Fuel Pressure increae modification--<<<
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Team Owner
Joined: Jul 2003
Posts: 24,650
Likes: 8
Fuel Pressure increae modification--<<<
Hey, I was browsing the Tech-tips forum, and ran across this tip, and Im wondering if it could damage a stock system?
This is a copy/paste fro mtech tips- Thanks!
tried this modification and my fuel pressure went from 30# to 40# with only this fifteen second mod. The modification is that I removed the vacuum line from the factory fuel pressure regulator. Also, I capped the fuel pressure regulator connection, so no dirt would get in, and plugged the vacuum line, to maintain vacuum on the engine. I tested the car and noticed a serious change in acceleration. I then took it on the highway, set the cruise for 70 with this mod I was getting an instantaneous reading of fuel mileage of 28-29 miles per gallon. I pulled off of the highway and switched back to having the vacuum line connected. I immediately noticed the power had reduced. I again took the car over the same stretch of highway and the mileage went down to 26-27. I thought the second mileage test would be higher than the first. I checked with my mechanic on this and he said the car is just running more efficiently with the mod than without. One other thing that got better for these test runs with the mod was the temperature of the engine went down. Normally, when the car is warmed up and going down the highway, it'll usually run about 208-211 degrees. With the mod it went to 184-187. My mechanic said that that may be caused due to the cooling effect of more fuel entering the cylinder. I don't know if the temperature differential is going to be a constant, because as you can tell, the tests I did were not scientific in any way. But, I feel there is an improvement, if only in my car. I was told about this mod. via someone who works on, restores and sells parts for nothing but Corvettes. So I thought I'd give it a try. Just make sure that the pressure you attain, if you do this mod, is not too high for your system. Of course you can always put a small needle valve in the vacuum line to reduce the press., if necessary. If this works as well on all, none or slightly modified, Corvettes as if did on mine, then there are going to be a lot more wolves in wolf's clothing out there:-{
This is a copy/paste fro mtech tips- Thanks!
tried this modification and my fuel pressure went from 30# to 40# with only this fifteen second mod. The modification is that I removed the vacuum line from the factory fuel pressure regulator. Also, I capped the fuel pressure regulator connection, so no dirt would get in, and plugged the vacuum line, to maintain vacuum on the engine. I tested the car and noticed a serious change in acceleration. I then took it on the highway, set the cruise for 70 with this mod I was getting an instantaneous reading of fuel mileage of 28-29 miles per gallon. I pulled off of the highway and switched back to having the vacuum line connected. I immediately noticed the power had reduced. I again took the car over the same stretch of highway and the mileage went down to 26-27. I thought the second mileage test would be higher than the first. I checked with my mechanic on this and he said the car is just running more efficiently with the mod than without. One other thing that got better for these test runs with the mod was the temperature of the engine went down. Normally, when the car is warmed up and going down the highway, it'll usually run about 208-211 degrees. With the mod it went to 184-187. My mechanic said that that may be caused due to the cooling effect of more fuel entering the cylinder. I don't know if the temperature differential is going to be a constant, because as you can tell, the tests I did were not scientific in any way. But, I feel there is an improvement, if only in my car. I was told about this mod. via someone who works on, restores and sells parts for nothing but Corvettes. So I thought I'd give it a try. Just make sure that the pressure you attain, if you do this mod, is not too high for your system. Of course you can always put a small needle valve in the vacuum line to reduce the press., if necessary. If this works as well on all, none or slightly modified, Corvettes as if did on mine, then there are going to be a lot more wolves in wolf's clothing out there:-{
Drifting
Joined: Jul 2003
Posts: 1,613
Likes: 0
From: Orlando FL
Re: Fuel Pressure increae modification--<<< (RED-85-Z51)
careful with fuel mixtures. i only have a basic unserstanding, but these are my thoughts. first, the 85 has a special fuel regulator. don't let anyone tell you differently. no other vette or f-body before or after, had the same regulator. that much i am sure of. as far as increasing pressure (and therefor amount of fuel in each injector fire) there is a balance. the ignition system will only burn off so much fuel because the spark only lasts so long and is only capable of doing so much. adding more fuel than your ignition system can hburn off MAY cause the oil layer to be washed down off the cylinder walls, resulting in ruined piston rings and cylinder walls. (if the amount of fuel is too extreme) also, if the ECM sees that there is too much unburnt fuel it will try to cut back, therefor defeating the increased pressure anyway.
just remember this as a general rule. if you upgrade one system, all the other associated systems are dealing with new parameters. so although you may gain power/HP/torque in one area, there may be a system further down the line that is becoming more restrictive. thus starts the cyclical upgrading spiral.
just remember this as a general rule. if you upgrade one system, all the other associated systems are dealing with new parameters. so although you may gain power/HP/torque in one area, there may be a system further down the line that is becoming more restrictive. thus starts the cyclical upgrading spiral.
