Boost leak maybe?

Canada Nissan Automotive
1

I hoping one of you could help me. I drive a Ca18det silvia, the other day i took it down to secret street, and found that i was running waaay slower then i expected to. In fact my best time was when i turned my boost controller off, when im at full boost (11psi) i can hear a screaming whistle of air and my car seems to be running slow. In fact my buddies have commented on just everyday driving that my car feels slower then it used to. Im wondering why this could be, ive heard that these cars have notoriously weak turbo gaskets could it be that?

I still make full boost fine, but have noticed that it is fluctuating slightly, i only hear the whistle at full boost, could it be leaking from my blow off aswell? (i have a greddy type rs, real greddy not a knock off) I checked all my vacum lines on the boost controller and they all seem fine, any other ideas? I would really appreciate any input that you guys have. Thanks alot.
:dunno: :dunno:

Oh and my starts etc were not thaaat bad 0.07 with a 2.03 60ft was my best and the time was still staggeringly slow

2

boost leak 99.999999999999999999999999% sure, especially with that fluctuation you described.

could also be exhaust leak, sometimes that will hiss like a mother sucker as well.

do you know how to do a boost leak test?

3

even if you do, here is a good write up on a boost leak tester http://forums.nicoclub.com/zerothread?id=113785

4

the only thing that confuses me is that i still make full boost, if i had a boost leak wouldnt it not reach full boost? the fluctuation isnt everytime, it almost seems more dependent on temp then how hard im pushing the car.

5

it is most likely your manifold to turbo bolts, there are 4 of them and they are a bitch to tighten.

6

On a ca18 99.999999% sure it is the manifold to turbo.

Join the club buddy… Gotta take out the whole deal to replace that gasket or tighten it… possibly the bitchest thing to do on ca18.

7

goody, thats what i was afraid of, hmmm but if im pulling the turbo off, maybe i should just slap on a t28 instead, im sure i can find a way to justify that.

8

First mod on a CA … replace the shitty t25 with a s14 or s15 t28

9

Sounds like my leaky BOV. Whistles like crazy at full boost. I disconnected the BOV and it went away. Pull the vacuum line off your BOV and take it for a rip and see what it sounds like.

10

you can easily make full boost with boost leaks. the turbo just has to work a whole lot harder, so you’re losing efficiency at the same time.

11

problem is u wont hold that boost due to leak, so u’ll lose it as fast u build it…

12

i can even get boost CREEP with boost leaks (when you build boost past the wastegate setting depsite the wastegate being open). it always depends on the size of the leak too.