Fueling & Injection - Dual intank walbros in stock plastic tank....is 70 PSI too high??

Hey guys. I'm getting 70 PSI at idle for fuel pressure with a dual walbro setup. I have the stock plastic tank and bucket assembly thats been modified for twin walbros. -8 AN feed line to the stock F body rail, and a "T" in the line that goes back to the tank and through the stock in-tank regulator. Also 80 lbs injectors. Anyone see any problems when trying to tune this, and should I be concerned about it?

The weird thing is that with stock injectors, it seemed to be where it should, at around 58-60 PSI. Now with the 80's, I'm suddenly at 70 psi.

Stock inj psi taken with the dual pumps??
Both pumps on all the time?

Stock inj psi taken with the dual pumps??
Both pumps on all the time?

You know what...after thinking about it, when I tested the pressure with the stock injectors, it was with only one pump on at a time.

And yes, both pumps are on all the time. My tuner said I should be ok without a hobbs type of switch setup.

No reason to run 2 pumps all the time....Put 1 on a switch.

Sounds like the factory regulator can't keep up with the amount of fuel being supplied from both pumps. You should probably go to an adjustable fuel pressure regulator, new rails, and a real return line instead of using the factory T.

Sounds like the factory regulator can't keep up with the amount of fuel being supplied from both pumps. You should probably go to an adjustable fuel pressure regulator, new rails, and a real return line instead of using the factory T.

Problem is that I already did the whole fuel system using 1/2" aluminum line and all AN fittings with braided hose at the ends. I REALLY don't want to rip it apart and essentially start from scratch. If it runs a little rich at idle, I don't really care. As long as it's not going to cause a problem down the road. I would much rather run a hobbs switch than redo my entire fuel system.

Is it for the car in your sig? If so, you should have the boost referenced regulator to do it right.

Is it for the car in your sig? If so, you should have the boost referenced regulator to do it right.

Yes, it's the car in my sig. And there are different definitions to "right" lol. Lonnies uses the stock in-tank reg with dual walbros and a hobbs switch and they have had some pretty big HP cars use that setup. Plus, I can always change it and improve down the road, but I JUST got this car streetworthy and am not ripping it apart so soon to change the entire setup. I just need to get it going for now so I can drive the damn thing.

What I'm curious about at this point is if 70 PSI at idle will actually hurt anything besides making it run a bit rich at lower RPM?? Some gas engines run 70-80 PSI fuel pressure from the factory and are fine.

Yes, it's the car in my sig. And there are different definitions to "right" lol. Lonnies uses the stock in-tank reg with dual walbros and a hobbs switch and they have had some pretty big HP cars use that setup. Plus, I can always change it and improve down the road, but I JUST got this car streetworthy and am not ripping it apart so soon to change the entire setup. I just need to get it going for now so I can drive the damn thing.

What I'm curious about at this point is if 70 PSI at idle will actually hurt anything besides making it run a bit rich at lower RPM?? Some gas engines run 70-80 PSI fuel pressure from the factory and are fine.

You can have big power without boost. That's what I'm getting at. If you were n/a, then it wouldn't be an issue. But having a boosted setup, the boost reference is the way to go.

The stock regulator obviously isn't up to the task. It's supposed to maintain it at 58lbs. If you had an aftermarket adjustable regulator, you could set your base pressure is in a range from something like 30-60lbs. Which means as a boosted engine, if it's a 1:1 regulator, for every 1psi of boost, the fuel pressure will also raise 1psi. Then you would adjust your injector flow rate table to one pressure straight across the board.

i would run the fuel pressure switch to kick on the second pump...

You can have big power without boost. That's what I'm getting at. If you were n/a, then it wouldn't be an issue. But having a boosted setup, the boost reference is the way to go.

The stock regulator obviously isn't up to the task. It's supposed to maintain it at 58lbs. If you had an aftermarket adjustable regulator, you could set your base pressure is in a range from something like 30-60lbs. Which means as a boosted engine, if it's a 1:1 regulator, for every 1psi of boost, the fuel pressure will also raise 1psi. Then you would adjust your injector flow rate table to one pressure straight across the board.

Ahhhh, I gotcha now. I'll talk it over with my tuner and see what he thinks as well. I'm sure we can come to some conclusion that works, and if it means changing the fuel system up, I guess I'll have to bite the bullet.

Ahhhh, I gotcha now. I'll talk it over with my tuner and see what he thinks as well. I'm sure we can come to some conclusion that works, and if it means changing the fuel system up, I guess I'll have to bite the bullet.

It shouldn't be too bad. You have the lines ran to the engine bay already. I'd mount the regulator where you want it and run the lines to a point where it would be easy to fix under the car.

i didnt notice you had a turbo setup.. i had this regulator on my talon and it worked great if you search the net you could find a better price and they make a -10an sized one also


http://www.ebay.com/itm/IE-Fuelab-FPR-Stealth-kit-for-DSM-Evo-Fuel-Lab-eclipse-talon-/280806703781?pt=Motors_Car_Truck_Parts_Accessories&hash=item41616242a5&vxp=mtr#ht_1125wt_952