AFPR Whats everyone setting there's at?
Thread Starter
Member

Joined: Jul 1999
Posts: 196
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From: B.C
Car: 89 Trans Am GTA
Engine: 383 TPI
Transmission: 700R4
Axle/Gears: 3:27
AFPR Whats everyone setting there's at?
Just installed one and was wondering what everyone is set at. I know there is fine tunning and depending on what mods and stuff but just curious. Thanks.
Senior Member
Joined: May 2000
Posts: 625
Likes: 0
From: Where the Devil Dances, IL
Car: 87Z
Engine: ?
Transmission: A4
43.5 psi 
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87 Z28 305 TPI, Auto, LT-1 cam (@.50 418/430, 194/199, LSA 111), roller timing set, 2.73, Gutted air boxes, K & N fillters, Dyno Max 3" cat back, 8.8 mm spirals, air foil, BFG Drag radials,170* Stat and TB bypass.
Old Best 15.414 @ 87.47.
new best 15.006 @ 89.55.
w/ drag radails 14.6 @ 93
“Fallen But Not Forgotten”

------------------
87 Z28 305 TPI, Auto, LT-1 cam (@.50 418/430, 194/199, LSA 111), roller timing set, 2.73, Gutted air boxes, K & N fillters, Dyno Max 3" cat back, 8.8 mm spirals, air foil, BFG Drag radials,170* Stat and TB bypass.
Old Best 15.414 @ 87.47.
new best 15.006 @ 89.55.
w/ drag radails 14.6 @ 93
“Fallen But Not Forgotten”
<font face="Verdana, Arial" size="2">Originally posted by new87:
43.5 psi
</font>
43.5 psi

</font>
Q: What fuel pressure setting will give me the best performance?
A: The stock setting is 42 PSI. Much track testing has showed that any type of increase will greatly benefit both horse power and torque. Here's some dyno testing on a stock 350 motor which substantiates those claims:
42 PSI (stock) 46 PSI 50 PSI
RPM Torq HP Torq/diff HP/diff Torq/diff HP/diff
------------------------------------------------------------------------
2250 237.7 101.8 254.9/17.2 109.2/ 7.4 275.0/37.3 117.8/16.0
2500 241.7 115.1 262.1/20.4 124.8/ 9.7 283.3/41.6 134.9/19.8
2750 241.5 126.5 275.2/33.7 144.1/17.6 297.0/55.5 155.5/29.0
3000 237.1 135.4 278.2/41.1 158.9/23.5 305.5/68.4 174.5/39.1
3250 233.8 144.7 278.9/45.1 172.6/27.9 311.3/77.5 192.6/47.9
3500 241.0 160.6 278.2/37.2 185.4/24.8 309.5/68.5 206.3/45.7
3750 246.6 176.1 283.4/36.8 202.4/26.8 303.3/56.7 216.6/40.5
4000 250.4 190.7 278.3/27.9 212.0/21.3 298.0/47.6 227.0/36.3
4250 251.6 203.6 272.5/20.9 220.5/16.9 289.1/37.5 233.9/30.3
4500 253.5 217.2 257.3/ 4.2 220.5/ 3.3 277.0/23.5 237.3/20.1
4750 245.0 221.6 242.1/-2.9 219.0/-2.6 266.4/21.4 240.9/19.3
5000 227.6 216.7 225.0/-1.4 214.2/-2.5 237.8/10.2 226.4/ 9.7
It shows that by increasing the fuel pressure to 50 PSI, results in maximum torque increase of 58 ft-lbs (along with a much flatter torque curve) and a maximum horse power increase of 19 HP over stock. 46 PSI also provides a noticable increase which should work well for day-to-day street driving. An adjustable fuel pressure regulator (see Chap 5.2) is required to increase the fuel pressure.
Q: How do I correctly set the fuel pressure on my new adjustable fuel pressure regulator?
A: The correct way to adjust your fuel pressure is with the vaccum line of the fuel regulator disconnected. The instructions with many adjustable fuel regulators don't tell you to do this, but it is essential! You must remove and plug the vaccum line going to the regulator or you will be getting false readings, similar to adjusting the timing on vacuum advance distributor. What you are attempting to do is set the maximum fuel pressure. At idle, fuel pressure is reduced due to high vacuum, so the presence of the vacuum line is detremental to fuel pressure. Repeat the process until you have the desired reading.
That doesn't make sense to me. I have a 305 and from factory it was running at 46psi. when we put the afpr on we set it at 36 and my car got 3 tenths in the quarter. So if my 305 runs best at 36psi, then i would imagine that the 350 would be best at about 40 to 45 psi I mean they already have bigger injectors to meet the larger displacement.I would think that anything above 45 psi would make a stock 350 run pretty rich. could someone please clarify if this is wrong.
The reason you saw the increase in tenths is probly due to your stock , almost stock car's prom is way to rich from the factory. and by decreasing the FP it actually cut fuel out.
Brendan
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1987 IROC-Z L98,SR,EB 6085's,LPE 219/219 SR Cam, Crane 1.6RR, EB TPI Base, 58mm TB, Stock T5, 30lb SVO, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, Aluminum DS, 94 Disk Rear, Adjustable Prop Valve, Precision 3.73 Gears, Weld in Sub-Frame Connectors, Hotchkis LCA's, KYB Shocks/Struts, Poly Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm, Big stereo, 730SD Conversion.
To see the ROC, Check out the webpage Here
Brendan
------------------
1987 IROC-Z L98,SR,EB 6085's,LPE 219/219 SR Cam, Crane 1.6RR, EB TPI Base, 58mm TB, Stock T5, 30lb SVO, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, Aluminum DS, 94 Disk Rear, Adjustable Prop Valve, Precision 3.73 Gears, Weld in Sub-Frame Connectors, Hotchkis LCA's, KYB Shocks/Struts, Poly Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm, Big stereo, 730SD Conversion.
To see the ROC, Check out the webpage Here
Senior Member
Joined: May 2000
Posts: 625
Likes: 0
From: Where the Devil Dances, IL
Car: 87Z
Engine: ?
Transmission: A4
<font face="Verdana, Arial" size="2">Originally posted by AFRO IROC Z:
So if my 305 runs best at 36psi, then i would imagine that the 350 would be best at about 40 to 45 psi I mean they already have bigger injectors to meet the larger displacement.I would think that anything above 45 psi would make a stock 350 run pretty rich. could someone please clarify if this is wrong.</font>
So if my 305 runs best at 36psi, then i would imagine that the 350 would be best at about 40 to 45 psi I mean they already have bigger injectors to meet the larger displacement.I would think that anything above 45 psi would make a stock 350 run pretty rich. could someone please clarify if this is wrong.</font>
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