rxman

I was reading in another post a couple of days ago. You guys were talking about vacuum psi on the boost gauge. And the numbers you guys were saying seemed high to me. One guy said he had 16psi around 1200rpms. Is that right? Mine car idles around 700-800rpms depending on the temp., with a vacuum of 12psi. Does that seem right?

Thanks,
Eric

dubulup

no - vacuum is in/Hg or something...boost is measured in psi.

if you have 12 in/Hg (or whatever) at idle, that is a little low.

Cihuuy

basically, 15 in/Hg is ok... mine is arnd 18in/Hg...

if your talking about psi, that means your refering to your boost gauge... yes?? if so then your boost is at 12psi... runing at this boost is ok but it all depeding on your mods..

apneablue

mine at 720rpm is between 15 & 16 in/hg

rxman

Sorry I meant hg for the vacuum, could it just be a vacuum leak or an engine going out? The engine has around 45k mile on it, it is a pettit street ported engine. Is this something I should worry about?

thanks,
eric

xstacy7

nice to hear that you have 45k on a Pettit streetported motor, becuase that's what I'm putting back into my 7

911GT2

Do you get full boost? If not, could be a vacuum/boost leak.

Mahjik

iTrader: (1)

A ported engine will have less vacuum. How much less depends on the size of the porting.

Your idle when warmed up looks great (700-800), however the vacuum still seems a little low even for a street port. I would expect somewhere around 14-15 here in the Midwest.

Are you having any boost problems?

rxman

Not really, it has been spiking. But it comes down to 10psi.

eric

Engberg

I was idling at 12 in Hg, had a blown manifold gasket. Working on getting that fixed now. I would point at a vac leak, not a blown or upset motor.

How bad are your spikes? You may want to take some precautions on those even if then eventually drop back to 10 psi. [pills, controller, etc.]

damian

iTrader: (2)

mine is same as apn's

mike172rg

Hmm. I have an auto. In neutral it pulls 18. In drive with the brake on its at 12. Is my motor ok? IT make 12-13 psi of boost at WOT

rxman

It spikes around 14 psi then slowly goes down, but it only spikes when the second turbo comes on.
I forgot to mention that it has been blowing a lot of smoke, like when I get off it after a hard run I have James Bond smoke screen come out the back. I was told this is due to coolant leaking into my turbos. Does this sound correct or am I way off?

eric

cpa7man

iTrader: (2)

I run 15-17 in HG.(at Idle) I was told it was a little low.
60k on original motor.

The car should not be smoking. Is smoke white or blue. White would be coolant, blue = turbo oil leak.

Man aren't these cars great!!