| Author |
Message |
jmldn
Samba Member
Joined: May 08, 2015
Posts: 152
Location: London
|
 Posted: Mon Jul 26, 2021 12:13 am Post subject: Fuel return |
 |
|
| 79 cabrio with twin 40 DRLA's, does anyone use/not use the return feed back to the tank? With fuel regulator. |
|
| Back to top |
|
 |
bomberbob
Samba Member
Joined: May 17, 2015
Posts: 688
Location: Iowa
|
| Posted: Mon Jul 26, 2021 4:54 am Post subject: Re: Fuel return |
|
|
How many ports are on your FPR, 2 or 3? I would run the return and use a 3 port. That way its not dead ended, you are always recycling fuel thats been in the engine compartment back to the tank, and bringing up fresh cooler fuel from the tank. Reduces changes of vapor lock.
_________________
1968 Beetle (storage)
1990 Jetta GLI megasquirted, burning E85 (currently in heavy maintenance)
2004 Jetta turbo GLI
Marion, Iowa |
|
| Back to top |
|
|
ashman40
Samba Member
Joined: February 16, 2007
Posts: 15985
Location: North Florida, USA
|
| Posted: Mon Jul 26, 2021 9:58 am Post subject: Re: Fuel return |
|
|
| jmldn wrote: |
| 79 cabrio with twin 40 DRLA's, does anyone use/not use the return feed back to the tank? With fuel regulator. |
Your 40 DRLAs are Dellorto carburetors similar to Weber 44 IDFs, right? With these you should be running a low pressure fuel pump in the 3-5psi range. Do low pressure fuel pressure regulators have a return line? Most carb fuel pressure regulators control pressure by restricting flow. I thought regulator return lines were only used with FI which runs higher fuel pressure at around 30psi+. Maybe you are running a blow-thru turbo? In which case you would need to vary the fuel pressure as the turbo pressure increases? Maybe these pressure variable regulators have a return?
Your stock engine's FI fuel system would have used a return line, but if your engine has been "upgraded" to dual carburetors your fuel delivery system should have been change to match the carb's needs. What kind of fuel regulator are you using?
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road  }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
|
| Back to top |
|
|
jmldn
Samba Member
Joined: May 08, 2015
Posts: 152
Location: London
|
| Posted: Mon Jul 26, 2021 12:44 pm Post subject: Re: Fuel return |
|
|
| ashman40 wrote: |
| jmldn wrote: |
| 79 cabrio with twin 40 DRLA's, does anyone use/not use the return feed back to the tank? With fuel regulator. |
Your 40 DRLAs are Dellorto carburetors similar to Weber 44 IDFs, right? With these you should be running a low pressure fuel pump in the 3-5psi range. Do low pressure fuel pressure regulators have a return line? Most carb fuel pressure regulators control pressure by restricting flow. I thought regulator return lines were only used with FI which runs higher fuel pressure at around 30psi+. Maybe you are running a blow-thru turbo? In which case you would need to vary the fuel pressure as the turbo pressure increases? Maybe these pressure variable regulators have a return?
Your stock engine's FI fuel system would have used a return line, but if your engine has been "upgraded" to dual carburetors your fuel delivery system should have been change to match the carb's needs. What kind of fuel regulator are you using? |
Malpassi regulator with single outlet to T piece to feed each carb. My question arose because i wondered if the carbs should be just fed and not have a return of any kind. |
|
| Back to top |
|
|
jmldn
Samba Member
Joined: May 08, 2015
Posts: 152
Location: London
|
| Posted: Mon Jul 26, 2021 12:45 pm Post subject: Re: Fuel return |
|
|
| bomberbob wrote: |
| How many ports are on your FPR, 2 or 3? I would run the return and use a 3 port. That way its not dead ended, you are always recycling fuel thats been in the engine compartment back to the tank, and bringing up fresh cooler fuel from the tank. Reduces changes of vapor lock. |
2 port Malpassi |
|
| Back to top |
|
|
|
