1999 Gen VI EFI to Q Jet 4L80E

[Erik the Awful]

This is a common misconception. The pump "can" produce 50-60 psi, but it really only makes the fuel flow. The regulator is what makes it 5 psi or 50 psi. If the passages within the regulator are big enough to relieve the excess flow, it will regulate down to 5 psi.

 

[PlayingWithTBI]

50-60 psi is a lot to regulate to 5 psi though.

It won't build 50 - 60 PSI with a bypass regulator, just the 5 PSI you set it to.

Edit: Erik beat me to it, ha ha.

 

[Schurkey]

I'd expect the stock ECU will need more than just an RPM signal and throttle-position signal. MAP for load, CTS for engine temp--both of those will affect shift timing.

Nope, trans only needs RPM and TPS.

You also need MAP, MAF, and ECT for full functionality. MAP and MAF will calculate the load and determine line pressures, TPS is there for your shift points. If it can't calculate load, it's going to default to full line pressure... ...ECT will change up shifting and TCC lock when it gets hot, and frankly I'm not sure what will happen without ECT because if it's too cold it won't even lock the TCC.

That was my thinking. You expressed it better than I did.

 

[Moleman]

This is a common misconception. The pump "can" produce 50-60 psi, but it really only makes the fuel flow. The regulator is what makes it 5 psi or 50 psi. If the passages within the regulator are big enough to relieve the excess flow, it will regulate down to 5 psi.

Thats good to know.The 12-887 holley is a decent regulator its that whole 9 psi max thing is whats throwing me off. Me personally I just don't trust it to run that newer pump. One would think that they have some kinda rebuild kit for one with a stronger diaphragm and spring.

One thing I've noticed about mine the psi changes at night.

 

[Supercharged111]

I used this regulator 100 years ago to regulate an EFI pump down to 5-6psi for a carb, it worked beautifully. But it doesn't solve your transmission problem.

 

[tayto]

OP, have you priced out what it cost to adapt a TPS to a Qjet? there's only one company that makes a "kit" and it is NOT cheap especially if your crying about a $60 datalogging cable.

 

[BeXtreme]

I'm pretty sure the fuel pump doesn't flow enough fuel to overpower the spring. Remember, the fuel pressure regulator itself is what develops the pressure. The pump merely provides the flow. So long as the FPR can bypass the volume of fluid it will regulate the pressure.

That's not really how that works. The fuel pump is providing(and rated for) a certain volume at a given pressure. The regulator is adjusting the pressure before the carb using a variable sized orifice and returning the unused fuel back to the tank. The pump impellers are designed to have maximum efficiency and volume at the pressure they are designed for. Any difference in the pressure of the system from designed would result in a lower than designed volume. The EP381 flows enough volume in a standard fuel injection setup ,with the regulator after the injectors, to support ~450hp. I would bet that having the regulator before the carb like that you will likely run out of volume much sooner than that. I would bet that setup runs out of fuel closer to 350-400hp(which would probably still put it near what you are going to get from the TBI pump).

It sounds like the OP is wanting to run serious HP, so he will likely need to swap to something a bit more serious, like a walbro 455 in the tank or a Holley blue pump on the frame rail. The holley blue would be comparable flow rating to the walbro, but rated at a more carb friendly pressure.

 

[PlayingWithTBI]

The EP381 flows enough volume in a standard fuel injection setup ,with the regulator after the injectors, to support ~450hp. I would bet that having the regulator before the carb like that you will likely run out of volume much sooner than that. I would bet that setup runs out of fuel closer to 350-400hp(which would probably still put it near what you are going to get from the TBI pump).

IDK, I'm running my Blue Print "383" TBI at 20 PSI with the EP381, putting out over 400 HP, with no issues keeping ~12.5 AFR up to 5700 RPM (I may go to 6000 but I'm still breaking it in).

From "Fluid Power" classes I seem to remember, with a centrifugal pump, the higher the pressure, the lower the volume due to internal slippage.

 

[BeXtreme]

You also need MAP, MAF, and ECT for full functionality. MAP and MAF will calculate the load and determine line pressures, TPS is there for your shift points. If it can't calculate load, it's going to default to full line pressure. The TBI stuff is different. If you give it MAP but not MAF, it'll still default to max line pressure. With a 411 and custom OS, you can do MAP only and have it not max out the line pressure. ECT will change up shifting and TCC lock when it gets hot, and frankly I'm not sure what will happen without ECT because if it's too cold it won't even lock the TCC.

But you don't NEED any of those other inputs. They allow for more functionality, but would have to be adjusted and tuned for the new setup anyways. You can take an 0411 from a 4L80 vehicle in a junkyard, hook it up with a Tach and TPS input and it will shift and function just fine. You CAN NOT do that without those inputs. The transmission will not shift or function without those two inputs and they are the bare minimum for functionality. ECT and MAP should be easy to provide as well, even with the carb swap, but will require some adjustment to provide anything useful. MAF is not going to happen and isn't necessary at all.

TCC will lock up and function fine without ECT.

https://sites.google.com/site/sloppywiki/everything-ls/cheap-stand-alone-trans-controller

http://www.gearhead-efi.com/Fuel-In...-Anyone-using-0411-Standalone-to-control-4L80

Oddly enough, the hardest things to get to the computer will likely be TPS and Tach, since the computer is looking for a specific signal, that the HEi doesn't provide, and no one seems to make a cheap/easy solution to TPS on a quadrajet. You could probably run an early 80's-90's dual-sync HEI from a TPI engine to solve the tach signal issue, but that comes with other issues since you wouldn't be computer controlling the ignition.

 

[Supercharged111]

But you don't NEED any of those other inputs. They allow for more functionality, but would have to be adjusted and tuned for the new setup anyways. You can take an 0411 from a 4L80 vehicle in a junkyard, hook it up with a Tach and TPS input and it will shift and function just fine. You CAN NOT do that without those inputs. The transmission will not shift or function without those two inputs and they are the bare minimum for functionality. ECT and MAP should be easy to provide as well, even with the carb swap, but will require some adjustment to provide anything useful. MAF is not going to happen and isn't necessary at all.

Tell me how long you expect a 4L80 to live running full line pressure all day every day? And what would ECT and MAP require in terms of adjustment to provide anything useful?

And I misspoke on the ECT with regards to TCC function, that's a function of TFT which stays in this scenario.