No runs, no drips, no errors...
10-05-2008, 04:51 PM
#1
AudiWorld Super User
Thread Starter
No runs, no drips, no errors...
<center><img src="http://pictureposter.audiworld.com/711/customfuelrail2.jpg"></center><p>
Everything installed and tested PERFECT right from get-go! I love it when a plan comes together!
Running 66psi with smaller-than-stock RCE 155 cc/min balanced & blueprinted injectors and was 2.5psi low on my "guesstimated" setting before gauge.
While engine manifold vacuum at idle is over 22InHg it only backs fuel-pressure down 16psi. After shut-off rail fuel pressure lowers immediately to about 50psi, then slowly rises to 52psi (due to underhood heat) then falls gradually to "0" overnight. However, turning ignition to "on" position instantly primes fuel rail to 50psi which is my idle setting of 66psi minus manifold vacuum. I would've expected fuel pump to prime to my FPR setting of 66psi but it doesnt no matter how many times I cycle the key on/off. Once engine starts fuel rail pressure immediately spikes to FPR setting regardless if FPR is stock or adjustable. Brand new/unused FPR's test out at 58psi indicated on gauge (2 tested). 100k+ miles FPR's run between 48/54psi indicated on gauge (6 tested). 2 of the tested used gauges have torn diaphrams and won't hold a vacuum which means two things: 1; they don't back off fuel pressure at idle and 2; they cause a vacuum leak that would be virtually impossible to find or diagnose without a vacuum pump! Just because all vacuum lines are connected to their appropriate attachments doesn't mean what they're connected to isn't leaking vacuum!
No matter how hot engine bay gets fuel rail remains a constant 72F as long as pump is running. I presume that will drop in winter but probably never see more than 75/77F in the hottest month as the fuel rail has ALWAYS felt "cool" to the touch when I've felt it while the car is running. Tho pressurized fuel in the rail does get hot with engine turned off and that's why it spikes a higher pressure before dropping off.
Everything installed and tested PERFECT right from get-go! I love it when a plan comes together!
Running 66psi with smaller-than-stock RCE 155 cc/min balanced & blueprinted injectors and was 2.5psi low on my "guesstimated" setting before gauge.
While engine manifold vacuum at idle is over 22InHg it only backs fuel-pressure down 16psi. After shut-off rail fuel pressure lowers immediately to about 50psi, then slowly rises to 52psi (due to underhood heat) then falls gradually to "0" overnight. However, turning ignition to "on" position instantly primes fuel rail to 50psi which is my idle setting of 66psi minus manifold vacuum. I would've expected fuel pump to prime to my FPR setting of 66psi but it doesnt no matter how many times I cycle the key on/off. Once engine starts fuel rail pressure immediately spikes to FPR setting regardless if FPR is stock or adjustable. Brand new/unused FPR's test out at 58psi indicated on gauge (2 tested). 100k+ miles FPR's run between 48/54psi indicated on gauge (6 tested). 2 of the tested used gauges have torn diaphrams and won't hold a vacuum which means two things: 1; they don't back off fuel pressure at idle and 2; they cause a vacuum leak that would be virtually impossible to find or diagnose without a vacuum pump! Just because all vacuum lines are connected to their appropriate attachments doesn't mean what they're connected to isn't leaking vacuum!
No matter how hot engine bay gets fuel rail remains a constant 72F as long as pump is running. I presume that will drop in winter but probably never see more than 75/77F in the hottest month as the fuel rail has ALWAYS felt "cool" to the touch when I've felt it while the car is running. Tho pressurized fuel in the rail does get hot with engine turned off and that's why it spikes a higher pressure before dropping off.
10-06-2008, 12:56 AM
#5
AudiWorld Super User
Thread Starter
I have BBK's front and rear (323mm F/306mm R) so I have to have adjustable brake proportioning...
<center><img src="http://pictureposter.audiworld.com/711/pissedoff3.jpg"></center><p>
not necessary for "day-to-day/track-to-track" adjustability... but WAY different than stock proportioning to dramatically reduce rear bias or I'd be locking the rears up almost every time I touched the brakes if I had to rely on the OEM proportioning valve.
About the only time I touch it is when it snows and then it's just to back off rear bias one more "click" so the lever is facing the 3 o:clock position as viewed from top.
not necessary for "day-to-day/track-to-track" adjustability... but WAY different than stock proportioning to dramatically reduce rear bias or I'd be locking the rears up almost every time I touched the brakes if I had to rely on the OEM proportioning valve.
About the only time I touch it is when it snows and then it's just to back off rear bias one more "click" so the lever is facing the 3 o:clock position as viewed from top.
Thread
Thread Starter
Forum
Replies
Last Post
carl viking
A8 / S8 (D3 Platform) Discussion
31
07-30-2022 09:13 AM
texasaggie2011
A4 (B6 Platform) Discussion
8
09-14-2015 05:39 AM
bilbo6209
A6 / S6 (C5 Platform) Discussion
10
09-04-2015 04:07 PM
