Fuel rail?

[r10crw]

The fuel rail on the honda has a bore of six mm so am I right in saying that runing the fuel delivery lines in 6mm should be ok? Someone told me Id need at least 8mm but I cant see why if its reduced to 6 anyway. Admitidly the output from pump is 8. Cheers Craig.

[robin]

The fuel rail on the honda has a bore of six mm so am I right in saying that runing the fuel delivery lines in 6mm should be ok? Someone told me Id need at least 8mm but I cant see why if its reduced to 6 anyway. Admitidly the output from pump is 8. Cheers Craig.

It's hard to quantify, but an 8mm tube will flow the same fuel volume for less pressure drop, so it depends on how much headroom you have on fuel pressure. If the pump you are going to use can only just supply 300BHP fuel at 3.5bar (that's your fuel rail pressure I think) then the 6mm tube could make the difference between it running lean and not. Of course the longer the run, the more this is going to matter.

OTOH if your pump is happy to supply 300+BHP worth at 4.5bar then I doubt you'll lose a whole bar in the 1.5m from tank to rail in a 6mm pipe and it'll be just fine (albeit that the pump will always be doing a bit more work than it has to).

So if you can use 8mm to close to the rail, that will minimise stress on the pump and pressure drop in the line.

(To take your argument to it's logical conclusion, the bore of the injector is just 1mm or even less, so you could run a 2mm pipe back to the fuel pump - intuitively that feels like it won't work ).

Cheers,
Robin

[tut]

Yo Robin

His new fuel pump is rated to 400hp. Just been around, he and Alan are just taking his engine out prior to fitting the Honda. He has his new engine mounts ready to fit, so will be able to put the Honda in, then do the rest as the components arrive.

I will pass your info onto him as he may not get chance to go online.

tut

ps he has an old hydraulic engine frame that has not been used for years, so it took him a day to get that back into service. My new rear subframe arrived from Geary, so that will be going in shortly.

pss Alan Dickie whom you have not met, and bought a CAT C S1 which he rebuilt, also bought an S2 recently, which he again rebuilt and has just sold, has just bought a damaged VX 220 which he plans to repair, and fit an Astra diesel engine into, chipped to 200hp.

Compared to those two, I class as sane...........

[tut]

ps Watching them work together, I reckon that if they got together with yourself and John, you would clean up the market..........

tut

[r10crw]

Cheers Robin, glad you agree. Its just cause ive got a fang of 6mm already and saves me buying 8, as you might imagine costs are going out of control and the cheap conversion no longer looks so cheap.