I have a question i just installed a Vortech on my 99 mustang Gt automatic the blower has the factory 8 Psi pulley on it an i also installed a Anderson power pipe the problem is i am only seeing 5 Psi i have a friend with an 01 Gt auto with a Vortech and he only sees 5 Psi too whats the deal is it something with the auto trans causing this or what? :shrug: :shrug:
Psi ??????????
- Thread starter stangkid
- Start date
How far are you turning the car? Did it ever see 8 PSI?
What size is the pulley? I have the 3.3, power pipe and aftercooler, it made 11 psi @ 6000rpms and 14 psi @ 6400rpms
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I just installed the Vortech and it has the factory pulley that was installed on it when they sent with it the car hasnt seen more than 5 Psi at wide open right when the car hits 5 Psi is right about the time the car shifts my friend has a stock 01 gt auto with nothing but a Vortech with the factory power pipe and his does the same thing only hits 5 Psi about the time it shifts out at wide open thats why i was woundering if its anything to do with the auto trans with the Anderson power pipe and all my other mods shouldnt i be seeing more Psi than him. :shrug: :shrug:
GR8WHITE said:
At wide open the car only sees 5 Psi thats all i have ever saw never saw 8 Psi. the boost rises and about the time it its 5 Psi. is the time the trans shifts out. :shrug: :cuss: :cuss: :shrug:
It really depends on what mods you have. The easier the air can make it's way into the motor and back out again the more efficient it is which also means less boost. Don't take it as a bad thing. Your still getting the same amount of air being forced into the motor and power. My vortech charged trans am WS6 was supposed to run 9psi and I only saw 5psi max with all my intake and exhaust work. It put down 480 rwhp at 5 psi which is more then it should of put down at 9 psi!
I see about 6psi tops on mine and my blower has the 8psi pulley on it. what kind of numbers are you putting down?
I assume your car doesn't shift at red line and thats where the maximum boost is.
01rdcobra said:
I havent had time to get it on the dyno yet so im not sure on hp numbers my friend has an 01 stock with a Vortech and he put out 347hp with only 5 Psi so im hoping with my mods i can put out alittle better numbers than him.
what rpms exactly do you see 5psi at?
with a custom tune you should put down at least 360-370rwhp. I wouldn't worry about how much psi you are pushing, search around for a similar car with your setup and see what numbers they're putting down.
Have you checked to see if you are having belt slip issues. The stock tensioner tends to be a bit weak sometimes. Ford had a manual tensioner fix for a while. What is the belt length on your car also?
I found my problem guys i called Vortech and they ran the serial numbers off of my blower and the blower was bought new for a 99-02 cobra so it has the wrong pulley for my GT it has a 3.48 pulley on it and i need a 3.12 pulley he said that pulley should give me 8-10 Psi i bought the supercharger kit used so i guess the guy pieced the kit together with a head unit from a 99-02 cobra. :shrug: Thanks for all the help guys. :rockon: :rockon:
Did you alsoo tell them about the mods you have?stangkid said:
PSI is only a measure of resitance not airflow.
At a set rpm the blower will have the same air flow regardless. If there is a restiction the pressure (psi) will increase. If the restriction is minimised then the pressure will drop but the cfm will remain constant.
Improved intake, exhaust, headers, cams and heads all affect resistance. If your engine is less restrictive then the stock pulley will give you less psi. What you need to do is spin the blower faster to achevie the same psi but you will also increase air flow and HP.
Also a centrifugal blower will make more and more boost the faster it spins so you shouldn't see full boost until very high rpms. Going to WOT at 3500rpm will not acheive full boost as it does with a turbo because they are load dependant as opposed to rpm.
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