tri_longer 25 Posted April 6, 2007 We've just completed our rebuild and successfully managed to get the engine to turnover on first press of the button As part of the rebuild we have fitted a Stack dash system which comes complete with a fuel pressure sensor, which we have plumbed in after the fuel regulator. We have the pressure set around 5psi (which after a few searches on here looks a little high) however when we took it on a test run at Mallory Park, it was noticed that the pressue was dropping from the 5psi to around 1.5psi. Is there anything that is likely to be casuing this drop? Or is this normal. Not an area we are familiar with so any help from the carb gurus would be appreciated. Share this post Link to post Share on other sites
frodo_monkey 0 Posted April 6, 2007 Not an answer I'm afraid, but a question as I'm in a similar position as you I'm just about to turn my newly rebuilt engine over for the first time on a carb setup (with 2x FPR under the bonnet) - how exactly did you go about setting the fuel pressure? Sorry for the thread creep... Frodo Share this post Link to post Share on other sites
tri_longer 25 Posted April 6, 2007 Not an answer I'm afraid, but a question as I'm in a similar position as you I'm just about to turn my newly rebuilt engine over for the first time on a carb setup (with 2x FPR under the bonnet) - how exactly did you go about setting the fuel pressure? Sorry for the thread creep... Frodo No probs. Because the STACK dash has a sensor we 'T' pieced this into the fuel line just after the fuel regulator, and connected it up to dash. Normally you would use a gauge attached to the reg but the sensor does the same job for you. It was then simply a case of turning the reg adjuster nut until we had the desired pressure. Not really going to help you i'm afraid unless you have the same dash. Share this post Link to post Share on other sites
frodo_monkey 0 Posted April 6, 2007 Ah OK. I'm on the std clocks but as you say I have a small gauge that attaches just after my 2nd FPR. Am I wrong in assuming that when you have the ignition on the fuel pump should have power to it and you should be able to set the pressure? Share this post Link to post Share on other sites
tri_longer 25 Posted April 6, 2007 Ah OK. I'm on the std clocks but as you say I have a small gauge that attaches just after my 2nd FPR. Am I wrong in assuming that when you have the ignition on the fuel pump should have power to it and you should be able to set the pressure? Thats what our orignal setup was like (pre-crash) so I would say yes that sounds correct. However we didn't set it up so I'm not sure on the procedure that was used, but what you said makes sense. Share this post Link to post Share on other sites
frodo_monkey 0 Posted April 6, 2007 Thanks for your replies - I'm off outside to look at it and scratch my head! Back on topic... Share this post Link to post Share on other sites
PsychoSimon 0 Posted April 6, 2007 From what i remember when i had carbs on my nova (yes i had a nova lol ruuuuuude bwoy!) the pressure was about 3.5psi on idle. This however dropped when fuel was being used to about 1.5psi as yours does (this was when it was on the rollers) and the operator said that was normal. Share this post Link to post Share on other sites
tri_longer 25 Posted April 6, 2007 From what i remember when i had carbs on my nova (yes i had a nova lol ruuuuuude bwoy!) the pressure was about 3.5psi on idle. This however dropped when fuel was being used to about 1.5psi as yours does (this was when it was on the rollers) and the operator said that was normal. Just for clarification anyone with a 205 care to comment Share this post Link to post Share on other sites
midnight motorsport 0 Posted April 6, 2007 Just for clarification anyone with a 205 care to comment what fuel pumps and regulators are you running? Share this post Link to post Share on other sites
tri_longer 25 Posted April 7, 2007 what fuel pumps and regulators are you running? Pump is a Facet Silver Top rated to 200bhp and one Filter King fuel reg, not sure if there are different models of these though. Share this post Link to post Share on other sites
midnight motorsport 0 Posted April 7, 2007 Pump is a Facet Silver Top rated to 200bhp and one Filter King fuel reg, not sure if there are different models of these though. silver top facet is ok, but on all of our race cars, we try to bin the facet, as they just dont flow enough, imo, they say they are rated to 200, but this is sort of rubbish, a lot of the thirsty old beasts we run, used to run out of fuel on the top end as the pumps could not keep up, sometimes though we use to run slightly larger bore pipe from the pump to the regulator and that helped, but the best pump iv found so far and never had trouble with is a holley red top, nice, But anyway getting back to the pressure, set it to 4.5 at idle, and run it, if it drops off too much, when giving it some try 5 but this is really the limit as the float valve wont be able to hold the pressure, if not try bigger diameter pipe and fittings, if not, facet red top, but ultimate is holley red top, (low pressure, high volume) hope this helps, cheers jay Share this post Link to post Share on other sites
