbro 255, with the Vortech and the stock 12.1 disk and base pressure at 43psi it goes rich as hell.
11.8's AFR's. From the moment I floor it to red line.
But I want to install a fuel pressure gauge to look at my pressure at the rail...

thanks everyone who took the time to reply and help out.
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Old 09-15-2008, 02:06 PM   #20
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so the stock fuel pump was WEAK!!!!!!!! Glad it is all good now...
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