wardy18 33 1 Cars Posted July 12, 2008 hi Just a quick question, what is the ideal pressure required for a set of Twin 45 Webers on the XU9 engine with Rally cam and 10.9 CR?! I finally got round to buyin a guage to test mine the other day and it turned out the fuel regulator is running at 3 psi, i thought carbs needed 5.5psi?!?! I have a Red Top Facet fitted with a Fuel Regulator, going to move to the Silver Top Competition Facet soon as i dont need to bother with a regulator at all with this so much more reliable but what psi should i be settin the regulator at now for optimum performance, oh and this is purely a race engine so emissions are irrelevant hehe (oh and Guernsey has no MOT at all :) ) thanx simon Share this post Link to post Share on other sites
hodgy 0 Posted July 14, 2008 i run 3.5psi on my webbers! Share this post Link to post Share on other sites
tri_longer 25 Posted July 14, 2008 I have been told that the floats on the carbs can only handle 5psi max, in fact i'm sure that I picked that up of here somewhere. Were running fairly similar setup, the fuel pressure guage (digital not analogue) varies bewteen 4.5 and 5.2. We had to turn it up from 3.5 as when we were running at MIRA this weekend we found it was hesitant at around 6k. Uppped the pressure a bit and it ran great for the rest of the day. So well in fact that my mate set a new course record for Mod Prod 1.4-2.0. Share this post Link to post Share on other sites
wardy18 33 1 Cars Posted July 14, 2008 so i would be pretty safe if i upped it to say 5psi and ran it at that?! Share this post Link to post Share on other sites
tri_longer 25 Posted July 14, 2008 so i would be pretty safe if i upped it to say 5psi and ran it at that?! see no reason why not unless someone else knows better, as i said my info is 2nd hand, but at that level ours seems to run fine. Share this post Link to post Share on other sites
wardy18 33 1 Cars Posted July 14, 2008 maybe ill start at 4.5psi just to be safe i was told my Guy Croft that if you run a Silver Comp Facet pump you dont really need a regulator so i assume as this pump will only run at 5.5psi that the carbs can take it Share this post Link to post Share on other sites
ashley peddle 3 Posted July 14, 2008 i had 2 regs on my 40's... first put it down to 5psi and the second ranged from 5 to 0 iirc. mine was set at 3.5 (as above) and never had any problems Share this post Link to post Share on other sites
projectpug 0 Posted July 14, 2008 I again use 2 regulators and have it set at 3.5 psi , no issues with it so far Share this post Link to post Share on other sites
