|
Post by 79turbostang on Sept 22, 2009 22:00:13 GMT -5
well i was working at the shop today and finally got to pull out my new 84 svo after putting a new tank and fuel pump in it. well i took it out for the first time in 2 years of the car sitting. I got to about 3 thousand rpms and it started to sputter and would not build boost... so what should tohe fuel pressure be, people are telling me that is need to be 5 to 6 psi with the car running and that just doesn't sound right. I just think is still has bad gas in if because it sat for so long
|
|
|
Post by Stinger on Sept 22, 2009 22:32:25 GMT -5
Sounds like you are talking to people who have never heard of EFI.
It should be about 38psi with the vacuum line removed from the regulator or 32psi or so with the vacuum line on the regulator.
Boost leaks cause them to run like you describe.
|
|
|
Post by filasfinest86 on Sept 22, 2009 22:46:22 GMT -5
I am also Debating on fuel pressure for my car according to this web site www.hangar18fabrication.com/fuelpump.html BLOW THRU PSI AND LB PER HOUR are calculated by THESE FORMULAS Fuel Pressure = (base fuel pressure) + (boost pressure) + (line losses) + (10-15 psi if running a dead head regulator OPTIONAL) EX: (MY BASE WAS 6 PSI)+(12PSI BOOST)+(5PSI Line LOSS)+ (15PSI I want a regulator, DONT add 15 if you dont have a regulator) =WHAT I NEED about 40 psi FREE FLOW RATE: Fuel required = (target Hp) * (BSFC) Fuel required = 1000 Hp * .6 (lbs/hr)/Hp = 600 lbs/hr MY EX: (230 HP)X (.6 FOR TURBO CARS)=WHAT I NEED=140lbs/HR or 40 gph im assuming your 79 is carbed?? this prolly isnt the same with fuel injected?? maybe the FUEL PRESSSURE FORMULA IS FOR A FOUR BARREL THAT SEEMS REALLY HIGH DOESNT IT SO MAYBE /2?? SOMEBODY SHED SOME LIGHT I SAW THIS FORMULA AND ITS DRIVIN ME NUTS@
|
|
|
Post by Stinger on Sept 23, 2009 13:42:41 GMT -5
He said 84 SVO which is efi. He needs the pressure I stated.
As for your fuel pressure, I don't mess with carb stuff but the formula looks correct.
|
|
|
Post by filasfinest86 on Sept 23, 2009 17:38:07 GMT -5
He said 84 SVO which is efi. He needs the pressure I stated. As for your fuel pressure, I don't mess with carb stuff but the formula looks correct. Oh okay sorry bout that the 7 PSI threw me off and i didnt know they had efi back then... thought it might have been one of those draw thru carb deals..... Thanks for you input tho stinger 40 PSI STILL SOUNDS OKAY FOR A CARB??
|
|
|
Post by 79turbostang on Sept 23, 2009 22:46:11 GMT -5
man stinger right on the money with fuel pressure i tested it this morning and was 32psi... well ill have to let them no that there specs are way off... i might think that i need to rebuild the turbo.. when i get to the shop tomorrow I'm going to take it off and check for shaft play and go on from the. thanks stinger when i bring it home from the shop and clean it all up ill get some pics up for you all of it
|
|
|
Post by Stinger on Sept 25, 2009 10:29:40 GMT -5
You don't need to remove the turbo to check for shaft play. Just remove the inlet elbow and grab it and wiggle it around. Don't get rough with it or "force" it over...just let it move the little bit it will on its own.
If it doesn't smoke, there is a 99% chance the turbo is just fine. A blown turbo will not make it sputter either.
|
|
|
Post by Stinger on Sept 25, 2009 10:30:46 GMT -5
Thanks for you input tho stinger 40 PSI STILL SOUNDS OKAY FOR A CARB?? As I said, I don't mess with turbo carb stuff so I'm not qualified to answer that question. I just said the equation looked correct.
|
|
|
Post by 79turbostang on Sept 27, 2009 0:22:02 GMT -5
well i pull the turbo off to and it does have a tiny bit of shaft play but now bad it all. the car does smoke but just for a second on start up but the only reason that lead me to the turbo is because when you rev the engine and let of you can hear a scraping sound inside the turbo... and also do you no how hard it is to rebuild a 84 svo turbo and if you gave a diagram of it
|
|
|
Post by Stinger on Sept 27, 2009 2:11:40 GMT -5
Can you feel it scraping when you spin it by hand (without forcibly pushing it to the side)? If not and if there aren't marks on the wheel/housing indicating they have touched, it's fine.
|
|
|
Post by 79turbostang on Sept 27, 2009 13:17:26 GMT -5
nope i can not when i spin it looks and feels fine but when the turbo was on the car the sound was coming from the exhaust wheel of the turbo.. but when i looked at it the wheel looks fine and i don't see any metal shavings
|
|
|
Post by Stinger on Sept 27, 2009 14:23:41 GMT -5
I have a hard time believing the turbo is bad then...
|
|
|
Post by 79turbostang on Sept 27, 2009 21:08:39 GMT -5
OK cool ill just put it back on... it might have just been something but the turbo making some noise.. thanks for the help
|
|