JohnRoberts Posted March 11, 2021 Report Share Posted March 11, 2021 Hi Guys Does anybody know the thread size of the fuel outlet. Thanks JohnR Quote Link to post Share on other sites
c.hydes Posted March 12, 2021 Report Share Posted March 12, 2021 If you mean the petrol tank, mine is 1/2" UNF x 20TPI. Just brought a larger adaptor (brass with push on adaptor)to allow more fuel to flow and it screws directly in in place or the nut and copper pipe. Colin. Quote Link to post Share on other sites
JohnRoberts Posted March 12, 2021 Author Report Share Posted March 12, 2021 Hi Colin Thanks for that. Can you give me details of the supplier and part number please. Best regards JohnR Quote Link to post Share on other sites
c.hydes Posted March 12, 2021 Report Share Posted March 12, 2021 17 minutes ago, JohnRoberts said: Hi Colin Thanks for that. Can you give me details of the supplier and part number please. Best regards JohnR John, got mine from here: https://www.trgb.co.uk/products/large-bore-fuel-tank-outlet-pipe Quote Link to post Share on other sites
JohnRoberts Posted March 12, 2021 Author Report Share Posted March 12, 2021 Thanks Colin Quote Link to post Share on other sites
Steves_TR6 Posted March 12, 2021 Report Share Posted March 12, 2021 (edited) I bought one of those too but yet to fit it, looks well made Edited March 12, 2021 by Steves_TR6 Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 13, 2021 Report Share Posted March 13, 2021 Surely the hole in the bottom of the tank needs enlarging to mate with a larger diameter pipe? Screwing a 1/2” diameter adaptor into a 5/16” hole does not change the original supply hole that is drilled in the tank. You need to drill out larger the hole in the tank outlet union that is brazed into the tank. snake oil part? Quote Link to post Share on other sites
Steves_TR6 Posted March 13, 2021 Report Share Posted March 13, 2021 I understand that the part fits the original hole but has a larger bore, achieved with thinner walls ? i’ll post pics when i get to it! Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 13, 2021 Report Share Posted March 13, 2021 (edited) 58 minutes ago, Steves_TR6 said: I understand that the part fits the original hole but has a larger bore, achieved with thinner walls ? i’ll post pics when i get to it! So the hole in the tank is not any larger to allow more fuel flow. The outlet hole in the tank remains as the restrictor. Peter W PS. I have fallen in now. Larger outlet means that a larger diameter rubber pipe can be fitted. The larger tank outlet union external diameter is the same as the inlet to the Bosch or what have you pump. Meaning bigger flexible pipe is used but no increase in fuel flow through the tank outlet restriction. Edited March 13, 2021 by BlueTR3A-5EKT Quote Link to post Share on other sites
c.hydes Posted March 13, 2021 Report Share Posted March 13, 2021 36 minutes ago, BlueTR3A-5EKT said: So the hole in the tank is not any larger to allow more fuel flow. The outlet hole in the tank remains as the restrictor. Peter W PS. I have fallen in now. Larger outlet means that a larger diameter rubber pipe can be fitted. The larger tank outlet union external diameter is the same as the inlet to the Bosch or what have you pump. Meaning bigger flexible pipe is used but no increase in fuel flow through the tank outlet restriction. On my tank the hole through the tank is 7.9mm, but the original pipe I/D when removed was 6.2mm. The new adaptor I/D is 7.9mm all way through, so increases the diameter by 1.7mm. This gives an increase in I/D of +30%, but an increase in area of +65%, so for a fixed head of petrol this must be a significant benefit without re-drilling and re-tapping the tank? Colin. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 13, 2021 Report Share Posted March 13, 2021 4 minutes ago, c.hydes said: On my tank the hole through the tank is 7.9mm, but the original pipe I/D when removed was 6.2mm. The new adaptor I/D is 7.9mm all way through, so increases the diameter by 1.7mm. This gives an increase in I/D of +30%, but an increase in area of +65%, so for a fixed head of petrol this must be a significant benefit without re-drilling and re-tapping the tank? Colin. Thank you that is an excellent explanation and photo demonstration. I understand now, the new union seats on a crush washer rather than inside the tank outlet with an olive, hence the increased area through the bore. Peter W Quote Link to post Share on other sites
Steves_TR6 Posted March 13, 2021 Report Share Posted March 13, 2021 Thanks for the pics Colin, nicely explained. now, how many extra BHP will i get ..... :-) Quote Link to post Share on other sites
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