Car bogs in the corners, road race.

[Rokker]

I agree with you, but I would think that it would be ok in the straights if it is just fuel slush. Mine keeps bogging until I let go of the throttle for 5-10 seconds.

My theory is that I´m using up fuel on the straights, in the turns the bowls are very low, causing fuel to slush away from the jet´s and therefore the bog appears to be in the turns, But in reality it is just low on fuel.

Btw thi happened with fuel bowls real low and full over the glass. Same symptoms...

Can you post a summit link to the race style float ?
What does that float actually do compared to stock ?

And jet extentions, I don´t see the reason for running them if not dragracing? As lateral g will make the fuel go to the side of the bowl, I don´t see how moving the pickup of the jets back and forth would help ? Not saying, just asking..

[wmhjr]

Originally Posted by Rokker

I agree with you, but I would think that it would be ok in the straights if it is just fuel slush. Mine keeps bogging until I let go of the throttle for 5-10 seconds.

My theory is that I´m using up fuel on the straights, in the turns the bowls are very low, causing fuel to slush away from the jet´s and therefore the bog appears to be in the turns, But in reality it is just low on fuel.

Btw thi happened with fuel bowls real low and full over the glass. Same symptoms...

Can you post a summit link to the race style float ?
What does that float actually do compared to stock ?

And jet extentions, I don´t see the reason for running them if not dragracing? As lateral g will make the fuel go to the side of the bowl, I don´t see how moving the pickup of the jets back and forth would help ? Not saying, just asking..

I can't at all agree with your conclusions. Here's why.

If you were simply "using up all the fuel on the straights" then even in the straights, at some point you'd lose fuel and the problem would start. I believe it is statistically so improbable that you would end up running the bowls out JUST at the time that you enter a turn (even when the straights are of different lengths) that it's frankly impossible for me to consider. Add in your initial comment about it happening when you "do donuts" and that IMHO totally disproves the theory that long straights are simply consuming your fuel.

If you're using stock lines (meaning probably 3/8 at BEST with multiple restrictions) and a stock pickup, and you're running a strong 502 at 600hp, you're in bad shape. That's way insufficient for that combo.

It's still just a guess, but with such a restrictive fuel system for that combo you could be starving the bowls all the time when you're on the motor. You can't see the sight glass when you're in the car and pushing it. Could be that when you're under load, no matter what the floats are set to the small line and weak pump/location can't supply enough fuel, causing low bowls, then causing starvation at lateral loads.

At that power level, I would replace your fuel line with 1/2"/-8AN, replace your sending unit with one from RobbMC which can handle -8AN, make sure you have dual 3/8" supply at a minimum to the carbs, install an Aeromotive 13205 deadhead regulator (if you don't have a regulator) and either put a RobbMC 1043 pump or a rear mounted better electric pump. For non-FI applications, I'm personally fond of RobbMC mechanical pumps, but that's a personal preference. Once you've done that you know that short of a sumped tank, your fuel delivery to the carb is rock solid and then it's just air bleeds, jets, and float adjustments.

[orangevert]

I had a 950 Prosystems and if I braked really hard with it. it would want to bog out as well.

[Rokker]

Going road racing tomorrow so the new fuel pump got temporarily installed.
Engine compartment is done. Thank you guys for all the help !

I´m planning to open my fuel tank in the winter, make a room with baffles to keep the fuel available, on acc, deac, and lateral movement. Four baffles. And will use a 1/2" tube in the stock pickup. The idea of a 90 degree bend in the bottom of the tank would look like crap. I found that out after I got the parts. Big heavy lump, that will stick down to much and easily will get hit by a rock or hitting something while backing up. For now this will have to do. The fuel pump will be moved to the back too.

Felt like it picked up 100hp on top of second gear.

Plumbing part one :-)




Here´s the red pump versus the Holley HP150.
The red one is like a baby, compared to the sturdy piece of engineering the heavy HP150 feels like.




I also found that when adding pressure from the new pump, the primary needle and seat wouldn´t hold the fuel back. Fuel bowl was full of dirt, rust etc. probably could have saved me the fuel pump install, but it sure feels good to have a much better fuel system up and running.

[Rokker]

Mounted the pump in the back where it should be. And AN8 fuel line from tank. Will modify the pickup in the winter and make a baffled room for the pickup inside the tank.



Car still bogs in the corners even in low speeds, not running out of fuel. It´s noticable even in roundabouts now. Seems even worse after the fuel system upgrade, maybe the fuel bowls are filled faster now ?
Any other suggestions are welcomed. Hopefully some that doesn´t cost me as much as the fuel system.

What do you guys say ? Road racing floats ?
I don´t believe rear extension is the cause of my problem, as this happens even while only using the primaries.

[wmhjr]

Wow. That sucks. You might try one thing. Reset your system so the bowls are 25% and no higher and see if anything changes. Just a thought - don't know if it will have an effect or not.

[Rokker]

After my last post i noticed the car would have bad idle qualities and stopped a few times. Left the pump on but engine off. Was dripping from the secondary boosters. I`m running 7psi, took the needle and seat out, cleaned. Did not see any debris on it, but has been fine since.

I would love to mount a camera inside the fuel bowl to actually see what is happening when I`m turning. As the problems where worse with higher secondary fuel level when the needle and seat wouldn`t shut off, I think this is a good indication that what is happening is "fuel is going places where it shouldn`t be right" ? I don`t see how a rear jet extention would cure this, as we are talking about lateral movement not acceleration mainly.

What carb mods should I try ?

Btw, when at the track I ran the bowls real low, and real high. Both the same and one high one low etc. So I kinda feel it`s something a fuel bowl level won`t cure. It behaved exactly the same on the track no matter what.
Btw, let`s not rule out timing, mechanical stuff etc. I`m all ears. Man I need to talk to Patrick.. Thanks, for the help guys !

[Rokker]

Originally Posted by wmhjr

Wow. That sucks. You might try one thing. Reset your system so the bowls are 25% and no higher and see if anything changes. Just a thought - don't know if it will have an effect or not.

As for now, I think this is my best bet, so I`ll try it out one more time. Worst case scenario, it didn`t help right ?

[wmhjr]

BTW, I should clarify something. I'm running at the 600hp level with a built 462, and have run both a custom built 4150HP based 900cfm and currently a Pro-Systems Pro-Series 1000cfm built on a 4150HP base. I'm running 1/2" fuel supply, the 13205 regulator with a bleed orifice using 1/4" vent to the tank and the Poncho version of the RobbMC mechanical pump connected to a stock unsumped tank using the RobbMC A-body sending unit/pickup with 2 -8AN ports.

I can run the car down the straights at 6000rpm regardless of distance, and throw the car into hard bends, pretty much anything I want to do. Neither my fuel pressure nor my engine cares in the least. When the pedal goes down, the rpms go up. Period.

I think it's really important to sort out obvious inadequacies in fuel delivery before trying to troubleshoot performance issues by messing with different floats and/or jets.

[ccracin]

Originally Posted by wmhjr

If you were simply "using up all the fuel on the straights" then even in the straights, at some point you'd lose fuel and the problem would start. I believe it is statistically so improbable that you would end up running the bowls out JUST at the time that you enter a turn (even when the straights are of different lengths) that it's frankly impossible for me to consider. Add in your initial comment about it happening when you "do donuts" and that IMHO totally disproves the theory that long straights are simply consuming your fuel.

If you're using stock lines (meaning probably 3/8 at BEST with multiple restrictions) and a stock pickup, and you're running a strong 502 at 600hp, you're in bad shape. That's way insufficient for that combo.

It's still just a guess, but with such a restrictive fuel system for that combo you could be starving the bowls all the time when you're on the motor. You can't see the sight glass when you're in the car and pushing it. Could be that when you're under load, no matter what the floats are set to the small line and weak pump/location can't supply enough fuel, causing low bowls, then causing starvation at lateral loads.

At that power level, I would replace your fuel line with 1/2"/-8AN, replace your sending unit with one from RobbMC which can handle -8AN, make sure you have dual 3/8" supply at a minimum to the carbs, install an Aeromotive 13205 deadhead regulator (if you don't have a regulator) and either put a RobbMC 1043 pump or a rear mounted better electric pump. For non-FI applications, I'm personally fond of RobbMC mechanical pumps, but that's a personal preference. Once you've done that you know that short of a sumped tank, your fuel delivery to the carb is rock solid and then it's just air bleeds, jets, and float adjustments.

BTW, I should clarify something. I'm running at the 600hp level with a built 462, and have run both a custom built 4150HP based 900cfm and currently a Pro-Systems Pro-Series 1000cfm built on a 4150HP base. I'm running 1/2" fuel supply, the 13205 regulator with a bleed orifice using 1/4" vent to the tank and the Poncho version of the RobbMC mechanical pump connected to a stock unsumped tank using the RobbMC A-body sending unit/pickup with 2 -8AN ports.

I can run the car down the straights at 6000rpm regardless of distance, and throw the car into hard bends, pretty much anything I want to do. Neither my fuel pressure nor my engine cares in the least. When the pedal goes down, the rpms go up. Period.

I think it's really important to sort out obvious inadequacies in fuel delivery before trying to troubleshoot performance issues by messing with different floats and/or jets.

Pay attention to what was written here. Addressing these issues will make your life much simpler. I promise! Good luck!