Tony,

Stock pressure on the 2G's is 43 psi with the FPR vacuum line removed. When you reconnect the line, it usually drops to around 38 or so.

Hope that helps,

Andy

The stock pressure is 43.5 psi with the vacuum line to the regulator disconnected, but please get in the habit of searching before you start a thread. This topic has been very well covered in the past.

Grrr.... that Andy guy is just too fast for me.

donmagicjuan said:

The stock pressure is 43.5 psi

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Trying to get that last .5 psi really sucks doesn't it? Especially if you have a gauge that reads in 5 psi increments...

Actually you make more horsepower than I do so you should be faster!

Evidently it takes just a little too long to type, also. Mine reads in 2 psi increments, so not quite as bad...

andymoraitis said:

Actually you make more horsepower than I do so you should be faster!

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Har har! You mean you can't squeeze enough out of that 50 trim yet? I thought those things were the size of a Pinto!

Nah, more like the size of a Yugo. I actually don't know how much power it makes, but I'll be tracking it in the next month or so once the weather cools. If the clutch can hold it, it'll make a good run.

The good thing for me is I'm not traction limited (small jab). Really, you make great numbers on your setup and you should be pretty damn proud.

Why thank you, kind sir.
Really, what's so bad about wheelspin? All the ladies love the smell of scorched rubber (except my wife... )

andymoraitis said:

Tony,

Stock pressure on the 2G's is 43 psi with the FPR vacuum line removed. When you reconnect the line, it usually drops to around 38 or so.

Hope that helps,

Andy

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so should i remove the vacuum line? if i do do i increase the pressure? thanks

What exactly do you not understand? You remove the vac line off the AFPR, Set the fuel pressure to 43psi (43.5psi if you have an accurate enough gauge and can do so), Put the vac line back on... And drive. Goodluck.

tyger1 said:

so should i remove the vacuum line? if i do do i increase the pressure? thanks

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There is only one way to do this, you should really search and read before posting new threads so at least you'll know what questions to ask.

To set fuel base pressure, remove the vacuum line from the fpr and set the pressure to 43.5 psi, then reconnect the vacuum line. Before you set the base pressure, unscrew the vacuum fitting on the FPR and apply tafflon to the threads and reinstall. After you set the base pressure to around 43.5, mark the adjustment rod where it meets the body of the fpr, remove the ajustment rod and wrap a liberal amount of tafflon around and right below the mark, reset your base pressure to 43.5 and make sure the tafflon tape covers the threads between the rod and FPR. Now tighten down the lock nut (be careful not to allow the adjustment rod to move with the lock nut), and leave the fpr alone.

Both the vacuum fitting and adjustment rod will leak pressure affecting proper 1:1 rise rate.

oldman said:

Mark the adjustment rod where it meets the body of the fpr, remove the ajustment rod and wrap a liberal amount of tafflon around and right below the mark. Both the vacuum fitting and adjustment rod will leak pressure affecting proper 1:1 rise rate.

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Bruce,

I'm glad you mentioned this. I've been seeing a change in my readings as of late. When the motor would heat up, I would see pressure readings change and actually run lower than when the motor was cool. Thinking it was simply the gauge, I ignored it until I read your post. As a small experiment, I wrapped the adjusting rod with Teflon and screwed it back in (everything else was already teflon wrapped). Now it reads correctly at 43 psi and when I pull the vacuum line, it goes to 38. I took the car out and beat the snot out of it, re-checked the reading and it was still 38 with the vac line on and 43 with the vac line disconnected.

Thanks very much for the tip as it seems that this would explain why I'd sometimes knock at the same boost level and tune while it wouldn't at other times. Not being at a consistent 1:1 will certainly affect volume to the rail and that appears to have been my issue. I told you I'm not that bright.

Thanks bud, the beers are on me!

Andy

^^^ Like Bruce mentioned the adjusting screw on the Aeromotive FPR's usually leak. If you do a proper boost leak test, you will more then likely see a leak here. As for the teflon tape I think that pipe dope might be a better choice. While tape can break off and clog small orfices (not so much an isse here) the other advantage to dope is you can adjust the regulator and the dope will still seal where as the tape most likely won't. I know I have made adjustments to mine several times and it still seals 100%, without adding anymore dope.

The fpr on are cars/the aftermarket adjustable fpr's that we require are what is called a 1:1 ratio. This means that the fpr will add 1 psi of fuel pressure for every 1 psi of boost it see's via the pressure port. This is why you set the base pressure of 43-44 psi with the vacuum line disconnected so the fpr is referencing atmospheric pressure. When you connect the vacuum line back up & the car is at idle it is creating vacuum. Since its a 1:1 regulator, the vacuum will pull the fuel pressure down. The amount it pulls down to depending on your setup, but most "stock" setups (ie idle hasn't been changed, cams added, etc)see around 37-38 psi at idle with vacuum line hooked up. If yours doesn't pull down like this when you hook the vacuum line back up, time to start looking for other issues, a boost leak test would be a good place to start.

No problem Andy, I suspect most AFPR users have the same problem but just don't know it.

I have always known the adjustment screw leaks and liquid taffloned it last year, since 30 psi/8500 rpm is where I'm shooting for on the latest project, I decided to test and make sure my 255 and afpr was up to par. I removed the vacuum hose from the IM at the T where it splits into AFPR and boost gauge, connect a hose from the air compressor to the T. Next I powered up the pump via the "fuel pump check connector" on the firewall and increase air pressure 5psi at a time from the compressor. The system held up to 15psi without any leaks what so ever, I can litterally go away for 30 mins and the boost gauge sits at 15psi while the fuel pressure gauge sits at 58.5 psi when I come back. At 20 psi, I started losing pressure slightly, soapy water on the adjustment screw revealed that my liquid tafflon was not holding the pressure. By the time I got to 30psi on the boost gauge, fuel pressure was at 70psi, 3.5 psi below the target of 73.5 psi. I then remove the rod, cleaned off the liquid tafflon rewraped it with tafflon tape like described above, 73.5 psi on the dot with no leakage what so ever.

A static test like this is not 100% accurate since the injectors are not firing but it did reveal a problem I did not know I had, or I thought I've solved.

oops, sorry Daren, took a couple of calls half way through my post, wasn't ignoring your post.

iam having this problem now so let me check mine.

I tried adjusting my AFPR but could not get the fuel pressure above 20-25 psi? I checked for leaks and doubled checked all the vaccum lines and it is all good. what could cause this? I read a post on a similar problem but that did not help me. any suggestions?

thanks

tyger1 said:

I tried adjusting my AFPR but could not get the fuel pressure above 20-25 psi? I checked for leaks and doubled checked all the vaccum lines and it is all good. what could cause this? I read a post on a similar problem but that did not help me. any suggestions?

thanks

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Are you saying with the adjustment rod all the way in and vacuum line off the AFPR, you're only getting 20-25psi?

The Aeromotive AFPR comes with 2 springs. You would've needed to switch out the installed one for the heavier one for it to work properly. Did you do this? The softer spring would probably only get you to the pressure you're describing. Otherwise, you're looking at a much more serious problem.

oldman said:

Are you saying with the adjustment rod all the way in and vacuum line off the AFPR, you're only getting 20-25psi?

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yeah. all the way in and backed all the way out with the vacuum line off. I am staying steady around 25psi i doubled checked for any leaks but found none.

donmagicjuan said:

The Aeromotive AFPR comes with 2 springs. You would've needed to switch out the installed one for the heavier one for it to work properly. Did you do this? The softer spring would probably only get you to the pressure you're describing. Otherwise, you're looking at a much more serious problem.

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well the aeromotive part number is 13109. i did not get any extra spring. i also upgraded my fuel rail to an Aeromotive and notice that with it tighten on the fuel injectors still move. i tried tightening it more but still the same. it is not leaking but it just moves.

oh another thing. i got no power when i stomp on the accelerator. seem like the engine bogs down.

If your fuel pressure is only 25 psi, why would you go out and try to floor the engine? You know you will run lean and possibly damage your engine, don't you?

I have the 13105 regulator purchased through Import Evolution. On their site they only list the pressure range for the heavier spring, yet it came with a softer one installed. Where did you buy your regulator? Are you saying turning the adjustment rod makes no difference in fuel pressure? If it were mine, I would pull the regulator off and check the internals. Something doesn't sound right.

As far as the injectors spinning, this is normal as long as you have no leaks at the seals when performing a boost leak test. The insulators do not have to be so tight that you can't spin the injectors in order for them to seal.

yeah, with the vacuum line off I can back the adjusting screw all the way out and it'll make no difference. the pressure stays constant at 25psi. i know the warlbro 255 pump is working. i did a rewire kit and could hear it. I also disconnected the line going to the regulator and a good amount of fuel shoots out. i ' guess i'll pull apart the regulator and see WTF going on or i'll just get ahold of aeromotive inc.