Need a little help

[Red-Skittle]

The past few days I've notice a vaccuum loss when driving. When accelerating as I get to 2 RPMs vaccuum starts dropping from 10 to 15 and when I get to 3 RPMs to shift I've dropped to 20. Also, when still in gear and decelerating vaccuum drops to 25 then the usual 20, but when I take it outta gear it climbs back up to 20.

All vaccuum lines are connected correctly so any other ideas?

Have a block-off plate sealed with red RTV and BOV sealed with the same RTV.

Thanks for your input,
Stephen

[thirdcoast]

That actually sounds pretty normal.

During closed throttle decel there is a lot of load on the motor, and it will be pulling a lot of vacuum in the IM. I used to have a vacuum alert on my boost gauge that would beep under 24 inHg, it lasted an hour before I took it off. Mine does it, and based on an understanding of how vacuum works, it happens to everyone.

With vacuum dropping on slow accel, this is also normal, as you aren't putting the motor under much load, you won't be building boost, and eventually the intake tract will seek equilibrium. This also happens to my car.

You said this just started, then it seems to me like you used to have a problem, that has now resolved itself.

Also, physics dictates that a vacuum leak will manifest itself anytime the car is on, so if the car is fine at idle (no jumping idle, unsteady idle, or high/low idle) then you probably don't have a leak.

[Red-Skittle]

Well, before it use to hold vaccuum at 10 through steady acceleration and when decelerating it only dropped to 20.

Maybe nothing is wrong just the car was acting different then usual.

[thirdcoast]

Quote: Originally Posted by Red-Skittle

Well, before it use to hold vaccuum at 10 through steady acceleration and when decelerating it only dropped to 20.

Maybe nothing is wrong just the car was acting different then usual.

Vacuum and boost also vary with weather and temperature changes.

Depending on something as little as humidity, you can vary between 20-15 inHg at idle. Since we're making our way into winter, this is probably the cause, this has probably been going on the whole time, but if you're like me, you rarely look at your boost gauge during normal driving, so you just now noticed.

Hope this helps

[Red-Skittle]

Has been but forgot to mention I lost boost too. had it set at 20psi and dropped to 15 when this started happening. That have to do with weather change too?

[thirdcoast]

Quote: Originally Posted by Red-Skittle

Has been but forgot to mention I lost boost too. had it set at 20psi and dropped to 15 when this started happening. That have to do with weather change too?

if you're on PVM controlled boost, yes.

[Red-Skittle]

Quote: Originally Posted by thirdcoast

if you're on PVM controlled boost, yes.

PVM? I have a FM wga so...

[thirdcoast]

Quote: Originally Posted by Red-Skittle

PVM? I have a FM wga so...

My mistake, I meant PCM Controlled boost.

[Red-Skittle]

Guess this would as good a place to ask as any. Does anyone know a good launch RPM for the SRT? I've been going from 2k but wanna know what is best.

[BluFlame]

Sounds about right but you need to feather off the line then nail the gas when you feel the tires catch. Another mistake rookies with stock turbos make is taking the car to redline in 1st and 2nd gear. Mopar clearly states that this cars power band is between 54-5800 rpm and shifting at 6250 is not needed on a stock turbo car at the track until 3-4th gears. If the car is hooking in 2nd then its fine but I used to shift my stock turbo car at 58-5900 rpm in 1-2 and redline the rest of the way. Earned me a 13.7 timeslip with just an intake and the rear section of my exhaust removed!

[Red-Skittle]

So 2k is the right RPM to launch? Cool, just need to get motor mounts. What else would help wheel hop?