Engine/Transmission (1994 - 1998) low boost, hissing sound

[darom]

A pretty much stock 94 5spd with the stock plate full forward, timing 16* and a boost elbow installed.



Two questions:

My boost is about 17-18psi max, I still get pretty decent gas mileage 19mpg on the freeway. Are these turbo psi number low?



When I run a/c and shut the engine off, I am hearing a loud hissing noise coming from the front radiator area. Is it normal? Or do I have a leak somewhere in the condenser or turbo intercooler tubing? The a/c still works great.



Thanks!

Denis

 

[tp0d]

The hissing is normal operation of the AC.



Boost looks a little low, what kind of air filter do you run? Stock setup doesnt flow enough, I highly recommend a BHAF, fleetguard pn# AH19037, available at fleetfilter.com, or many other places.



For a test, try pinching off your rubber wastegate line with a pair of vicegrips/etc (dont cut it), and go for a drive. That will tell you your max boost. I have mine plugged off, hasnt been used since I modded my plate to a #10. Max boost of about 36psi with my stock hx35.



good luck



-j

 

[bmoeller]

For a stock '94, the boost is right on. That is where the wastegate is set at. http://dodgeram.org/tech/dsl/Facts/94specs.html



The hissing is normal on shutdown. No worries.

 

[DonTX]

That was helpful to me as well, mine does that hissing when shutting down, I had just not had the inclination to check it out and see what the heck was happening. Now I know it is normal. Still wonder what is doing that though, and why it hisses.

 

[hsmith]

AC pressures equalizing upon shutdown would be my guess.

 

[darom]

Great, thanks for your replies, guys. The whole thing about hissing was making me uncomfortable (coming from a Chevy v8 world). I have a stock air box. I am ready to install the Scotty II and #10 plate I will post the psi results then.



Thanks again for your input!