[Fot] TR6 race car re-build - Fuel line questions

Thu Jun 12 08:44:03 MDT 2025

Great responses, recommendations from all - very much appreciated.  Thought I would summarize the key recommendations:

1.      Fuel Regulator - 1-4 psi (with 3 psi discharge) placed up front with meter for ease of tuning, etc.

2.      Fuel Pump - also capable of 1 - 4 psi (consistent with Pierce Manifold’s recommendation). 

3.      Fuel Line – hard line (3/8”) front to back with -6AN braided PTFE to connect carbs, pump, regulator, and fuel cell.

4.      Fuel Return line - after the regulator, back to the fuel cell with a .040" restrictor.  This helps maintain much more consistent fuel pressure at idle VS wide open.

5.      Fuel Cell Pickups – either 2 duckfoot pickups, one in each back corner, or Holley HydraMat

https://www.holley.com/products/fuel_systems/hydramat/

6.      Fuel Safety addition - Revolution fuel pump controller - Pump only runs if there is a tach signal from the ignition.   

https://www.revolutionelectronics.com/Products/Fuel_Pump.html

7.      Brands - Holley seems to be the brand of choice, also mentioned - Carter (high volume/low pressure specifically for multi-Webers) 

8.      Weber Fuel Bowl Tip- When you shut off the car, shut off the fuel pump first, and let it run a couple minutes to drain down the [Weber] fuel bowls. Mitigates hot fuel in the bowls heated by exhaust manifold.

9.      Fuel Cell Dipstick Tip – dipstick marking - fill one gallon at a time and mark the dipstick at each level.

10.   Fuel Line Spec Chart - https://historicracinggroup.com/resources/Reference_Material/Canton/Fuel Consumption and Flow Quick Ref by CM Filters.pdf

Oh, don’t run out of gas while on the track!

Thanks again to all that responded!

Mark

From: Bob Kramer [mailto:rkramer56 at gmail.com] 
Sent: Thursday, June 12, 2025 8:36 AM
To: rocky spitfire4.com
Cc: Jason Ostrowski; Mark Cook; Friends of Triumph Group Email
Subject: Re: [Fot] TR6 race car re-build - Fuel line questions

Holley makes a pickup attachment called Hydramat that will suck fuel from anywhere it touches making the one pickup style fuel cells even better than adding a second pickup. We use it in the ChampCar. Before we added one we found that we would have fuel pickup issues with a couple of gallons of fuel in the cell. The strategy we use on our 15 gallon tank is to start full, run 2 hours, add 10 gallons at each stop and before the Hydramat we had drivers coming in early  for a "miss", throwing off the whole plan. The only drawback is that you can completely run out of fuel. It'll miss and then stop pretty quickly!

www.holley.com/products/fuel_systems/hydramat/

On Thu, Jun 12, 2025 at 2:12 AM rocky spitfire4.com via Fot <fot at autox.team.net> wrote:

For years I just had the stock metal line in my full-race Spitfire, which ran under the floorboard. Eventually it got pinched. The system I installed was an ATL cell in the trunk, with a duckfoot pickup in each back corner, two Holley red fuel pumps leading to a T-fitting – all in the trunk – then a single line through the passenger compartment just under the door (as far from me as possible) to a regulator under the hood mounted on the firewall, then to the carbs. Regulator has a gauge installed where I can see it. I don’t really refer to it while driving (although I can), primarily I use it when setting fuel pressure to the carbs. For the Spitfire 2½ pounds of fuel pressure was wholly sufficient (the Holleys would deliver 7). For the TR6 maybe something else. Oh, and ALL lines braided since they were all vulnerable. 

I ordered my fuel cell direct from ATL and specified the two pickups. Roundy-round guys usually only have one, in the right-rear corner, because they only turn left. We go both ways. I also ordered the cell with a dipstick to know the fuel level. And then  ?? <https://cdn.jsdelivr.net/gh/joypixels/emoji-assets@v7.0.0/png/64/1f606.png>  discovered that while the cell had the place to put the dipstick in, the foam inside did not! I had to take the top off, pull the foam out, figure out where the hole needed to be and cut the hole in the foam. Then the first time I filled the cell, I filled it one gallon at a time and marked the dipstick. It’s worked great ever since. I also learned not to fill the cell full to the top because it would splash out of the overflow and corners got all excited that I was spilling gas. Filling it a gallon short got me through all races. For autocrossing (with the two pickups) 3 gallons worked fine. 

--Rocky Entriken

From: Fot <fot-bounces at autox.team.net> On Behalf Of Jason Ostrowski via Fot
Sent: Wednesday, June 11, 2025 11:08 PM
To: Mark Cook <mecook at mindspring.com>
Cc: Friends of Triumph Group Email <fot at autox.team.net>
Subject: Re: [Fot] TR6 race car re-build - Fuel line questions

Lots of questions there. 

I’m not a TR6 guy but I’d like the fuel pressure regulator to be in the engine compartment. For Tuning and regulating purposes; close to where you are at when you’re watching the motor and gauges.

Jason Ostrowski

Friendly Ghost Racing 

1969 Triumph GT6+ racecars

Sent from my iPhone

On Jun 11, 2025, at 10:17 AM, Mark Cook via Fot <fot at autox.team.net> wrote:

All,

So, I have gutted and stripped the #55 ‘69 TR6 race car first purchased, having a proper roll cage installed and painted, and will be installing a newly built engine with triple Weber 45 DCOEs.  Will be ordering some parts while cage is installed and body painted.

Brings me to my questions.   What size fuel lines – 5/16” (-5) or 3/8” (-6)?  Also, thoughts on 100% steel braided PTFE, or combination of metal fuel line (front to back) with braided to connect to the fuel cell and Webers?  Fuel pump, filter and pressure regulator will be in the trunk with the fuel cell.   Return line?  The 6 previously had fuel injection and a fuel return line.  Not sure it is necessary for the Webers.

Thanks!

Mark Cook

During Chuck Arnold’s ownership (pre-2018)                             Prior Owner 2018-2023                                                                          Now (coffee table stage)                                                                                                                                                                                                                  

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