Caleb
05-04-2010, 10:43 PM
I'm trying to narrow down the culprit of my fuel issue and its weird to explain and I may have found it just need some advice.
This is something that's been going on for a while now and we see it happen all the time at the track. I approach the lane to do a burnout. I start doing it and the following things have happened:
1. Do a burnout and when I let off the gas it dies and I have to push my pedal to the floor and start it meaning little to no fuel. And this is at normal idle temps and so forth.
2. Do a burnout, roll up to the line, start stalling and then when I give it half throttle to take off, again runs out of fuel and dies and again, push the pedal to the floor to get it started and proceed to embarrass myself down the track again.
3. Skip the burn out, stall, take off strong and then sometimes during 2nd and 3rd gear, top end is fuel starved between 4,000-6,500 RPM SOMETIMES. Its random when it decides to starve and sometimes it doesn't do it at all.
The last visit up at the track we noticed that the fuel was boiling in the air filter between the carb and regulator. So we found it was vapor locking under extreme heat. So I insulated the fuel line as best as I could with 3/8's rubber hose and 2 layers of Heat Reflective tape that was directly by the headers. I couldn't quite get the 12 inches of line that I could see that's running by the lower side of the headers, but just the main portion coming out of the heads. For some strange reason that helped drop the temp of the engine oddly enough ( maybe because the fuel wasn't as hot?). And after driving for an hour I noticed its not boiling but after I get done driving and let it sit and idle for about 5-10 minutes, I see a few bubbles start popping up from the regulator side of the fuel filter.
Right now the cars fuel pump(Inline Holley Blue) is behind the rear drivers side seat on the outside and my exhaust dumps about in that spot. Were thinking about relocating it just on the inside of the car to reduce the temps on the fuel pump(since it has metal casing) unit itself just in case if that's heating the fuel as its being pumped up to the front.
But here's the weird thing, I start it up and the engine is still cold and it warms up for the few minutes. I take off and decided to give it a little gas to get it going up to about 3,000 rpm, nothing major and then it just poof poofs and dies and again, and I notice this happens during just slight slight inclines in the road when less then a 1/4 of a tank. It just repeats the symptoms from the track of being fuel starved but yet not under any really extreme conditions.
And also when I decided to take it to a vacant road while the engine temp is around 140F(still getting to normal idle temps) and run it through the gears hard. Sometimes it runs perfectly with no engine starving of fuel and then other times, 2nd and 3rd just don't wanna go anywhere past 4-5k sometimes.
I'm tempting to pull the tank and buy a new float and sock for it. Re-run all the fuel lines and insulate them and see how that runs after that. And if it doesn't work, I've thought about maybe adjusting the secondaries on the carb, or running a slightly richer set for no top end fuel starvation.
My guesstimate is that I'm running around 425 crank horsepower with the Edelbrock Performer RPM package ( http://www.edelbrock.com/automotive_new ... _410.shtml (http://www.edelbrock.com/automotive_new/mc/crate_engines/performer_rpm_410.shtml) ) w/ flat top pistons running 10:1 and .030 over. I'm running just under 6psi on the regulator for fuel. I'm running this carb and I know a lot of you guys hate Edelbrocks but its just what I'm using and what the dads used to adjusting.
http://www.edelbrock.com/automotive_new ... nder.shtml (http://www.edelbrock.com/automotive_new/mc/carbs_acc/thunder.shtml)
650cfm Manual Choke and is that sufficient enough for what I'm running?
So my ultimate question is? Other than vapor locking, anyone else know what could be the issue? Or am I on the right track with finding the culprit?
This is something that's been going on for a while now and we see it happen all the time at the track. I approach the lane to do a burnout. I start doing it and the following things have happened:
1. Do a burnout and when I let off the gas it dies and I have to push my pedal to the floor and start it meaning little to no fuel. And this is at normal idle temps and so forth.
2. Do a burnout, roll up to the line, start stalling and then when I give it half throttle to take off, again runs out of fuel and dies and again, push the pedal to the floor to get it started and proceed to embarrass myself down the track again.
3. Skip the burn out, stall, take off strong and then sometimes during 2nd and 3rd gear, top end is fuel starved between 4,000-6,500 RPM SOMETIMES. Its random when it decides to starve and sometimes it doesn't do it at all.
The last visit up at the track we noticed that the fuel was boiling in the air filter between the carb and regulator. So we found it was vapor locking under extreme heat. So I insulated the fuel line as best as I could with 3/8's rubber hose and 2 layers of Heat Reflective tape that was directly by the headers. I couldn't quite get the 12 inches of line that I could see that's running by the lower side of the headers, but just the main portion coming out of the heads. For some strange reason that helped drop the temp of the engine oddly enough ( maybe because the fuel wasn't as hot?). And after driving for an hour I noticed its not boiling but after I get done driving and let it sit and idle for about 5-10 minutes, I see a few bubbles start popping up from the regulator side of the fuel filter.
Right now the cars fuel pump(Inline Holley Blue) is behind the rear drivers side seat on the outside and my exhaust dumps about in that spot. Were thinking about relocating it just on the inside of the car to reduce the temps on the fuel pump(since it has metal casing) unit itself just in case if that's heating the fuel as its being pumped up to the front.
But here's the weird thing, I start it up and the engine is still cold and it warms up for the few minutes. I take off and decided to give it a little gas to get it going up to about 3,000 rpm, nothing major and then it just poof poofs and dies and again, and I notice this happens during just slight slight inclines in the road when less then a 1/4 of a tank. It just repeats the symptoms from the track of being fuel starved but yet not under any really extreme conditions.
And also when I decided to take it to a vacant road while the engine temp is around 140F(still getting to normal idle temps) and run it through the gears hard. Sometimes it runs perfectly with no engine starving of fuel and then other times, 2nd and 3rd just don't wanna go anywhere past 4-5k sometimes.
I'm tempting to pull the tank and buy a new float and sock for it. Re-run all the fuel lines and insulate them and see how that runs after that. And if it doesn't work, I've thought about maybe adjusting the secondaries on the carb, or running a slightly richer set for no top end fuel starvation.
My guesstimate is that I'm running around 425 crank horsepower with the Edelbrock Performer RPM package ( http://www.edelbrock.com/automotive_new ... _410.shtml (http://www.edelbrock.com/automotive_new/mc/crate_engines/performer_rpm_410.shtml) ) w/ flat top pistons running 10:1 and .030 over. I'm running just under 6psi on the regulator for fuel. I'm running this carb and I know a lot of you guys hate Edelbrocks but its just what I'm using and what the dads used to adjusting.
http://www.edelbrock.com/automotive_new ... nder.shtml (http://www.edelbrock.com/automotive_new/mc/carbs_acc/thunder.shtml)
650cfm Manual Choke and is that sufficient enough for what I'm running?
So my ultimate question is? Other than vapor locking, anyone else know what could be the issue? Or am I on the right track with finding the culprit?