What psi should a RRFPR generate? DASC

the governor · 01-30-2008, 10:26 AM

What psi should a RRFPR generate at full throttle? I know they are rated at 92psi. Is this the max it can generate or is 92psi the pressure it should flow at full throttle? My fuel pressure gauge is reading 80psi at full throttle and 7lbs boost. Is this the correct fuel pressure?

DustenT · 01-30-2008, 04:44 PM

Quote:

Originally Posted by el pollo loco

What psi should a RRFPR generate at full throttle? I know they are rated at 92psi. Is this the max it can generate or is 92psi the pressure it should flow at full throttle? My fuel pressure gauge is reading 80psi at full throttle and 7lbs boost. Is this the correct fuel pressure?

Stock the DASC RRFPR is about 80psi at full throttle, I cranked up the pressure on the RRFPR 2 full turns which resulted in 92psi at full boost. Also, the fuel pressure can vary depending on how you drive. If you feather the throttle a little more, or hit full boost at a higher RPM the fuel pressure is usually higher.

sigh...that is the major pitfall of a RRFPR. NickG Stage 3? LOL

the governor · 01-30-2008, 05:28 PM

So the RRFPR is adjustable and can be adjusted back to 92psi?

DustenT · 01-30-2008, 06:39 PM

Quote:

Originally Posted by el pollo loco

So the RRFPR is adjustable and can be adjusted back to 92psi?

Is 80psi the absolute MAX you are seeing, all the time?

What the elevation difference between where you are and Madison?

Take the car out and get the revs up to 3500 rpms under 1/2 throttle (don't boost up to 3500, just get the revs up while in vacuum) and then boost it up to redline, what does the fuel pressure show? I wouldn't be as concerned about the reading as I would with the way it feels. You can actually FEEL the car pull back timing when it gets lean. If you aren't feeling that, I'd leave it be.

the governor · 02-01-2008, 01:57 AM

80 psi is the absolute max I have seen. I tried taking the car to 3500 revs in vac, never entering boost and then running to red line. It generated 78-79psi. The car didnt feel like it cut back but it felt the same from 4500 to redline. The evelation difference between Madison and Monrovia is 300ft.

elevation of Madison, WI 863 ft
elevation of Monrovia, CA 560 ft

DustenT · 02-01-2008, 03:00 PM

Quote:

Originally Posted by el pollo loco

80 psi is the absolute max I have seen. I tried taking the car to 3500 revs in vac, never entering boost and then running to red line. It generated 78-79psi. The car didnt feel like it cut back but it felt the same from 4500 to redline. The evelation difference between Madison and Monrovia is 300ft.

elevation of Madison, WI 863 ft
elevation of Monrovia, CA 560 ft

That seems odd. What do you have for vacuum at idle? Should be around 15 in/mg. If it's less than that it's a good indication that you may have a vacuum leak. Double check the vacuum line doing to the RRFPR too, a small leak in that would result in less pressure.

the governor · 02-02-2008, 01:19 AM

Vac at idle is 15-17 in/mg. Once I clean out some space in the garage I'll chek all the lines to make sure.

Dusten as always thank you for your help!

the governor · 02-07-2008, 11:01 PM

Dusten today I was down in Huntington Beach elevation 50ft and getting readings of 87-90 psi it is also 12 degrees warmer today than last week, currently 77 degrees. I was still reading 87-90 psi when I got back to the Monrovia area, could the temperature play a major factor in the fuel psi?

thesk8nmidget · 02-07-2008, 11:56 PM

hmm well i bet it would have to do with the temp. since fuel's more dense in the cold.

DustenT · 02-08-2008, 01:05 AM

Quote:

Originally Posted by el pollo loco

Dusten today I was down in Huntington Beach elevation 50ft and getting readings of 87-90 psi it is also 12 degrees warmer today than last week, currently 77 degrees. I was still reading 87-90 psi when I got back to the Monrovia area, could the temperature play a major factor in the fuel psi?

Good question. I hardly even paid attention to max psi to tell you the truth, when I set it for 92psi, it was summertime. I had the gauge there just to make sure that the pressure was actually going up under boost.

You can see that the RRFPR is the obvious weak point in the DASC system. BUT...it works. And (as NickG has shown) larger injectors and software only net an additional couple - 20 hp.

the governor · 02-08-2008, 02:25 AM

Your absolutely right, its not perfect but its rock solid. I guess a motorswap is the only real cure

I hope to get it dyno'd soon w/ AF ratio and that should point out any real problems. I'll wait until then....

DustenT · 02-08-2008, 04:45 AM

Quote:

Originally Posted by el pollo loco

Your absolutely right, its not perfect but its rock solid. I guess a motorswap is the only real cure

I hope to get it dyno'd soon w/ AF ratio and that should point out any real problems. I'll wait until then....

I'll be interested to see that. We can compare them to some others I have in my private collection. I think I have a copy of Chad's (ZeroG) dynos somewhere.

the governor · 02-09-2008, 12:02 AM

DustenT · 02-11-2008, 03:14 AM

The fuel pressure looks normal to me. Boost looks low, might want to check the line going to the gauge.

the governor · 02-11-2008, 05:39 AM

The boost gauge has been reading 7lbs. I'll get back there and check the line.

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